Search

The widespread of antibiotics has resulted in potential threats to the aquatic environment and human health. The visible light-assisted peroxymonosulfate (PMS) activation method is considered to be an effective way to remove antibiotics in wastewater. In this study, Mn/Fe bimetal doped graphitic carbon nitride (MnFe-CN-x) was first synthesized for PMS activation under visible light towards tetracycline (TC) removal. The optimized MnFe-CN-50 possessed the excellent photocatalytic activity, PMS activation performance and photo-Fenton-like synergistic effect. In the photo-Fenton-like system, TC (20 mg L−1) was degraded by 99 % in 50 min and the kinetic constant was 0.074 min−1. The high dispersion of Mn and Fe in carbon nitride inhibited the recombination of charge carriers in MnFe-CN-x, increased its photocurrent density and charge mobility, effectively optimized the electronic structure, and promoted the generation of 1O 2. Based on the analytical results of predictive toxicity evaluation software (TEST), it was confirmed that MnFe-CN-x could effectively reduce the environmental risks associated with antibiotic contamination. This study provided new insights into synthesizing bimetal-doped graphitic carbon nitride and the use of synergistic effects of photocatalysis and PMS activation to remove organic pollutants from wastewater. [Display omitted] • Mn/Fe bimetal-doped carbon nitride catalysts was designed and synthesized. • MnFe-CN-50 has high activity as photocatalyst and PMS activator for TC removal. • The effects of various operational parameters and water matrices were studied. • 1O 2 were generated via photogenerated charges activation of PMS. [ABSTRACT FROM AUTHOR]

N and S co-doped porous carbon was prepared by decorating the waste disposable medical masks (WDMM) with thioacetamide (TAA) as the N/S source and then carbonizing at high temperature, which was subsequently incorporated Co-doped LaFeO 3 to obtain NSC@LaFe x Co 1-x O 3 catalysts. The resulting catalysts were used to construct an advanced oxidation process (AOP) based on activation of peroxymonosulfate (PMS) to degrade tetracycline (TC) in water. The physicochemical properties of the as-obtained catalysts were characterized and environmental factors affecting the catalytic performances of NSC@LaFe x Co 1-x O 3 /PMS were systematically investigated. The results showed that N and S co-doped porous carbon derived from thioacetamide (TAA)-functionalized WDMM at high temperature could be used as good support for LaFe x Co 1-x O 3. The synergistic effects between N/S co-doped carbon and polyvalent metals (Co2+/Co3+ and Fe3+/Fe2+) endowed NSC@LaFe x Co 1-x O 3 with enhanced catalytic performances, in which nearly 100% of TC could be removed by NSC@LaFe 0.95 Co 0.05 O 3 /PMS system within 10 min under the conditions of 0.2 g/L of catalyst dose, 2.5 mmol/L of PMS concentration and 10 mg/L of initial TC concentration. Furthermore, the constructed NSC@LaFe 0.95 Co 0.05 O 3 /PMS system exhibited a wider pH adaptability (3.0 ∼ 10.0), good salt resistance and reusability as well as high mineralization. The mechanisms and possible pathways of TC degradation by NSC@LaFe 0.95 Co 0.05 O 3 /PMS system were proposed and the ecotoxicity of TC and its intermediates was also evaluated. This study demonstrated the feasible transformation of waste masks into porous carbon with high added value for water pollution control and remediation, accomplishing the dual purposes of recycling and resource utilization of waste masks and protecting the environment. [Display omitted] • Porous carbon derived from waste disposable medical masks as a carrier for LaFe 0.95 Co 0.05 O 3. • NSC@LaFe 0.95 Co 0.05 O 3 exhibited strong catalytic performances and structural stability. • NSC@LaFe 0.95 Co 0.05 O 3 /PMS with a removal rate of near 100 % in 10 min under optimal conditions. • NSC and polyvalent metals synergistically catalyze PMS to mineralize TC with high efficiency. • Turning waste masks from "waste" into "treasure", and then treating "waste" with "waste". [ABSTRACT FROM AUTHOR]

Cyanide is widely used in electroplating processes to ensure the quality of metal plating. Alkaline chlorination process is commonly employed to remove cyanide from electroplating wastewater. However, several drawbacks exist, including the formation of toxic intermediates, high consumption of chemical reagents, and low removal efficiency of metal-cyanide complexes. In this study, persulfate advanced oxidation process was explored for the removal of cyanide from electroplating wastewater. The metal ions typically present in the electroplating wastewater, including Cu2+, Zn2+, Fe2+, Ag+ and Ni2+, may activate peroxydisulfate (PDS) to oxidize cyanide. Among these metal ions, cyanide can be most effectively removed in the presence of Cu2+ and PDS, likely due to the activation of PDS by Cu2+ and Cu(II)-cyanide complex. The results of lab studies indicated that 99 % removal of cyanide (4 mM) could be achieved in the presence of 10 mM PDS and 1 mM Cu2+ within 20 min. The results of radical scavenging experiments, radical probe tests and electron paramagnetic resonance (EPR) studies showed that sulfate radical (SO 4 •−) and hydroxyl radical (OH•) were primarily responsible for cyanide removal and the complexation of cyanide and Cu2+ significantly enhanced the formation of SO 4 •−. Cyanate and nitrite were the main by-products detected. For real electroplating wastewater, the addition of 40 mM PDS could almost completely remove cyanide (19.5 mM) in 20 min. [Display omitted] • Cyanide can be efficiently removed from electroplating wastewater by direct addition of PDS. • Cu2+ and Cu(II)-cyanide complex are important activators. • Cyanate and nitrite are the main by-products. • The reaction stoichiometric efficiency for most efficient cyanide removal was 65 %. • Effective removal of cyanide in real electroplating wastewater was demonstrated. [ABSTRACT FROM AUTHOR]

This study evaluates the effectiveness of coupling solar photo-Fenton (SPF) with granular activated carbon (GAC) filtration to remove three selected micropollutants (benzotriazole, carbamazepine and diclofenac) from municipal wastewater treatment plant (WWTP) effluent. SPF was first studied stand-alone at natural pH with simulated and real irradiation in raceway pond reactors (RPR) in different water matrices. The scenario with the poorest removal was the use of real WWTP effluent as water matrix; the removal achieved was 25 % of benzotriazole, 57 % of carbamazepine and up to 80 % of diclofenac (6 mg L−1 of iron, 40 mg L−1 of H 2 O 2 , 15 cm depth, 0.49 kJ L−1). In the second phase, fresh and regenerated GAC were studied in different water matrices, showing that the complex matrices had a higher influence on the regenerated GAC. Thus, the breakthrough of regenerated GAC was achieved quicker than fresh GAC. The aim of the work was to extend the GAC lifetime by a pre-oxidation process; thus, SPF was applied for 5 minutes (0.05–0.08 kJ L−1) as a first step. GAC lifetime was extended between 2 and 12 times thanks to the pre-treatment by SPF, equaling the lifetime of the regenerated GAC to the fresh one in the more complex matrix. [Display omitted] • A pre-oxidation step with SPF can improve performance and applicability of GAC. • The role of chelating agent molar ratio is dominant if compared to iron dosage. • Regenerated GAC is more vulnerable to water matrix composition. • When combined to SPF, regenerated GAC lifetime is similar to the fresh one. • 5 minutes of SPF as pre-step can increase up to 12 times the GAC lifetime. [ABSTRACT FROM AUTHOR]

Hypochlorite mediated oxidation had been established as an efficient process for degrading organic pollutants in water. In this research work, it was evaluated the synergistic potential of solar light irradiation combined with hypochlorite on a emerging contaminant model such as Nimesulide (NIM), a nonsteroidal anti-inflammatory drug. These experiments shown that at pH 3.0, where only hypochlorous acid (HOCl) prevails, the degradation constant of NIM exhibited an increase from 2.50 × 10−4 s−1 (under dark conditions) to 1.53 × 10−3 s−1 (sun-simulated radiation), signifying an approximately six-fold acceleration in degradation. Moreover, under approximately neutral pH value (7.5) wherein both HOCl and hypochlorite ion (ClO−) coexist, the enhancement observed was approximately twofold, in particular a mineralization up to 32 % was observed. This investigation also included quenching experiments conducted at varying pH levels, shedding light on the role of specific reactive species and their contributions to the degradation mechanism. The impact of synergistic effect between solar-simulated irradiation and hypochlorite systems on NIM degradation showcases a remarkable kinetic enhancement, particularly evident at lower pH values. The degradation byproducts have been identified via high resolution HPLC-MS and the main ion formed during the reaction have been monitored by IC-MS. Experiments in real sewage treatment plant waters using sun radiation revealed the promising potential and efficiency of this alternative method, despite a comparatively lower degradation rates when compared with UV lamp application. This approach offers a sustainable and economically advantageous solution for wastewater treatment. [Display omitted] • Sun-simulated radiation was used to activate free active chlorine in water. • Photogeneration of reactive oxygen and chlorine species was determined using competition kinetic approach. • Efficient degradation of Nimesulide was provided in real sewage treatment plant water. • Sun-simulated irradiation modifies the chlorinated products formation. [ABSTRACT FROM AUTHOR]

Tartaric acid (TA) as an organic assistant was investigated to degrade sarafloxacin (SARA) in an advanced oxidation process (AOP) with CuO catalyst. The promotional effect of TA is to activate H 2 O 2 decomposition to •OH and HO 2 •/O 2 •- by accelerating the Cu(II)/Cu(I) redox cycle on the CuO surface while inhibiting 1O 2 generation. TA could increase the conversion percentage of H 2 O 2 to •OH from 18.47 % to 46.23 % and decrease the conversion percentage of H 2 O 2 to O 2 from 71.98 % to 45.64 % on CuO in 60 min. In addition, TA was further demonstrated to coordinate with the surface Cu(II) by forming Cu(II)-TA, which leads to an acidic environment and exposing more Cu active sites on the surface and releasing Cu2+ into aqueous solution, thus boosts the AOP. Adding TA into the reaction system not only improves the heterogeneous Fenton-like process (HFLP) but also promotes homogeneous Fenton-like process. In the SARA/TA/CuO/H 2 O 2 system, •OH, HO 2 •/O 2 •- and 1O 2 are the primary oxide species for SARA degradation. Plausible mechanisms for the degradation of TA and SARA were proposed as well. [Display omitted] • TA greatly enhanced sarafloxacin degradation. • TA promoting H 2 O 2 decomposition to •OH and inhibiting 1O 2 generation. • Cu(II)-TA leads to an acidic environment and exposing more Cu active sites on surface. • TA not only improves heterogeneous Fenton-like process but also promotes homogeneous Fenton-like process. • The conversion efficiency of H 2 O 2 to •OH and O 2 on CuO was quantified. [ABSTRACT FROM AUTHOR]

In this study, non-targeted analysis revealed that the Fe2+/perodisulfate/Cl- system degraded aniline (AN) and nitrobenzene (NB), yielding 7 types and 4 types of aromatic chlorides, respectively. In order to explore their chlorination mechanism and the influence of different functional groups, various reactions (radical adduct formation (RAF), hydrogen atom abstraction (HAA) and single electron transfer (SET)) of benzene series with various functional group with sulfate radical (SO 4 ·-), hydroxyl radical (·OH), chlorine radical (·Cl) and dichloride anion radicals (Cl 2 ·-) were explored by Gibbs free energy (ΔG), and the subsequent reactions of SET and HAA products (organic free radical) were innovatively explored by ΔG. This study revealed that the reaction between benzene compounds containing electron-donating groups and ·Cl was dominated by HAA rather than RAF; the reaction between benzene compounds containing electron-withdrawing groups and ·Cl was dominated by RAF. Aromatic compounds containing electron-donating groups can undergo SET reaction and generate aromatic chlorides in the presence of O 2 and Cl-. Combined with the product analysis, it was found that the HAA reaction of aromatic compounds will lead to the obvious formation of biphenyl compounds and aromatic chlorides in the presence of Cl-. Compared with the conditions of RAF of ·Cl and chlorination of SET products, the chlorination reaction between HAA products and Cl- is ubiquitous, which is more likely to be the key to the formation of aromatic chlorides in mixed systems. This study provides a theoretical basis for further study on the formation risk of chlorinated products in advanced oxidation process. [Display omitted] • Both AN and NB produced aromatic chlorides in the Fe2+/PDS/Cl- system. • The main reaction between benzene series with electron-withdrawing groups and ·Cl is RAF. • The ΔG of the subsequent reaction of SET products and HAA products was calculated. • SET products of aromatic compounds can be chlorinated under the action of O 2 and Cl-. • HAA products and Cl- are the key to the formation of aromatic chloride. [ABSTRACT FROM AUTHOR]

The utilization of peracetic acid (PAA) as an oxidant in advanced oxidation processes (AOPs), known as PAA-based AOPs, has garnered significant attention in the field of water treatment due to its minimal toxicity. This review comprehensively presents the advancements in research on various methods for activating PAA, including metal catalysts, non-metallic catalysts, external energy input and natural anions. Thorough examination was conducted on the impacts of operational parameters such as pH value and PAA concentration on both the reaction system and pollutant conversion process. Furthermore, the key issues such as the change of PAA/H 2 O 2 concentration, the types of active substances and their contribution rates, as well as relatively accurate catalytic mechanism are discussed in detail. Given the crucial role played by organic free radicals in degrading emerging pollutants within PAA-based AOPs systems, our focus was directed towards identifying specific organic radicals generated within the PAA system. Finally, we comprehensively analyze challenges and difficulties encountered in current research on PAA-based AOPs systems along with potential avenues for future investigation. [Display omitted] • PAA-based AOPs can effectively remove emerging pollutants in water. • The current PAA-based AOPs system is mainly metal-catalyzed. • Unique to the PAA system is the production of organic free radicals. • Challenges and future directions of PAA-based AOPs are proposed. [ABSTRACT FROM AUTHOR]

In this work, Cu-Fe bimetal-embedded carbonaceous CuFe@C materials were prepared by high-temperature pyrolysis of CuFe-MOFs precursors synthesized through a facile two-step feeding approach. Through adjusting the reaction time of each feeding step, CuFe-MOFs of uniform dispersed crystals with controlled sizes were obtained. The carbonized composites were then applied to activate persulfate (PMS) for Reactive Brilliant Red X-3B (RBRX-3B) degradation in water. The removal rate of RBRX-3B was up to 98% in 40 min in the CuFe@C 600 /PMS system, indicating that the CuFe@C 600 catalyst showed excellent sulfate radical-based oxidation (SR-AO) activity in the degradation process. The effects of PMS dosage, initial pH, RBRX-3B concentration on the degradation efficiency were investigated in detail. Based on quenching experiments, a possible mechanism for the CuFe@C 600 /PMS system was proposed. The catalyst had good reusability, in which the removal rate of RBRX-3B could attain 82% after 5 times of repeated recycling. It also showed satisfactory removal effect on other organic pollutants, i.e. Congo red, Methyl orange, Reactive blue and p-nitrophenol. This study provided a valuable strategy for the treatment of wastewater containing organic pollutants using MOFs-derived materials. • CuFe-MOF crystals with controlled sizes were obtained by two-step synthesis method. • The carbonized composite CuFe@C 600 was fabricated by high-temperature pyrolysis. • CuFe@C 600 /PMS degraded 98% of Reactive Brilliant Red X-3B in 40 minutes. • It showed effective degradation on Congo red, Methyl orange, Reactive blue et al. • The CuFe@C 600 catalyst had satisfactory stability and reusability. [ABSTRACT FROM AUTHOR]

Transition metals as activators of peroxymonosulfate (PMS) are effective catalysts for the degradation of organic pollutants. The construction of multiple active sites is the key for enhanced PMS activation. Herein, we prepared ZIF-8 derived Fe- Ni nitrogen-carbon with highly dispersed bimetallic active sites, achieving a small amount of highly efficient catalytic performance for tetracycline (TC) degradation. The Fe and Ni elements in the catalyst were uniformly dispersed, resulting in a high specific surface area of 367 m2/g. Even at low metal concentrations (Fe=0.83%, Ni=0.33%), Fe-Ni-N-C/PMS showed superior performance in degrading total carbon TC. Its reaction rate constant was 1.71 times higher than Fe-N-C/PMS and 2.13 times higher than Ni-N-C/PMS. This significant improvement was attributed to the synergistic effect of the bimetallic components and the highly dispersed active sites. The mechanism was proposed that Fe-Ni-N-C activates PMS to generate hydroxyl radicals ( • OH), sulfate radicals (SO 4 •− ), superoxide radicals (O 2 •−), and singlet oxygen (1O 2) to further degrade TC. Among them, 1O 2 and SO 4 •−were the main reactive oxygen species. This work has provided a new insight into the development of transition metals with multiple active sites for the degradation of organic pollutants. [Display omitted] • A highly dispersed MOF derivative Fe-Ni-N-C was prepared. • The Fe-Ni-N-C had a large number of exposed active sites. • The dispersed bimetallic active sites in Fe-Ni-N-C efficiently activated PMS. • Fe-Ni-N-C/PMS generated a large amount of free radicals, efficiently degrading TC pollution in water. [ABSTRACT FROM AUTHOR]

Currently, ciprofloxacin (CIP) in water environments has attracted wide attention. In order to degrade CIP by electrocatalysis, it is very important to develop catalysts with high catalytic activity as particle electrodes. In this study, Jacaranda shell was made into biochar (BC) by calcination, Ce and Cu modified BC (Ce-Cu/BC) was prepared by a simple impregnation and calcination method as a particle electrode in a three-dimensional electro-Fenton (3D/EF) system to degrade CIP. Characterization of the Ce-Cu/BC particle electrodes was conducted using SEM, XRD, and XPS, revealing the porous structure of the calcined jacaranda shell base, confirming successful loading of Ce and Cu. Optimal operating conditions for CIP removal were determined to be 4 g/100 mL particle electrodes dosage, initial pH of 5, 8 V voltage, and 2 mM Fe2+ concentration, resulting in a maximum CIP removal rate of 84.97% with an energy consumption of 1.32 W•h. Stability tests demonstrated the robustness of Ce-Cu/BC, while comparative tests and radical extinction experiments highlighted the high electrocatalytic activity of the 3D/EF system, primarily attributed to the indirect oxidation of •OH, an active substance generated within the system LC-MS and UV full-band scanning analyses were employed to propose potential CIP degradation pathways. [Display omitted] • Ce-Cu doped activated carbon was synthesized as a particle electrode for the three-dimensional electro-Fenton system. • Rare use of Jacaranda shell, considered green waste, as biochar (BC). • Biochar doped with Ce and Cu could achieve 90% CIP removal in 30 min in a 3D/EF system. • Identification of intermediates generated by CIP degradation and ecotoxicity assessment of the intermediates. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS) based advanced oxidation process (AOP) is used for the degradation of the organic molecules due to ease of reactive oxygen species (ROS) generation through activation. In this study, bimetallic FeCo nanoparticles (NPs) supported on N-doped porous carbons are prepared for the first time by in-situ co-precipitation of metal ions in ZIF-67 followed by carbonization. The prepared nanocomposite, denoted as Fe(x)Co@N-CZ-67, is used to activate PMS for Fenton-like degradations of tetracycline (TC) and dyes. The results reveal that about 96% of TC is degraded by Fe(0.4)Co@N-CZ-67 in 4 min. The catalyst can also degrade three organic dyes, namely methylene blue, neutral red and methyl orange with outstanding reaction rates of 1.75, 1.80 and 2.62 min−1, respectively. The excellent catalytic activities of the catalysts can be ascribed to the synergistic effects between Fe and Co that enhance the electron transfer rate, uniform dispersion of NPs, presence of N in support, and generation of surface PMS complexes with high oxidation activity. Based on the quench experiments, SO 4 •–, •OH, O 2 •− and 1O 2 are determined to be the ROS responsible for degradations organic molecules. Fe(x)Co@N-CZ-67 shows excellent catalytic activity over ten consecutive cycles with negligible metal leaching and remarkable structural stability. [Display omitted] • Synthesis of bimetallic FeCo nanoparticles embedded N rich porous carbon (Fe(x)Co@N-CZ-67). • Fe(x)Co@N-CZ-67 is used as catalyst to degrade tetracycline (TC) and dyes by AOPs. • The catalyst activated peroxymonosulfate (PMS) and generated reactive oxygen species. • The catalyst could rapidly degrade TC and toxic dyes to low molecular weight compounds. • Excellent activity is due to synergistic effect of Fe and Co, and porous support. [ABSTRACT FROM AUTHOR]

The significant accumulation of quinclorac in soil and its transport within the environment have grave implications for the growth and development of flora and fauna in natural ecosystems. This study marks the first instance of employing FeS 2 loaded on biochar to activate PMS for direct degradation of QNC in soil. Experimental results show that the FeS 2 @BC/PMS system successfully removed 90.77% of QNC from contaminated soil after 6 h of reaction at 2 g/L FeS 2 @BC, 4 mM PMS, and 30 mg/kg QNC-polluted soil. The distribution of QNC in both water and soil phases before and after degradation indicated that QNC was desorbed from the soil and then degraded, and it was difficult to degrade directly from the soil surface. Soil component removal experiments showed that soil Fe/Mn minerals and organic matter acted synergistically and antagonistically during the degradation of QNC by the FeS 2 @BC/PMS system, respectively. Quenching experiments and ESR assays revealed that 1O 2 was the main reactive oxygen species responsible for removing QNC. Seed germination and potting experiments showed that the FeS 2 @BC/PMS system effectively alleviated root deformity and reduced the growth inhibition of roots, stems, and leaves caused by QNC during mung bean seed germination and seedling growth. The results suggest that the FeS 2 @BC/PMS system can effectively remediate QNC-polluted soil, which may provide a reference for the remediation of organic contaminated soil. • FeS 2 @BC efficiently catalyzed PMS for the removal of QNC in soil. • Fe/Mn minerals and organic matter in the soil acted synergistically and antagonistically on QNC degradation, respectively. • The 1O 2 generated and converted during the degradation process played a dominant role in QNC degradation. • The FeS 2 @BC/PMS system effectively alleviated the root deformity and reduced the growth inhibition of plants caused by QNC. [ABSTRACT FROM AUTHOR]

Dye toxins, emitted by industries, pose a significant threat to living beings and aquatic life by absorbing light radiation and inhibiting the growth of essential bacteria and microbes, making their removal crucial for health of living beings and flora and fauna. This research endorsed a hydrothermal synthetic route for the photocatalyst CeO 2 /CdS/g-C 3 N 4 @ZIF8 (or CCdGZ) fabrication to remove a set of hazardous dyes from wastewater streams. Corresponding Analytical methods evaluated the successfully developed CCdGZ photocatalyst's structural, morphological, and compositional properties. Powder X-ray photoelectron (PXRD) analysis showed the structural properties of CCdGZ and the quantum dot nature of the CeO 2 -CdS hybrid in the heterostructure with a crystallite size of 0.16 nm. The photocatalyst's optical responses were examined using UV–vis spectrophotometry and the UV-diffuse reflectance spectroscopy (UV-DRS) technique. Tauc's plot determined the energy band gap of the CCdGZ to be ∼2.64 eV, confirming a slight modification of the valence band (VB) and conduction band (CB) edges of the moieties CeO 2 , CdS, and g-C 3 N 4. Thus, the heterostructure's moieties synergised to produce photocatalytic degradation. Under visible light irradiation, the photocatalyst CCdGZ photodegraded Victoria blue R (VBR) dye by 96.54% in 55 min. Photodegradation followed pseudo-first-order kinetics with a specific reaction rate of 0.06159 min−1 {coefficient of determination (R2) = 0.99847}. The corresponding TOC removal was 83.27%, while COD got reduced to 78.98% of its initial magnitude. Multiple reaction parameters, heterostructure reusability (over 89% efficient till the 5th run), the scavengers' experiment, inorganic ion effects, and water matrices were also evaluated. The study concludes with a photocatalytic reaction mechanism that explains the moieties' roles. This study designs a heterostructure photocatalyst that disintegrates emerging non-degradable organic pollutants in the UV–visible range, is recoverable, and has better photostability. [Display omitted] • Facile and novel fabrication of a photocatalytic heterostructure CeO 2 -CdS QDts/2D g-C 3 N 4 @ZIF8 (or CCdGZ). • CeO 2 -CdS existed as quantum dots (QDts) in CCdGZ heterostructure with crystallite size of 0.61 nm. • CCdGZ heterostructure displayed a successfully engineered staggered type II heterojunction nature. • During study of mineralization, TOC removal was 83.27%, while COD got reduced to 78.98%. • CCdGZ heterostructure expressed a superior photocatalytic degradation for Victoria blue R dye up to 96.54% within 55 min. [ABSTRACT FROM AUTHOR]

This work comprehensively studied the kinetic degradation of ciprofloxacin (CIP), levofloxacin (LEV), and sulfanilamide (SAA) by UV/PS/Cl and UV/H 2 O 2 /Cl. UV contributed to the degradation of SAA to a great extent, resulting in the highest degradation, compared with the other PPCPs. 10 mM of Cl- slightly enhanced the degradation of LEV and SAA, while higher concentrations of Cl- (up to 1000 mM) inhibited the degradation of all the PPCPs in most processes. Increasing the concentration of Cl- to 1000 mM resulted in the decrease in the concentrations of •OH (which decreased by 88 – 96%) and SO 4 •- (which decreased by 67.4%) in UV/PS/Cl. With the increase in the concentration of Cl- to 1000 mM, the contributions of •OH and SO 4 •- to the degradation of the PPCPs were almost completely masked by the contribution of Cl• (except in the case of SAA). The relationship between the natural logarithms of the second-order rate constant of SO 4 •- and Cl• with PPCPs versus the Hammett constant was established and used to determine the second-order rate constant of SAA towards SO 4 •-. Acidic pH and neutral pH were conducive for the degradation of the PPCPs in the process. The presence of various constituents, including anions (i.e., HCO 3 -, SO 4 2-, and NO 3 -) and metal cations (i.e., Fe2+, Ni2+, Co2+ and Mn2+) inhibited the degradation rate of the PPCPs to varying degrees. In the presence of 10 mM Cl- and other anions, •OH and SO 4 •- were consumed by Cl-, up to 71 – 90% and 8 – 10% in UV/PS/Cl, respectively. Toxicity assessment showed that 10 mM Cl- in UV/PS/Cl and UV/H 2 O 2 /Cl did not cause any significant inhibition on the growth of Chlorella vulgaris and Escherichia coli (E.Coli), compared with that in the absence of Cl-. In summary, Cl• is an important radical that can replace •OH and SO 4 •- in UV/PS or UV/H 2 O 2 under saline conditions. [Display omitted] • Kinetic degradation of three PPCPs was investigated in UV/PS/Cl and UV/H 2 O 2 /Cl. • Cl• played the main role in 10 – 1000 mM Cl- in UV/PS and UV/H 2 O 2. • Acidic pH and neutral pH were conducive for the degradation of the PPCPs. • Anions and metal cations inhibited the degradation rate of the PPCPs. [ABSTRACT FROM AUTHOR]

Cobalt and its oxides are the most recognized catalysts for advanced oxidation processes based on peroxymonosulfate (PMS). However, the easy optimization of morphology, defects and metal components of Co-based catalysts to generate more active centers remains challenging. In this study, a kind of multicomponent cobalt-based catalyst has been synthesized with a simple and effective strategy by introducing sodium carbonate in the precursor solution. The appropriate concentration of sodium carbonate favored the construction of multi-level pore structures, thus facilitating the exposure of more active centers and accelerating the mass transfer of the guest materials during the removal process. Besides, the sodium carbonate concentration is beneficial for modulating the degree of carbon defects and the efficiency of metal components of Co and CoO, resulting in higher conductivity and greater electron transfer media, which helps activate PMS for degradation of PNP. The honeycomb-like Co-CoO architecture (Co-CoO/NC-h) showed the best performance of PNP degradation with a removal rate of 99.3% in 25 min, and the activity was still up to 93.4% after 5 cycles. The magnetic Co-CoO/NC-h presented strong recovery stability due to the enhanced interaction between cobalt and cobalt oxide nanoparticles with nitrogen-doped carbon. Quenching tests and EPR demonstrated the specific contribution of free and non-free radicals in the degradation of PNP. The biological toxicity of the solution after degradation reaction was evaluated, and possible degradation pathways for PNP were proposed. Overall, this work provides a simple and effective strategy for tuning morphology, defects and metal components to activate PMS for the degradation of organic pollutants in wastewater. [Display omitted] • A simple and effective strategy for tuning morphology, defects and metal components. • Easy exposure of more active centers and accelerating the mass transfer. • High PNP degradation performance, stability and universality over a wide pH range. • Biological toxicity were evaluated and degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

Pharmaceutical-induced pollutants are emerging contaminants that pose a growing threat to the environment around the world. Recently, extensive efforts have been made to develop effective methods for removing pharmaceutical-induced pollutants from aqueous media by taking advantage of the structural and physicochemical properties of MXene such as large surface area, abundant surface terminations, and hydrophilicity. Most importantly, MXene exhibits an active surface area that makes it suitable for adhering to a variety of materials such as metal oxides, quantum dots, and carbon-based materials, thus enhancing the catalytic properties or increasing the surface area of the resulting materials. MXene-functionalized composites have been used in adsorption of pollutants from water and various degradation techniques, such as photodegradation and sonodegradation. These composites have also been used to activate peroxymonosulfate into sulfate radicals, which decompose pharmaceutical pollutants and other pollutants. Despite ongoing advancements, research gaps remain, particularly in understanding the mechanisms underlying the removal process and optimizing MXene-based adsorbents and catalysts. This review offers an exhaustive overview of recent studies on the adsorption and degradation of pharmaceutical pollutants in water using MXene and MXene-functionalized composites. It integrates existing knowledge with the goal of encouraging further research and guiding the creation of enhanced techniques for the elimination of pharmaceutical pollutants from water, leveraging the distinctive attributes of MXene. We anticipate that this review will assist in the development of more improved methods of removing pharmaceutical-induced pollutants from water based on the properties of MXene. [Display omitted] • Sources of pharmaceuticals-induced pollutants and their toxicological effects are explored. • MXene and MXene-functionalized materials are introduced. • Mechanism of removing pharmaceutical-induced pollutants using MXene-functionalized materials is summarized. • Challenges and future perspectives are presented. [ABSTRACT FROM AUTHOR]

The rapid accumulation of spent lithium-ion batteries (SLIBs) poses a global challenge in terms of their disposal and management. Considering the substantial quantity of transition metals contained in SLIBs, the preparation of derived catalysts for environmental remediation has emerged as a promising approach for the recycling of SLIBs. Herein, the citric acid-based sol-gel method was employed to synthesize the catalyst from SLIBs. The derived spent cathode material (LiNi x Co y Mn 1−x-y O 2 , NCM) composites exhibit superior catalytic activity and display higher adaptability to the environment, effectively removing typical azo dye, methylene blue (MB), as well as various organic contaminants, sulfamethoxazole (SMX), levofloxacin (LVF) and rhodamine B (RhB) in 30 min. The Co2+ and Mn2+ ions in the catalyst play a crucial role in activating PMS to generate 1O 2 and O 2 •−. The degradation of MB proceeds through several reaction pathways, including demethylation, oxidation, and ring-opening reactions, as confirmed by the Fukui function and UPLC-QTOF-MS analyses. The assessment of toxicity in the degradation products was conducted using T.E.S.T. and ECOSAR 2.0. This proposed method can be highly suggested as a promising strategy for the recycling and utilization of SLIBs, transforming them into efficient catalysts for PMS systems in environmental remediation. [Display omitted] ● Spent cathode material-derived catalyst was used to degrade methylene blue by PMS. ● The catalytic activity of SG-NCM400 was greatly improved compared to C-NCM. ● The redox cycles of Co2 + /Co3 + and Mn2 + /Mn3 + /Mn4 + promoted the production of 1O2 and O2•− by PMS. ● Toxicity assessment revealed a low ecotoxicity of most intermediates. ● The SG-NCM400/PMS system exhibited great practical potential in water purification. [ABSTRACT FROM AUTHOR]

The treatability of perfluorocarboxylic acids (PFCA) (perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA)) and perfluorosulfonic acids (PFSA) (PFBS, Perfluorooctanesulfonic acid PFHxS and Perfluorooctanesulfonic acid (PFOS)) via a bubble column with non-thermal plasma discharges in the argon headspace were investigated in individual solutions and from surface water sourced from a contaminated site. High degradation (>90%) could be achieved for PFOA, PFHxS and PFOS within 40 min treating the contaminated surface water. Overall, treatability correlated with the length of the perfluorinated carbon chain, with a decrease in treatability associated with a reduction of the length of the perfluorinated backbone. Experiments with prepared PFAS solutions at initial concentrations of 10, 25 and 50 μg/L found higher initial concentrations of PFCA and PFSA were associated with faster degradation rates suggesting the treatment efficiency was limited by mass transfer of PFAS. Negligible breakdown was observed for PFBA at any of the concentrations trialled, indicating limitations when treating more hydrophilic PFAS, which may require combining this treatment approach with a polishing step, such as nanofiltration. [Display omitted] • Plasma discharge at the liquid surface could achieve >90% for PFOA, PFHxS and PFOS within 40 min for a 2 L bubble column. • Degradation rates were found to be pseudo first order suggesting the treatment efficiency was limited by mass transport of PFAS to the surface. • The treatability of PFAS correlated with the length of the perfluorinated carbon chain, with shorter chain compounds being less amenable to treatment. [ABSTRACT FROM AUTHOR]

The existing microelectrolytic materials are hindered in applying advanced oxidation processes due to their poor stability and easy bonding. Therefore, ternary iron-carbon microelectrolytic microspheres (SA@Fe-Ni-C) have been prepared by a simple embedding process and used to activate persulfate (PDS) to degrade thiocyanate (SCN-). The doping of Ni not only accelerates the electron transport and promotes the effective reduction of Fe3+ but also forms the cycle system of Fe2+/Fe3+ and Ni2+/Ni3+, which ensures the high catalytic activity of the catalyst. It was found that both free radicals (SO 4 •-, •OH and O 2 •-) and non-free radicals (1O 2 and electron transfer) contributed to the removal of SCN-. The DFT results showed that Fe was the leading activation site of PDS, and Ni could also promote the activation of PDS. Finally, the high stability of SA@Fe-Ni-C and its anti-interference ability were verified by 5-cycle and coexistence ion experiments. This study provides some guidance for the synthesis of new micro-electrolytic materials and the treatment of industrial wastewater by an advanced oxidation process. [Display omitted] • The SA@Fe-Ni-C exhibited excellent performance for PDS activation. • The SCN- can be rapidly degraded within 30 min at a 95.27% removal efficiency. • The SO 4 •-, •OH, O 2 •- and 1O 2 and e- were all involved in the degradation of SCN-. • The SA@Fe-Ni-C exhibited excellent recyclability more than five times. • The SA@Fe-Ni-C/PDS system can effectively degrade SCN- in a wide pH range (3−11). [ABSTRACT FROM AUTHOR]

Mining activities consume millions of cubic meters of water per year. Flotation, a crucial step in mining operations, uses a significant amount of water, and its treatment can contribute to a closed-loop system. Treatment is required owing to flotation reactants partially degraded and these residual reagents may cause a decline in separation efficiency. An overview of wastewater treatments can help to broaden the amount of water reuse and contribute to the circular economy. This study discusses existing techniques for removing collector surfactants used in mining. It first presents an investigation on wastewater composition and on the main flotation reactants used. Secondly, state-of-the-art technologies for treating wastewater contaminated with flotation collectors are discussed. Lastly, a critical evaluation is provided, highlighting the advantages and drawbacks of different techniques. Surfactants, particularly xanthates and amine derivatives, are identified as the primary contaminants in wastewater. Adsorption, biodegradation, ozonation, Fenton reaction, and photocatalysis, combined with electrochemical treatments, are found to be the most promising technologies. However, further research is needed to analyze by-products and to study real conditions for effective application. Overall, treating mining wastewater contaminated with collectors can contribute to reduce water consumption in the mining industry, benefiting environmental engineering efforts. [Display omitted] • Reuse water can affect the recovery efficiency of ore flotation. • This is due to interferents in the water such as ions and partially degraded flotation reagents. • This article discusses how to remove flotation reagents from reused water. • Adsorption, flotation, biodegradation, and AOP were the methods explored that had the best results. • It was concluded that it is necessary to understand which by-products can affect flotation. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the high oxidation potential of hydroxyl and sulphate radicals generated by UV-C assisted persulphate (PS) and peroxymonosulphate (PMS) processes in natural water. The effects of initial oxidant concentration on degradation processes were investigated using TOC, PS, pH, and UV 254 measurements in samples taken at specific time intervals. The particle size distribution profiles were also determined for the raw water and effluent samples from the PS/UV-C and PMS/UV-C. Accordingly, the final removal rates were 19%, 40%, and 55% for PS/UV-C doses of 0.2 mM, 0.5 mM, and 1.0 mM, respectively, while the TOC removal was 20%, 35%, and 64% for 0.2 mM, 0.5 mM, and 1.0 mM PMS/UV-C, respectively. The results showed that the rate constants of TOC removal followed first-order kinetics for both PS and PMS. The general assessment of energy consumption during the PS/UV-C and PMS/UV-C processes showed that the time required for the same amount of TOC removal decreased as the initial PS/PMS concentration increased, so that the energy required decreased in relation to volume and mass. Overall, the obtained results were used for a comparative analysis of the oxidation process, and the recommended process was evaluated with samples taken from the effluent of each unit of the drinking water treatment plant to determine the correct location for the treatment process. The results showed that the PS/UV-C process should be designed after filtration, rather than after sedimentation, and the end of the treatment plant. [Display omitted] • UV-C assisted PS and PMS can oxidize pollutants in natural water. • 19–55% achieved for PS/UV-C doses of 0.2–1 mM. • PS/UV-C and PMS/UV-C are effective in removing particles. • Energy consumption decreased as initial PS/PMS concentration increased. • PS/UV-C should be applied after filtration. [ABSTRACT FROM AUTHOR]

2,4-dichlorophenol (2,4-DCP) was degraded by synthesizing a novel carboxymethyl cellulose (CMC) stabilized Fe/Ni nanocomposite and activating persulfate (PS), meaning Fe/Ni-CMC-PS system. The feasibility of the degradation of 2,4-DCP in Fe/Ni-CMC system was determined by the comparison of blank, PS, nZVI, nZVI-PS, Fe/Ni-CMC and Fe/Ni-CMC-PS systems, respectively. The consequences of different influencing factors showed that the degradation efficiency reached the optimum value of 95.62% when pH was 5.5, Fe/Ni-CMC dose was 0.8 g/L, Fe/Ni ratio was 0.10 (W t (Fe) :W t (Ni) = 9:1) and PS concentration was 2 mM. At the same time, the inhibition effect of natural organic matter (humic acid) and inorganic anions on the activity of iron-based materials was studied. The quenching experiments showed that SO 4 .- radical and .OH radical were mainly produced in the reaction system of Fe/Ni-CMC-PS, and SO 4 .- radical was the primary free radical to degrade 2,4-DCP. Based on the consequences of DFT calculation and experimental analysis, the possible mechanisms of degrading 2,4-DCP by Fe/Ni-CMC-PS was proposed, which provided a novel idea for the actual practice of iron-based materials in the treatment of environmental water pollution. [Display omitted] • A novel CMC stabilized Fe/Ni nanocomposite was fabricated. • The advanced oxidation system was formed by activating PS in iron-based bimetallic materials. • The degradation effect of Fe/Ni-CMC-PS system on 2,4-DCP was significantly higher than nZVI. • The reaction mechanism was determined by DFT calculation and experiment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Evaluation of electro-Fenton (EF) for phenol degradation using iron electrodes. • Optimization of reaction parameters for EF process. • Low cost NaCl was found the most effective electrolyte. • AC assisted EF process enhanced TOC removal significantly. • More ferrous ions were formed during AC assisted EF process. Abstract The objective of the present study was to investigate the efficacy of electro-Fenton (EF) oxidation process for the removal of phenol from synthetic wastewater (initial phenol concentration = 250 mg/L) under varying reaction conditions using iron electrodes. The lab scale EF runs were performed in a 1 L beaker placed on magnetic stirrer assembly. Maximum COD and TOC removals of ∼84% and ∼52%, respectively, were obtained within 30 min reaction at the following operating conditions: stoichiometric amount of H 2 O 2 = 37.2 mM, pH = 5.2 (unadjusted), electrical conductivity = 125 μS/cm (adjusted using NaCl), stirring speed = 100 rpm, current density = 0.8 mA/cm2 and inter-electrode gap = 4 cm. At the above condition, complete phenol removal was obtained within 5 min. The effect of activated carbon (AC) as co-catalyst on the performance of EF process was also studied at the above reaction condition. With AC assisted EF process, TOC removal was increased to 75% from 52.2% (in EF). The enhanced degradation was due to the combined effect of adsorption and oxidation reactions. During modified EF, ferrous iron recycling was also higher compared to that observed during conventional EF process. [ABSTRACT FROM AUTHOR]

The development of a new catalyst is of great significance for the potential application of advanced oxidation processes using sulfites as the sources of sulfate radical. In this study, a novel composite catalytic material, Li 3 PO 4 -Co 3 O 4 , was synthesized to activate sulfite to degrade metronidazole (MNZ) in water. Characterization techniques were used to characterize the prepared materials. The key factors affecting the degradation of MNZ, including molar ratio of Li 3 PO 4 and Co 3 O 4 , catalyst dosage, sulfite concentration, pollutant concentration and initial pH, were investigated. Under the optimal experimental conditions, the degradation rate of MNZ can reach 94% within 30 min. The effects of ions on the degradation of MNZ in water were investigated. The XPS test showed that Li 3 PO 4 could increase the content of oxygen vacancy on the catalyst surface to enhance the activation performance, and the conversion between Co2+ and Co3+ was the key factor for the activation of sulfite. By electron paramagnetic resonance detection and reactive oxygen species (ROS) clearance experiments, it was concluded that the main ROS in Li 3 PO 4 -Co 3 O 4 /S(IV) system were SO 4 •− and •OH, and the production and transformation mechanisms of SO 4 •− and •OH were fully revealed and demonstrated. MNZ is degraded into multiple intermediate products through two pathways, which are ultimately mineralized into inorganic small molecules. The toxicity analysis of the intermediate products indicate that the system has a strong detoxification effect on MNZ. In addition, the catalyst has good reusability and low metal ion leaching characteristics, indicating that the catalytic system has good practical application potential. [Display omitted] • An emerging catalytic material Li 3 PO 4 -Co 3 O 4 was first synthesized. • The composite material has more oxygen vacancy content than Co 3 O 4. • The conversion between Co2+ and Co3+ was the key factor for activating sulfite. • Li 3 PO 4 -Co 3 O 4 /S(IV) system can significantly reduce the ecological toxicity of MNZ. • SO 4 •−and •OH are the main ROS involved in the degradation process of MNZ. [ABSTRACT FROM AUTHOR]

Nonradical-based peroxymonosulfate (PMS) activation has recently caught increasing attention due to its less susceptible to environmental interference in the complex water matrix, but the performance of activators still requires further development for efficient pollutants degradation in wastewater treatment. Herein, a novel Co-Ni bimetal oxide loaded biochar was fabricated to boost nonradical PMS activation for enhancing sulfamethoxazole (SMX) degradation. According to the results, the as-obtained catalyst exhibited excellent SMX degradation efficiency of 96.2% within 30 min through complete nonradical oxidation pathway (including both 1O 2 and mediated electron transfer). Co was confirmed to be the active sites to generate 1O 2 dominated nonradical pathway. The biochar acted as the porous material to achieve the electron transfer oxidation process, as well as Ni ensured sufficient electron transfer rate and bound Co active sites to prevent the leaching of metal ions. Meanwhile, the prepared Co-Ni bimetal oxide loaded biochar possessed a remarkable catalytic degradation durability in the complex water environment conditions and showed universality for various organic contaminants. This study offers a valuable clue on the rational design of novel catalyst to induce the nonradical pathway-based persulfate activation. [Display omitted] • Facile preparation of Co-Ni bimetal oxide loaded biochar for PMS activation. • Boosting nonradical PMS activation by induction of Co-Ni bimetal oxide. • Synergy of 1O 2 and mediated electron transfer dominating SMX degradation. • Less leaching of Co and quicker electron transfer in the presence of Ni. [ABSTRACT FROM AUTHOR]

Clean water availability is becoming a matter of global concern in the last decades. The responsible entities for wastewater treatment do not have the proper facilities to deal with a wide range of pollutants. Special attention should be given to emerging contaminants, whose presence in water bodies may cause adverse effects on the aquatic ecosystem and human health. Most studies in the literature do not consider the development of their solution in real matrices, which can hinder the applicability of the explored alternative in the real scenario. Therefore, in this work, we demonstrate the applicability of hybrid magnetic nanoparticles for removing paracetamol (PCM) from simulated and real matrices by catalytic wet peroxide oxidation (CWPO). To achieve carbon coating, the nanoparticles were prepared via the traditional route (resorcinol/formaldehyde, CoFe@CRF). A new methodology was also considered for synthesizing thin-layered carbon-coated magnetic nanoparticles (phloroglucinol/glyoxalic acid, CoFe@C PG). TEM images revealed a multi-core shell structure formation, with an average carbon layer size of 7.8 ± 0.5 and 3.2 ± 0.3 nm for resorcinol/formaldehyde and phloroglucinol/glyoxalic acid methodology, respectively. Screening the materials' activity for PCM oxidation by CWPO revealed that the nanoparticle prepared by phloroglucinol/glyoxalic acid methodology has higher performance for the degradation of PCM, achieving 63.5% mineralization after 24 h of reaction, with similar results for more complex matrices. Iron leaching measured at the end of all reactions has proven that the carbon layer protects the core against leaching. [Display omitted] • A novel methodology has been proposed for obtaining thin-layer carbon-coated NPs. • Both traditional and novel catalysts were tested in the CWPO of paracetamol (PCM). • The thin-layer carbon-coated catalyst displayed higher activity and stability. • The catalyst proved to be robust, allowing similar PCM and TOC removal considering complex matrices. [ABSTRACT FROM AUTHOR]

Ethylene glycol (EG) has been widely used to produce polyethylene terephthalate (PET) bottles, antifreezes, and de-icing fluid. However, EG possesses toxic detrimental effects on human and aquatic creatures. The degradation of EG in catalytic ozonation based advanced oxidation processes was rarely reported before. In this regard, a novel porous catalyst, magnetic MIL-53(Al/Fe)-metal-organic framework (MOF) derived Al 2 O 3 /Fe 3 O 4 (w Al-Fe@MOF) was synthesized for the first-time using PET, iron, and aluminum scraps for efficacious catalytic ozonation system (COS) of EG. A maximal EG degradation and mineralization of 97.03 ± 2.79% and 57.75 ± 2.60% were obtained in w Al-Fe-based COS, which was higher than sole O 3 (70.76 ± 3.90%; 22.65 ± 2.20%) and O 3 /H 2 O 2 (74.51 ± 2.58%; 36.57 ± 3.10%). The w Al-Fe@MOF displayed only about 18% drop in deterioration efficiency after 5th cycle of reusability, demonstrating outstanding stability and recyclability. The electron paramagnetic resonance and radical scavenging tests confirmed that surface adsorbed ˙ OH ads were majorly accountable for EG degradation. Phytotoxicity revealed that COS effectively reduced the toxicity of EG towards Vigna radiata. The energy consumption and operating cost were found to be 0.863 kWh m−3 order−1 and 0.086 $ m−3 order−1, indicating w Al-Fe@MOF based COS could be highly appropriate for wastewater purification in real field applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Photoactivated advanced oxidation processes have excellent performance in removing recalcitrant pollutants from water. However, the high operating cost associated with the energy consumption of UV lamps is a big drawback. In this work, the design and optimization of the reflector in a tube-in-tube membrane photoreactor were carried out using a ray tracing methodology to maximize the light deployed to the reactor. Simulations were carried out using different lamps/reactor arrangements with 1, 2 and 3-sided flat reflectors and with circular and parabolic geometries. Results showed that direct radiation is maximized when the distance reactor-lamps is minimized, increasing optical efficiency. On the other hand, it was observed that for the flat reflectors, the closer the furthest point of the reflector to the center of the reactor, the higher optical efficiency is achieved due to the reduction in the number of bouncing rays in the reflector. In the case of parabolic geometries, some additional considerations are necessary, since not only the distance at which the reflector is placed matters, but also its geometrical focus. The best performance is achieved for those in which the distance from the furthest point of the reflector to the center of the reactor was lower and the lamps placed near the focus of the parabola. For the studied reflector geometries, the calculated optical efficiencies when using anodized aluminum were 46.1%, 56.5%, 60.0%, 41.8%, and 65.9% for reflectors of 1, 2, and 3 sides, cylinder, and parabola, respectively. Model predictions were successfully validated using experimental ferrioxalate actinometry data, confirming the huge potential of this simple simulation methodology for photoreactor design purposes. [Display omitted] [ABSTRACT FROM AUTHOR]

Kinetic degradation of five typical pollutants including clothianidin (CLO), levofloxacin (LEV), p-nitrosodimethylaniline (RNO), paracetamol (PCM), and basic fuchsin (BF) by UV/persulfate (UV/PS) and other advanced oxidation processes (AOPs) (i.e., UV/H 2 O 2 , Fe2+/H 2 O 2 , electrochemical process, UV/PS/heat, UV/PS/Fe2+, UV/PS/Fe 2 O 3 , and UV/PS/rGO) were studied. The result showed that all pollutants were effectively degraded by UV/PS with different degradation rates. The oxidizing factors contributing to the pollutant degradation in UV/PS were studied, showing that UV is the predominant contributor to CLO degradation, while its contribution is negligible in the degradation of other compounds. •OH and SO 4 •- were the main radicals contributing to the degradation of all pollutants in UV/PS, except CLO. The second-order rate constant of •OH and SO 4 •- towards pollutants was determined according to the competition kinetic model, to be in the range of 109-1010 M−1 s−1. The degradation rate of pollutants in different AOPs were varied, because the oxidizing factors and their role in AOP systems directly affect the degradation efficiency of pollutants. In all AOPs, •OH radical played a major role in their degradation. The presence of water matrices has different influences on the degradation rates of pollutants. For example, 10 mM NO 2 - inhibited the degradation of pollutants to 99.1%, whereas Br-, SO 4 2-, and F- had a lower inhibitory effect on their degradation. HPO 4 2- can improve the degradation rate of BF, but it also significantly inhibited the degradation of PCM. The results also revealed that UV/PS/Fe2+ and UV/PS/rGO can remarkably increase the degradation efficiency of all pollutants, while using α-Fe 2 O 3 and heat were less efficient. In addition, other parameters including COD removal, energy consumption, and toxicity assessment were also investigated to evaluate the potential application of UV/PS in practice. [Display omitted] • Kinetic degradation of five typical pollutants was investigated in UV/PS. • •OH radical contributed in the degradation of pollutants in AOPs. • Pollutants were degraded differently in each AOP. • Br-, SO 4 2-, and F- slowly inhibitedthe degradation of pollutants; NO 2 - reduced their degradation up to 99.1%. • UV/PS/Fe2+ and UV/PS/rGO remarkably increased the degradation efficiency of all pollutants. [ABSTRACT FROM AUTHOR]

Activation of persulfate (PS) under artificial light sources has been extensively studied as PS based advanced oxidation process (AOP) for degradation of organic pollutants. Here, we demonstrate the enhanced photodegradation of organic pollutants under real sunlight (Sun) in presence of persulfate (PS), (Sun/PS system). Sun/PS caused complete degradation of acid orange (AO7, a colored-dye pollutant), with pseudo-first-order rate constant value (k obs (AO7)) of 0.052 min−1 (sunlight dosage, Q light 3.9–5.6 kJ/L and 58.3–64.8 kJ/L in the UV range 300–400 nm and visible range 400–800 nm respectively, AO7 = 2 mg/L (5.7 µM), PS = 0.6 mM). In contrast, AO7 degradation was incomplete under Sun alone (0.2 %), and PS alone (1.6 %). Moreover, Sun/PS caused 91 % reduction of total organic carbon (mineralization) within 240 min. Radical scavenging and ESR results confirmed the formation of SO 4. − and HO. in Sun/PS system, revealing PS activation by Sun enhances degradation, and mineralization of AO7. Other pollutants such as, acetaminophen (AAP, a colorless pharmaceutical contaminant), and, Malachite Green (MG, a carcinogenic pollutant), were effectively degraded, and mineralized by Sun/PS system in comparison to Sun and PS alone. Moreover, Aliivibrio fischeri (A. fischeri) bioluminescent assay reveals AO7 and AAP pollutants were moderately toxic while, MG was highly toxic. Importantly, the toxicity of these pollutants was removed after Sun/PS treatment. The present findings on evaluation of Sun/PS system highlight, Sun/PS may be applied as an activated PS based AOP for water treatment to remove organic pollutants, and it would be useful as a clean, low-cost approach for resource poor environment but having abundant Sun. [Display omitted] • Activation of persulfate by natural sunlight is proposed (Sun/PS). • Sun/PS caused effective degradation than Sun and PS alone. • AO7, AAP and MG were degraded with k obs 0.052, 0.017 and 0.102 min−1 by Sun/PS. • AO7, AAP and MG showed high mineralization of 91 %, 89 % and 64 % by Sun/PS. • No toxic effect towards A. fischeri after treatment by proposed Sun/PS. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Magnetic alumina nanocomposite was introduced as an efficient ozonation catalyst. • Catalytic ozonation of benzotriazole in secondary wastewater effluent was studied. • Catalyst performance increased significantly by increasing calcination temperature. • Mechanism of catalytic ozonation process for benzotriazole removal was elucidated. • The catalyst also showed a significant performance in phosphorus removal. Abstract This research aimed at studying the degradation of benzotriazole (BT), an abundant contaminant in many natural waters, using catalytic and non-catalytic ozonation processes performed in a semi-continuous reactor. Magnetic alumina nanocomposite (MANC) was successfully synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and vibrating-sample magnetometer (VSM). The results revealed that the MANC dramatically enhanced the removal rate of BT. Experiments were evaluated at different solution pH values, catalyst doses, initial benzotriazole concentrations, and oxygen gas flow rates. The results showed that the removal rate of BT strongly influenced by the initial pH, and it increased by enhancing the pH value from 2 to 10 in both catalytic and non-catalytic ozonation. However, the catalyst showed its highest activity at pH near to its point of zero charge, indicating the critical importance of surface hydroxyl groups of alumina. Introducing tert-butyl alcohol (TBA) to the reactor highly decreased the degradation efficiency in the non-catalytic ozonation process, suggesting that the MANC catalyzes the decomposition of ozone to hydroxyl radical. The catalyst stability experiments after four successive runs showed that the catalyst was efficient and stable. Finally, the degradation of BT in secondary municipal wastewater effluent was studied under optimum operating conditions in order to examine the performance of the catalyst in the presence of components available in real streams. The results indicated no significant decrease in the performance of the catalyst. Furthermore, the catalytic ozonation process had also a great performance for removing phosphorus. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Utilization of visible-light in photocatalysis is one of the key aspects of achieving effective application. Non-metal doping solely is often not adequate to give a genuinely practical solution because of challenging separation process. Here, we demonstrate the facile synthesis of modified TiO 2 by non-metal N-doping and surface modification through a one-step solvothermal method. Under this process, both N-dopant and CTAB could be introduced in one process thus creating N-doped mesoporous TiO 2 after template removal using calcination. N 2 physisorption indicated high specific surface area up to 148.60 m2/g. Furthermore, the adsorption-desorption isotherm curve exhibited type IV thus confirming the presence of a mesoporous structure, with H1 and H2 hysteresis loop for slow and fast ramp calcination, respectively. Various characterizations were also carried out to explain the possible band-gap reduction mechanism which leads to the workability extension of the as-synthesized photocatalyst. Faster and superior settling capability was shown qualitatively using static settling test. The performance of the modified photocatalysts showed improved performance in methylene blue (cationic dye) and methyl orange (anionic dye) degradation under visible light (λ > 400 nm) as compared to other commercially available TiO 2 photocatalysts. In conclusion, facile modifications introduced in this research proved to bring constructive effect, establishing better photocatalyst with effective utilization of visible light and also simple to retrieve catalyst. [ABSTRACT FROM AUTHOR]

Highlights • Synthesis of tin chloride modified graphite electrodes by the electrode-less deposition method. • Salicylic acid was employed as the hydroxyl radical scavenger. • The optimal current intensity for the initial production rate of 6.6 × 10−6 mol L−1 min−1 hydroxyl radicals was 0.4 A. • At higher current intensities 0.6 A, 0.8 A and 1 A corrosion rate was of the order 0.176, 0.381 and 0.386 mm h−1 respectively. • An E.coli killing efficiency of 99.99% was achieved with a contact time of 5 min at a current intensity of 0.4 A. • Among the commercially available electrodes, graphite electrode was found to be the most feasible alternative for installation of an onsite water treatment plant. Abstract A tin-chloride modified graphite electrode (Sn/G) was synthesized by the chemical deposition method. Cyclic voltammetry (CV) was used to examine the formation of hydroxyl radicals at the coated (Sn/G) electrodes. An electrochemical reactor was designed with the coated graphite electrode (Sn/G) and stainless steel as the anode and cathode respectively. The production and quantification of hydroxyl radicals at the (Sn/G) electrode was carried out in a UV–vis spectrophotometer. Salicylic acid (SA) was employed as the hydroxyl radical scavenger in the current study. The amount of hydroxyl radical formation was enumerated in terms of the resulted hydroxilated products: 2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid. The optimal current intensity for hydroxyl radical formation was found to be 0.4 A since at higher current intensities 0.6 A, 0.8 A and 1 A corrosion rate was of the order 0.176, 0.381 and 0.386 mm h−1 respectively. An E.coli killing efficiency of 99.99% was achieved with a contact time of 5 min at a current intensity of 0.4 A. To assess the applicability of the electrochemical oxidation process in the public water supply system, a cost analysis of the economics of the various commercially available electrodes revealed that the graphite electrode is the most lucrative viable alternative. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) are commonly known as efficient water treatment techniques able to oxidize a great variety of pollutants from water that are otherwise difficult to be converted. Nevertheless, AOPs are costly processes, particularly, because of the electrical costs associated. In this regard, photovoltaic (PV) energy can be used to power the AOP in a reliable and autonomous way. In this work, the steps for sizing a solar PV system for water treatment using AOPs are described. Additionally, the feasibility of the use of a PV array without batteries to supply the electrical power needs of a UV/H 2 O 2 advanced oxidation system for degrading natural water containing 12 and 3 μg L −1 of anthracene and benzo[a]pyrene, respectively, two of the priority polycyclic aromatic hydrocarbons because of their harmful effects on living beings, was studied. It was found that more than 99% of anthracene and benzo[a]pyrene were removed and about 45% of the total organic matter was mineralized after 15 and 90 min of treatment, indicating the high efficiency of the system. Finally, the investment costs of the UV/H 2 O 2 -PV system for a small application were estimated with and without batteries in order to define the optimum PV array configuration. The PV array designed and applied allows for the decontamination of persistent pollutants in natural water in an environmentally-friendly and sustainable way. [ABSTRACT FROM AUTHOR]

Landfill leachates are a complex wastewater originated by the decomposition of organic matter combined with pluvial water percolation. The complex and variable composition of this wastewater provides acute and chronic toxicity, in addition to resistance to biological processes. This requires an advanced treatment, such as photo-Fenton technique. This study aims to evaluate the phytotoxicity and the biodegradability improvements of samples of landfill leachates treated by photo-Fenton using oxalate and citric acids as organic ligands. Some parameters were analyzed to support this research, such as total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD 5 ) and simple aromatic compounds (Abs. 254 nm). Removals of simple aromatic compounds achieved 44% and 31% for oxalic and citric acids, respectively. TOC removals of 47% for ferrioxalate and 33% for ferricitrate were obtained. The biodegradability had an improvement, evidenced by the increase in the BOD 5 /COD ratio (0.18 to 0.39) and by the Zahn-Wellens test (D t  > 70%). Regarding the phytotoxicity, the absolute germination, relative radical growth, relative hypocotyl growth and LC 50 values indicate that the photo-Fenton process provides great enhancements. For the evaluated parameters, the best results regarding the toxicity and biodegradability assessments were provided by the ferricitrate complex. [ABSTRACT FROM AUTHOR]

To improve the performance of the nanoscale zero-valent iron (nZVI)-based advanced oxidation process (AOPs), a sulfidation pre-modification endowed nZVI with stable reduction nature mechanism was proposed, and a coupled system of activating PMS with sulfidized nanoscale zero-valent iron supported by biochar(S-nZVI/BC@PMS) was constructed in this study. It could be found that sulfidation state and formation, largely dependent on the sulfidized modification method, had a great impact on the enhancement for nZVI/BC in activating PMS for Acid Red 73 degradation. Compared with original nZVI/BC, the formed FeS shell blocked the external air to protect the internal Fe0, and S-nZVI/BC became relatively hydrophobic, which could slow down the material corrosion by water and dissolved oxygen to enhance the reaction durability. Appropriate sulfidation reduced the electrochemical impedance and enhanced the electrical conductivity of the catalyst, which facilitated the electron transfer in the system, and the participation of reducing sulfur species enabled the reaction to form a positive cycle and ensure a prolonged duration. Excessive sulfidation caused the material to become unstable and thus susceptible to air erosion, reducing the efficiency of contaminant removal. Due to the FeS protective shell, hydrophobicity of S-nZVI/BC and the promoted electron transfer in the system, S-nZVI/BC@PMS system secured more free radicals and had longer reaction time under the same conditions. In addition, S-nZVI/BC had good antioxidant properties, universality, and reusability for practical applications. These findings not only elucidated the superiority of S-nZVI/BC@PMS system but also provided new insights into cost-saving and efficient advanced oxidation processes. [Display omitted] • FeS shell on S-nZVI/BC surface could prevent internal Fe0 from being oxidized. • Hydrophobicity of S-nZVI/BC enhanced the durability of the reaction. • Appropriate sulfidation could promote electron transfer in the coupling system. • S-nZVI/BC@PMS system secured more free radicals and had longer reaction time. [ABSTRACT FROM AUTHOR]

Microbial desalination cells (MDCs) are bioelectrochemical devices that can recover usable energy and chemicals from organic wastes and concurrently desalinate saltwater. MDCs can also produce the green oxidant, H 2 O 2 , through a two-electron oxygen reduction reaction occurring on the cathode electrode. If MDCs producing H 2 O 2 are used in the pretreatment of brackish water or seawater for reverse osmosis (RO) processes, the salinity of feed water can be reduced in MDCs and the MDC-produced H 2 O 2 can be utilized onsite to oxidize organic contaminants or disinfect microorganisms in the feed water. This strategy of using MDC pretreatment may substantially alleviate the energy requirements and biofouling tendency of downstream RO units. Herein, we assessed the applicability of a combination of H 2 O 2 -producing MDCs and ultraviolet (UV) or UV 254nn -based advanced oxidation process (AOP) (i.e., UV/H 2 O 2) as pretreatment for RO processes. We first examined the effect of catholyte conditions, which is one of the most crucial factors directly affecting the H 2 O 2 composition and decomposition, on the performance of MDCs. Then, we evaluated the microorganism disinfection efficiencies of advanced photo-oxidation processes using H 2 O 2 obtained from MDCs. The MDC investigated herein achieved 93.1% desalination efficiency and > 5.0 mM H 2 O 2 concentration. In addition, UV-based AOP with the produced H 2 O 2 demonstrated up to 15-fold higher inactivation kinetics than that by UV 254 nm disinfection alone. [Display omitted] [ABSTRACT FROM AUTHOR]

Photothermal catalysis of functional materials triggered by light-irradiation to local heating approach attracts growing attention, but one key detail affecting catalytic thermodynamic process was often ignored that thermal-conductive surface of functional materials directly contacting reaction solution easily delivers heat to the reaction system, leading to weakening heating effect in the interfacial local catalytic microenvironment. Herein, a functional low-thermal-conductivity layer that Mn-coupling porous SiO 2 shell layer was constructed over the Co 3 O 4 nanospheres. Specifically, SiO 2 with porous channels introduced acts as the thermal-insulation layer to prevent the heat dissipation of the photo-heating core of Co 3 O 4. More importantly, porous channel and inserted MnO x active species could further offer an additive special reaction microenvironment over the photo-heating core of Co 3 O 4. Additionally, the introduction of Mn and structural remodeling through tailored annealing temperature (600–800 °C) can give improved catalytic hybrids abundant valence states and interfacial effects. A series of Co@Mn/m-SiO 2 catalysts were fabricated based on the above control tactic. The Co@Mn/m-SiO 2 catalysts exhibit superior activating ability for peroxymonosulfate (PMS) to degrade bisphenol A (BPA) and other pollutants including 2, 4-dichlorophenol (2, 4-DCP), phenol (PhOH), oxytetracycline (OTC), and tetracycline (TCN). Specifically, Co@Mn/m-SiO 2 -700 was shown to achieve complete degradation of 20 ppm BPA in less than 10 min under optimal conditions. In addition, we demonstrated that functional silica layer modified Co 3 O 4 affords a better photo-heating effect compared to bare Co 3 O 4 sphere in air or water, thereby contributing to a faster PMS activation efficiency. Besides, thermal treatment processing for Co@Mn/m-SiO 2 catalyst makes the surface reactive species be optimized to generate more beneficial redox pairs and reach excellent photothermal catalytic efficiency in various pollutants treatment. [Display omitted] • Mn-coupling porous SiO 2 shell layer is constructed over the Co 3 O 4 nanospheres. • The exquisite structure of Co@Mn/m-SiO 2 possesses high catalytic activity, photothermal effects, and low heat dissipation. • Temperature-dependent optimal Co@Mn/m-SiO 2 exhibits enhanced activated ability for PMS. • Functional porous SiO 2 shell reinforces the photo-to-heat effect in local microenvironmet. • Excellent photothermal catalytic efficiency in various pollutants treatment was achieved by Co@Mn/m-SiO 2 -700. [ABSTRACT FROM AUTHOR]

Sulfate radical (SO 4 • −)-based advanced oxidation processes (AOPs), such as the electro-activated peroxymonosulfate (E-PMS) process, have shown great potential for environmental remediation. As oxygen competes with PMS for electrons at the cathode in the E-PMS process, oxygen was proposed to be one of the negative factors reducing the generation of SO 4 • − in previous studies. Surprisingly, our preliminary experiment found that polytetrafluoroethylene-black carbon (PBC), which could efficiently produce H 2 O 2 in the E-PMS process as a cathode, could produce an 18.4 times greater steady-state concentration of SO 4 • − than Pt cathodes with nearly no production of H 2 O 2. In addition, the generation of SO 4 • − in the E-PMS process with a Pt cathode can also be significantly enhanced by dosing H 2 O 2 in the system. Quenching experiments and electron paramagnetic resonance (EPR) analysis demonstrated that H 2 O 2 could react with PMS at the cathode to produce superoxide radicals (O 2 • −). Furthermore, O 2 • − reacted with PMS in solution to generate SO 4 • −. In addition, the influence of various water matrices on carbamazepine (CBZ) removal was also discussed. Finally, the degradation pathways of CBZ were proposed and corresponding toxicity of products was analyzed by ecological structure activity relationships (ECOSAR) analysis. This study may present novel and fundamental insights into the E-PMS process and a simple and convenient approach to regulate the generation of SO 4 • − during PMS activation. [Display omitted] • E-PBC-PMS significantly promote CBZ mineralization with less energy consumption. • The H 2 O 2 -induced E-PMS process vastly enhanced the generation of SO 4 • −. • O 2 • − , as a driving agent, was responsible for the enhanced SO 4 • − production. • Electrolysis, PMS, and H 2 O 2 were necessary to facilitate the generation of O 2 • −. [ABSTRACT FROM AUTHOR]

Dye wastewater released from several dyes induced industries are harmful towards the living, non-living environment and human. Consequently, existence of dye in water bodies is becoming a rising concern to environmentalists and citizens. Dye wastewater should be treated prior to release in an open water body to minimize its negative impacts. A long term sustainable and efficient treatment methods should be established to reduce and overcome the impacts. Although there have been significant advances in the management and treatment of such effluent using physical, chemical and biological methods. However, due to lack of information on effective dye removal methods, it is difficult to decide on a single unique technique that resolves the prevailing dye wastewater. Therefore, this paper reviews recent research on various (physical, chemical, biological, advanced oxidation process (AOPs) and hybrid) dye removal methods to compare efficiency, evaluation performance, merits and demerits. Among the existing methods, most of them have a common disadvantage which is the generation of secondary pollutes, takes long time and costly. This paper especially highlights AOPs method for dye removal as these are known as one of the promising and most effective dye removal techniques these days. This paper also suggests the application of AOPs methods possess the best performance in terms of faster dye removing as well as cost effective, time oriented and environmentally friendly. Additionally, this paper addressed the difficulties and future prospects of this emerging method that links to sustainable development. [Display omitted] • Environment and human health both are harmed due to open discharge of dye wastewater. • Wastewater containing dye should be adequately treated using eco-friendly technologies. • Physical, chemical, biological, advanced and hybrid treatment approaches are common and most applied. • Advanced treatment based photocatalytic approach appears most effective for dye degradation. • More research on catalyst preparation cost and market analysis in required. [ABSTRACT FROM AUTHOR]

Steel processing hydroxide sludge (SPHS) is a waste from the treatment of rinse water generated during stainless steel processing. Cr(VI) concentrations of up to 20 mg/L were observed in the leachate of a landfill mono-section receiving SPHS. This was surprising since the rinse water is free of Cr(VI) and compliance tests of the fresh SPHS gave no indication of Cr(VI) mobilization. The aim of this study was to identify the processes conducive to the formation of Cr(VI) with emphasis on the effect of H 2 O 2 used in the elimination of NO 2 − . Rinse water, SPHS, and the landfill leachate were characterized in samples collected over a period of several months. The water treatment process was downscaled to laboratory conditions and the generated SPHS was investigated for Cr(VI) desorption. Results showed that overdosing H 2 O 2 with respect to NO 2 − caused the formation of Cr(VI) which adsorbed to the SPHS and was only desorbed in presence of a competing anion. This hampers the recognition of the true leaching potential in compliance testing. Therefore, Cr(VI) leaching from the landfill is attributed to patchy zones of deposited SPHS that was generated from process water treatment at overdosed H 2 O 2 . In conclusion, Cr(VI) formation may circumvented by an automated process control based on the monitoring of either NO 2 − or H 2 O 2 . [ABSTRACT FROM AUTHOR]

In this article, a first report on novel hybrid technique (hydrodynamic cavitation + hydro gels packed bed adsorption) has been reported for dye degradation and subsequent adsorption of dye molecules. Initially, hydrodynamic cavitation (HC) was employed for the degradation of crystal violet dye molecules and subsequent adsorption of dye molecules have been carried out by adopting synthesized polymer hydro gels. Poly-acrylic acid (PAA)/nano composite hydro gels have been synthesized via ultrasound assisted emulsion polymerization technique. Modified bentonite clay was used as a cross-linker during the synthesis of PAA in the presence of ultrasound for the uniform dispersion of bentonite clay in the hydro gel matrix and to improve the adsorption capacity of the hydro gels. The morphology of synthesized hydro gels has been studied by XRD and TEM analysis. Operational parameters such as effect of inlet pressure on CV dye removal, effect of bentonite clay content in PAA hydro gel, effect of quantity of hydro gel loading in packed bed, effect of pH, and effect of inlet flow rate to the packed bed on integral removal of crystal violet dye in the hybrid system have been investigated. The combined process of hydrodynamic cavitation and packed bed hydro gel demonstrated the higher percentage removal of the crystal violet dye as compared to packed bed hydro gel alone. Synergistic effect of combined technique was evaluated based on the total organic carbon removal from the dye solution. [ABSTRACT FROM AUTHOR]

Mn 2+ /H 2 O 2 /O 3 , an ozone-based advanced oxidation process, was investigated in acidic solution. Acetic acid (HAc) was selected as the target compound to be degraded because it is often the final product of macromolecules degraded by chemical oxidation. The results showed that only Mn 2+ /H 2 O 2 /O 3 could effectively remove acetic acid at initial pH 1.0, while others like O 3 , H 2 O 2 /O 3 , Mn 2+ /O 3 and Mn 2+ /H 2 O 2 almost had no removal ability, indicating that the coexistence of Mn 2+ , H 2 O 2 and O 3 was of great necessity to ensure the high removal rate of acetic acid in acidic solution. Optimized parameters suggested that there existed an optimal ratio of concentration of Mn 2+ to concentration of H 2 O 2 for acetic acid removal. The above results are of significance for effective treatment of acidic wastewater containing refractory pollutants. The mechanism study showed that Mn 2+ /H 2 O 2 /O 3 in acidic solution was not associated with the generation of hydroxyl radicals, but with the generation of highly active intermediate Mn 3+ . [ABSTRACT FROM AUTHOR]

Researchers have explored electrokinetic remediation (EKR) for two decades due to its applicability, cost-effectiveness, flexibility, and wider scope for the soil remediation of organic and inorganic contaminants. The integration of the EKR technique with persulfate-based advanced oxidation has received considerable attention recently. Persulfate (PS) can degrade into strong oxidants, such as sulfate (SO 4 •−) and hydroxyl radicals (•OH), which can degrade most of the hydrophobic organic contaminants (HOCs) in soil. Various studies have discussed the efficiency, synergistic effects, and futuristic scope of the EKR-PS technique. However, research on the challenges and limitations of the EKR-PS technique is limited. This review summarizes bench-scale studies of EKR-PS techniques, where new knowledge and insights have emerged, particularly regarding the role of surfactants, oxidants, and activators in the effective degradation of HOCs in low-permeability soils. We emphasize that it is essential to update our understanding of the enhanced EKR-PS technique in order to apply it to the remediation HOCs at the field level. Future research directions are also discussed. [Display omitted] • The EKR-PS technique has attracted researchers round the globe. • The EKR-PS technique has wide field-scale application, adaptive, and cost-effective. • Oxidants and activators play crucial roles in degradation of HOCs. • Surfactants coupled with Oxidants and activators enhances removal of HOCs. • Research on soil parameters, and co-contaminants in HOCs removal is warranted. [ABSTRACT FROM AUTHOR]

Surface oxidized pyrite (SOPy-90) was synthesized via calcination and showed much higher catalytic ability for sulfite than the pristine pyrite to degrade atrazine (ATZ). The impacts of SOPy-90 dosage, sulfite doses, and dissolved O 2 on the ATZ elimination by SOPy-90/sulfite system were studied. Furthermore, β-FeOOH was generated on the surface of oxidized pyrite, which played a significant role in the catalysis of sulfite by SOPy-90. The reaction pH (4.0–7.0) was acidified to 4 by adding SOPy-90, which was beneficial for the sulfite activation by both material and dissolved Fe2+ to produce SO 3 •−. The generated SO 3 •− was further oxidized by dissolved O 2 to form SO 4 •− as the predominant species, confirmed by the quenching experiments and EPR analysis. Besides, the Fe(II)/Fe(III) cycle was accelerated by the low-valent S(−II) on the SOPy-90 surface, thus enhancing the SOPy-90 catalysis capacity. The density functional theory (DFT) calculations revealed that Fe(II) was more likely to activate HSO 3 − to generate SO 3 •− on the SOPy-90 surface. The SOPy-90/sulfite system has good reusability and showed excellent performance to decompose ATZ in real water treatment. [Display omitted] • Surface oxide pyrite (SOPy-90) performed better in activating sulfite than pyrite. • The SOPy-90/sulfite system maintained good reusability in four sequential runs. • SO 4 •− was predominately responsible for atrazine degradation. • SOPy-90/sulfite exhibited greater potential than SOPy-90/PDS and SOPy-90/PMS in practical application. [ABSTRACT FROM AUTHOR]

Cobalt-based heterogeneous nanocatalysts have attracted much attention in activating persulfate to rapidly eliminate organic pollutant in water. However, it remains a challenge to realize the easily recovery of these nanocatalysts and reduce the leaching of Co ions. Herein, Co@C core-shell nanostructures are anchored on the surface of carbon cloth (CC). The as-obtained immobilized catalyst of Co@C/CC exhibits an enhanced catalytic activity and lower leaching of Co ions in comparison with the bare Co@C nanocatalyt because of the high electrical conductivity and carrier effect of CC. The Co@C/CC demonstrates efficient catalytic performance in activating peroxymonosulfate (PMS) for tetracycline (TC) degradation. 99% of TC can be quickly degraded by the Co@C/CC/PMS system, and the system has good durability and interference resistance as well as wide pH adaptability from 3 to 10. Scavenger quenching experiments and electron paramagnetic resonance (EPR) shows that the non-free radical pathway (1 O 2) is dominate contribute to the TC degradation. Finally, density functional theory (DFT) calculations yield C C as the primary attack site in TC, and the possible degradation pathways of TC are inferred. Importantly, the immobilized catalyst of Co@C/CC can achieve fast and simple collection and regeneration. This work provides new ideas for the preparation of efficient catalysts with easily recyclable for rapidly eliminate organic pollutant in water. • Co@C core-shell nanostructure anchored on carbon cloth (Co@C/CC) was prepared. • Carbon cloth can enhance the charge transfer and inhibit ion leaching. • Co@C/CC catalyst can achieve fast and simple collection and regeneration • Tetracycline is rapidly degraded in the Co@C/CC/PMS system. • The non-radical pathway is dominant in the Co@C/CC/PMS system. [ABSTRACT FROM AUTHOR]

Heterogeneous peroxymonosulfate (PMS) activation for the mineralization of pollutants has attracted growing attention, while alloying bimetal catalysts afford big promises in synergetic catalysis. Here, by an alteration of electrospun precursor, one-dimensional carbon nanofiber (CNF) integrated with Prussian blue analogs (PBA)-derived alloyed fine plasmonic FeNi 3 hybrid catalyst (FeNi 3 @CNF) was constructed by electrospinning technique with subsequent confinement calcination. The amount of PBA in fiber precursor and thermal treatment temperature were alternatively adjusted to control the distribution and concentration of alloyed FeNi 3 in carbon nanofiber. This unique structure combines the advantages of abundant internal porosity of N-doping carbon fiber and uniforms active FeNi 3 alloys with highly-exposed reactive sites, facilitating the electron transport and proximity of reactant molecules in catalytic oxidation. The synergistic and interfacial effect of optimal FeNi 3 @CNF endowed the ultra-fast degradation activity against bisphenol A (BPA) through rapid persulphate activation to generate four reactive active species. Specifically, 20 mg L−1 of BPA was completely degraded within 4 min with a reaction rate constant of 2.736 min−1. Impressively, by innovating the utilization of the Prussian blue precursor in electrospinning, the optimal FeNi 3 @CNF shows 18.5, 101.3, and 248.5 times activity enhancement in BPA degradation compared to that of Fe@CNF, Ni@CNF, and Fe&Ni@CNF, revealing the appreciable synergy of bimetallic alloys in PMS activation. In addition, the improved catalytic performance of FeNi 3 @CNF under light irradiation was also simulated, confirming that the enhanced photothermal conversion ability of plasmonic alloys and carbon fiber advance the degradation of BPA. [Display omitted] • Carbon nanofiber bearing alloyed ultrafine plasmonic FeNi 3 is constructed. • The exquisite structure of FeNi 3 @CNF possesses rich porous structure and enhanced charge transfer. • Excellent photothermal catalytic efficiency in BPA degradation can be achieved by FeNi 3 @CNF. • The reinforced intermetallic synergy for catalytic reaction is explored. [ABSTRACT FROM AUTHOR]

In this work, microorganism of Phanerochaete chrysosporium with iron-tolerating and accumulating abilities was cultivated and harvested as mycelial pellets, which could serve as a sustainable and environmental-friendly precursor for iron phosphide/N-doped biocarbon composite preparation. Through one-step pyrolysis process, the inherent Fe and P elements in mycelial pellet enabled the formation of well crystallized Fe 2 P particles, loading on N-doped biocarbon matrix. Benefiting from the porous structure, high specific surface area, N doping-induced defects and C O groups of biocarbon, as well as the good electron-donating property of Fe 2 P, the as-obtained Fe 2 P/BC composite performed well for bisphenol pollutant (e.g., BPAF) removal through peroxymonosulfate (PMS) activation. Specifically, almost complete BPAF removal was achieved within 30 min adsorption and 10 min catalysis process with an apparent reaction rate constant of 0.486 min−1. The good crystallinity and protective carbon layer wrapping on Fe 2 P enabled the wide pH adaptability and low iron leaching of Fe 2 P/BC in catalytic reaction. Inorganic anions and humic acid brought only slight inhibition for BPAF removal, which could be overcome by prolonging reaction time to 30 min. Further mechanism studies indicated that reactive oxygen species, e.g., SO 4 -•, •OH and 1O 2 were generated through both radical and non-radical pathways and contributed to BPAF degradation. After treatment by Fe 2 P/BC-PMS system, the total organic carbon (TOC) of original BPAF solution (20 mg L−1) was reduced by 51.6%. Fortunately, the residual degradation intermediate products showed much reduced ecotoxicity in both predicted (ECOSAR program) and experimental results (growth inhibition test using Raphidocelis subcapitata as ecological indicator). [Display omitted] • Fe-containing mycelial pellet served as sole precursor for Fe 2 P/BC composite preparation. • Both Fe 2 P particles and biocarbon matrix contributed to PMS activation. • Low iron leaching was observed in Fe 2 P/BC-PMS catalytic system. • BPAF degradation was dominated by 1O 2 , surface-bound SO 4 -• and •OH. • ECOSAR and growth inhibition test implied the detoxification of BPAF by Fe 2 P/BC-PMS system. [ABSTRACT FROM AUTHOR]

In this work, a three-dimensional cobalt-MOF ([Co 3 (cis-chhc)(H 2 O) 6 ] n , Co-H 6 chhc) (cis-H 6 chhc = 1,2,3,4,5,6-cyclohexane-hexacarboxylic acid) was hydrothermally synthesized to activate peroxymonosulfate (PMS). Co-H 6 chhc showed excellent sulfate radical-advanced oxidation processes (SR-AOPs) activation performance toward ATZ removal, in which 100% ATZ was degraded within 30 min due to the recycle of Co2+/Co3+. The effects of pH, PMS dosage, catalyst dosage, co-existing anions and natural organic matters (NOMs) for ATZ degradation were explored detailly. The reusability, stability and universality experiments were proceeded under optimal condition. It is worth noting that the long-term continuous ATZ degradation was accomplished via a self-developed device. • The Co-H 6 chhc showed good SR-AOPs catalysis performance toward ATZ degradation. • The influence of Cl− ion with different concentration for ATZ removal were explored. • The yield of HOCl played a key role on ATZ removal in Co-H 6 chhc/PMS/Cl− system. • A fixed-bed device was setup to remove ATZ for long-term operation. [ABSTRACT FROM AUTHOR]