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The band structures of semiconductor photocatalysts fundamentally determine the photocatalytic activity and the H2 production from the visible-light-driven water-splitting reaction.We synthesize a suite of multicomponent sulfide photocatalysts, (CuAg) xIn2xZn2(1-2x)S2 (0⩽x⩽0.5), with tunable band gaps and small crystallite sizes to produce H2 using visible-light irradiation. The band gap of the photocatalysts decreases from 3.47 eV to 1.51 eV with the increasing x value. The (CuAg)0.15In0.3Zn1.4S2 (x = 0.15) photocatalyst yielded the highest photocatalytic activity for H2 production owing to the broad visible-light absorption range and suitable conduction band potential. Under the optimized reaction conditions, the highest H2 production rate is 230 μmolm-2 h-1 with a visible-light irradiation of 2.7 x 10-5 einstein cm-2 s-1, and the quantum yield reaches 12.8% at 420 ± 5 nm within 24 h. Furthermore, the photocatalytic H2 production is shown to strongly depend on their band structures, which vary with the elemental ratios and could be analyzed by the Nernst relation. [ABSTRACT FROM AUTHOR]

To fulfill photocatalytic H2 production under visible light irradiation, (CuAg) xIn2xZn2(1-2x) S2 photocatalysts were synthesized using the precipitation and calcination. X-ray diffraction (XRD), ultraviolet-visible absorption spectra (UV-Vis), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDS), and inductively coupled plasma mass spectrometry (ICP-MS) were employed to investigate band structures of the photocatalysts and evaluate photocatalytic activities. The results show that the absorption edges shift to longer wavelengths up to visible-light region and band gaps decrease with the increase of x. In addition, the conduction band potentials are close to the redox potential of H+/H2 with the increase of x. The prepared (CuAg) xIn2xZn2(1-2x) S2 (x = 0. 05 - 0. 30) photocatalysts exhibit the activities of H2 production under visible light irradiation, and (CuAg)0.15In0.3Zn1.4S2(x = 0. 15) shows the highest photocatalytic activity. The band structures of (CuAg) xIn2xZn2(1-2x) S2 were manipulated by adjusting the composition ratio, which will help design visible-light-response photocatalysts with the high activity and stability. [ABSTRACT FROM AUTHOR]

Abstract: Much progress has been made in the development of novel visible light photocatalysts that split water into hydrogen (H2) and oxygen (O2). In this study, we examine the impact of initial solution pH on H2 production using an Ru/(CuAg)0.15In0.3Zn1.4S2 photocatalyst under visible light irradiation. In addition, the reaction mechanism was analyzed by examining the oxidation products of the electron donor (I‾) at different solution pH values. The results show that the initial pH significantly influenced the rate of H2 production and quantum yield (QY). In particular, the photocatalyst yielded the highest apparent QY (∼12.8%) at 420 ± 5 nm and highest H2 production rate (∼525 μmol h−1) at pH 2; with increasing pH, the H2 production and QY decreased significantly. The oxidation product of I‾ at pH < 6 was mainly I3‾, whereas at pH > 6 water splitting did not occur at all, so no IO3‾ or I2 were observed. [Copyright &y& Elsevier]

Abstract: Efficient photocatalytic water-splitting systems require stable photocatalysts that have photocatalytic activity with repeated consecutive use. This study investigated H2 production under visible light irradiation with an Ru/(CuAg)0.15In0.3Zn1.4S2 photocatalyst and KI as an electron donor. In addition, the stability and reusability of the catalyst were evaluated over multiple cycles of H2 production and catalyst regeneration. The results show that sintering temperature influenced the crystallinity and photocatalytic activity, as indicated by the X-ray diffraction analyses and H2 production rates. In particular, the catalyst sintered at 873 K yielded the highest quantum yield of 4.6% at 420 ± 5 nm of wavelength. After seven consecutive reaction cycles, the quantum yield decreased from 4.6% to 3.0% at the end of the seventh cycle. The decrease probably occurred because (1) particles of the catalyst underwent pronounced aggregation, which led to the increase in particle size; and (2) a release of significant metal ions was observed during H2 production, which led to a loss of the catalyst mass and potential changes in the photocatalytic activity. This study will help facilitate a search of stable photocatalysts for water splitting. [Copyright &y& Elsevier]

[Display omitted] • Three flat-sheet immobilized photocatalytic membrane reactors (PMRs) based on Bi 2 WO 6 -g-C 3 N 4 /PVDF were constructed and compared. • A novel vertical PMR exhibited excellent photocatalytic removal performance. • Anti-fouling property of the PMR was analyzed by filtering bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA) and XDLVO theory. • PMR possessed superior long-term stability even after 6-cycles in 18 h continuous flow mode. • The atrazine's degradation pathway and its intermediates' toxicity were investigated. The high efficiency, anti-fouling performance and long-term stability of photocatalytic membrane reactors (PMRs) are critical in practical applications. Here, three flat-sheet immobilized PMRs based on Bi 2 WO 6 -g-C 3 N 4 /polyvinylidene fluoride (PVDF) photocatalytic membrane were constructed and compared for atrazine (ATZ) degradation under simulated sunlight. The photocatalytic removal rate of ATZ by the vertical PMRs was remarkable, at 78.98% in 6 h, and had a stable removal rate (about 65%) under continuous flow mode (18 h). Additionally, the reactor presented superior reusability and long-term stability with an ATZ removal rate of 65% even after at least 6 cycles in continuous flow mode. By filtering bovine serum albumin (BSA), humic acid (HA) and sodium alginate (SA) under simulated solar irradiation, it demonstrated good anti-fouling ability, which was further proved by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory. The degradation pathway and evolution of the intermediates were proposed by HPLC-QTOF-MS/MS and DFT calculations. The PMR in this work has great potential in the water treatment industry. [ABSTRACT FROM AUTHOR]

When MW is combined with different AOPs, MW promotes the formation of active groups (such as •OH, •SO 4 −, •O 2 − and 1O 2) of the system through thermal or non-thermal effects. Thus, MAOPs have great prospects in removing pollutants from wastewater, wastewater sludge, soil and landfill leachate, etc. [Display omitted] • The advantages of MAOPs based on different AOPs are introduced. • The wide application of MAOPs in different fields is given. • The effect of MW on the AOPs was discussed. • The future research objectives and challenges of MAOPs are presented. Microwave (MW) technology has been widely studied in the field of environmental remediation due to its rapid and uniform heating, "hot spot" effect, and nonthermal effect. MW combined with advanced oxidation processes can mineralize any pollutant. In this article, the theory of MW radiation is introduced, and the latest progress in research on microwave-enhanced advanced oxidation processes (MAOPs, including Fenton/Fenton-like, persulfate, photocatalysis, electrocatalysis, etc.) for degrading organic pollutants in wastewater, sludge, and soil is reviewed, and compares it with traditional treatment methods. We found that MAOPs improved pollutant degradation efficiency. The mechanisms of MAOPs are discussed, MW technology could be combined with AOPs to enhance the production of active species (such as •OH, •SO 4 −, •O 2 −, and 1O 2). However, applications of MAOPs are currently limited to the laboratory scale. Overall, this review may provide insights for the future development of MAOPs. [ABSTRACT FROM AUTHOR]

Antibiotics in surface water adversely affect food safety and aquatic ecosystem, which hinder biological water treatment, and advanced oxidation technology (AOPs) is of great significance. This study achieved nitroimidazole antibiotic metronidazole (MNZ) removal in a dielectric barrier discharge plasma (DBDP) process. A ternary Bi 2 Mn 4 O 10 /NiF (BMON) was synthesized via microwave-assistant to enhance the DBDP process. Compared with Bi 2 Mn 4 O 10 , BMON has a more stable structure with lower ion dissolution but higher oxygen vacancy (Vö) content. The DBDP process generates active species, and O 2 ⋅ − acts as an intermediate in forming 1 O 2 ⋅ − to degrade MNZ through multipath. The cycle of lattice oxygen (O L)/O 2 and Mn+/M(n−1)+ maintain the charge balance on the BMON surface, during which the transformation of Vö and 1O 2 improve the catalytic efficiency. Furthermore, MNZ possible degradation pathways were proposed by DFT calculations and ESI-QTOF-MS detection. The DBDP/BMON process exhibited great potential for heterogeneous catalytic in nitroimidazole antibiotic degradation. [Display omitted] • A ternary Bi 2 Mn 4 O 10 /NiF with high stability and high activity was synthesized via microwave-assistant coprecipitation method. • Systematically analyzed the relationship between oxygen vacancy and ternary metal elements. • DBDP/BMON generated 1O 2 to attack the high electron cloud density part on MNZ in multipath. • The DBDP/BMON process reduces the bioaccumulation of MNZ and diminished the overall eco-risk. [ABSTRACT FROM AUTHOR]

A novel Bi 2 WO 6 -g-C 3 N 4 /polyvinylidene fluoride (PVDF) composite ultrafiltration (UF) membrane (BWO-CN/PVDF) was prepared by microwave hydrothermal and immersion precipitation phase transformation method. The BWO-CN/PVDF-0.10 exhibited an outstanding photocatalytic removal rate of atrazine (ATZ) (97.65 %) under the simulated sunlight and enhanced permeate flux (1356.09 L·m−2·h−1). The multiple optical and electrochemical detection confirmed that combining ultrathin g-C 3 N 4 and Bi 2 WO 6 can increase carrier separation rate and prolong its lifetime. The quenching test revealed that h+ and 1O 2 were the prominent reactive species. Additionally, after a 10-cycle photocatalytic process, the BWO-CN/PVDF membrane presented remarkable reusability and durability. And it showed excellent anti-fouling performance by filtering BSA, HA, SA, and Songhua River under simulated solar irradiation. The molecular dynamic (MD) simulation showed that the combination of g-C 3 N 4 and Bi 2 WO 6 can enhance the interaction between BWO-CN and PVDF. This work opens up a new idea for designing and constructing a highly efficient photocatalytic membrane for water treatment. [Display omitted] • The visible-light responsive Bi 2 WO 6 -g-C 3 N 4 /PVDF composite UF membrane was prepared. • The composite membrane possessed excellent photocatalytic property, permeability and durability. • The anti-fouling and mechanical properties of the membrane were enhanced. • An internal electric field and S-scheme heterojunction were formed between Bi 2 WO 6 and g-C 3 N 4. • The interactions between Bi 2 WO 6 , g-C 3 N 4 and PVDF were proved by molecular dynamic simulation. [ABSTRACT FROM AUTHOR]

The sulfate radical-based advanced oxidation processes (SR-AOPs) offer huge potential for the removal of organic pollutants. In this study, Co(II)-intercalated δ-MnO 2 (Co-δ-MnO 2) catalyst was successfully prepared by a simple cation exchange reaction. The obtained Co-δ-MnO 2 exhibited high catalytic performance for the removal of dimethyl phthalate (DMP) under the activation of peroxymonosulfate (PMS), with the degradation efficiency reaching 100% within 6 h. Experiments and theoretical calculations revealed that interlayer Co(II) provided unique active sites in Co-δ-MnO 2. In addition, radical and non-radical pathways were confirmed to play a role in Co-δ-MnO 2 /PMS system. •OH, SO 4 • ̶, and 1O 2 were identified to be the dominating reactive species in Co-δ-MnO 2 /PMS system. This study provided new insights into the design of catalysts and laid a foundation for developing modifiable layered heterogeneous catalysts. [Display omitted] • Co(II)-intercalated δ-MnO 2 (Co-δ-MnO 2) was used to catalyze the PMS activation. • Co(II)/Co(III) cycle was realized in the nanoconfined interlayer of Co-δ-MnO 2. • DMP were degraded through the oxidation of •OH, SO 4 • ̶, and 1O 2. • Radical and non-radical pathways were confirmed to jointly promote degradation. • DFT analysis indicated that Co has higher PMS adsorption capacity than Mn. [ABSTRACT FROM AUTHOR]

• CuFe 2 O 4 /diatomite efficiently activated PMS for 100% removal of mixed pesticides. • CuFe 2 O 4 /diatomite/PMS system exhibited excellent anti-interference capability. • All O in ROS originated from PMS, independent of dissolved oxygen in water. • The generation of 1O 2 went through the process: PMS → O 2 •– → 1O 2. • The evolution of degradation intermediates and degradation pathways were proposed. Peroxymonosulfate (PMS) activation is a promising technology for water purification, but the removal performance of multiple pollutant matrices and the mechanism for reactive species transformation in the heterogeneous catalytic system remain ambiguous. Herein, a novel CuFe 2 O 4 /diatomite was fabricated for PMS activation to achieve efficient removal of typical pesticides. Uniform distribution of CuFe 2 O 4 on diatomite efficiently alleviated the agglomeration of CuFe 2 O 4 and increased specific surface area (57.20 m2 g−1, 3.8-fold larger than CuFe 2 O 4). CuFe 2 O 4 /5% diatomite (5-CFD)/PMS system showed nearly 100% removal efficiency for mixed pesticide solution within 10 min (0.10 g L−1 5-CFD and 0.40 g L−1 PMS) and excellent anti-interference performance towards various coexisting substances (≥90% removal efficiency). The electrochemical measurements confirmed that the lower charge transfer resistance of 5-CFD significantly enhanced the electron-transfer capacity between 5-CFD and PMS, accelerating the reactions among Fe(III)/ Fe(II), Cu(II)/ Cu(I), and PMS, further generating •OH (261.3 μM), 1O 2 (138.8 μM), SO 4 •– (11.8 μM), and O 2 •–. The O in reactive oxygen species didn't originate from dissolved oxygen (DO) but PMS, independent of the low solubility of DO and slow diffusion rate of O 2 in water. Furthermore, the production of 1O 2 went through the process: PMS → O 2 •– → 1O 2 , and SO 4 •– could rapidly convert into •OH. The degradation pathways and the evolution of intermediates were proposed by HPLC-QTOF-MS/MS and DFT calculations. QSAR analysis illustrated that the toxicity became lower with the reaction process. This study provides novel insights into the mechanism for pesticide degradation and active species transformation and the anti-interference capability of systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Effective remediation of pesticide-contaminated sites is challenging due to high concentrations of pollutants with complete habitat destruction. Herein, microwave (MW)-activated persulfate (PS) system was proposed for remediation of organochlorine pesticide contaminated soil with atrazine (ATZ) as representation. The results revealed that the MW/PS system could achieve 97.9% of ATZ (50 mg/kg) degradation after treatment of 60 min, superior to that by conventional heat-activated PS. And more excellent degradation performance was identified in relatively higher microwave temperature (80 °C) with appropriate PS concentration (24 mmol/L), MW power (400 W) and water-soil ratio (1:1). Moreover, the MW/PS system possessed high tolerance to co-existing substances including C l − , H C O 3 − and H 2 P O 4 − , and appropriate organic substance content favored ATZ degradation in soil. Reactive oxygen species consisting of S O 4 • − , O H • , O 2 • − and 1O 2 contributed to ATZ decomposition, among which O 2 ∙ − played a principal role. The ATZ degradation pathway was then elucidated by combination of HPLC/MS spectra and DFT calculations, and ATZ overall toxicity was effectively alleviated in MW/PS system in term of toxicity assessment. Additionally, the MW/PS system presented high-performance degradation on such organochlorine pesticides as trichloro ethylene, tetrachloride, hexachlorobenzene and chlordane, suggesting great potentials of this system for remediation of organochlorine pesticides contaminated sites. [Display omitted] [ABSTRACT FROM AUTHOR]

Diatomic metals catalysts (DAMCs) have attracted researchers' attention in Fenton-like reactions for persistent organic pollutants elimination. A novel composite of Cu–MnO 2 loaded on the nickel foam (Cu–MnO 2 /NF) was synthesized and creatively combined with a microwave (MW) enhanced Fenton-like system—promoting the p -nitrophenol (PNP) removal efficiency to 92.4% within 10 min. The synergistic effect (ξ) between Cu–MnO 2 /NF and power-control MW-Fenton-like process was up to 11.69 ≫ 0, and the non-thermal result significantly contributed. The participation of Cu–MnO 2 /NF significantly increased the system's energy efficiency from 3.58 mg·kWh−1 to 44.35 mg·kWh−1. Different from specific degradation, the system maintained high removal efficiency with various pollutants (methylene blue (MB), rhodamine B (RhB), bisphenol A (BPA), and diclofenac sodium (DCF)). The stability of CuMnO 2 /NF was verified via the recovery experiment, and the applicability of the MW-Fenton-like system has been confirmed. The PNP degradation mechanism was systematically discovered by electron paramagnetic resonance (EPR) detection and radical scavenging experiments. Multiple active species (HO•, e−, O 2 •-, h+, and 1O 2) were generated on the Cu–MnO 2 /NF surface via electronic transfer and the selective absorption of microwaves. Overall, this study proposes a new possibility in the MW-Fenton-like technology investigation. [Display omitted] • MW enhanced Cu–MnO 2 /NF Fenton-like system has high efficiency in PNP removal. • The synergy between catalysts and microwaves was systematically investigated. • The non-thermal effect is the major activation factor in the MW-Fenton-like system. • The application of Cu–MnO 2 /NF could increase energy efficiency effectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Anchoring FeCo 2 O 4 on diatomite supplied more active sites for 100% ATZ removal. • The system exhibited high adaptability to pH conditions and complex water matrices. • High mineralization (>57%) with minimal leached Co was maintained after 6 cycles. • Co/Fe bimetallic valence conversion generated abundant ROS dominated by SO 4 •−. • ATZ degradation pathways were proposed by mass spectra and DFT calculations. The adaptability and stability of catalysts guarantee efficient catalytic performance. Hence, we fabricated FeCo 2 O 4 /diatomite for efficient peroxymonosulfate (PMS) activation. Distinct from stacked FeCo 2 O 4 , FeCo 2 O 4 /diatomite possessed a 1.2-fold larger specific surface area (94.84 m2 g−1), achieving 100% ATZ removal within 10 min at 0.2 g L−1 PMS and 0.1 g L−1 FeCo 2 O 4 /diatomite. The system could adapt to a broad pH range (3–11) and complex water matrices, efficiently removing multiple contaminants. High removal performance (>92%) and mineralization (>57%) were maintained after six cycles with minimal leached Co (0.10 mg L−1). The conversion between ≡Fe(III)/≡Fe(II) and ≡Co(III)/≡Co(II) could trigger PMS persistently, producing abundant active species, in which SO 4 •− was dominant. Then, intermediates and degradation pathways were proposed based on DFT calculations and ESI-QTOF-MS/MS data. Toxicity analysis showed that most intermediates were more eco-friendly than ATZ. This study developed FeCo 2 O 4 /diatomite with superior catalytic performance, high adaptability, and stability for eliminating refractory organic pollutants. [ABSTRACT FROM AUTHOR]

Chloronitrobenzenes are typical refractory aromatic halogenated nitroaromatic and high-toxic contaminants. The reduction process of chloronitrobenzenes cannot realize their mineralization, and the existence of chlorine group is detrimental to degradation through single chemical oxidation technology. Herein, the Au nanoparticles and graphitic carbon nitride co-modified TiO 2 nanotube arrays (Au/g-C 3 N 4 /TNAs) photoanodes were fabricated to degrade o -chloronitrobenzene (o -CNB) target pollutant in photoelectrocatalytic (PEC) system. The Au/g-C 3 N 4 /TNAs fabricated with 0.20 mM HAuCl 4 0.4 H 2 O (Au/g-C 3 N 4 /TNAs-0.20) had more superior optical and photoelectrochemical properties than other fabricated photoanodes. Au/g-C 3 N 4 /TNAs-0.20 photoanode increased dechlorination efficiency through reduction process, which was beneficial to o -CNB degradation and TOC removal. The coexistence of anions and humic acid inhibited the PEC degradation of o -CNB. The photogenerated electron, •O 2 −, hole and •OH participated in o -CNB degradation in PEC system. The degradation pathway of o -CNB was inferred through GC-MS spectra and DFT calculation. The acute toxicity and bioaccumulation factor of o -CNB were effectively reduced by PEC degradation. [Display omitted] • Au/g-C 3 N 4 /TNAs photoanodes were fabricated for PEC degradation of o -CNB. • The g-C 3 N 4 and Au nanoparticles improved photoelectrochemical properties of TNAs. • Au/g-C 3 N 4 /TNAs photoanode increased dechlorination and TOC removal rate of o -CNB. • Degradation pathways of o -CNB were proposed by GC-MS analysis and DFT calculation. • Overall toxicity of o -CNB was reduced after PEC degradation by Au/g-C 3 N 4 /TNA-0.20. [ABSTRACT FROM AUTHOR]

[Display omitted] • The matrix NiF participated in the formation and construction of the 3D ternary LDH. • Established DBDP + ZnFe-LDH/NiF was an efficient, robust, and energy-wise system for DUR degradation. • Ternary metals electron transfer promoted the sustainability generated of functional active species in DBDP. • DFT calculation and experiments illustrated the possible DUR degradation pathway. Dielectric barrier discharge plasma (DBDP) has attracted much attention because of its energy saving, high efficiency, and simultaneous production of various active substances. In this work, a three-dimensional (3D) ZnFe-layered double hydroxides (LDH)/nickel foam (NiF) was rationally engineered and synthesized to overcome the problem of active substances insufficient use and clogged pipes in DBDP. With the assistance of ZnFe-LDH/NiF, the removal efficiency of diuron (DUR) increased from 85.98 % to 96.52 %, and the energy efficiency increased from 1074 mg·kWh−1 to 1281 mg·kWh−1. In various circumstances, the DBDP + ZnFe-LDH/NiF process performed a strong anti-interference ability, high stability, and reusability. The improvement of catalytic degradation ability could be attributed to the combined action of the Fenton-like process and O 3 catalysis, all three elements participating in the electron transfer. With the help of quenching experiments, reactive oxygen species (ROS, including OH, 1O 2 , and O 2 −) were identified as the dominant active substance, significantly contributing to DUR elimination. Density functional theory calculation (DFT) and quadrupole-time of flight-liquid chromatography/mass spectrometry (Q-TOF-LC/MS) reached the same conclusion that C N and C−Cl were the main sites attacked by electrophiles and radicals. In summary, the combination of DBDP and ZnFe-LDH/NiF sheds new light on catalyst design and DBDP application. [ABSTRACT FROM AUTHOR]

Designing non-metallic catalyst as persulfate (PS) activator for effective organic pollutants degradation in water is challenging. Herein, bovine-derived bone chars (BBCs) were prepared with different temperatures (300, 500 and 700 °C), which contained ordered mesoporous structures, thus realizing great phenol uptake (149.84 mg/g) with 100% degradation in combination with PS within 180 min. Furthermore, both reactive species (S O 4 • − ; · O H , O 2 • − and 1O 2) and electron transfer process contributed to phenol removal due to the abundant defects and functional groups on BBC700. Owing to the multiples mechanisms, the BBC700/PS system exhibited an excellent phenol mineralization rate of 89.6 ± 1.85%, accompanied by strong anti-jamming capacity to relatively extensive pH range (3.0–7.0), various co-existing constituents and water bodies. Additionally, DFT calculations and GC-MS were used to illustrate the 7 kinds of degradation intermediates and the overall toxicity was efficiently alleviated, thus proposing a tailored non-metallic catalyst with great potential in water purification. [Display omitted] • Adsorptive-catalytic capability of bovine-derived bone char was demonstrated. • S O 4 • − , · O H , O 2 • − and 1O 2 were identified in the BBC700/persulfate system. • Electron transfer process mediated by BBC700 contributed to phenol degradation. • Possible degradation pathway of phenol was proposed by CC-MS and DFT calculations. [ABSTRACT FROM AUTHOR]

Singlet oxygen (1O 2) has been regarded as an excellent active species for the effective degradation of pollutants. However, generating 1O 2 with high selectivity still remains a significant challenge. Herein, 1O 2 generation of 100% selectivity for peroxymonosulfate (PMS) activation was achieved by a strategy of indium-doped β-MnO 2 catalyst, affording a dimethyl phthalate degradation rate of 93% within 180 min. Indium active sites served as the active center of the PMS adsorption, and the redox cycling of indium among different valances promoted PMS activation by breaking S–O bond. Density functional theory calculation results demonstrated that HSO 5 - could be easily adsorbed at indium site to generate 1O 2 via effective electron transfer. The indium active sites and oxygen vacancies jointly regulated the PMS decomposition by a non-radical pathway with simultaneous 1O 2 generation. This work developed a novel indium-doped β-MnO 2 catalyst for complete selective generation of 1O 2 for highly efficient degradation of pollutants. [Display omitted] • A 5% indium doped β-MnO 2 /PMS system was established to remove DMP. • Indium served as the active site for PMS adsorption and activation. • Nonradical pathway (1O 2) was responsible for DMP degradation in the system. • DFT analysis indicated that indium doping promoted the breaking of S–O bond in PMS. • 1O 2 was produced on both indium site and oxygen vacancy during PMS activation. [ABSTRACT FROM AUTHOR]

Heterojunction photocatalysts Fe 2 O 3 –ZnO@C/g-C 3 N 4 (FZCCN) were prepared by precipitation and calcination in this study. Systematic characterization demonstrated that the tight interfacial contact was established between Fe 2 O 3 –ZnO@C and g-C 3 N 4 , and the FZCCN-4 (theoretical mass ratios of ZnO and g-C 3 N 4 was 4) had large BET surface area (110.136 m2 g−1). Bisphenol A (BPA) was selected to estimate the photocatalytic properties of FZCCN and the degradation reaction kinetics was analyzed at the same time. The results showed that, FZCCN-4 had the highest removal rate of BPA (100%, 60 min). The degradation rate of BPA by using FZCCN-4 was approximately 32 and 130 times higher than that of g-C 3 N 4 and Fe 2 O 3 –ZnO@C, respectively. ·O 2 − was proved to be the main active species by capture experiment and electron spin resonance. The UV–vis and PL results proved the formation of heterojunction in FZCCN. This study also identified the intermediates of BPA degradation and tested their toxicity. The excellent visible light catalytic performance of Fe 2 O 3 –ZnO@C/g-C 3 N 4 makes it an ideal material for degrading contaminants. [Display omitted] • The heterojunction photocatalyst Fe 2 O 3 –ZnO@C/g-C 3 N 4 was synthesized. • The Fe 2 O 3 –ZnO@C/g-C 3 N 4 catalyst had a large specific surface area. • The catalyst presented efficient removal performance of BPA. • The catalyst had a good adaptability in the range of pH = 5.0–10.0. [ABSTRACT FROM AUTHOR]

Designing Fe-carbon catalyst with multiple active sites for persulfate (PS) activation to water purification is challenging. Herein, nitrogen-doped biochar (NBC) loaded with ferrous sulfide (FeS) was synthesized via two-step ball milling. In FeS@NBC BM /PS system, both electron transfer process and reactive oxygen species (ROSs) including SO 4 ⋅ − , O ⋅ H , O 2 • − and 1O 2 contributed to phenol degradation. Surface-bound S(II) not only interacted with PS for generating SO 4 • − , but also accelerated Fe(III)/Fe(II) circulation by reducing Fe(III). NBC was favorable for phenol adsorption and exposure of oxygen-containing groups, graphitic and pyridinic N active sites, which mediated electron transfer or ROSs formation. Owing to multiple active sites, this system fast achieved almost complete phenol degradation with excellent adaptability to wide pH range of 3–9, high anti-interference capacity to coexisting substances, and was efficient to various water matrices. Furthermore, phenol degradation pathways were elucidated by DFT calculations with intermediate products showing lower toxicity, demonstrating great potentials of proposed system. [Display omitted] • Ball-milled N-doped biochar-supported FeS is synthesized for persulfate activation. • FeS@NBC BM shows 27.7 and 9.88-fold catalytic activity compared to NBC BM and FeS@BC. • Surface-bound S(II) participates in SO 4 • − formation and promotes Fe(III)/Fe(II) cycle. • Graphitic/pyridinic N mediate electron transfer or nucleophilic addition of PS. • Both radical and non-radical pathways are involved in phenol degradation process. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuO-Fe 2 O 3 /MXene was fabricated using a rapid microwave hydrothermal method. • The optimal synthetic and degradation conditions were investigated. • Effect of coexisting matter was researched based on DFT calculations. • Catalytic mechanism was proposed accompanied by degradation pathway analysis. CuO-Fe 2 O 3 /MXene was fabricated using a rapid microwave hydrothermal method and used for the enhanced peroxymonosulfate (PMS) activation and atrazine (ATZ) degradation. The ATZ degradation rate could reach up to nearly 100% within 60 min at pH = 6.4, with low dosage for CuO-Fe 2 O 3 /5% MXene (0.1 g‧L-1) and PMS (0.37 mM). Experimental results and DFT calculations showed that coexisting matter had little influence on ATZ degradation at low concentrations, indicating the excellent anti-interference capability of the system. Circulation and interaction of ≡Fe(III)/≡Fe(II) and ≡Cu(II)/≡Cu(I) produced SO 4 •- and •OH, O* and SO 5 •- could participate in the formation of 1O 2. Then, ATZ degradation pathways, including dealkylation, dichlorination-hydroxylation, alkyl hydroxylation, alkyl oxidation, olefination, and deamination-hydroxylation processes, were proposed based on DFT calculations and ESI-QTOF-MS/MS data. QSAR analysis illustrated that most intermediates were more environmentally friendly than ATZ. This study developed novel materials with superior catalytic performance for elimination of refractory organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

Coexistence of heavy metals and endocrine disrupting compounds in polluted water with competitive adsorption behavior necessitates design of tailored adsorbents. In this work, β-cyclodextrin modified magnetic rice husk-derived cellulose (β-CD@MRHC) which can provide independent functional sites for effectively binding the above two types of contaminants was synthesized and used for Pb(II) and BPA elimination in both unit and multivariate systems. Characterizations results confirmed successful β-CD grafting and Fe 3 O 4 loading, and the β-CD@MRHC had excellent magnetic property for its effectively recovery from water, which was not affected by the adsorption of pollutants. The β-CD@MRHC possessed superior adsorption performance with maximal Pb(II)/BPA uptake of 266.2 or 412.8 mg/g, severally, and the adsorption equilibrium was fleetly reached in 30 and 7.5 min. Moreover, the β-CD@MRHC could accomplish synergetic Pb(II) and BPA elimination through averting their competitive behaviors owing to diverse capture mechanisms for Pb(II) (ion exchange, complexation and electrostatic attraction) and BPA (hydrogen bonding and host-guest inclusion). Furthermore, after three cycles of step-wise desorption, the binding of Pb(II) as well as BPA byβ-CD@MRHC dropped slightly in dualistic condition. In summary, β-CD@MRHC was a promising tailored adsorbent to practical application for simultaneously removing heavy metals and organic matters from wastewater with high-performance magnetic recovery. [Display omitted] • Rice husk was modified by synergistic effects of β-CD grafting and Fe 3 O 4 loading. • β-CD@MRHC possessed excellent uptake of Pb(II) (266.2 mg/g) and BPA (412.8 mg/g). • Pb(II) and BPA could be simultaneously removed by β-CD@MRHC without competition. • Applying an external magnetic field could easily separate β-CD@MRHC from water. • Magnetic separation property of β-CD@MRHC was not affected by adsorbed pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • The visible-light responsive 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction was fabricated. • The Bi 2 WO 6 /g-C 3 N 4 catalyst presented superior removal performance of ATZ herbicide. • The catalyst possessed superior separation and migration rate for charge carriers. • Reactive radicals and intermediates of ATZ were identified and proposed. Atrazine (ATZ), as a widely used s-triazine herbicide, has persistence and biological toxicity in the environment. Photocatalytic technique is considered as sustainable and promising strategy for the degradation of emerging organic pollutants. Thus, 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction photocatalysts were synthesized via one-step hydrothermal method for ATZ degradation. The Bi 2 WO 6 /g-C 3 N 4 -0.15 exhibited 99.96% removal efficiency for ATZ and the rate constant was approximately 25, 4.8 and 10 times greater than the rate constants of Bi 2 WO 6 , g-C 3 N 4 and "Bi 2 WO 6 + g-C 3 N 4 ", respectively. The influence of synthesis reaction factors of Bi 2 WO 6 /g-C 3 N 4 and various environmental factors including catalyst dosage, ATZ concentration, pH, common anions and HA on photocatalytic property of Bi 2 WO 6 /g-C 3 N 4 were also investigated. The radical-quenching experiments proved that holes (h+), 1O 2 and O 2 – played pivotal roles in ATZ degradation in Bi 2 WO 6 /g-C 3 N 4 photocatalytic system. The ATZ degradation pathway involved dealkylation, alkyl hydroxylation, alkyl oxidation, dechlorination-hydroxylation and deamination-hydroxylation reactions, which was proposed by HPLC–MS/MS results and density functional theory (DFT) analysis. Moreover, quantitative structure–activity relationship (QSAR) evaluation showed that the ecotoxicity of many intermediates declined compared with ATZ. The 3D/2D Bi 2 WO 6 /g-C 3 N 4 heterojunction exhibited excellent photostability and pH adaptability, showing efficient practicality in the removal of refractory organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

Ethylenediaminetetraacetic acid crosslinked β-cyclodextrin modified biochar (BC-CD MW) was fast prepared by microwave-assisted one-pot process, and was applied to remediation of Cd and Pb contaminated soil. Batch adsorption studies showed that the BC-CD MW possessed superior adsorption performance with maximal monolayer Cd(II)/Pb(II) uptake of 39.56 or 208.36 mg/g spanning broad pH range of 2.0–6.0. Furthermore, by applying BC-CD MW dosage of 5%, labile Cd and Pb portions in soil were reduced from 74.91% to 56.61%–30.65% and 28.30% after simulated remediation of 30 days at 40% moisture content. In comparison with BC, the stable residue state content increased by 30.84% and 18.91% for Cd and Pb, respectively, by BC-CD MW treatment. Besides, the BC-CD MW was identified to implement Cd and Pb stabilization in soil via combined roles of electrostatic attraction, complexation and pore filling. Overall, this work suggested BC-CD MW as a high-performance amendment for heavy metals stabilization in soil. [Display omitted] • β-cyclodextrin was combined with biochar via microwave-assisted one-pot process. • The maximum uptake of Cd(II) and Pb(II) by BC-CD MW were 39.56 and 208.36 mg/g. • Labile Cd and Pb were reduced by 59.08% and 50.00% after 30 days of remediation. • Cd and Pb were stabilized by electrostatic attraction, complexation and pore filling. [ABSTRACT FROM AUTHOR]

Bioremediation by phosphate-solubilizing bacteria (PSB) has attracted extensive attentions due to its economical and eco-friendly properties for lead (Pb) passivation in soil. Herein, bone char (BC) supported biochemical composite (CFB 1 -P) carrying advantages of BC, PSB, iron sulfide (FeS) and carboxymethyl cellulose (CMC) was designed and applied to Pb passivation. The composite at a mass ratio of BC:CMC:FeS = 1:1:1 possessed high passivation efficiency (65.47%), and has been demonstrated to offer appropriate habitat environment for PSB to defend against Pb(II) toxicity, thus enhancing the phosphate-solubilizing amount of PSB to 140.72 mg/L for passivating Pb(II). Batch experiments showed that the CFB 1 -P possessed excellent adsorption properties with maximal monolayer Pb(II) uptake of 452.99 mg/g during an extensive pH range of 2.0–6.0. Furthermore, by applying CFB 1 -P dosage of 3% into Pb-contaminated soil, the labile Pb fractions were reduced from 29.05% to 6.47% after simulated remediation of 10 days, and converted into steady fractions. The CFB 1 -P was demonstrated to achieve high Pb(II) passivation through combined functions of chemical precipitation, complexation, electrostatic attraction and biomineralization, accompanied by the formation of more stable crystal structures, for instance, Pb 5 (PO 4) 3 OH, Pb 3 (PO 4) 2 and PbS. These results suggested CFB 1 -P as a potential alternative for efficient remediation of Pb-contaminated soil. [Display omitted] • Bone char supported CMC-stabilized FeS (CFB) with loading of PSB was prepared. • CFB provided effective shelter for PSB being free from toxic effect of Pb(II). • Phosphate solubilized by CFB 1 -P could reach 140.72 mg/L at 30 °C within 48 h. • Chemical precipitation, complexation and biomineralization related to Pb removal. • CFB 1 -P can transform Pb(II) into such stable structures as Pb 3 (PO 4) 2 and PbS. [ABSTRACT FROM AUTHOR]

[Display omitted] • CuFeO2/NPC composites were prepared at no nitrogen sources and reductant. • CuFeO2/NPC can effectively activate PDS to degrade nimesulide. • The OH, SO4- and 1O2 were the main reactive species for nimesulide degradation. • Mechanism of PDS activated by CuFeO2/NPC was clarified in detail. • Degradation pathway was proposed combined with HPLC/MS spectra and DFT calculation. The nitrogen self-doped porous carbons (NPCs) were prepared using alfalfa as raw material by pyrolysis method without additional nitrogen sources at various pyrolysis temperatures. The NPC supported CuFeO 2 (CuFeO 2 /NPC) composites with large BET surface area (113.18 - 517.56 m2 g−1) were successfully prepared by hydrothermal method without reductant. The NPC prepared at 600 °C (NPC-600) supported CuFeO 2 (CuFeO 2 /NPC-600) possessed the highest catalytic performance for activating peroxydisulfate (PDS) to degrade nimesulide compared to other CuFeO 2 /NPC composites. The OH, SO 4 - and 1O 2 were the main reactive species for nimesulide degradation. The oxygen-containing functional groups, pyridinic N, graphitic N, and Fe3+/Fe2+ and Cu2+/Cu+ redox cycles were demonstrated to be extremely important in activating PDS to produce reactive species. The degradation pathway of nimesulide was proposed combined with the HPLC/MS spectra and DFT calculation, and the overall toxicity of nimesulide were effectively alleviated in CuFeO 2 /NPC-600+PDS system according to toxicity prediction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Addition of Cu/Fe-AO-PAN to DBDP process can improve 4-FP abatement, as well as defluorination efficiency and TOC removal. • Enhanced 4-FP removal was attributed to the Fenton-like process between Cu/Fe-AO-PAN and H 2 O 2 produced by DBDP. • The formation of binuclear metal complexes when H 2 O 2 , Cu2+ and Fe3+ existed simultaneously was proposed. The enhancement effect of Cu/Fe-amination-polyacrylonitrile (Cu/Fe-AO-PAN) as a catalyst for H 2 O 2 produced by dielectric barrier discharge plasma (DBDP) on 4-fluorophenol (4-FP) degradation was explored. The addition of Cu/Fe-AO-PAN significantly increased the 4-FP removal rate and degradation energy efficiency from 61.0% and 1777 mg kWh−1 to 75.6% and 2203 mg kWh−1, respectively. The homologous total organic carbon (TOC) removal and defluorination efficiency were both increased (from 52.1% to 63.0% and 48.0% to 54.2%, respectively). The role of H 2 O 2 production was investigated by influencing parameter analysis and radical scavenging experiments. OH was verified to be a reactive species that increased 4-FP abatement, and was generated through electron transfer and binuclear metal complex formation between Cu/Fe-AO-PAN and H 2 O 2 during the Fenton-like process. This study provides a new insight into efficient wastewater treatment under DBDP process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The visible-light responsive Fe(III)-TiO 2 /PVDF composite membranes were prepared. • The composite membrane exhibited abilities of both filtration and photocatalysis. • Reactive radicals and degradation intermediates during reaction were identified. • The anti-fouling and mechanical properties of the membrane were enhanced. • The composite membrane showed an excellent reusability for 9 cycles. A novel Fe(III)-TiO 2 /polyvinylidene fluoride (PVDF) composite ultrafiltration (UF) membrane was prepared by using phase inversion method. The structural characteristics, as well as the photocatalytic, antifouling and reusability properties, of composite membranes were investigated. Our results showed that the reaction of bisphenol-A (BPA) degradation fitted the pseudo-second-order kinetics models. The Fe-TiO 2 /PVDF-0.10 composite membrane achieved a higher BPA degradation efficiency (69.9%) within reaction time of 180 min than pristine PVDF membrane 45.1%. The quenching tests and ESR results confirmed the dominant role of hole (h+) and O 2 − as active species responsible for BPA degradation in the photocatalytic system. Combing pathway of photocatalytic degradation of BPA and quantitative structure activity relationship (QSAR) analysis indicated decline in toxicity of most intermediates compared with BPA. Additionally, the composite membrane also exhibited a higher permeation flux (585 L·m−2·h−1) and water flux recovery rate (>70%) under simulated visible-light irradiation, indicating better antifouling property of the membrane. Moreover, excellent durability and reusability were demonstrated by a insignificant loss of photocatalytic efficiency losses (4%) after 9-cycle operation. The incorporation of Fe(III)-TiO 2 could improve physical and chemical properties of UF membrane in terms of hydrophilicity, mechanical properties and thus photocatalytic anti-fouling performance, which broadens the application field of membrane filtration technology. [ABSTRACT FROM AUTHOR]

The dielectric barrier discharge plasma (DBDP) process has received extensive attention for the removal of organic contaminants from water. A novel microwave-assisted hydrothermal method was used to easily and rapidly synthesize MnFe 2 O 4 catalysts. Based on the DBDP process, MnFe 2 O 4 can enhance 4-fluorophenol (4-FP) abatement from 44.15% to 58.78% through the catalysis within 18 min. Then, the adjunction of O 3 generated by discharge can further boost 4-FP degradation to 94.94%. After the whole optimization process is complete, the associated pseudo-first-order reaction kinetic constant and energy efficiency were enhanced from 0.0327 to 0.1536 min−1 and 2067.13 mg kW h−1 to 4444.75 mg kW h−1, respectively. With the help of the condition, blank and radical capture experiments, the catalytic performance caused by MnFe 2 O 4 and O 3 was attributed to the joint action of Fenton-like reactions, photocatalysis (ultraviolet, UV), photoassisted Fenton reactions and O 3 catalysis. The overall downward trend of the possible intermediate toxicities indicated that the DBDP/MnFe 2 O 4 /O 3 process can effectively remove and mineralize 4-FP without the generation of more toxic intermediates. In addition, during the 5 cycles, MnFe 2 O 4 can maintain excellent recovery, efficiency and durability. In summary, the coupling of discharge plasma and MnFe 2 O 4 sheds new light on catalysis for wastewater treatment. [Display omitted] • MnFe 2 O 4 was obtained through microwave-assisted synthesis. • Excellent catalytic performance was formed between MnFe 2 O 4 and DBDP. • Catalysis essence was the promotion of •OH generation through multiple AOPs. • MnFe 2 O 4 was easily recovered from solution. [ABSTRACT FROM AUTHOR]

• Fe(III)-ZnS/g-C 3 N 4 catalyst was synthesized by a microwave hydrothermal method. • An SMPR was built for synchronous PNP wastewater treatment and catalyst recycling. • A PNP removal rate of 91.6% was achieved by the SMPR under simulated solar light. • The toxicity of PNP wastewater decreased overall after the photo-Fenton reactions. A submerged membrane photocatalytic reactor (SMPR) was constructed for the advanced treatment of p -nitrophenol (PNP) wastewater and rapid recycling of powdery catalyst, including a suspended photocatalytic system and a submerged microfiltration (MF) membrane system. To evaluate the performance of the SMPR, a visible-light responsive Fe(III)-ZnS/g-C 3 N 4 photo-Fenton catalyst was successfully synthesized by the microwave hydrothermal method, and several techniques were used to characterize the resulting catalyst. The key operation factors on the wastewater treatment efficiency were successively optimized. When the influent PNP concentration was 10 mg·L−1, initial pH was 5, catalyst dosage was 1.0 g·L−1, H 2 O 2 concentration was 170 mg·L−1, aeration rate was 0.50 m3·h−1, and operation time was 4 h, the PNP removal rate was 91.6% by the SMPR under simulated solar light irradiation. The rejection rate of the catalyst by the MF membrane was 100%, which realized the rapid separation and recycling of the suspended catalyst powders and avoided the catalyst loss and secondary pollution. The toxicity calculation results of PNP and its possible degradation products indicated that the toxicity of PNP wastewater decreased overall after the visible-light-driven photo-Fenton reactions. This study provided a combined photocatalysis-membrane filtration process that had a high treatment efficiency of refractory wastewater and solved the problem about the separation and recycling of the powdery catalyst synchronously. [ABSTRACT FROM AUTHOR]

• CuFeO 2 /BC were prepared by hydrothermal method without additional reducing agent. • CuFeO 2 /BC as heterogeneous Fenton-like catalyst degraded efficiently TC. • The optimization of TC degradation depending on RSM based on CCD was conducted. • Fe3+/Fe2+ and Cu2+/Cu+ redox cycles contribute to the catalytic activity of CuFeO 2 /BC. • The degradation intermediates of TC and toxicity analysis were evaluated. The heterogeneous Fenton-like catalysts biochar modified CuFeO 2 (CuFeO 2 /BC) were fabricated by hydrothermal method without additional chemical reducing agent. The systematic characterization demonstrated that higher CuFeO 2 particles dispersion and larger BET surface area of CuFeO 2 /BC catalyst contributed to higher catalytic activity towards the tetracycline (TC) degradation compared to pure-phase CuFeO 2. The optimum conditions for TC removal were 598.63 mg L-1 of CuFeO 2 /BC-1.0, 57.63 mM of H 2 O 2 and pH = 6.27 according to the result of a response surface methodology based on the central composite design. The CuFeO 2 /BC-1.0 exhibited an excellent reusability and good stability by recycling degradation. The OH was evidenced to the main active radical by scavenging experiments and electron spin resonance. The XPS revealed that the high catalytic efficiency was attributed to the synergistic effect of Fe3+/Fe2+ and Cu2+/Cu+ redox cycles, and the degradation intermediates of TC and toxicity analysis were evaluated. [ABSTRACT FROM AUTHOR]

• NaLa(CO 3) 2 decorated magnetic biochar was prepared via one-pot hydrothermal method. • La-Fe-BC has excellent phosphate uptake of 330.86 mg/g over a wide pH range of 3–8. • La-Fe-BC can be magnetically recycled with over 65% of removal efficiency remained. • La (H CO 3) 2 + and La (CO 3) 2 - on La-Fe-BC are believed to enhance the phosphate uptake. • Electrostatic and ligand exchange dominated the phosphate adsorption by La-Fe-BC. Phosphate elimination is vital for the remediation of eutrophication to avoid deterioration of water quality. Lanthanum (La) based adsorbents have been proven to have the potential for the removal of phosphate in contaminated water because of its strong affinity for phosphate. Herein, we report the high efficiency of NaLa(CO 3) 2 decorated magnetic biochar described as La-Fe-BC for the elimination of phosphate in water. The adsorbent was simply and facilely prepared through a one-pot hydrothermal method, and the characterization results confirmed the effective activation of biochar by KHCO 3 and the successful infusion of NaLa(CO 3) 2 and Fe 3 O 4 onto the surface of La-Fe-BC. The batch adsorption studies revealed that the La-Fe-BC exhibited an excellent monolayer phosphate uptake of 330.86 mg/g over a wide pH range of 3.0–8.0, undisturbed affinity to phosphate in the presence of various co-existing ions (e.g. NO 3 - , S O 4 2 - and C l -), prominent magnetic separation efficacy of 91%, superior reusability with more than 88% of desorption efficiency and 65% of phosphate uptake maintained after five adsorption-desorption recycles. Thermodynamic results presented a negative value of Δ G 0, clearly indicative of a favorable and spontaneous reaction, while the positive values of Δ H 0 and Δ S 0 affirmed the endothermic characteristic of phosphate uptake onto La-Fe-BC with an increase in randomness. The La groups (i.e. La (CO 3) 2 - and La (H CO 3) 2 +) on La-Fe-BC are believed to enhance the phosphate binding owing to a combination of electrostatic attraction and inner-sphere complexation via ligand exchange. Overall, this study enables the omnidirectional enhancement of tailored adsorbents to the depollution of phosphate contaminated water. [ABSTRACT FROM AUTHOR]

• Zn 0.94 Fe 0.04 S/g-C 3 N 4 was synthesized by a rapid microwave hydrothermal method. • This catalyst exhibited high activity with large surface area and short synthetic time. • Photo-Fenton reactions played a dominant role in the PNP degradation. • PNP degradation involved denitration and hydroxylation processes. The visible-light responsive hybrid catalysts (Zn 0.94 Fe 0.04 S/g-C 3 N 4 or ZCN) were synthesized by a rapid microwave hydrothermal method. Our results showed that the deposition of Fe-doped ZnS onto g-C 3 N 4 sheets prevented the aggregation of Zn 0.94 Fe 0.04 S and increased the surface area for mass transfer and light absorption. The highest degradation rate of p -nitrophenol (PNP) was 96.0% and the total organic carbon removal rate was 55.4% after 60-min simulated solar light irradiation on ZCN with Fe doping and g-C 3 N 4 loading ratios of 0.04 and 0.20, respectively. Hydroxyl radical played a dominant role in PNP degradation, which was primarily attributed to the photo-Fenton reactions. The PNP degradation pathway involved denitration and hydroxylation reactions according to the Density Function Theory calculations and HPLC-MS/MS results. The QSAR analysis indicated that the toxicity of most intermediates was lower than PNP. This study develops novel materials with superior photocatalytic activity for elimination of refractory organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

• Addition of PMS in dielectric barrier discharge (DBD) plasma can improve PFOA degradation and TOC removal. • Bubbling the O 3 (plasma) produced by discharge into plasma/PMS process performed a better effect. • Enhanced PFOA removal was attributed to increment of •OH and SO 4 •−. • The mechanism and possible degradation pathway of PFOA were proposed. Perfluorooctanoic acid (PFOA) has been used as a dispersant in the fabrication of fluoropolymers and is classified as a "likely carcinogen" by the United States Environmental Protection Agency. In this work, the enhanced degradation of PFOA in water by dielectric barrier discharge (DBD) plasma in a coaxial cylindrical structure with the assistance of peroxymonosulfate (PMS) was explored. The effects of PMS dosage, input voltage and solution circulation rate on PFOA removal were studied and analysed. Further, the activation of PMS by O 3 (plasma) produced by discharge was conducted through a gas pump (gas flow rate) to realize O 3 (plasma) secondary utilization. The results showed that with the addition of 445 mg·L−1 of PMS, the degradation of PFOA was improved by 26.6% (from 54.4% to 81.0%), which was further increased to 94.8% through the secondary utilization of O 3 (plasma). The enhanced degradation efficiency could be attributed to the formation of SO 4 •− and •OH through PMS activation. A possible degradation pathway of PFOA was proposed based on density functional theory (DFT) analysis and the related literatures. In addition, further toxicity analysis of the intermediates demonstrated that the toxicity at the oral 50% lethal dose (LD 50) in rats and the bioaccumulation factor were reduced. The overall findings could provide new insight into wastewater treatment. [ABSTRACT FROM AUTHOR]

Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs), as a promising technology for water decontamination, are constrained by low reaction kinetics due to limited reaction selectivity and mass transfer. Herein, we designed a nanoconfined FeCo 2 O 4 -embedded ceramic membrane (FeCo 2 O 4 -CM) under flow-through pattern for PMS activation. Confining PMS and FeCo 2 O 4 within nanochannels (3.0-4.7 nm) enhanced adsorption interactions (-7.84 eV vs -2.20 eV), thus boosting mass transfer. Nanoconfinement effect regulated electron transfer pathways from PMS to FeCo 2 O 4 -CM by modulating the active site transformation to ≡Co(III) in nanoconfined FeCo 2 O 4 -CM, enabling selectively generating 1 O 2 . The primary role of 1 O 2 in the nanoconfined system was confirmed by kinetic solvent isotope experiments and indicative anthracene endoperoxide (DPAO 2 ). The system enabled 100% removal of atrazine (ATZ) within a hydraulic retention time of 2.124 ms, demonstrating a rate constant over 5 orders of magnitude higher than the nonconfined system (3.50 × 10 3 s -1 vs 0.42 min -1 ). It also exhibited strong resilience to pH variations (3.3-9.0) and coexisting substances, demonstrating excellent stability indicated by consistent 100% ATZ removal for 14 days. This study sheds light on regulating electron transfer pathways to selectively generate 1 O 2 through the nanoconfinement effect, boosting the practical application of PMS-based AOPs in environmental remediation and potentially applying them to various other AOPs.

To address the issues of ZVI's susceptibility to oxidation and aggregation, ball milling and Na 2 S·9H 2 O modification were employed on ZVI to enhance its efficiency in removing Cr(VI) from effluent. The characterization results expressed that S-mZVI bm had mesoporous and macroporous structures, enabling successful capture of Cr(VI). Moreover, S-mZVI bm had the highest adsorption capacity for Cr(VI) (350.04 mg/g) at pH = 2.00 and reached kinetic equilibrium within 420 min. Furthermore, the adsorption of Cr(VI) by S-mZVI bm conformed to the Avrami-fractional-order model, demonstrated that the adsorption process indicated a complex multi-adsorption process. Meanwhile, the adsorption also fit to Langmuir and Sips models, suggesting monolayer-level adsorption with heterogeneous sites located on S-mZVI bm . The S-mZVI bm could enhance Cr(VI) adsorption through various synergistic mechanisms, such as electrostatic interaction, chemical precipitation, surface complexation, and reduction. Overall, this research presented an innovative perspective for the modification of ZVI, and S-mZVI bm could be widely applied in the practical remediation of wastewater containing Cr(VI)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Phosphorus (P) plays a crucial role in plant growth, which can provide nutrients for plants. Nonetheless, excessive phosphate can cause eutrophication of water, deterioration of aquatic environment, and even harm for human health. Therefore, adopting feasible adsorption technology to remove phosphate from water is necessary. Biochar (BC) has received wide attention for its low cost and environment-friendly properties. However, undeveloped pore structure and limited surface groups of primary BC result in poor uptake performance. Consequently, this work introduced the synthesis of pristine BC, parameters influencing phosphate removal, and corresponding mechanisms. Moreover, multifarious metal-doped BCs were summarized with related design principles. Meanwhile, mechanisms of selective phosphate adsorption by metal-doped BC were investigated deeply, and the recovery of phosphate from water, and the utilization of phosphate-loaded adsorbents in soil were critically presented. Finally, challenges and prospects for widespread applications of selective phosphate adsorption were proposed in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The self-sufficient heterogeneous photo-Fenton (SH-PF) system was constructed for doxycycline hydrochloride (DOH) degradation with hydroxyapatite (Hap) modified CuFeO 2 (Hap/CuFeO 2 ) composites through H 2 O 2 in-situ production. The modification of Hap could improve the specific surface area, visible-light response, light conversion efficiency, photoelectron lifetime and oxygen vacancies (OVs) of CuFeO 2 , which was conducive to H 2 O 2 production and DOH degradation in SH-PF system. Notably, Hap/CuFeO 2 fabricated with 0.5 g Hap (Hap/CuFeO 2 -0.5) displayed more superior performance for DOH degradation compared to other synthesized catalysts. The Hap/CuFeO 2 -0.5 load and initial solution pH for DOH degradation in SH-PF system were optimized, and the Hap/CuFeO 2 -0.5 had good reusability and stability. The • OH was the main active species for DOH degradation, and the facilitation effect of • O 2 - and photoelectrons on DOH degradation was associated with the H 2 O 2 production in the present work. In addition, the capture of photogenerated holes suppressed the recombination of photogenerated carriers, elevating the production of photoelectrons and thereby enhancing H 2 O 2 production and DOH degradation. The degradation pathways for DOH were proposed and the comprehensive toxicities of DOH were relieved after degradation in SH-PF system., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Polycyclic aromatic hydrocarbons (PAHs) in soil are potentially harmful to human health. However, the use of photocatalysis technology to treat soil contaminated with PAHs remains challenging. Therefore, TiO 2 /α-FeOOH composite photocatalyst has been synthesized by hydrothermal method and sol-gel method and applied to photocatalytic degradation of fluoranthene in soil. The morphology, elements, crystal structure, optical properties, electrochemical characteristics, and photocatalytic activity of TiO 2 /α-FeOOH have been characterized. Results showed that TiO 2 is tightly fixed on the surface of α-FeOOH, and TiO 2 /α-FeOOH had higher photocatalytic activity on photocatalytic degradation of fluoranthene in soil under simulated sunlight. The degradation efficiency of TiO 2 /α-FeOOH is 3.0 and 4.8 times higher than that of TiO 2 and α-FeOOH, respectively. This is attributed to enhanced photocatalytic ability by enhancing the transfer capacity of electrons and holes and broadening the spectrum absorption range. The highest degradation efficiency was achieved when the pH of the soil is neutral, the ratio of water/soil is 10:1, and the dosage of catalyst is 50 mg/g. In addition, it was proved that •O 2 - , h + , and 1 O 2 are the main active substances in the photocatalysis of TiO 2 /α-FeOOH. The possible mechanism of a Z-type electron transfer structure was also proposed. The degradation products of fluoranthene were detected, and the degradation pathway was deduced., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In situ growth of dispersed active sites on substrates is a strategy for designing highly efficient catalysts for sulfate radical (SO 4 •- )-based advanced oxidation processes (SR-AOPs). Here, magnetic biochar composite (Fe 3 O 4 /BC) was fabricated as an activator to trigger PDS (peroxydisulfate) for norfloxacin (NOR) removal, achieving reliable NOR removal efficiency (>90%) within 10 min. Based on the synergistic effect between Fe 3 O 4 and BC, the removal rate increases to 0.0265 L mg -1 min -1 . Fe 3 O 4 /BC exhibited decent adaptability, stability, and recyclability toward affecting factors variation during PDS activation, attributed to the synergistic effect between Fe 3 O 4 and BC. The electron transfer of magnetic Fe 3 O 4 coupled with the adsorption and conduction function of carbon skeleton, which overcomes typical problems as crystal agglomeration, metal leaching, and catalysts recovery etc. The electron-rich Fe(II) sites promote the radical pathway by generating reactive oxygen species (ROS, • OH, SO 4 •- and O 2 • - ), and radicals evolution contributing to the form of 1 O 2 in non-radical pathway. Under the effect of multipath in NOR degradation, HPLC-QTOF-MS spectroscopy and DFT calculation revealed the possible degradation pathway of NOR. In addition, according to toxicity prediction, the overall NOR contamination toxicity of NOR was effectively alleviated by Fe 3 O 4 /BC + PDS system. Overall, this study presents a promising composite in PDS activation and views the active species evolution in the NOR removal system, which is crucial for mechanism study in relevant research in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Activated peroxymonosulfate (PMS) processes have emerged as an efficient advanced oxidation process to eliminate refractory organic pollutants in water. This study synthesized a novel spherical manganese oxide catalyst (0.4KBr-β-MnO 2 ) via a simple KBr-guided approach to activate PMS for degrading dimethyl phthalate (DMP). The 0.4KBr-β-MnO 2 /PMS system enhanced DMP degradation under different water quality conditions, exhibiting an ultrahigh and stable catalytic activity, outperforming equivalent quantities of pristine β-MnO 2 by 8.5 times. Mn(V) was the dominant reactive species that was revealed by the generation of methyl phenyl sulfone from methyl phenyl sulfoxide oxidation. The selectivity of Mn(V) was demonstrated by the negligible inhibitory effects of Inorganic anions. Theoretical calculations confirmed that Mn (V) was more prone to attack the CO bond of the side chain of DMP. This study revealed the indispensable roles of high-valent manganese species in DMP degradation by the 0.4KBr-β-MnO 2 /PMS system. The findings could provide insight into effective PMS activation by Mn-based catalysts to efficiently degrade pollutants in water via the high-valent manganese species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Polycyclic aromatic hydrocarbons (PAHs) in soil have potential harm on human health. However, remediation of PAH-contaminated soils through photocatalytic technology remains a challenge. Therefore, the photocatalyst g-C 3 N 4 /α-Fe 2 O 3 was synthesized and applied to photocatalytic degradation of fluoranthene in soil. The physicochemical properties of g-C 3 N 4 /α-Fe 2 O 3 and various degradation parameters, such as catalyst dosage, the ratio of water/soil, and initial pH, were investigated in detail. In soil slurry reaction system (water/soil=10:1, w/w), the optimal degradation efficiency on fluoranthene was 88.7% after simulated sunlight irradiation for 12 h (contaminated soil=2 g, initial fluoranthene concentration=36 mg/kg, catalyst dosage=5%, and pH=6.8), and the photocatalytic degradation followed pseudo-first-order kinetics. The degradation efficiency of g-C 3 N 4 /α-Fe 2 O 3 was higher compared with P25. Degradation mechanism analysis showed that •O 2 - and h + are the main active species in photocatalytic degradation process of fluoranthene by g-C 3 N 4 /α-Fe 2 O 3 . Coupling g-C 3 N 4 and α-Fe 2 O 3 enhances the interfacial charge transport capacity via Z-scheme charge transfer route and inhibits the recombination of photogenerated electrons and holes of g-C 3 N 4 and α-Fe 2 O 3 , then significantly improves the production of active species and photocatalytic activity. Results showed that photocatalytic treatment of soil by g-C 3 N 4 /α-Fe 2 O 3 is an effective strategy for remediation of soils contaminated by PAHs., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Herein, magnetic porous pinecone-derived hydrochar (MPHC MW ) co-activated by KHCO 3 and K 2 FeO 4 through one-step microwave-assisted pyrolysis was innovatively synthesized for hexavalent chromium (Cr(VI)) and anthracene (ANT) removal from water. The analyses of characterization consequences and co-activation mechanisms not merely proved the high specific surface area (703.97 m 2 /g) and remarkable microporous structures of MPHC MW caused by the synergistic chemical activation of KHCO 3 and K 2 FeO 4 , but also testified successful loading of Fe 0 and Fe 3 O 4 on MPHC MW by the process of carbothermal reduction between K 2 FeO 4 and carbon matrix of hydrochar. The resultant MPHC MW possessed pH-dependence for Cr(VI), while adsorption for ANT was hardly impacted by the pH of solution. Moreover, the adsorption processes of MPHC MW could attain equilibrium within 60 min for Cr(VI) and 30 min for ANT with multiple kinetics, and the corresponding adsorption capacity for Cr(VI) and ANT was 128.15 and 60.70 mg/g, respectively. Additionally, the adsorption percentages of MPBC MW for Cr(VI)/ANT was maintained at 87.87/82.64% after three times of adsorption-desorption cycles. Furthermore, pore filling, complexation, electrostatic interaction, reduction and ion exchange were testified to enhance the removal of Cr(VI), while the ANT removal was achieved via π-π stacking, complexation, pore filling and hydrogen bonding force., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Norfloxacin (NOR) is an emerging antibiotics contaminant due to its high resistance to microbial degradation and natural weathering. In this study, Fe-doped ZnS photocatalyst (Zn 0.9 Fe 0.1 S) was deposited on nickel foam (Ni-foam) to improve photocatalytic activity under visible light irradiation. The mass ratio of Zn 0.9 Fe 0.1 S and Ni-foam was optimized to be 0.03 g catalyst versus per g Ni-foam (0.03 Zn 0.9 Fe 0.1 S/Ni-foam), which led to the highest removal rate of 95%. The optimal degradation condition for NOR over 0.03 Zn 0.9 Fe 0.1 S/Ni-foam was pH at 7.0, initial NOR concentration of 5 mg L -1 , and initial photocatalyst concentration of 11.7 g L -1 , with the highest first-order reaction rate constant of 0.025 min -1 and mineralization rate of 63.1%. The NOR removal rate on 0.03 Zn 0.9 Fe 0.1 S/Ni-foam photocatalyst (95%) was approximately four times of that obtained on Zn 0.9 Fe 0.1 S photocatalyst (25%). The increased photocatalytic performance could be attributed to the function of Ni-foam as excellent electron collectors that provided efficient photoinduced charge separation from Zn 0.9 Fe 0.1 S. The reactive species responsible for the degradation of NOR were photo-generated holes, hydroxyl radical, and superoxide radicals. Nearly 90% of the photocatalytic efficiency was retained over seven cycles and the released metal ion concentrations were <0.3% of the total mass of photocatalyst, suggesting high stability of the photocatalyst during the photocatalytic reactions. The aqueous/solid mass transfer and intraparticle mass transfer for Zn 0.9 Fe 0.1 S/Ni-foam were not limiting factors for the degradation of NOR. Therefore the Zn 0.9 Fe 0.1 S/Ni-foam photocatalyst could be applied in the degradation of hazardous pollutants., (Copyright © 2019. Published by Elsevier Ltd.)

Nickel foam (NF)-functionalized Co 3 O 4 -Bi 2 O 3 nanoparticles (CBO@NF) synthesized using a facile one-step microwave-assistant method were employed as catalysts to activate peroxymonosulfate (PMS) with bisphenol A (BPA) as the target pollutant. The crystallinity, morphology, and chemical valence state of the synthesized CBO@NF were analyzed using XRD, SEM, and XPS, respectively. Moreover, effects of the preparation parameters, including the calcination temperature and calcination time as well as the loading dosage, were evaluated in detail. A degradation efficiency of 95.6% was achieved within 30 min with the optimal degradation system. The CBO@NF/PMS system shows great catalytic activity in a pH range from 3.0 to 11.0. The stability and reusability of the CBO@NF supported catalyst was evaluated through a recycling experiment. In addition, the possible degradation mechanism was also explored using a quenching experiment and electron paramagnetic resonance (EPR) detection. The result shows that both the surface-bound SO 4 - and OH play significant roles during the degradation process, where the electron transfer of Co 2+ /Co 3+ , Bi 3+ /Bi 5+ , and Ni 2+ /Ni 3+ realizes the sustained regeneration of the active radicals. This work provides new insight for the practical applications of sulfate radical-based advanced oxidation processes (SR-AOPs) in wastewater treatment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

An effective peroxymonosulfate activator, ZnCo 2 O 4 , was synthesized through a microwave-assisted method. According to response surface methodology (RSM) using Box-Behnken design (BBD), the effects of four parameters, microwave temperature, microwave time, calcination time and calcination temperature, were investigated, and the results show that both the microwave temperature and calcination temperature have a great influence on the catalytic activity during the preparation process. In addition, a quadratic model is valid for computing and predicting the observed responses. The characteristics of the synthesized ZnCo 2 O 4 catalyst were analyzed with various equipments. The results show that the ZnCo 2 O 4 nanosheets are cubic crystals with a spinel structure and a high surface area of 105.90 m 2 ‧g -1 . Under the conditions of [ZnCo 2 O 4 ] = 0.2 g‧L -1 and [PMS]/[BPA] molar  = 2.0, the bisphenol A degradation efficiency reaches 99.28% within 5 min in the ZnCo 2 O 4 /PMS system. ZnCo 2 O 4 possesses great stability and reusability according to recycling experiments. In addition, the possible active radical species were confirmed through quenching experiments and EPR detection, indicating that surface-bound SO 4 - and OH play vital roles during the degradation process., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Degradation of perfluorooctanoic acid (PFOA) is important because of its global distribution, persistence and toxicity to organisms. In this work, the PbBiFeO 3 photocatalyst was prepared by the hydrothermal method. The effect of doping amount of reduced graphene oxide (rGO) on the decomposition of PFOA was investigated under 254 nm UV light. The results indicated that 100 mg L -1  PbBiFeO 3 with 0.5 wt% rGO exhibited the highest degradation efficiency for 50 mg L -1 PFOA at pH = 2.0 from aqueous solution. The removal rate of PFOA reached 69.6% after 8 h UV irradiation under the optimal conditions (PFOA concentration of 50 mg L -1 , Pb BiFeO 3 /0.5% rGO concentration of 100 mg L -1 , and pH of 2.0). The total organic carbon removal rate and defluorination rate were 28.0% and 37.6%, respectively. During the degradation process, four major intermediates with shorter chain length than PFOA (∼C4C7) were identified. The mechanism responsible for PFOA decomposition was supposed that OH attacked PFOA to form perfluoroalkyl alcohol and then was transferred to perfluoroalkyl fluoride which can easily undergo hydrolysis to form shorter-chain perfluorocarboxylic acids than PFOA. This indicated that the photocatalytic degradation of PFOA was an oxidation process through stepwise losing of CF 2 group., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A series of Fe-doped ZnS (Fex-ZnS) photocatalysts were synthesized using a one-pot hydrothermal method. The physicochemical properties of the as-prepared Fex-ZnS microspheres were characterized by different microscopic and spectroscopic techniques. Fe doping did not obviously change the morphology and crystallinity of ZnS, but effectively broadened the light response range into the visible-light region. Degradation of p-nitrophenol (PNP) was used to evaluate the photocatalytic performance of the Fex-ZnS catalysts under visible light irradiation with the addition of H2O2 to facilitate photo-Fenton-like reactions. The highest PNP removal rate of 83.8% after 180 min of irradiation was achieved under the optimal conditions, including a doping ratio of 6%, a H2O2 concentration of 3 mmol L-1 and a catalyst dosage of 0.8 g L-1. The effects of aqueous/solid mass transfer and intraparticle mass transfer limitations on the PNP degradation reactions were analyzed, indicating that the variations of catalyst size caused by different Fe doping ratios did not affect the photocatalytic reactions in this study. The PNP removal mechanism of the Fex-ZnS photocatalyst with H2O2 addition under visible light irradiation was proposed.

The sulfide photocatalyst of Zn 0.9 Fe 0.1 S was successfully synthesized by a facile microwave-assisted method, and Zn 0.9 Fe 0.1 S photocatalysts were characterized using SEM, EDX, XRD and BET. The specific surface area of synthesized Zn 0.9 Fe 0.1 S is 78.1 m 2 g -1 , and total pore volume is 0.4 cm 3 g -1 . With bisphenol A (BPA) as a target pollutant, photocatalytic system of UV + Zn 0.9 Fe 0.1 S + H 2 O 2 was set up. Some influencing parameters, including H 2 O 2 dosage, initial pH value, initial concentration of BPA and Zn 0.9 Fe 0.1 S dosage, were investigated, and the stability of the Zn 0.9 Fe 0.1 S was also studied during the photocatalysis. The optimum values of operating parameters were found at an initial pH value of 5.0, a H 2 O 2 dosage of 0.15 mmol L -1 and a Zn 0.9 Fe 0.1 S dosage of 0.08 g when the initial concentration of BPA was 10 mg L -1 . Under the optimal conditions, the highest removal rate of BPA achieved 95%. After seven consecutive reaction cycles, the degradation efficiency of BPA could still reach 85% and there was only a little dissolution of Zn 2+ and Fe 2+ . Compared with the traditional photo-Fenton system, the UV + Zn 0.9 Fe 0.1 S + H 2 O 2 system can not only improve the degradation efficiency of BPA, but also reduce the dosage of H 2 O 2 and thus reduce the processing cost., (© 2016 The American Society of Photobiology.)