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[Display omitted] • A simple strategy for polyphenolic nano-microspheres (PTA) by TA crosslinking. • This adsorbent exhibited tunable pH-responsive metal coordination structures. • High selective adsorption with larger K d of 84400 mL/g and 95 % efficient regeneration. • Yielding a high treatment capacity of ∼ 5250 L/kg sorbent for application. The proficient advancement of nanoscale adsorbents assumes a pivotal role in the enhanced elimination of heavy metals to trace concentrations. Nevertheless, within the realm of engineering, the attainment of elevated selectivity and effective regeneration remains an arduous endeavor. In this context, we propose a novel structure-tunable sorption/regeneration mechanism by designing TA cross-linked polyphenolic nano-microspheres (PTA). These PTAs exhibit tunable pH-responsive metal coordination structures, enabling high sequestration and purification in removing heavy metals, and facilitating efficient regeneration. Taking Pb(II) as an example, under neutral conditions, the PTAs form a six-coordination configuration with Pb(II) ions, resulting in larger selectivity of K d : 84400 mL/g with a 99 % removal efficiency even in the presence of various cations, anions, and organic acids. This performance far surpasses that of the commercial ion exchanger D001, exhibiting an enhancement factor of nearly 250 times, rendering it amenable for deployment in a wide array of contaminated water sources, encompassing lake water and industrial wastewater. Notably, the PTA also demonstrates exceptional practical utility, affording a voluminous treatment capacity of 5250 L per kilogram of adsorbent in wastewater scenarios. Furthermore, under acidic conditions, the transformation of PTA's metal coordination into a weaker two-coordination facilitates the efficient desorption of Pb(II) with an impressive efficiency of up to 99.0 % across multiple cycles. In contrast, commercial cheated resins D401 and D418 experience a significant 70 % decrease in reuse performances after the first cycle. This study provides a new perspective and platform for efficient adsorbent development through coordinated structural changes, it holds the potential to alleviate the challenges associated with deep restoration of heavy metal-contaminated wastewater. [ABSTRACT FROM AUTHOR]

• Synergetic interactions between ZVI and Sch during premixing process existed. • Premixing time and mass ratio played essential roles in As(III) removal. • Mass and electron transfer occurred between Sch and ZVI during the premixing. • Recrystallization of Sch and the corrosion process of ZVI were accelerated. • As(III) removal capacity of ZVI/Sch mixtures improved by premixing. Although the enhanced removal of heavy metals using zero valent iron (ZVI) assisted by schwertmannite (Sch) was achieved in previous studies, their interactions between Sch and ZVI seems to be bidirectional and impact on the As(III) removal by ZVI/Sch mixture remains elusive. This study investigated As(III) removal in the mixed suspensions of ZVI and Sch with various premixing times and mass ratios. Batch experiments demonstrated that ZVI/Sch mixture with the premixing time of 3 h and mass ratio of 2:1 exhibited excellent performance in As(III) removal. The results indicated that synergetic interactions between ZVI and Sch during premixing process played crucial roles, particularly in terms of morphological variations. Results of FTIR and XPS revealed the mass and electron transfer occurred between Sch and ZVI during the premixing process, resulting in the accelerated recrystallization of Sch and the corrosion process of ZVI. Furthermore, the premixing process was found to significantly improve the As(III) removal capacity of ZVI/Sch mixture without altering the As(III) removal pathway, including the adsorption/precipitation/oxidation processes of ZVI and surface complexation/ion exchange/channels inlay of Sch. These findings shed light on the complex interactions between ZVI and Sch in As(III) removal and offer promising opportunities for the development of efficient treatment strategies in As(III)-contaminated environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • V(V) reduction and denitrification, coupled with S0 oxidation, were observed. • 96.7 ± 2.2 % and 99.0 ± 1.1 % of V(V) reduction and NH 4 +-N oxidation were accomplished. • V(V) was reduced by MAGs containing genes (narG , napA) or MHCs (OmcB , MtrA). • NH 4 +-N was oxidized to NO 3 –-N/ NO 2 –-N, and then reduced to N 2 or assimilated. • NH 4 +-N oxidation was primarily facilitated by nitrifiers (e.g., Anaeromyxobacter sp.). The extensive use of ammonium (NH 4 +) as a precipitant in non-ferrous metallurgy, such as vanadium production, leads to the co-occurrence of toxic heavy metals and NH 4 +-N in the resultant wastewater. Finding an efficient and cost-effective method for simultaneously removing vanadate [V(V)] and NH 4 +-N in a single step has remained unexplored. This study presents a novel approach by establishing the synchronous bio-elimination of V(V) and NH 4 +-N in a sulfur (S0)-based autotrophic system. Remarkably, 96.7 ± 2.2 % of V(V) and 99.4 ± 0.8 % of NH 4 +-N were successfully removed within 24 hrs. V(V) was transformed into V(IV) precipitates, while S0 was oxidized into sulfate, achieving complete nitrogen removal. Fifty-six genomes were retrieved and constructed from metagenomic binning, unveiling symbiotic interactions involved in sulfur, nitrogen, and vanadium transformation. With the annotation of functional genes (e.g., nar , nir , nap , nor , nos , sox , sor , dsr) and multi-heme c-type cytochromes, it was identified that V(V) reduction and denitrification, coupled with S0 oxidation, were mediated by species such as Sulfuricurvum sp., Achromobacter sp., and Thiomonas sp.. Meanwhile, NH 4 + oxidation was accomplished by Anaeromyxobacter sp.. Furthermore, autotrophs harnessed inorganic carbon through the Calvin-Benson-Bassham and Wood-Ljungdahl pathways to synthesize organic intermediates, which were subsequently consumed by heterotrophic organisms (e.g., Pseudomonas sp.) to facilitate V(V) reduction and denitrification. The quantification of transcripts associated with genes responsible for V and N metabolism provided additional evidence of these metabolic pathways' existence. This study offers a sustainable and environmentally friendly strategy for mitigating the adverse environmental impacts of vanadium production wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A robust polyoxometalate and metal–organic framework hybrid is designed. • The hybrid is a catalytic reservoir for generation of reactive oxygen species. • The hybrid can eradicate bacteria and enhance wound healing efficiently. • Antibacterial mechanism is investigated. Infections by bacteria always post significant challenges to global human health. Recent developed non-antibiotic treatment, such as using metal–organic frameworks (MOFs) to kill bacteria by generating reactive oxygen species (ROS) represents a promising strategy. However, drawbacks including low efficiencies of ROS generation and high concentrations of toxic metal ions released always exist. We have creatively designed a robust polyoxometalate (POM) and MOF hybrid (denoted as CuPOM-MOF@S) that functions as an efficient catalytic reservoir for cascaded generation of ROS (mainly ·OH) from H 2 O 2 thus eradicating bacteria and enhancing wound healing at an administration dosage as low as 5 μg∙mL−1. The remarkable antibacterial capability surpasses those for most MOF-based materials reported thus far, which is mainly attributed to the reservation of massive catalytic copper ions, the synergistic effect regarding catalytic activity between MOFs and Keggin-type POMs as well as its bacteria-capturing ability by the coated surfactants. Its biological safety is investigated and confirmed by cell cytotoxicity and body weight assessment. This work presents a prospective strategy towards cascaded ROS generation by combining inorganic catalytic POMs with MOFs thus for multiple biomedical applications including treating bacterial infections and cancer as well as inducing biological signal responses. [ABSTRACT FROM AUTHOR]

[Display omitted] • OA with 8 carbons provides better adsorption capacity through steric hindrance. • –COOH competes between OA/H 2 bpydc and H 2 bpdc to bind Zr cluster to form defects. • L-cysteine modification introduces more adsorption sites such as –COOH and –SH. • Easy recyclability and separation of aerogel beads were provided. • Adsorption capacity for Pb2+, Cd2+ and Cu2+ increased by 66.2, 10.7 and 5.8 times. Threats caused by heavy metal ions have prompted people to develop porous and functionalized materials to remove them. Metal–organic frameworks (MOFs) show potential for heavy metal ions removal due to the high specific surface area, tunable pore size, flexible designability and favorable stability. However, the intrinsic microporous structure and powder form limit their applications. Herein, we designed a shapeable aerogel bead incorporated with L-cysteine-modified defective UiO-67 for Pb(II), Cd(II) and Cu(II) adsorption. The pristine UiO-67 powders were firstly modified by introducing the modulator (octanoic acid) and an extra ligand (2,2′-bipyridine-5,5′-dicarboxylic acid) to construct defects, both of them competed with the original ligand to coordinate to Zr clusters, resulting in an increased BET surface area (from 337.66 to 1,037.14 m2/g) and mesoporous ratio (from 34 % to 74 %) of the pristine UiO-67. Then, the graft of L-cysteine containing –COOH and –SH introduced more active adsorption sites. Moreover, the powder material was incorporated into sodium alginate aerogel beads which enhanced the recyclability and further improved the adsorption capacity for Pb(II), Cd(II) and Cu(II). These appealing advantages endow the adsorbent with quicker adsorption equilibrium (240 min), and outstanding removal capacities for Pb(II) of 661.2 mg/g, Cd(II) of 296.2 mg/g and Cu(II) of 326.4 mg/g. The chelation and ions exchange between the numerous functional groups including –COOH, –OH and –SH and the heavy metal ions are the main mechanisms for effective adsorption. This work provided a novel approach for the application of MOFs in environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • New crosslinking agents based on the combination of Calcium and Europium applied on pectin. • Deep structural changes after crosslinking with Eu or Ca + Eu. • Pectin crosslinked with Eu results in a fully amorphous material. • Pectin crosslinked with Ca + Eu results in a semicrystalline material. • Low methoxylation pectin crosslinked with Ca + Eu can remove pharmaceuticals and heavy metals simultaneously. The contamination of water resources by heavy metals and pharmaceuticals is a significant threat to human health and the environment. Pectin is a promising material for removing heavy metals from water. However, its removal efficacy for other types of pollutants is limited. In this study, we developed a novel approach to enhance the remediation capacity of pectin (with a low degree of methylation) by crosslinking it with different agents: calcium, europium, and their combination. We performed scanning electron microscopy, infrared spectroscopy, and X-ray diffraction experiments to understand the molecular structure of pectin after gelation with the three agents. Our results showed that calcium, europium, and their combination all induce the gelation of pectin. However, the reticulated pectin structures exhibited significant structural differences depending on the type of crosslinking agent used, which affected the adsorption capacity. Specifically, calcium cations partially formed a crystalline "egg-box" structure, whereas europium cations produced a more homogeneous network without crystalline regions. The dual-crosslinking system comprising calcium and europium cations resulted in an intermediate network with both crystalline and amorphous regions. Our findings suggest that dual-cross-linked pectin is a highly effective adsorbent for the simultaneous removal of both heavy metals and pharmaceutical products. This novel approach of crosslinking pectin with multiple agents has the potential to significantly enhance its remediation capacity, offering a promising solution for the simultaneous removal of multiple pollutants from water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis and modification of cross-linked (MIP) for recovery of Pb(II) and As(V). • Analytical techniques were used to characterize and confirm the synthesized material. • Integrative mechanisms for recognition and selective recovery were discussed. • Studying isotherms modeling, kinetics, and thermodynamics parameters of recovery. • Solvent types, interfering ions, selectivity, and regeneration were investigated. A cross-linked molecularly imprinted polymer (MIP) was synthesized and functionalized by metal oxide nanoparticles (TiO 2 and SiO 2) to form a potential cross-linked (MIP) nanocomposite via binding of Nano-TiO 2 and Nano-SiO 2 to cross-linked chitosan. Where chitosan acted as a functional monomer, glutaraldehyde (Glu) acted as an organic cross-linker with bifunctional reactive groups, and lead (II) and arsenic (V) acted as templates. This work is composed of a binary of promising ideas: (a) a facile preparation of cross-inked molecularly imprinted polymer (MIP) via bulk polymerization method, and (b) the functionalization of newly fabricated cross-linked (MIP) using metal oxide nanoparticles. The fabricated cross-linked biopolymer nanocomposite was used for simultaneous and selective recovery of toxic metal ions from water. Microwave irradiation was applied as an assisted technique to estimate the performance of the synthesized material. The properties and structure of the fabricated Nano-TiO 2 @Cross-linked Chitosan@Nano-SiO 2 were characterized by FT-IR, XRD, TG/DTA, BETs, SEM-EDX, TEM, and XPS. The results indicated that Pb(II) at pH 5.0 ± 0.15 and at time varied from 5 sec to 25 sec exhibited recoveries capacity 97.99–99.81% and Q max 81.97 mg/g, while As(V) at pH 4.0 ± 0.15 and at 5 sec to 20 sec, exhibited recoveries capacity 96.38–99.72 % and Q max 625.00 mg/g. The cross-linked MIP nanocomposite exhibited an improved specific surface (388.0 m2/g) and mesopore size (15.18 nm) compared to its precursors. Freundlich and pseudo -second-order equation well-fitted the experimental data. Pb(II) and As(V) recoveries were exothermic, spontaneous, and governed by entropy change. Solvents subjected to eliminate the templates, interfering ions, selectivity, and reusability experiments were carried out. Newly integrative mechanisms for implementing cross-linked (MIP) nanocomposite for recognizing and recovering metal ions were adequately explained. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of antifouling BGM nanobioaerogel utilizing industrial byproduct. • Statistical optimization based on mechanical stability and adsorption capacity. • High surface area and abundant functional groups in BGM provided stable structure. Fabrication of mechanically stable porous materials with excellent adsorption capacity for different types of heavy metal ions simultaneously is still scientifically and technically challenging. Herein, the Response Surface Methodology (RSM) was employed to statistically fabricate the biological materials (collagen, chitosan) functionalized graphene–magnetite (BGM) hybrid nanobioaerogel. RSM statistically predicted the concentration of GO, Fe2+, collagen–chitosan mixture and glutaraldehyde as 6.78 mg/mL, 0.20 M, 61.39 mg/mL and 68.63 µM, respectively, for the maximum responses of Young's modulus (5.26 kPa) and adsorption capacity. Various spectroscopic and microscopic techniques demonstrated the porous interconnected network structure and superparamagnetic behavior of BGM hybrid nanobioaerogel with a saturation magnetization value of 19.34 emu/g. The nanobioaerogel exhibited fast and high adsorption for Cu(II) (183.96±5.68 mg/g, 29 min), Cd(II) (67.04±1.53 mg/g, 36 min), Cr(VI) (134.49±5.21 mg/g, 45 min) and As(III) (64.62±2.40 mg/g, 40 min) at optimum pH 5.0 and 60 °C in multicomponent system, which is almost four times higher than commercially available activated carbon and other reported literatures. The adsorption process follows the Langmuir isotherm suggesting the monolayer chemisorption, follows pseudo–second order (Cu(II)) and intraparticle diffusion (Cd(II), Cr(VI) and As(III)) models and suggesting rate–limiting step is surface binding and internal pores. ATR–FTIR spectrum revealed that hydroxyl, amine, carboxylate, carbohydrate and iron functional groups in hybrid BGM nanobioaerogel interacted with the heavy metals in a multicomplex manner. It was easily regenerated and reused for multiple adsorptions–desorption cycles. In addition, it also showed >5 log reduction in 4 h against different pathogens and antibiofouling agents. [ABSTRACT FROM AUTHOR]

[Display omitted] • OH groups were introduced to the Si surface after the alkali treatment. • The introduction of OH groups enhances the adsorption capacity of Halloysite. • Cd/Pb promotes H migration in Si-OH and forms covalent bonds with residual O atom. • Si-OH provides a pathway for adsorbing CdCl 2 /PbCl 2 on Si (0 0 1) surface. We attempted to activate the Si surface of Halloysite (Hal) to enhance its adsorption capacity for heavy metal (HM, CdCl 2 /PbCl 2) vapors through thermal-alkali modification. A combination of experimental and simulation methods was used to analyze the stabilization mechanism of CdCl 2 /PbCl 2 comprehensively. FTIR, 1H MAS NMR, and XPS results confirm the generation of Si-OH groups on the alkali-treated Hal (AHal) surface. The adsorption performance of adsorbents was investigated in a two-stage high-temperature adsorption setup, and the results show that a relatively short alkali treatment time (20 min) improved the adsorption capacity of Hal, while a longer treatment time (60 min) led to a negative impact. XPS results revealed that the adsorption of CdCl 2 /PbCl 2 involved both physical and chemical adsorption. Grand Canonical Monte Carlo simulations demonstrated an increased adsorption potential of AHal and enhanced reactivity with the HMs. Density functional theory was employed to investigate the adsorption mechanism of Cd/Pb compounds on the Si surface. Compared to raw Hal, AHal exhibited higher adsorption energy for HMs after introducing Si-OH groups, resulting in a more stable configuration. The stabilization of Cd/Pb monomers on the Si surface primarily relies on promoting the H migration from Si-OH to interlayer O and then forming covalent bonds with the remaining active O atoms, while Si-OH played a role in facilitating the occurrence of De-HCl reaction, thereby transforming the adsorption of metal chlorides into more stable metal monomers adsorption. [ABSTRACT FROM AUTHOR]

• The addition of RM complements the silica-aluminum phase of the FGS system. • The maximum acceptance of alkali by the FGS system is characterized. • FGS has the potential to be used as a non-load bearing material in engineering. • Heavy metals are stabilized by gel adsorption and precipitation. Municipal solid waste incineration fly ash (MFA) and Bayer red mud (RM) were coprocessed with geopolymer technology. The two wastes were used as precursors to synthesize a geopolymer. The ratio of the two wastes and the amount of alkali used, and their effects on the properties of the geopolymer, were investigated. The mechanical properties, mineral compositions, and IR spectra indicated that a 56 d compressive strength of 13.11 MPa was achieved for samples made with 40% MFA and 60% RM and the addition of 7% Na 2 O as the alkali. The alkaline conditions enabled dissolution of the raw materials, a phase change of the aluminosilicate, and a higher degree of polymerization for the gel products. The SEM–EDS and leaching tests showed that gel networks consisting of N-A-S-H and C-(A)-S-H gels immobilized heavy metals by physical wrapping and chemical bonding. A dense matrix limited the release of the toxic elements. The levels of Zn, Ni, Pb, Cu, Cr, and Cd leaching were within the acceptable limits of Chinese and US norms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Identified the potential of nanodiamonds (NDs) as electrocatalysts for chromium. • Modified ND electrode demonstrates superior chromium removal capacity. • Electrosorption system showed improved electrical conductivity via the graphitized NDs. • ND-based redox-assisted flow-through electrosorption system was optimized. Effective removal of hexavalent chromium (Cr(VI)) from water is challenging due to the need for a highly selective process. Efficient chromium removal may potentially be achieved through the use of redox-assisted flow-through electrosorption. In this study, graphitized nanodiamonds (NDs) were annealed under various conditions and the ND with the lowest internal resistance was applied to an activated carbon cloth electrode. The ND-modified electrode was then used as the cathode in a flow-through electrode cell with pristine carbon cloth as the anode. Effective chromium removal was found through a dual pathway mechanism, whereby Cr(VI) is directly electrosorbed at the anode while Cr(VI) is reduced to Cr(III) at the cathode, and subsequently precipitated as Cr(OH) 3 under the locally high cathodic pH conditions. The effects of flow rate and charging/discharging voltage on Cr(VI) removal were further investigated, revealing that sufficiently low flow rates (i.e., ≤1 mL min−1) are required for effective Cr(OH) 3 precipitation and sufficiently high (i.e., >1.4 V) reverse voltages are needed during the discharging period to enable full desorption. Overall, the system displayed high Cr removal capacity (i.e., up to 39.51 µmol g−1) and favorable redox of Cr(VI) to trivalent chromium Cr(III) and Cr(III) to Cr(VI). These results suggest that the ND-modified electrode is a promising tool for the removal of toxic metal ions from wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel hydrophilicity-tunable CMPA-CS polymer was prepared in-situ. • CMPA-CS exhibits ultrahigh adsorption capacity, rate and selectivity for Hg(II). • CMPA-CS efficiently reduces Hg(II) levels from 0.578 ppm in real water to 1.106 ppb. • The active and abundant O − and N − sites were responsible for Hg(II) adsorption. Conjugated microporous poly(aniline)s (CMPAs) are an intriguing material platform for the selective capture of toxic heavy metal ions from water. However, the hydrophobic, monotonous N heteroatom and microporous properties limit their application scopes, particularly for the in-depth treatment requiring to a parts per billion (ppb) level. Herein, we report a novel chitosan-anchored CMPA (CMPA-CS), as designed through delicately exploiting the chitosan as either adsorption sites or pore templates for CMPA to acquire highly functionalized mesopores that could considerably facilitate Hg(II) adsorption. The CMPA-CS thus displayed excellently wide pH suitability (1.0–13.0), large capacity (862.1 mg g−1), ultrafast removal rate (k 2 = 0.163 mg g−1 min−1), high affinity (K d = 7.1 × 106), and strong anti-interference performance (selectivity of minimum 94.5% under the extreme influence of 100-fold-concentration cations). Besides, the Hg(II) concentration could be decreased from 0.578 ppm to less than 1.106 ppb in Minjiang river water substrates, below the EPR drinking water standards of 2 ppb. Comprehensive characterization revealed that the removal mechanism of Hg (II) was primarily a synergetic chelation reaction from the unique nitrogen ligands and O-containing groups, with the following features intensified: (i) good wettability to increase the interaction between CMPA and Hg(II) as contributed by the plentiful oxygen-containing groups; (ii) hierarchical mesopores that would promote ions transport efficiency as created by the chitosan. The new insight in this work can offer valuable guidelines for the design and structure optimization of CMPAs, facilitating its real-world commercial implementation. [ABSTRACT FROM AUTHOR]

• Modified mangrove filler (MAC) was successfully synthesized. • A green pH-responsive adsorptive modified polylactic acid membrane was prepared. • The highest pure water permeability was 2306.6 ± 97.1 L.m−2.h−1.bar−1 using 3 wt% MAC. • Rejection of Cu, Pb, and Ni reached > 99.95% at pH 10. • 3MAC-PLA exhibited FRR of 72.4% after 4 cycles. A novel green pH-responsive adsorptive membrane was prepared by incorporating amino-activated carbon (AC) modified mangrove particles (MAC) into polylactic acid (PLA) ultrafiltration (UF) membranes via the non-solvent induced phase separation (NIPS) technique. The performance of MAC was investigated at various concentrations (ranging from 0 to 6 wt%). The successful synthesis of the material was confirmed through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction, and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDS) spectroscopy. The membranes were characterized by SEM, surface zeta potential, pure water permeability, pore size, and porosity analysis, among others. Static adsorption and dynamic filtration were carried out to study the membranes' water permeability and rejection performance of pH responsiveness at pH 4, 7, and 10. The results demonstrated that the addition of MAC improved water permeability from 1336.4 ± 96.4 L.m−2.h−1.bar−1 in the original PLA to 2306.6 ± 9.7 L.m−2.h−1.bar−1 in the 3MAC-PLA membrane (3 wt% MAC). Moreover, the rejection of heavy metal ions increased from 18.15, 17.31, and 17.50% for Cu2+, Pb2+, Ni2+ ions at pH 4, to 99.95, 100, and 99.95% at pH 10 for the 3MAC-PLA membrane; respectively. According to the equilibrium data, the Freundlich isotherm provided the best fit for the experimental data, implying a non-uniform affinity for adsorption on heterogeneous surfaces via chemisorption. The maximum adsorption capacities achieved at pH 7 were 4.2 mg.g−1 for Cu2+, 5.0 mg.g−1 for Ni2+, and 6.8 mg.g−1 for Pb2+; respectively. Overall, the addition of MAC enhanced the properties of the pristine PLA, opening new potential for these composite membranes in the wastewater treatment industry. [ABSTRACT FROM AUTHOR]

This study provides a new idea for the heavy metal ions and organic matter pollution coexisting systems remediation and MFC degradation efficiency optimization. [Display omitted] • The bi-directional promotion effects on heavy metals and organics removal were realized via manganese-iron cycling in the microbial fuel cell (MFC). • The enriched deep-sea bacteria responsible for degrading complex heavy metals and organics were analyzed. • Photocurrent efficiency increases by 0.5-fold in the presence of Fe3+ and Mn4+. • Fe3+ and Mn4+ shuttles electrons for enhanced activation and generation of OH in MFC. With the rapid development of industry and agriculture, the heavy metal ions and organic matter pollution coexistence systems become increasingly common, aggravating environmental damage and endangering water safety. Therefore, an urgent need to find a general method to achieve the typical removal of two pollutants or promote the removal of one to improve another degradation, solving the related pollution problems. Meanwhile, the related research microorganism's salt and heavy metal tolerance is lower, limiting the related research. Therefore, the study makes the deep-sea sediment as the strain source, obtaining the low-valence manganese-oxidizing functional bacteria (OMF) with salt-tolerant and heavy metal-tolerant characteristics, constructing the closed-circuit microbial fuel cell (MFC), carried out the degradation mechanism of saliferous compounding heavy metals-organic wastewater by manganese and iron cycling processes. The results showed that under the salt content conditions of 3%, pH = 6, external resistance of 510 Ω, Mn2+ concentration of 11 g/L, Mn2+:Fe2+ = 1:0.3 and OMF (Rhodococcus erythropolis: Microbacterium kitamiense : Dietzia = 1:2:1) inoculation amount of 20%. The maximum removal rates of organic pollutants (400 mg/L), Cu2+ (250 mg/L), Co2+ (150 mg/L) and Ni2+ (200 mg/L) were 94.72%, 91.23%, 99.89% and 99.97%, respectively. Realizing the heavy metal ions and organic matter pollution coexisting systems purification. The manganese-iron cycle mediated by oxidized low-valent manganese functional bacteria has a dual effect on the pollutant's degradation process through MFC. Firstly, the synergistic redox cycle transformation of iron and manganese promoted the production of OH and accelerated the degradation of organic matter. Secondly, the ferromanganese oxidation products and bio-nanowires enhance material oxidation and electron transfer, improving the organic pollution oxidation and heavy metal ions fixation efficiency. This study provides a new idea for the heavy metal ions and organic matter pollution coexisting systems remediation and MFC degradation efficiency optimization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-culture of the two algae had the highest nutrient and metal removal efficiency. • The higher tolerance of Chlorella to metals due to the higher GSH and SOD activities. • There was no significant biomagnification of the metals in the algae-shell food chain. This research the bait microalgae Chlorella sp. and Isochrysis zhangjiangensis were fed to Ruditapes philippinarum (clams) using two types of cultures, monoculture and co-culture, simulating the conditions, and presence, of common heavy metals Cu2+, Pb2+ and Cd2+ in cultured waters. The effects of microalgae growth, antioxidant activity, and changes in nutrient TN and TP were investigated. The metal contents of the culture solution, algal cells, and four tissues of Ruditapes philippinarum were analyzed. The results showed that the highest nutrient removal efficiency was achieved under the co-culture of three heavy metals, with the removal rates of TN and TP ranging from 47.26% to 51.36% and 78.28% to 87.72%, respectively. The higher tolerance of Chlorella sp. to heavy metals compared to Isochrysis zhangjiangensis was probably due to the higher glutathione and super oxide dimutase activities exhibited by Chlorella sp. cells, which increased by 28% and 40.64%, respectively. Isochrysis zhanjiangensis , Chlorella sp. and their co-culture group had the highest removal rate of Pb2+, which were 20.15%, 26.56% and 29.19%, respectively, followed by Cd2+ and Cu2+. The enrichment of the four tissues from the Ruditapes philippinarum organism for heavy metals, was in the order of visceral mass > gill > coat membrane > muscle. The biotransfer coefficients of the three metals in the microalgae- Ruditapes philippinarum food chain biomagnification ranged from 0.24 to 0.79, which indicated that there was no significant biomagnification of the metals in the transfer process of the food chain. The results of this study reveal the mechanism of heavy metal transport in the algae-shellfish system, which would provide a theoretical basis for improving the ecological environment, and can improve the quality of cultured shellfish products. [ABSTRACT FROM AUTHOR]

[Display omitted] • rSBR improve sulfate removal by upregulating dissimilated sulfate reductase. • Bioaugmentation with immobilized rSBR accelerates the metabolism of sulfate. • rSBR remove heavy metals via coprecipitation. • Bio-AnMBR removes approximately 99.4% of sulfate and 95.6% of metal removal. Sulfate-rich metal-laden wastewater (SRMLW) shows a significant threat on the ecological environment and human health. Sulfate-reducing bacteria (SRB) can remove sulfate from wastewater in anaerobic membrane bioreactor (AnMBR). This study constructed recombinant genetic engineered SRB (rSRB) and investigated the sulfate and heavy metals removal efficiency for treating SRMLW by immobilized-microbial bioaugmentation using rSRB (IMrSRB) coupled with AnMBR (Bio-AnMBR). The results show that Bio-AnMBR removed sulfate (99.4%) from SRMLW by upregulating key genes (Sat , DsrAB , AprAB , QmoABC , DsrC and DsrMKJOP) and enzymes (APS reductase, Dissimilatory sulfite reductase, Trithionate reductase and Thiosulfate reductase) in dissimilatory sulfite and sulfate respiration processes. Bio-AnMBR achieved synergistic biodegradation of sulfate and nitrogen by stimulating the activity of these bacteria related to the conversion of nitrogen and sulfate. Microbial analysis indicated that the relatively high abundance of rSRB (79.2%) and functional genes (70.1%) upregulated the activities of key enzymes associated with sulfate metabolism system, thus increasing the production of S (66.4 mg/L) and H 2 S (23.8 mg/L). Bio-AnMBR significantly improved the tolerance to heavy metals by increasing concentrations of CO32–, S2-, and HS-, which was configured to reduce heavy metals (95.6%) via precipitation of metal sulfide (81.3 mg/L), metal carbonates (30.7 mg/L) and metal hydroxides (18.7 mg/L). Bio-AnMBR increased system stability, shorted hydraulic retention time (HRT), decreased the production of soluble microbial products (SMP), extracellular polymeric substances (EPS) and waste-sludge production (WSP), as well as improved effluent quality. In conclusion, data in this study indicate that application of Bio-AnMBR is a feasible strategy for the treatment of SRMLW. [ABSTRACT FROM AUTHOR]

[Display omitted] • MEC for effective simultaneous removal of sulfates and heavy metals.. • Electric fields further enhance the tolerance of heavy metals on microorganisms. • CuS and Cu(OH) 2 are the fate of Cu. • More functional genes related to sulfate metabolism enhanced at low Cu2+ level. It is poorly understood how the mechanism of heavy metals affect sulfate-reducing bacteria (SRB) in microbial electrolysis cell (MEC) system, however, this is essential to improve the effectiveness of sulfate reduction in acid mine drainage (AMD). This study evaluated the impact of Cu2+ on MEC performance using SRBs enriched biocathode. The sulfate reduction rate and pathway, the fate of Cu, as well as the succession of microbial community were investigated. Results showed that MEC performance was optimized at influent Cu2+ concentration of 20 mg/L, while slight inhibition was observed at 40 mg/L. The removal of Cu2+ was accomplished through bioprecipitation and biosorption, forming CuS and Cu(OH) 2. However, MEC performance was inhibited at higher Cu2+ concentrations (60 mg/L) due to damaged cell structure, increased charge transfer internal resistance, and altered microbial communities. Specifically, the relative abundance of Firmicutes and Bacteroidota decreased, and functional genes related to sulfate reduction metabolism were reduced, leading to impairment of the assimilatory and dissimilatory sulfate reduction pathways. This knowledge provides revealing insights and theoretical support for developing a feasible approach to realize the treatment of wastewater containing multiple pollutants. [ABSTRACT FROM AUTHOR]

In this work, we have designed and fabricated a highly durable multifunctional self-assembly gating membrane with in-situ detection of heavy metal ions (Cu2+ and Fe3+) and pH values of treated solution, ionic-stimuli controllable gating (from 0 to 15,330 L m−2 h−1 bar−1), exceptional mechanical stability and excellent anti-fouling properties (94.8%), these features will undoubtedly enhance the practical application of smart gating membrane. [Display omitted] • A polyzwitterionic gating membrane with wide range of permeance regulation. • The fluorescence and color of membrane is responsive to metal ion and pH. • The membrane shows great mechanical stability and anti-fouling capability. The smart gating membranes with stimuli-response permeation variations have attracted tremendous interest in the field of wastewater treatment. Specifically, successful integration of accurate porous architecture, precise water permeance regulation, long-term duration and in-situ detection of multiple environmental signals in a visualized way is highly desired yet still exclusive. Herein, a smart gating membrane with a combination of accurate porous adjustment and multi-signals detection is developed by assembling poly[2-(1-(4-vinylbenzyl) pyridin-1-ium-4-yl) ethane-1-sulfonate] (PVPES)-grafted SiO 2 nanoparticles on cellulose membrane. The membrane exhibits uniform packing architecture with highly tunable water permeance from 0 to 15,330 L m−2 h−1 bar−1, mediated via polymeric shell thickness control and external salt-stimulation; besides, in-situ detection of heavy metal ions and pH values of the treated solution is simultaneously achieved via the pH-induced discoloration and heavy metal ion-dependent fluorescence of PVPES. What's more, the membrane shows great mechanical stability against repeated bending, vibration or abrasion, as well as great anti-fouling capability, which together contributing to a long service life. We believe the membrane developed here will definitely promote the practical application of smart gating membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual-confinement enables the facile fabrication of magnetic MOF microspheres. • The BET specific surface area of magnetic MOF microspheres is up to 1002 m2·g−1. • The microspheres exhibit superb multi-targeted adsorption for MG, TC and Cu(II). • The adsorption capacities for MG, TC and Cu(II) are up to 1823, 909, 2305 mg·g−1. • Both magnetic properties and adsorption efficiencies remain positive after 5 cycles. Considering the diversified threats to freshwater, it is challenging to achieve highly efficient treatment of wastewater containing organic dyes, antibiotics, and heavy metal ions. Herein, we put forward a series of magnetic adsorbents based on an aromatic polymer-mediated dual-confinement strategy. The aromatic polymer plays double roles in both encapsulating magnetic Fe 3 O 4 nanoparticles and providing nucleation sites for the metallic and organic precursors of zeolitic imidazolate framework-8 (ZIF-8). The internal and external confinement enables stable magnetic response and subsequent epitaxial growth of ZIF-8, resulting in recyclable metal–organic framework (MOF) microspheres as adsorbents. The BET specific surface area of the MOF microspheres is up to 1002.0 m2·g−1, and the maximum adsorption capacities of malachite green (MG), tetracycline (TC), and Cu(II) predicted by the Langmuir isotherm at 303.15 K are 1823.60, 909.09 and 2305.44 mg‧g−1, respectively. The MOF microspheres exhibit excellent broad-spectrum adsorption capacities for the three pollutants in neutral and strongly alkaline environments. In addition, the overall adsorption performances remain positive after 5 cycles of adsorption–desorption experiments accompanied by nearly invariable saturation magnetization. This study develops a competitive magnetic adsorbent for the multi-targeted removal of dyes, heavy metals, and antibiotics, which can balance the cost-effective preparation, impressive adsorption capacities, and high cycling stabilities toward the remediation of complex wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A salt-tolerant polyelectrolyte hydrogel was fabricated. • Mutual interactions of adjacent cations and aromatic rings endow the hydrogel with salt-tolerant properties. • The composite gradient hydrogels present enhanced adsorption and catalytic performance. • The gradient hydrogel matrix demonstrates good stability and reusability used in the saline solutions. The integration of nanostructured materials into hydrogel matrix with chemical gradient holds great promise in gathering the pollutants and enhancing their adsorption or photocatalytic performance. However, the electric potentials rooting in the common gradient polyelectrolyte hydrogel are almost completely shielded by the co-existing counter-ions. In this study, a salt-tolerant gradient polycationic electrolyte hydrogel was fabricated by free radical copolymerization under the induction of unilateral UV illumination, which was used as nanofillers matrix. The cation-π interactions between the adjacent cations and aromatic rings endow the gradient polycationic electrolyte hydrogels deserving the salt-tolerant properties. Thus, the build-in electric potentials are still reactive on enrichment of the anionic heavy metals in highly concentrated salt solutions, altering the defects of the common gradient polyelectrolyte hydrogel. Using Sb(V) adsorption and Cr(VI) photocatalytic reduction as target reactions, the gradient composite hydrogels always display fast and high removal capacities towards these anionic pollutants in the saline solutions of 500 mM, as well as good stability and reusability. This salt-tolerant hydrogel matrix provides a smart material platform with self-driven forces in the fields of pollutant enrichment and removal. [ABSTRACT FROM AUTHOR]

• Fulvic acid could cause the collapse of octahedral structure of iron minerals. • Van der Waals forces dominated fulvic acid and iron mineral interaction. • Fulvic acid could enhance the adsorption capacity of Fe minerals for Cu(II). • Hydrated Cu(II) was more inclined to coordination with –OH of fulvic acid. The dynamic interactions among iron (Fe) oxides and organic matter (OM) play vital roles in controlling the geochemical cycling of carbon (C) and toxic trace metals. Although the effects of OM on the Fe oxides transformation, and dynamic with toxic trace metals have been studied previously, it is still poor to understand the mechanistic and quantitative on the C sequestration during the Fe(III) mineralization process, and kinetics with hydrated Cu(II) in the acid drainage. In this study, Mössbauer spectroscopy, X-ray absorption spectroscopy (XAS), high resolution transmission electron microscopy (HRTEM), and density functional theory (DFT) were used to elucidate the underlying mechanism for the fine structure of iron minerals, fulvic acid (FA) sequestration and hydrated Cu(II) coordination on Fe oxides. FA dosages played an essential role in the formation of Fe oxides, which can inhibit the formation of Fe-O octahedrons and benefit to the Fe-O tetrahedron. FA molecules were mainly sequestrated on the surfaces of Fe oxides and van der Waals forces were the main interaction between FA and Fe oxides. The hydrated Cu(II) oxides mainly distributed on the surface of iron oxides as divalent oxidation states, and feasible coordinated with phenolic hydroxyl group of FA and Fe oxides. The knowledge of the dynamic coupling between Fe oxide transformation under the effect of FA and the fate of hydrated Cu(II) on Fe oxides provided the basis for predicting the geochemical process of Fe, C and toxic trace metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • A versatile coagulant capable of removing broad-spectrum metal ions is prepared. • Inorganic and organic groups in coagulant work synergistically in metal removal. • The coagulant simultaneously removes a wide variety of free metal ions. • Metal-organic complexes are removed in both low and high salinity water. • ATR-FTIR technique elucidates metal ion removal mechanism in real time. Complete removal of metals in wastewater remains challenging due to the co-existence of multiple types of free and complexed metal ions, which hold distinctive molecular properties. Current technologies face the problem of specificity in metal capture that simultaneous removal of various metal ions is highly inefficient. Herein, we report a versatile hybrid coagulant with the capability of indiscriminately removing multifarious metal ions through the synergistic effect of its organic and inorganic groups. Diverse customized organic groups collectively capture metal ions, meanwhile inorganic polynuclear aluminum aggregate into flocs for easy separation from water. The coagulant is the first to achieve nearly full removal toward a wide range of metal ions including free metal ions covering hard acids (La3+, Zr4+, Mn2+), soft acids (Hg2+, Cd2+, Pd2+) and borderline acids (Zn2+, Ni2+, Co2+), as well as a typical complexed metal ion, i.e., Cu-citrate. Free metal ions were captured through complexation with hard base –OH and soft base -SH, while complexed metal ion was removed via ion exchange by -N+(CH 3) 2 RCl− and ligand exchange by Al-OH. The coagulant exhibited excellent stability and reusability in several recycling processes. The versatile coagulant provides a highly efficient way for heavy metal pollution control, which is applicable for the treatment of any wastewaters with unpredictable metal species. [ABSTRACT FROM AUTHOR]

Illustration of reaction mechanisms of simultaneous degradation of SMT and removal of Cr(VI) in 1Fe-2Cu-Al 2 O 3 -800/H 2 O 2 system. [Display omitted] • A novel flexible self-supporting Fe-Cu-Al 2 O 3 nanofibrous membrane was prepared. • Synchronous detoxification of Cr(VI) and SMT was realized in Fe-Cu-Al 2 O 3 /H 2 O 2. • Reduced Cr(III) incorporates into iron oxide to form a stable Fe-Cr(III) complex. • Fe(II)/Fe(III) cycle could mediate Cr(III)/Cr(VI) cycle to accelerate SMT degradation. The co-existence of sulfamethazine (SMT) and heavy metal Cr(VI) may alter their migration and conversion laws and even their biological toxicity owing to their different physicochemical properties, greatly aggravating their environmental risks and elevating the difficulty of remediation. Herein, a novel flexible self-supporting Fe-Cu-Al 2 O 3 nanofibrous membrane (1Fe-2Cu-Al 2 O 3 -800) was synthesized via a sol–gel method with the combination of electrospinning serving as a heterogeneous catalyst for simultaneous SMT degradation and Cr(VI) removal. Copper and iron elements were highly dispersed in the alumina nanofibrous matrix in the form of Fe(III), Cu(I), and Cu(II) species. There exists a wide applicable range of environmental pH for the 1Fe-2Cu-Al 2 O 3 -800/H 2 O 2 system, exhibiting excellent catalytic selectivity and recycling performance. The surfaced-bound hydroxyl radicals activated by reductive Cu(I) species were the main active species of SMT degradation. Meanwhile, anionic Cr(VI) was rapidly adsorbed on 1Fe-2Cu-Al 2 O 3 -800 through electrostatic interaction, and then directly reduced to Cr(III) by adjacent reductive ≡Cu(I) species and subsequently incorporated into iron oxide to constitute a stable Fe-Cr(III) complex. Moreover, the degradation kinetics results showed that Fe(II)/Fe(III) cycle in the 1Fe-2Cu-Al 2 O 3 -800/H 2 O 2 system could mediate Cr(III)/Cr(VI) cycle to prominently accelerate the SMT degradation through Haber-Weiss-type reaction, thereby having a synergistic effect. Overall, this work would provide new insights and a feasible strategy for the remediation of organic–inorganic composite pollutions, including SMT and Cr(VI). [ABSTRACT FROM AUTHOR]

[Display omitted] • The pre-concentration of forward osmosis (FO) increases capture efficiency of nano channels. • An FO-electroosmotic integrated chip for trace heavy metal detection was developed. • "Pump effect" replaces the osmotic pressure of draw solution, becoming the new driving force of FO. • The detection accuracy of Cr3+ by UV spectrophotometer has been improved by two decimal places. The focus of this study is on the enhanced concentration effect of the pump effect in forward osmosis (FO) and electroosmotic integrated chip. The study investigates the strengthening effect of the FO process, driven by the pump effect, on the electroosmotic flow process under the same energy consumption, using low-concentration heavy metal ions (Cr3+) as the target enrichment. In the chip system, the pump effect, caused by capillary pressure difference, successfully replaces the osmotic pressure of the draw solution as a new driving force for the FO process. By adjusting the size and number of channels and avoiding errors, the study achieves the highest efficiency of the FO process in the chip, concentrating Cr3+ from 1.26 × 10−4 mol/L to 8.01 × 10−4 mol/L (6.4 times) within 32 min. Excluding the influence of the electrokinetic (EK) limit of low-concentration samples, the concentration efficiency of an individual electroosmotic chip in this study is positively correlated with cross-nanochannel voltage (V cn). The integrated FO and electroosmosis chip reduce the duration required to concentrate 50 mL Cr3+ sample to the limit from 90 min to 16 min (5.6 times) compared to the single electroosmotic process. Furthermore, a series of Cr3+ samples with concentrations below the detection limit of the UV–vis spectrophotometer were concentrated and detected by the integrated chip. The results indicate that the concentration limit of the FO-electroosmotic integrated chip for samples can increase the detection limit of Cr3+ from 1.37 × 10−4 mol/L to 3.67 × 10−6 mol/L. [ABSTRACT FROM AUTHOR]

[Display omitted] • A precise grafting strategy to prepare the multifunctional MXene-based membrane. • The membrane demonstrated excellent superhydrophilic, anti-oil adhesion, chemical stability, and flexibility properties. • The membrane showed outstanding separation performance (6731.8 L m−2 h−1 bar−1 and >99.97%) for high viscosity emulsions. • The successful modification of the pyromellitic acid groups ensured efficient heavy metal ions removal performance (>99%). Industrial development generates large quantities of oily wastewater, which poses a serious threat to the environment and human health. Heavy metal ions, dyes, and some water-soluble pollutants are also discharged with oily wastewater. Therefore, there is an urgent need for multifunctional separation technologies to deal with various pollutants. As an emerging two-dimensional material, titanium carbide (Ti 3 C 2 T x) is of great importance in the field of oil–water separation because of the abundant hydrophilic groups on its surface. Herein, we developed a precise grafting strategy to modify MXene sheets with pyromellitic acid groups and prepared a multifunctional MXene-based membrane. Benefit from the abundant hydrophilic groups on the MXene sheets' surface, the as-prepared membrane demonstrated outstanding superhydrophilic and anti-oil adhesion properties, and also showed remarkable separation performance (6731.8 L m−2 h−1 bar−1 and >99.97%) for high viscosity emulsions. Importantly, the presence of grafting groups improved the removal efficiency of several heavy metal ions (>99%) by the membrane. Additionally, it also demonstrated superior chemical stability, flexibility, and efficient separating harsh emulsions. This work provides a new insight into the development of the multifunctional MXene-based membrane materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrasonic excitation promoted the internal diffusion phase of FA carbonation. • 28-day UFA solidified body has the highest compressive strength (32.2 MPa). • UFA solidified body showed the highest degree of hydration and polymerization. • UFA solidified body has high immobilization efficiency of Cu, Pb, and Zn. • Considering sustainability, the UFA scenario was recommended for application. Ultrasonic carbonation technology is effective for municipal solid waste incineration fly ash (MSWI FA) pretreatment. However, the subsequent disposal route is unclear. In this study, the mechanical strength and heavy metal immobilization effects of raw FA (RFA), washed FA (WFA), conventional carbonated FA (CFA), and ultrasonic carbonated FA (UFA) as cement aggregates in the preparation of concrete were investigated in comparison. The reaction kinetic analysis showed that ultrasonic excitation promoted the internal diffusion phase of the carbonation reaction. The compressive strength of the 28-day solidified bodies was in the order of UFA (32.2 MPa) > CFA (22.8 MPa) > WFA (16.4 MPa) > RFA (12.6 MPa). The 3-day UFA solidified body showed the highest degree of hydration and polymerization through 29Si solid-nuclear-magnetic analysis. The nano-CaCO 3 in the UFA provided more nucleation sites and hydration reaction sites for the hydration reaction. In addition, the fine UFA particles filled the pores between cement particles, enhancing the strength of the product. Heavy metal leaching tests described that CFA and UFA met the criteria for resource utilization (HJ/T 1134–2020), and the immobilization efficiency of Cu, Pb, and Zn in the UFA solidified body was above 95.6%, 99.3%, and 99.2%, respectively, mainly by the dual immobilization of carbonate chemical precipitation and cement hydration. Considering 11 environmental impact factors and economic benefits, life-cycle-assessment and cost-benefit analysis were selected. The integrated environmental-economic results show that cement usage is the main influencing factor. UFA scenario was recommended as engineering applications with low global warming potential. [ABSTRACT FROM AUTHOR]

Aptamer-based sensing and selective recovery of heavy metals and rare earth elements from aquatic environments. [Display omitted] • Biomolecules can detect and recover heavy metals (HMs) and rare earth elements (REEs) • Aptamer-based materials are emerging for detecting and recycling HMs and REEs. • Metal-specific aptamers can bind to specific targets with high affinity. • Engineered aptamers have the potential to contribute to environmental sustainability. Heavy metals (HMs) and rare earth elements (REEs) are used in a wide range of industrial and technological applications, but they can also have harmful effects on the environment and human health when released into the environment. Due to their environmental impact and economic importance, there is an increasing interest in detecting and recovering HMs and REEs. Various methods are being developed and optimized for sensing and recovering HMs and REEs, including sensors, (bio)sorbents, and extraction techniques. However, these methods require on-site and routine environmental monitoring professionals, sample pretreatment is complex and requires expensive equipment, and adsorbents/solvents can cause additional environmental pollution. Recently, various biomolecules with hydrophilic properties that can be produced in an eco-friendly manner have been developed to detect and recover HMs and REEs in water. Especially, aptamer-based materials that specifically bind to target molecules are emerging as promising alternatives for detecting, recovering, and recycling HMs and REEs. This article comprehensively reviews recent advanced methods for selecting metal-specific aptamers and their use as biosensors for HMs in environmental samples. Furthermore, sustainable strategies are discussed for potential applications of engineered aptamer-based materials in developing more environmentally friendly techniques for sensing and recovering valuable HMs and potentially REEs. [ABSTRACT FROM AUTHOR]

[Display omitted] • SZVMn is prepared using sulfidation with freshly formed S0 as sulfidizing agent. • Efficient removal of Cr(VI) by SZVMn: maximum capacity of 190.8 mg/g. • SZVMn surpasses nZVMn in terms of matrix resistance and long-term storage ability. • Low S/Mn molar ratio at 0.1 in material synthesis is beneficial to Cr(VI) removal. • Cr(VI) is rapidly reduced by Mn0 and later by dissolved/surface-bound Mn2+. Both zero-valent manganese (ZVMn) and sulfide possess high reducibility and strong affinity towards heavy metals in high oxidation states. The feasibility and behavior of combining these two components to create sulfidated zero-valent manganese (SZVMn) for hexavalent chromium (Cr(VI)) removal, however, remain largely uninvestigated. This study aims to explore the behaviors and mechanisms of Cr(VI) removal utilizing SZVMn, which was synthesized by borohydrides reduction of divalent manganese salt, followed by sulfidation using freshly generated elemental sulfur. SZVMn comprised a mixture of low-crystallinity Mn0, MnO x , and MnS x , with the fraction of MnS x increasing with higher S/Mn molar ([S/Mn]) ratio. The optimal [S/Mn] ratio was determined to be 0.1, achieving the highest Cr(VI) removal capacity of 190.8 mg/g. At [S/Mn] ratio exceeding 0.1, Cr(VI) removal declined due to higher consumption of Mn0 as a result of increased S dosing during material formation. SZVMn outperformed bare ZVMn in terms of preservation and resistance to coexisting ions. The removal of Cr(VI) occurred primarily through the rapid reduction of Cr(VI) to Cr(III) via Mn0 and MnS x initially, followed by slow reduction via dissolved/surface-bound Mn2+, along with precipitation of Cr(III) as Cr(OH) 3. This study provides a deep understanding of the interactions between Cr(VI) and SZVMn derived from freshly-generated elemental sulfur, offering new insights into Cr(VI) removal processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advancements in cellulose-based adsorbents for environmental remediation overviewed. • Modification of surface functionalities in cellulose and their role are discussed. • Cellulose-based composites, hybrids, and cellulosic bio-materials are reviewed. • A wide range of adsorbate included: potentially toxic, precious, and radionuclides. The abundance of cellulose in nature, as well as its biocompatibility and functional groups, has paved the way for the development of advanced cellulose-based technologies for water and wastewater treatment. This comprehensive review provides a detailed overview of recent advances in cellulose-based adsorbents, focusing on surface functionalization and potential applications in water and wastewater treatment technologies. The investigation of numerous cellulose-based adsorbents has demonstrated that the introduction of surface functional groups such as carboxyl, succinate, amine, imidazole, amidoxime, thiol, thioether, sulfonate, dithiocarbamate, xanthate, phosphate, and so on through chemical modification techniques significantly improves their adsorption properties and selectivity towards metallic species. The review delves into the use of cellulose-based adsorbents for the removal of potentially toxic elements, radionuclides, and the recovery of precious metals from water and wastewater. Furthermore, the potential of blended adsorbents that incorporate various types of cellulose in the form of composites, nanocomposites, and hybrids is highlighted. Furthermore, this review assesses cellulosic biomaterials with varying cellulose contents to determine their potential as metal sorbents. Finally, current research trends, gaps, challenges, and future perspectives in this field are brought to the forefront. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molten chlorides can be recycled to extract heavy metals from fly ash effectively. • The migration and reaction of Cd, Cu, Pb in molten salt differ from those of Zn. • Heavy metal oxide and chloride in molten salt can be converted into each other. • Zn2+ can react with Si 2 O 7 6- formed by O2– and SiO 2 , to be stabilized as Ca 2 ZnSi 2 O 7. • For recovery, heavy metals can be enriched in the slags of molten salt. Molten salt thermal treatment has been demonstrated to be effective in dissolving heavy metals in municipal solid waste incineration (MSWI) fly ash. However, the complex thermochemical reactions of various heavy metals during the process remain unclear. This study investigated the migration and transformation mechanisms of typical heavy metals during molten salt (NaCl-CaCl 2) cyclic thermal treatment of fly ash at 600–750 °C, as well as the leaching characteristics and recovery methods of heavy metals in the reacted products. Molten chlorides could be recycled to extract heavy metals from fly ash, which reduced the leaching toxicity of heavy metals in the reacted slags. Over 64.3% of Cd, Cu and Pb in fly ash were transferred to molten salt while the migration rate of Zn was restrained to only 32.3% during the cyclic process at 750 °C. Regarding Cd, Cu, and Pb in molten salt, the chlorination and dissolution of their oxides were significant, while the combination of their chlorides with free O2– to form oxides precipitation was weak. However, the above reaction characteristics of Zn were the opposite. Furthermore, Zn2+ could be stabilized into hardystonite (Ca 2 ZnSi 2 O 7) in molten salt by reacting with Si 2 O 7 6- generated from the combination of O2– and SiO 2. Besides, increasing the reaction temperature facilitated the chlorination and dissolution of heavy metals. For recovery, heavy metals could be concentrated on the insoluble matters of molten salt, with a maximum concentration of approximately 5 times that in fly ash. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe and N co-doped biochar served as catalytic particle electrode in 3D-EF process. • 3D-EF process exhibited excellent ability in Ni-EDTA decomplexation and removal. • Surface-bound O 2 − induced by catalytic particle electrode was the major ROSs. • Rapid removal of Ni-EDTA in 3D-EF process occurred within the initial 1 min. • Main active sites on the surface of catalytic particle electrodes were identified. Heavy metal complexes pose a challenge in terms of their resistance to removal due to their stable and intricate structure. In this study, we explored the utilization of Fe and N co-doped biochar derived from rice husk (Fe-N-RHBC) as catalytic particle electrodes in a three-dimensional electro-Fenton (3D-EF) system for the decomplexation and removal of a model pollutant, Ni-EDTA. The characterization analysis and comparison of catalytic activities confirmed the beneficial effects of Fe and N co-doping on various aspects, such as the types of active sites, interfacial electron transfer properties, and H 2 O 2 decomposition capacity. Compared to other investigated oxidation systems, the 3D-EF process demonstrated rapid removal of Ni-EDTA within the initial minute, with a maximum H 2 O 2 utilization of 99.1% after 30 min. The prepared catalytic particle electrodes exhibited high stability and catalytic capacity even after three consecutive cycles. Throughout the reaction, several processes, including anode oxidation, particle electrode polarization, catalysis, and adsorption of Fe-N-RHBC, as well as cathodic electro-deposition, synergistically contributed to the treatment of Ni-EDTA. The surface-bound O 2 − radicals and 1O 2 generated by the Fe-N-RHBC catalytic particle electrode played a crucial role in the decomplexation and removal of Ni-EDTA. Building upon these findings, we further proposed potential mechanisms for the removal of Ni-EDTA in the 3D-EF system using the Fe-N-RHBC catalytic particle electrode. [ABSTRACT FROM AUTHOR]

[Display omitted] • Partially calcined CaCO 3 contains both CaO and CaCO 3 in one material. • PCC had a slower dissolution rate of CaO compared to the mixture of CaO and CaCO 3. • PCC treated 154.6 L/kg PCC of heavy metal-contaminated groundwater. Calcium-based materials, known for their ease of handling and cost-effectiveness, are commonly used for removing heavy metals from groundwater. Unfortunately, among the calcium-based materials, calcium carbonate (CaCO 3) is not a viable means of removing heavy metals due to its low solubility. Calcium oxide (CaO) with high solubility, obtained through the calcination of CaCO 3 , does effectively remove most heavy metals by raising the pH to alkaline condition. However, the dissolution of CaO increases the system temperature rapidly due to the heat associated with hydration, and excessive alkalinity is released due to rapid dissolution and pores become clogged due to hardening. To overcome these problems, this study proposed partially calcined CaCO 3 (PCC) as a potential remediator of groundwater contaminated with multi-heavy metals. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) analysis confirmed the co-existence of CaCO 3 and CaO phases in one material. In the partially calcined CaCO 3 samples, the amount of CaO present increased with calcination temperature and residence time. More CaO was observed to result in greater removal of heavy metals. Compared to a binary mixture of CaO and CaCO 3 , PCC showed a slower dissolution rate of CaO, indicating control over CaO dissolution kinetics. It was determined that 1 kg of PCC was capable of purifying approximately 154.6 L of contaminated groundwater with an 18.2 wt.% CaO content, twice as much as the binary mixture of CaO and CaCO 3. Based on the results, partially calcined CaCO 3 is a potential reactive medium to remediate groundwater contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • A highly active metal-free nanosheet based on B, N, S, P-doped carbon was prepared. • The BNSP-C has a specific surface area of 755.58 m2/g and a conductivity of 75.82 Ω. • It has a linear range of 0.1–130 μg/L for Cd(II) and 2–150 μg/L for Pb(II). • LODs of the sensor are as low as 0.10 μg/L for Cd(II) and 0.45 μg/L for Pb(II). • It can be used for direct analysis of heavy metals in fruits, vegetables and rice. Designing and synthesizing efficient and economical electro-sensing interface materials is essential for screening trace heavy metal ions in foods. In this study, we developed a multi-doped BNSP-C material with Zeolitic imidazolate framework-8 (ZIF-8) and non-metallic atoms (B, N, S, and P) for the simultaneous detection of the heavy metals Cd(II) and Pb(II) in complex food samples. The in situ doping of heteroatoms positively modifies the microstructure and current efficiency of the carbon precursor, creating additional active sites and defects, and imparting the material with improved electrical properties. The detection system optimized by square-wave anodic stripping voltammetry, was sensitive up to 1.290 and 0.661 μA·μM−1·cm−2. BNSP-C-Nafion/GCE has a high selectivity for target ions under the challenge of multiple coexisting ions and molecules. Furthermore, the current signals of Cd(II) and Pb(II) only dropped to 97.19 % and 98.98 % of the initial currents after a 30-day stability test. The strong catalytic activity and persistence of the BNSP-C-Nafion sensor were confirmed. This study explored the enhancement and detection of the ZIF-based electrochemical signals. In addition, we provided a convenient and green electrochemical technique for the simultaneous detection of Cd(II) and Pb(II). [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of poly(VAn-EGDMA) monolith with high surface area and voluminous pores. • Monolith template is homogeneously decorated with chromoionophoric IDMP molecules. • IDMP@poly(VAn-EGDMA) sensor is selective for Pb(II), Hg(II) and Cd(II) sensing. • Rapid and selective colorimetric sensing of Pb(II), Hg(II), and Cd(II) in ≤ 30 s. • 3-in-1 sensing methodology is simple, low-cost, portable, reliable and renewable. This article presents a simple, low-cost, eco-benign, and portable naked-eye solid-state sensor for the selective and sensitive colorimetric detection and recovery of ultra-trace concentrations of Pb(II), Hg(II) and Cd(II) from environmental/industrial sources. For solid-state sensing, an indigenously synthesized polymer monolith, i.e., poly(VAn-EGDMA), in-built with high surface area and interlinked meso-/macro-pore network serves as a template for the voluminous and uniform decoration of chromoionophoric probe molecules, i.e., 2-((1H-benzo[d]imidazol-2-yl)diazenyl)-4-methoxyphenol (IDMP) onto the monolith perforations via. direct immobilization technique. The structural and surface topological properties of poly(VAn-EGDMA) monolith and probe-loaded polymer, i.e., IDMP@poly(VAn-EGDMA) sensor, are characterized through FE-SEM, HR-TEM, EDAX, XPS, p-XRD, SAED, FT-IR, BET and BJH analysis. The IDMP@poly(VAn-EGDMA) sensor forms a selective/stable metal complex through visually imposing enhanced charge transfer color transitions from its original canary yellow to dark denim blue, brownish green and lapis blue for varying concentrations of Pb(II), Hg(II) and Cd(II), respectively. The sensor reusability has been tested by decomplexing the IDMP-Mn+ complex with 0.1 M HCl and repeating the sensor performance consistently for eight consecutive cycles. The IDMP@poly(VAn-EGDMA) sensor exhibits pH-dependent ion-sensing, demonstrating a wide linear response range for Pb(II) (0–200 ppb), Hg(II) (0–150 ppb), and Cd(II) (0–150 ppb), with a detection limit of 0.44, 0.56, and 0.52 ppb, respectively. The three-in-one sensor exhibits pH-dependent sequential selectivity, chemical/thermal stability, and data reliability/reproducibility, thus proving effective for on-spot sensing of various sources of contaminated samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • The co-combustion modes can improve the whole combustion performance. • The synergistic effect decreased the gas emission in co-combustion process. • Ash deposition trend depended on the evolution pattern of ash properties. • Evolution behavior and environment risk of heavy metals was evaluated. Mixed combustion of carbon-rich fraction (RC) from coal gasification fine slag and corncob char (CC) is an effective way of energy recycling. In this paper, the co-firing performance and kinetics of RC and CC were studied, and gas emission pattern, ash sintering trend and the migration and transformation behavior of heavy metals during combustion were explored. The results showed that the combustion performance was enhanced and the reaction activation energy was reduced during the blends burning. The synergistic effect between co-combustion reactions decreased emissions of gaseous pollutants. With the increasing RC compounding ratio and combustion temperature, the ash sintering tendency weakened. Cr and Ni were mostly enriched in the bottom ash, whereas Cu, Zn, As, Cd, and Pb tended to migrate to fly ash and flue gas. Cu, Zn, As, and Pb were in the form of stable fractions. Temperatures accelerated the chemical forms of Cr, Ni, Cu, Zn, and Cd being transformed into stable fractions. The environmental evaluation index suggested that the potential environmental risks of Cr, Zn, Cd, and As were relatively high. The results of this study provide guidance for the synergistic combustion disposal of double solid waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • Activated bipolar electrochemistry of biochar in porous media. • Cr conversion by B-BC-based BEC was superior to that of WO-BC and W-BC. • Soil texture affected the property of BEC, with the best Cr conversion in the sand. • There was a linear interval between Cr conversion and voltage gradient. • Biochar-based BEC rapidly changed the speciation of Cr in actual soil. Bipolar electrochemistry (BEC) refers to the redox actuation occurring at the wirelessly connected conductors, the bipolar electrodes (BPEs), but the redox behavior of biochar-based BEC in porous media remains unclear. This study evaluated the redox behavior of biochar-based BEC in porous media using the conversion rates of Cr(III) and Cr(VI). Results showed activated BEC in porous media, with bamboo biochar (B-BC) BPEs exhibiting superior redox properties compared to wood (WO-BC) and walnut biochar (W-BC). Soil texture influenced BEC performance, with sandy soils exhibiting the highest Cr conversion rates (36.22% for Cr(III) to Cr(VI) and 48.6% for Cr(VI) to Cr(III)). A linear relationship existed between Cr conversion and voltage gradient (2.2–4.2 V/cm). Excessive biochar addition (>2.5% w/w) reduced Cr conversion. Further analysis revealed exceptional electron transfer capability of B-BC and WO-BC, producing ·O 2 - and ·OH with catalytic activation and indirect oxidation potential. Overall, our findings suggest biochar-based BEC induction in porous media, facilitating rapid changes in heavy metal speciation, primarily driven by direct oxidation of biochar. Exceptional biochar behavior arises from intricate properties such as honeycomb structures, quinoid groups, phenolic-OH, and high crystallinity. Optimizing biochar's structure, functional groups, and crystallinity holds promise for effective implementation of biochar-based BEC in porous soil remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simultaneous removal of nitrate, phosphate, Cr and Pb was achieved in Fe-C CWs with variable hydraulic loadings. • High removal of heavy metals (95%) was maintained by micro-electrolysis process when hydraulic loadings were elevated. • NO 3 –-N removal rate and N 2 O emission flux decreased with increasing heavy metal loadings. Heavy metal and nitrate pollution, as a primary water quality issue in shallow groundwater, is posing a severe threat to public health from drinking groundwater. In this study, iron-carbon (Fe-C) fillers were applied in constructed wetlands (CWs) to enhance the nutrient and heavy metal removal simultaneously, while the interaction of effective nitrate reduction and heavy metals mitigation under variable influent hydraulic loadings was also investigated. Groundwater is not conducive to biological heterotrophic denitrification due to its low dissolved organic matter content. Fe-C fillers can form plentiful microscopic galvanic cells and act as inorganic electron donors to promote the autotrophic denitrification process. The results showed that Fe-C micro-electrolytic CWs showed excellent simultaneous removal of nutrients and heavy metals. The nitrate nitrogen (NO 3 –-N) removal rate was as high as 75.77% due to the increased autotrophic denitrification process, while the removal of total nitrogen (TN) and total phosphorus (TP) could reach 73.72 % and 89.04% with a low nitrous oxide (N 2 O) emission of 12.12 μg m-2h−1. Besides, the removal rates of chromium (Cr) and lead (Pb) reached 98.96% and 97.09%, respectively. However, the presence of heavy metals might inhibit denitrification by competing with nitrite for electrons and generating free radicals, which decreased the denitrification by 10.02–39.05% particularly with the increasing of the hydraulic loading. On the other hand, heavy metals promoted TP removal by forming metal phosphate precipitates and complexations with phosphorus. This study provides comprehensive insights into processes and mechanism of simultaneous nutrient and heavy metal removal in CW. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effectiveness of copolymers in treating effluents containing inorganic pollutants was assessed. • The copolymer exhibits greater adsorption affinity towards soft metals. • Copolymers adsorb mixtures of the heavy metals Cd2+, Pb2+, and Cu2+. • The inclusion of heteroatoms in the copolymer enhances its ability to adsorb metals. Copolymers based on vegetable oils and sulfur have recently been developed using the inverse vulcanization technique for water remediation. This study aimed to create a copolymer with heteroatoms, such as nitrogen, to improve adsorption efficiency and examine the competition and synergy between heavy metals in the adsorption process. FTIR, 1H NMR, solid 13C NMR, zeta potential, nitrogen adsorption, Elemental analysis, TEM, and SEM were used to characterize the copolymers synthesized. Once metal adsorption was optimized using the synthesized copolymers, a comparative adsorption study was conducted for the removal of individual heavy metals, Cd2+, Pb2+, Zn2+, Mn2+, and Cu2+ (100 mg/L), using two copolymers, S/CO:80/20 and S/CO/TAA:80/14/6. The copolymers exhibited a higher affinity for soft metals, such as Cd2+, Pb2+, and Cu2+, when they are individually and in a mixture. After 1 h, the S/CO:80/20 copolymer removed 47%, 40%, and 13% of these metals. While with the S/CO/TAA:80/14/6 copolymer removal increased to 10%, 24%, and 53%, respectively respect to S/CO:80/20 copolymer. The introduction of heteroatoms in the copolymers improved their removal efficiency, particularly for heavy metals like Pb2+. Overall, this study demonstrates a promising approach for sustainable water remediation using copolymers. [ABSTRACT FROM AUTHOR]

• [-TPE-(COOH) 4 -Al-] n with lamellar nanostructure was synthesized through strong chelate effect and π-π stacking. • The obtained [-TPE-(COOH) 4 -Al-] n LNs exhibited excellent AIECL performance. • Combining [-TPE-(COOH) 4 -Al-] n LNs and CSDA strategy with high efficiency, an ultrasensitive ECL biosensor was constructed for miRNA-141 detection. In this work, [-TPE-(COOH) 4 -Al-] n LNs with lamellar nanostructures (LNs) were conveniently synthesized through the high affinity coordination between Al3+ and carboxyl groups of 1,1,2,2-tetra(4-carboxylphenyl)ethylene (TPE-(COOH) 4). As there was a strong chelate effect and π-π stacking, the [-TPE-(COOH) 4 -Al-] n LNs could extend not only on a flat surface, but also in a spatial stack. The obtained [-TPE-(COOH) 4 -Al-] n LNs exhibited excellent aggregation-induced electrochemiluminescence (AIECL) which was much stronger than that of the TPE-(COOH) 4 monomer. Furthermore, through stacking and adjustment of Al3+, they also possessed higher electrochemiluminescence (ECL) efficiency compared to the crystal structure based on TPE-(COOH) 4 , which has a denser aggregation structure that causes aggregation-caused quenching (ACQ) phenomenon. Meanwhile, the [-TPE-(COOH) 4 -Al-] n LNs with Al3+ as the coordination center were superior to the coordination aggregation structures with heavy metal or rare metal ions as the coordination centers in terms of cost and biocompatibility. Using [-TPE-(COOH) 4 -Al-] n LNs as a luminescent material, an ultrasensitive ECL biosensor was fabricated for miRNA-141 detection combined with the cascaded strand displacement amplification (CSDA) strategy. Compared to traditional strand displacement amplification (SDA) reaction, the output DNA usually obtained in the first cycle could further return to attend multiple cycle amplification, resulting in the generation of more output DNA and an obvious signal amplification. The constructed biosensor showed excellent detection performance with a linear range from 1 × 10-18 M to 1 × 10-9 M and a detection limit of 1.2 × 10-19 M. This study provided a more convenient and effective AIECL strategy for tetraphenylethylene (TPE) derivatives and broadened the application of ECL technology in ultra-sensitive biochemical detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ZEESD avoids heavy Zn metals and addresses the dendrite problem. • Working states can be monitored by chromatic transition of the ZEESD. • The ZEESD presents excellent environment suitability at −30 °C ∼ 60 °C. • The ZEESD possesses high energy storage capacity and excellent cycle stability. Zn-ion electrochromic energy storage devices (ZEESDs) incorporate electrochromism and energy storage into one platform that can visually indicate the working status through a real-time color change, attracting considerable attention in energy-saving buildings and intelligent electronics. However, typical ZEESDs generally consist of Zn metal electrodes and normal liquid electrolytes, resulting in the dendrite issues and restricted operating temperatures as well as inferior cycle stability. Herein, an all-solid-state dendrite-free ZEESD was constructed based on polyaniline (PANI) positive electrode, monoclinic WO 3 (m -WO 3) negative electrode and Zn2+-based gel electrolyte. Benefiting from the complementary synergistic effect of electrodes and electrolytes, the resultant ZEESD avoids heavy Zn metals, addresses the dendrite formation problem, and exhibits remarkable electrochromic and electrochemical performances. The prototype ZEESD possesses high energy/power density (97 Wh kg−1/976.2 W kg−1 and 28.6 μWh cm−2/0.27 mW cm−2), large optical modulation (∼52.4%@630 nm), high coloration efficiency (96.8 cm2 C−1 at 630 nm), along with outstanding cycling stability (∼94.4% capacity retention even after 6000 cycles). Impressively, the quasi-solid-state electrolyte maintained outstanding electrochemical activity enabling the ZEESD to cycle efficiently even under hash temperatures, presenting enormous potential for intelligent electronics in all-climate (−30 °C to 60 °C) conditions. This work provides a novel strategy to construct next-generation dendrite-free Zn-ion electrochromic energy storage devices for innovative consumer electronics even in harsh environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heavy metals leaching from toxic sludge was largely restricted through pyrolysis. • Facile lanthanum loading rendered derived biochar with robust phosphate capacity. • Combined method to analyze differentiated effects of coexisting species on adsorption. • Inner-sphere complexation triggered by electrostatic attraction was main mechanism. Phosphorus control and the disposal of municipal solid waste have drawn increasing concerns. Herein, we reported the reutilization and functionalization of highly toxic waste sludge derived from landfill leachate treatment process for biochar preparation and therefore phosphate elimination from aqueous media. Toxicity analysis confirmed largely declined heavy metal leaching and diminished ecological risks during biochar pyrolysis, providing a feasible option for the disposal and reutilization of toxic waste. Pre-loading of lanthanum rendered fabricated biochar with robust phosphate adsorption capacity, with optimized composite achieving maximum capacity of ∼94.4 mg P/g at pH 6. Effects of environmental factors, especially co-existing species (anions, cations and dissolved organic matters), were systematically evaluated combining experimental results and characterization analysis. Thereafter, adsorption behaviors of synthesized samples including kinetic, isotherm and thermodynamics were comprehensively explored. In virtue of characterization analysis, physicochemical properties of different composites and phosphate separation mechanism that involved electrostatic attraction and inner-sphere complexation were fully probed. Overall work investigated the feasibility of toxicity reduction via pyrolysis, phosphate uptake performance and inner mechanism, therefore highlighting the potential of waste reutilization for environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Culture pH have strong influence on cell surface properties and metal ion adsorption capacity. • –COOH, likely functional group for heavy metal removal, most abundant on cell surface at culture pH 9.5. • Monolayer biosorption confirmed by the rapid kinetics and Sips isotherm. • Linear increase of adsorption capacity with impact factor of metal ions confirmed. • Two valence metal has larger inhibition on biosorption capacity than single valence metal. Microalgal biomass has been established as a promising biosorbent for heavy metal ion (HMI) removal from contaminated waters. In this study, the cell surface properties of green alga Neochloris oleoabundans grown at different culture pH, i.e., 7.5, 8.5, and 9.5, which are referred to as B-7.5, B-8.5, and B-9.5, respectively, were investigated. The biosorption of three HMIs, i.e., Pb(II), Cd(II) and Zn(II), were studied systematically by these three types of biomasses. The results of isothermal analysis indicate that the biosorption was monolayer surface adsorption. Based on the Sips model, which best fits the experimental data among the three tested isotherm models, the biosorption capacities of all the three tested HMI on different biomasses followed the order B-9.5 > B-8.5 > B-7.5. The algal biomass obtained at culture pH 9.5, i.e., B-9.5, exhibited the highest biosorption capacities of Pb(II), Cd(II), and Zn(II) at biosorption pH 6.0, which were 100.01, 43.92, and 32.43 mg/g, respectively, corresponding to 3.0, 3.3, and 2.3 folds of that exhibited by B-7.5. FTIR, SEM, EDS and XPS were employed for characterization of cell surface. The XPS analysis revealed higher content of carboxyl (COOH) group on the B-9.5 cell surface than B-7.5 and B-8.5, which might be responsible for the much higher biosorption capacity of HMI by B-9.5. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acid pretreatment removed or passivated AAEMs in Pteris vittate L. (PV). • HCl-pretreated PV lost and leached more As, U, Pb, Mn, and Zn. • H 3 PO 4 -pretreated PV retained As, Cd, and Pb with low leaching concentration. • TGA-IST-FTIR-GC/MS system revealed emission, composition, relative yields, and volatiles. • Operational settings were jointly optimized via artificial intelligence. Not only should post-harvest hyperaccumulators rich in heavy metals (HMs) be properly disposed to avoid secondary HMs pollution, but also they should be valorized to enhance circular economy. This study aimed to characterize how As-hyperaccumulator (Pteris vittate L.) (PV) pretreated with HCl or H 3 PO 4 affected its physicochemical, HMs, decomposition, and volatile characteristics. The HCl-pretreated PV retained its original main components, physical properties, and chemical structures but introduced Cl to carbon chain, induced O loss, increased C content, and removed most minerals, in particular, alkali/alkaline earth metals. The favorable pyrolysis and gasification behaviors of PV were maintained via the HCl-pretreated PV, with the raised and narrowed temperature range of mass loss but with the increased energy demand for the decomposition. Compared with PV (276.74 kJ/mol), 5% HCl-pretreated PV reduced activation energy of its pyrolysis (260.62 kJ/mol). The H 3 PO 4 pretreatment destroyed carbon chain, loaded phosphorus oxygen group, and removed more organics and minerals in PV than did the HCl-pretreated PV. This in turn allowed for an earlier start and finish of devolatilization stage, an easier breaking of potential energy barrier, and improvement of reaction favorability. Unlike the two atmospheres, the acid pretreatments changed the temperature dependency of volatile products during the main reaction-temperature range. The volatile products which released from the pyrolysis and gasification at the temperature of maximum mass loss peak or 350 °C were collected. HCl-pretreated PV reduced the formation of ring-opening products, while H 3 PO 4 -pretreated PV emitted more aromatic compounds and selectively generated ketone, such as levoglucanone. More HMs were dissolved with the increased acid concentration, with HMs in HCl-pretreated PV being at a higher leaching concentration than those in the other treatments. H 3 PO 4 -pretreated PV retained As, Cd, and Pb at a low leachable rate. The best joint optimization was achieved with the combined settings of 5% HCl-pretreated PV or 10% H 3 PO 4 -pretreated PV at 10 °C/min in the N 2 atmosphere. Overall, findings provide new insights into how to best manage and valorize post-harvest and HM-laden hyperaccumulators. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multistep resource recovery of valuable metals from electroplating sludge. • Elimination of all the heavy metals by resources recovery. • Selective precipitation and hydroxide transformation of chromium. • Reagents of Na 3 PO 4 ·nH 2 O and NaOH were circulated in the recovery process of chromium. The recovery of chromium (III) is a key step for complete recycling of heavy metals from electroplating sludge. Therefore, thermodynamic equilibrium diagrams of Me - P O 4 3 - - H 2 O [Me: Cr (III), Zn (II), Cu (II), Fe (II), Fe (III), Ni (II)] systems at 298 K have been established, the thermodynamic analysis for the precipitation of chromium (III) using phosphates and the conversion of CrPO 4 to Cr(OH) 3 using caustic soda were conducted. The results showed that phosphate seemed preferentially combined with Cr (III) rather than other metal cations in order of Cr (III) > Fe (III) > Fe (II) > Zn (II) at the pH range of 1.0 ∼ 5.0. The verification experiment results indicated that about 94.1% Cr (III), 5.51 %Fe (II), and 0.33% Zn (II) reached were precipitated by adding 110% theoretical amount of Na 3 PO 4 ·12H 2 O at equilibrium pH equal to 2.0. As consistent with the thermodynamic analysis, alkali conversion of CrPO 4 with NaOH achieved a leaching efficiencies of Cr (III) and phosphorus were 5.1% and 90.6%, which realized phosphate recycling and the recovery of leached Cr (III). 99.7% Zn was deeply separated and recovered from Fe (II/III) by D2EHPA by two stages of counter current extraction with an O/A ratio of 1:2, 5 min stirring at 20 °C. And the optimal conditions for Zn stripping were considered as mixing 1 mol/L H 2 SO 4 and loaded D2EHPA with O/A ratio of 5:1 at room temperature for 5 min. The proposed process shows a promising industrial application in view of its low cost, complete recycling, and wide adaptability. Electroplating sludge will cause serious pollution to the environment if not properly treated. This study reports a new treatment method of electroplating sludge to achieve comprehensive recovery of all valuable metals. Compared with traditional process, this process exhibits a promising industrial application due to its no emissions, lower cost, complete reagent cycle, purer product, higher quality, broader adaptability, and greener production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Review the advanced thermal separation methods for heavy metals in MSWI fly ash. • Chlorination of heavy metals by NaCl/KCl requires excitation of Si-Al matrix. • Chlorides make heavy metals more volatile, but molten salts system does not. • XAFS is beneficial for exploring the thermal separation mechanism of heavy metals. • Recovery of heavy metals has good social benefits but poor economic benefits. Municipal solid waste incineration (MSWI) fly ash is categorized as a hazardous waste owing to the presence of heavy metals. The thermal separation of heavy metals from MSWI fly ash has the potential to not only purify the fly ash, but also enable the recovery of heavy metals. The main thermal separation methods include calcination thermal separation (700-1200℃), chlorination thermal separation (700-1000℃), reduction thermal separation (700-1000℃) and molten salts thermal separation (600-800℃). This paper presents a comprehensive review of these four thermal separation methods, comparing them in terms of separation effectiveness, economic feasibility, technical maturity, and environmental impact, etc. Additionally, the possibility of urban mining from MSWI fly ash was evaluated, and the results indicated that while it may be less cost-effective, it could bring significant environmental and social benefits. Finally, the limitations of the existing thermal separation methods and the focus of further research, including both mechanisms and experimental investigations were outlined. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ball milling of ZVS in Cu sulfate solution to induce reduction reaction. • Milling time and Si to Cu molar ratio playing as key factors. • Formation of Cu 2 O by the reduction to allow Cu removal from even acidic solution. • Selective separation of Cu from other heavy metals as Zn, Mn, Ni, Cd etc. to allow Cu enrichment for recycling. It is always a challenge to deal with industrial wastewater containing heavy metals. Selective removal and recovery of valuable metals such as copper particularly from acidic solutions are very important from both stances of resource supplying and environmental purification. Among all the divalent heavy metals, copper has the potential of being reduced to monovalent state. A new approach was proposed to ball mill zero-valent silicon (ZVS) in CuSO 4 solution and the solutions containing multi-metal ions to serve the purpose. In this study, both quantitative and qualitative data were reported on the induced mechanochemical reduction reaction to convert Cu2+ into Cu 2 O by ball milling with ZVS. Experimental parameters such as milling time and Si to Cu ratio were found to play important role in stimulating the reaction, and as a result, 97.32% Cu2+ was removed from the solution under Si/Cu molar ratio of 100. Even at a high concentration of sulfuric acid up to 4.6 mol/L, the copper removal percentage maintained a high value of 82.57%. Furthermore, in the sulfate solutions containing several other heavy metals of Zn, Mn, Ni, Cd, Co, Fe etc., the reduction reaction by zero-valent silicon occurred only on Cu2+ with other heavy metal ions remaining in the solutions. The feasibility of this technology has been verified by treating a leaching solution of NiS mineral, from which copper has been removed selectively from nickel, iron etc. This research may serve another purpose for applying waste silicon from the solar energy devices after lifetime in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanochemical reaction occurred between POPs-HMs in soil and NCC occurred. • More than 86% POPs and 98% HMs were degraded/solidified by mechanochemical reaction. • C-O bond of BDE209 is preferentially broken under mechanochemical action. • Mechanochemical technique is promising for POPs-HMs co-contaminated soil remediation. Mechanochemical method was proposed for the remediation of soil contaminated with heavy metals (HMs, Cu, Pb, and Cd) and persistent organic pollutants (POPs, PBDEs and PCBs) through ball milling with nanoscale Zero-valent Iron (nZVI)-CaO-Ca 3 (PO 4) 2 (NCC). The mechanical energy supplied by ball milling and NCC considerably enhanced the stabilization of HMs (Cu 99.22%, Pb 100.00%, and Cd 98.42%) as well as the efficiency of POP degradation (BDE209 99.57%, PCB3 94.55%, PCB4 94.07%, PCB5 86.96%). Upon an increase in the rotation speed from 0 to 650 rpm, the weak acid extractable fraction (F1) of Cu, Pb, and Cd gradually transformed into relatively stable (F2 + F3) and residual forms (F4) and gradually reached a steady state. Moreover, under the influence of SiO 2 and excited-state PO 4 3- in the soil, HMs also transformed from their originally mobile form to other stable forms. The C-O and C-Br bonds of BDE209 were cleaved during mechano-chemical reactions, yielding perbromobenzene, 2,3,4,5,6-pentabromophenol, and other low-brominated phenols such as 1,2,3,4,5-pentabromo-6-(2,3-dibromophenoxy)benzene. The C-Cl bonds of PCBs underwent selective cleavage, resulting in the formation of low-chlorinated biphenyls and hydrocarbons. Furthermore, the stability of C-Cl bonds increased with a higher number of chlorine atoms in PCBs, making them more difficult to degrade. This study offers an environmentally friendly and highly effective remediation approach for POPs-HMs contaminated soil. [ABSTRACT FROM AUTHOR]

[Display omitted] • AMD catalyzed red mud transformation into an effective adsorbent. • Sb(V), As(V), and Pb(II) removal capacities were 1638, 109 and 519 mg/g respectively. • Ca-bearing phases and Fe-(hydr)oxides played key roles in Sb and As immobilization. • A silicate gel that coats the Sb precipitates ensures their high stability at low pH. • Convertible sulfates play the dominant role in Pb(II) removal via formation of PbSO 4. Antimony (Sb), arsenic (As), and lead (Pb) are toxic metal(loid)s that can cause serious environmental pollution. The above emphasizes the need for a development of efficient technologies for metal(loid) removal, especially from low-pH environments due to the increased mobility of the contaminants under acidic conditions. Herein, for the first time, removal of Sb(V/III), As(V/III), and Pb(II) from acidic waters is described, using low-cost adsorbents synthesized from red mud (RM; a solid waste from the alumina industry) under the catalysis by acid mine drainage (AMD; acidic effluents from mines). The reactions between RM and AMD were studied to describe Fe/S/Ca/Al/Si speciation transformations during the adsorbent formation. In addition, Sb/As/Pb adsorption behavior and the relationship between adsorbent properties and Sb/As/Pb removal efficiencies were investigated. The maximum removal capacities for Sb(V), Sb(III), As(V), As(III), and Pb(II) reaching 1,637.8, 80.2, 109.2, 16.4, and 518.7 mg/g, respectively. The primarily Ca2+ from the Ca-bearing compounds (determined in RA2, synthesized under S RM /L AMD 2:1) contributed to Sb(V) removal (via precipitation of CaSb 2 O 5 (OH) 2 and formation of Sb-bearing precipitate, with silicate gel nanospheres securing high stability of the immobilized Sb). In the As immobilization process, Fe(III) (hydr)oxides (formed in RA4, synthesized under S RM /L AMD 4:1) such as goethite (α-FeOOH) and bernalite (Fe(OH) 3) played a dominant role. Convertible sulfates (e.g., CaSO 4 and Al 2 (SO 4) 3) in RA10 (synthesized under S RM /L AMD 10:1) ensured a high removal capacity for Pb(II) across a wide pH range (2 to 7) via PbSO 4 precipitation. In contrast, the formation of PbCO 3 and Pb 3 (CO 3) 2 (OH) 2 was the main mechanism for Pb(II) removal by unamended RM at pH 5.0, while no contaminant removal capacity was observed at pH 2.0. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hydrothermal assisted PMS activation strategy was proposed to produce HMF and FF. • Heavy metals in the biomass serve as PMS activators and Lewis acid catalysts. • The increase of metal contents in contaminated biomass promotes the final yields. • Valorization of contaminated biomass is sustainable and promising. Sustainable disposal of heavy metal contaminated biomass has always been a challenging task. Here, a strategy was proposed for directly producing valuable 5-hydroxymethylfurfural (HMF) and furfural (FF) from contaminated biomass through hydrothermal-assisted persulfate activation strategy. The optimal yields were obtained at 18.6 and 22.5 wt% for HMF and FF, respectively. The hydrothermal process promoted the release of Fe, Mn, Cu, Zn, and Cr from biomass into the liquid phase and then activated peroxymonosulfate (PMS) to destroy the lignocellulose structure and increase the accessible of cellulose and hemicellulose. Meanwhile, the metal and acidic environment provided by the reaction system act as natural catalysts to synergistically promote the production of HMF and FF. The controlled experiments revealed that Fe, Mn, Zn, and Cr played a major role in biomass conversion during this process. Moreover, possible reaction mechanisms and pathways were explored through quenching tests and density functional theory calculations. This study provides a simple pretreatment and promising valorization strategy for the sustainable utilization of heavy metal-contaminated biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • A viable strategy to fully convert solid wastes to photocatalysts (HSFSs). • Nearly 100% Cr was extracted from wastes during the preparation process of HSFSs. • HSFSs possessed rich microporous surface and rich effective metal coordination sites. • HSFSs effectively degraded high-concentration tetracycline (100 mg/L). The utilization of large-volume nickel–iron slags is largely limited by the existence of heavy metal chromium, resulting in a sharply increase environment problem. Here we report a viable strategy to fully convert nickel–iron slags into self-assembled flower-like silicate photocatalysts. Intriguingly, these decent 3D hierarchical architectures made from wild wastes are composed of core–shell structured silicates. In the meanwhile, nearly 100% chromium is extracted from the slags. Due to the high specific surface area and effective metal coordination sites (i.e., Na+, Mg2+ and Ca2+), the as-obtained silicate catalysts exhibit the extraordinary photocatalytic degradation rate (81.7 %) and the mineralization rate (27 %) of high-concentration tetracycline (100 mg/L) after 30-min Xe lamp irradiation, which are higher than those in most previous reports in terms of degradation and mineralization rates of the high-concentration tetracycline. This simple yet robust strategy to craft 3D self-assembled hierarchical flower-like silicate photocatalysts pave a novel way to the large-scale and value-added consumption of waste residues. [ABSTRACT FROM AUTHOR]