Developing new catalysts for efficient degradation of micropollutants in water is of significant importance in advanced oxidation processes (AOPs). Herein, TiO2/C coated Co3O4 nanocages ...(Co3O4@TiO2/C) were synthesized and their performance on micropollutants degradation was evaluated. Specifically, cobalt-based Zeolitic imidazolate framework (ZIF-67) coated by a thin layer of titanium species and polydopamine (PDA) was used as a precursor for the preparation of Co3O4@TiO2/C by two-step calcination. The catalytic performance of peroxymonosulfate (PMS) activation towards the degradation of organic pollutants was investigated by using atrazine (ATZ) and Bisphenol A (BPA) as typical micropollutants. The efficiency and the effect of TiO2/C shell on the as-synthesized catalyst were analyzed by comparing Co3O4 derived from ZIF-67 and Co3O4/C derived from ZIF-67/PDA. ATZ degradation results showed that the Co3O4@TiO2/C catalyst was the most efficient for catalytic oxidation when 99.5% of ATZ was removed within 4 min, which is 57.5% and 74.6% faster than that of Co3O4@C and Co3O4, respectively. The enhanced performance of Co3O4@TiO2/C is attributed to their unique nanocages structure and improved specific surface area. The catalysis mechanisms and ATZ degradation pathways were presented based on the results of electron paramagnetic resonance (EPR), XPS, and LC-MS analysis. Our results might have added to the design of heterogeneous catalysts of large surface area for efficient PMS activation in AOPs.
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•ZIF-67@Ti/PDA was used as a precursor for the fabrication TiO2/C coated Co3O4 nanocages.•The resultant catalysts were used to activate PMS for atrazine and Bisphenol A degradation.•The enhanced catalytic performance is ascribed to the introduction of a thin TiO2/C shell.•The degradation kinetics and mechanism have been elucidated.
In this work, zero-dimensional (0D) high crystalline PrFeO3 worm nanocrystals were loaded over a three-dimensional (3D) rectangular WO3 to construct a 0D/3D PFO/W Z-scheme heterojunction by an in ...situ ultrasonic synthetic process. This heterojunction exhibited excellent photocatalytic activities towards the degradation of organic pollutants such as rhodamine B (RhB), Methylene blue (MB), and tetracycline hydrochloride (TC) in the presence of small amounts of H2O2 under visible-light irradiation. For example, the k value of PFO/W + H2O2 was about 67, 107, 45, 27, 11 and 14 times higher than pure H2O2, PrFeO3, WO3, PFO/W nanocomposite, PrFeO3+ H2O2 and WO3+H2O2 respectively during the degradation of MB. The trapping experiments and ESR measurements identified that the generated ·OH, ·O2−, and h+ were the active species involved in the catalysis. Further, the ·OH radical could be continuously generated by Fe3+/Fe2+ and W6+/W5+ conversion and played the dominant role in the degradation of organic pollutants. The superior photocatalytic performance of the PFO/W + H2O2 system was derived from the synergistic effect of the Z-scheme heterostructure and dual photo-Fenton-like oxidation (Fe3+/Fe2+ and W6+/W5+). A possible mechanism was postulated based on the results obtained. In summary, this study provided new insights into synthesizing an effectively heterogeneous 0D/3D Z-scheme dual photo-Fenton-like catalyst for water clarification.
Hydrothermal and wet impregnation methods are presented in this study for synthesizing CoOx(1 wt%)/Sn/Zr-codoped Fe2O3 nanorod photocatalysts for the degradation of organic pollutants and ...deactivation of bacteria. A hydrothermal route was used to synthesize self-assembled rod-like hierarchical structures of Sn(0–6%) doped Zr–Fe2O3 NRs. Additionally, a wet impregnation method was used to load CoOx onto the surface of photocatalysts (Sn(0–6%)-doped Zr–Fe2O3 NRs). A series of 1 wt% CoOx modified Sn(0–6%)-doped Zr–Fe2O3 NRs were synthesized, characterized, and utilized for the photocatalytic decomposition of organic contaminants, along with the killing of E. coli and S. aureus. In comparison with 0, 2, and 6% Sn co-doped Zr–Fe2O3 NRs, the CoOx(1 wt%)/4%Sn/Zr–Fe2O3 NRs photocatalyst exhibited an E. coli and S. aureus inactivation efficiencies (90 and 98%). A bio-TEM study of treated and untreated bacterial cells revealed that the CoOx(1 wt%)/4%Sn/Zr–Fe2O3 NRs photocatalyst led to considerable changes in the bacterial cell membranes’ morphology. The optimal CoOx(1 wt%)/Sn(4%) co-doped Zr–Fe2O3 NRs photocatalyst achieved degradation efficiencies of 98.5% and 94.6% for BPA and orange II dye, respectively. As a result, this work will provide a facile and effective method for developing visible light-active photocatalysts for bacterial inactivation and organic pollutants degradation.
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•In-situ Sn/Zr-codoped Fe2O3 NRs catalyst has been developed via a hydrothermal approach.•The effect of Sn co-doping on the properties of Zr–Fe2O3 NRs was systematically studied.•CoOx (1 wt%) catalysts were wet impregnated on the in-situ Sn/Zr-codoped Fe2O3 NRs.•CoOx (1 wt%)/in-situ Sn/Zr-codoped Fe2O3 NRs achieved 90 and 98% E.coli and S. aureus inactivation efficiency.•Photo-Fenton reaction pushed 94.6%, 98.5% of orange II dye, and BPA degradation under λ ≥ 420 nm.
A novel strategy to prepare CuFe2O4 nanostructures functionalized SiO2 nanofibrous membranes with outstanding softness, favorable magnetic susceptibility, and high catalytic activity for the ...degradation of organic pollutant.
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Fenton or Fenton-like technique, as one of the advanced oxidation processes, plays a significant role in the removal of non-easily degradable organic pollutants; however, most of such catalysts are fragile with poor structural integrity under large deformation, thereby restricting their wide applications. Herein, soft copper ferrite nanostructures functionalized silica nanofibrous membranes (CuFe2O4@SNM) were fabricated through a novel strategy with the combination of in-situ dopamine polymerization, ion adsorption, and cohesive precipitation method. Benefiting from the high metallic ion adsorption capacity of polydopamine together with the rapid co-precipitation of adsorbed ions on fiber surface in alkaline solution, the membranes possessed homogenously distributed nanostructured CuFe2O4, large specific surface area, and high pore volume, which are a benefit for the improvement of Fenton-like catalytic activity towards organic pollutants decomposition. The resultant soft CuFe2O4@SNM provided favorable catalytic performance towards organic pollutants with a relatively high degradation degree of 96% in 20 min, a fast removal rate of 0.148 min−1, and outstanding recyclability. The successful preparation of such fascinating ceramic nanofibrous membranes would provide a reference for further exploitation of new type Fenton or Fenton-like catalysts with outstanding softness towards wastewater purification.
Photo-catalysis is an effective way to remove organic pollutants in aqueous system since it can accelerate water splitting under solar energy to produce ∙O2-, which oxidizes toxic and harmful organic ...substances. Here, nitrogen-contained carbon quantum dots (NCQDs) were prepared by microwave-promoted co-carbonation of glucose and poly(hexamethylene guanidine) (PHMG) and loaded on the surface of poly(ether sulfone) (PES) micro-porous membrane through cross-flow filtration. Spherical Bi2WO6 particles were subsequently coated on NCQDs layer by vacuum filtration to fabricate a three-layer composite membrane (TLCM). Close contact between NCQD and Bi2WO6 layers in TLCM formed laminated hetero-junction structure, which decreased the band gap to 2.35 eV from 2.90 eV of Bi2WO6. TLCM showed 99.9% photo-catalytic degradation efficiency (DE) for azo-dye Congo red (CR) under 50 W white light LED for 2.3 h with reaction rate constant of 0.02317 min-1. Possible decomposition products of CR were naphthylamine, benzidine and aniline analyzed by GC-MS. TLCM also displayed 72.23% DE for tetracycline (TC).
The design and construction of magnetic semiconductor-based nanoreactor with high activity and selectivity toward highly toxic pollutant is a ground-breaking investigation for practical ...photocatalytic applications. Here, uniformly distributed ion imprinted ZnFe2O4 was compounded by employing ion imprinting technique with microwave-assisted. Extremely high toxic Cr(VI) (chromate and dichromate) was able to be selectively reduced to innoxious Cr(III) due to existence of quite a number of Cr(VI) imprinted cavities, Cr(VI) was directly reduced by e− in the imprinted layer (reduction rate reached 92.67%). Significantly, modification of mesoporous channels in the imprinted layer facilitated organic pollutants easily to contact with ZnFe2O4, which ensured the simultaneous photocatalytic degradation of tetracycline (C/C0 = 0.416) in different reaction channels. With a promoted stability for recycling, our research offered a creative and practical technique for efficient identification and selective reduction of targeted ion among abundant ions, with simultaneous degradation of complex organic contaminants.
Ion imprinted ZnFe2O4 achieves the goal of selective Cr(VI) reduction with simultaneous organic pollutants degradation based on different reaction channels. Display omitted
•Ion imprinted ZnFe2O4 is developed by utilizing microwave-assisted ion imprinting technique.•The existence of Cr(VI) imprinted cavity in the imprinted layer enhances the reduction selectivity.•Mesoporous provides the channel for the contact of ZnFe2O4 and tetracycline.•Different reaction channels achieves Cr(VI) selective reduction and tetracycline degradation.
•Dual radical/nonradical reaction in CuO/PMS system with SO4•−, •OH, and 1O2 generating.•Weak acid or base solution was beneficial for SOCs degradation in CuO/PMS system.•HCO3− and NOM could inhibit ...CBZ and ATZ degradation, but no influence for SMX.
Synthetic organic compounds (SOCs) degradation in PMS system activated by heterogeneous catalyst based on copper has drawn great attention in water treatment process.
Copper oxide (CuO) was employed as the heterogeneous activator for PMS owing to the excellent performance one-electron transformation to degrade SOCs represented by three common organic contaminations of SMX, CBZ, and ATZ. Scavenging experiments and EPR detection were conducted to explore the various reactive species. Moreover, the responsibility of copper in different valence for SOCs degradation also has been investigated. Finally, the influence of different reaction parameter on SOCs degradation also were explored including reactants concentration (PMS and CuO), initial pH, and water matrices of bicarbonate (HCO3−) and natural organic matters (NOM).
Various reactive species generation including SO4•−, •OH, and 1O2 have been confirmed for SOCs degradation in CuO/PMS system with the dual radical/non-radical reactions. The primary SMX degradation was dominant for non-radical reaction approach while that of CBZ and ATZ was radical approach. This study confirmed the feasibility and potential of CuO serving as the efficient heterogeneous activator for PMS activation and provided a sustainable promising technology for water environment protection.
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In this work, Z-scheme V2O5 loaded fluorinated inverse opal carbon nitride (IO F-CN/V2O5) was synthesized as a product of ternary collaborative modification with heterostructure construction, element ...doping and inverse opal structure. The catalyst presented the highest photocatalytic activity and rate constant for degradation of typical organic pollutants Rhodamine B (RhB) and was also used for the efficient removal of antibiotics, represented by norfloxacin (NOR), sulfadiazine (SD) and levofloxacin (LVX). Characterizations confirmed its increased specific surface area, narrowed bandgap, and enhanced visible light utilization capacity. Further mechanism study including band structure study and electron paramagnetic resonance (EPR) proved the successful construction of Z-scheme heterojunction, which improved photo-generated charge carrier migration and provide sufficient free radicals for the degradation process. The combination of different modifications contributed to the synergetic improvement of removal efficiency towards different organic pollutants.
Display omitted The photocatalytic activity of graphitic carbon nitride is greatly enhanced through a ternary collaborative modification process, including element doping of fluorine, Z-scheme heterostructure construction with vanadium pentoxide and inverse opal structure modification.
Photocatalytic degradation of organic pollutants has shown its promise in wastewater purification, however the photocatalytic activity on most catalysts are still unsatisfactory due to the poor ...reactive oxygen species production as a result of sluggish charge separation. Here, an innovative silicotungstic acid mediated charge transfer system over the Z-scheme g-C3N4/H4SiW12O40/Ag3PO4 photocatalyst is proposed, exhibiting remarkable photocatalytic activity toward oxygen activation for reactive oxygen species generation. We verify that the H4SiW12O40 with the unique Keggin units could serve as charge transfer mediator to speed up charge transportation between g-C3N4 and Ag3PO4, as a result showing dramatically enhanced charge separation efficiency. By virtue of the aforementioned advantages, the as-prepared Z-scheme photocatalyst of g-C3N4/H4SiW12O40/Ag3PO4 shows excellent photocatalytic performance toward carbamazepine degradation, where the pseudo-first-order rate constant is estimated to be 78, 18, and 9 times higher than that of g-C3N4, Ag3PO4, and g-C3N4/Ag3PO4. The innovative design of using H4SiW12O40 as solid charge transfer mediator offers new viewpoints in designing high-efficient photoctalysts for environmental related applications.
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