The novel Fe-N co-doped ordered mesoporous carbon with high catalytic activity in m-cresol removal was prepared by urea-assisted impregnation and simple pyrolysis method.During the preparation of the Fe-NC catalyst,th...The novel Fe-N co-doped ordered mesoporous carbon with high catalytic activity in m-cresol removal was prepared by urea-assisted impregnation and simple pyrolysis method.During the preparation of the Fe-NC catalyst,the complexation of N elements in urea could anchor Fe,and the formation of C3N4during urea pyrolysis could also prevent migration and aggregation of Fe species,which jointly improve the dispersion and stability of Fe.The FeN4sites and highly dispersed Fe nanoparticles synergistically trigger the dual-site peroxymonosulfate (PMS) activation for highly efficient m-cresol degradation,while the ordered mesoporous structure of the catalyst could improve the mass transfer rate of the catalytic process,which together promote catalytic degradation of m-cresol by PMS activation.Reactive oxygen species (ROS) analytic experiments demonstrate that the system degrades m-cresol by free radical pathway mainly based on SO_(4)^(-)·and·OH,and partially based on·OH as the active components,and a possible PMS activation mechanism by 5Fe-50 for m-cresol degradation was proposed.This study can provide theoretical guidance for the preparation of efficient and stable catalysts for the degradation of organic pollutants by activated PMS.展开更多
Among the numerous transition metal catalysts,manganese-based compounds are considered as promising peroxymonosulfate(PMS)catalysts due to their low cost and environmental friendliness,such as cryptomelane manganese o...Among the numerous transition metal catalysts,manganese-based compounds are considered as promising peroxymonosulfate(PMS)catalysts due to their low cost and environmental friendliness,such as cryptomelane manganese oxide(K_(2-x)Mn_(8)O_(16):abbreviation KMnO).However,the limited catalytic performance of KMnO limits its practical application.In this work,iron-doped KMnO(Fe-KMnO)was prepared by one-step hydrothermal method to optimize its catalytic performance.Compared with KMnO/PMS system,Fe-KMnO/PMS system possessed more excellent removal efficiency of tetracycline(TC).Meanwhile,the Fe-KMnO/PMS system also exhibited good practical application potential and excellent stability.The mechanism of Fe-KMnO activation of PMS was further analyzed in detail.It was found that Fe participated in the redox of high-valent Mn,which promoted the activation of PMS.Moreover,The Fe site as an adsorption site enhanced the TC enrichment ability of the catalyst,reducing the mass transfer resistance and further enhancing the TC removal ability of Fe-KMnO/PMS system.This work not only provides an excellent PMS catalyst,but also offers new insights into the mechanism of PMS activation by bimetallic manganese-based catalysts.展开更多
Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation r...Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation rule of xylene under different conditions such as the ORP value of the spray liquid, pH value of the spray liquid, liquid-gas ratio of the spray liquid, residence time of xylene, and initial concentration of xylene was investigated. The results showed that at a low concentration, the pH value of the spray liquid had little effect on the degradation rate of xylene. The degradation rate of xylene rose with the increase of the ORP value of the spray liquid, the liquid-gas ratio of the spray liquid, the residence time of xylene, and the initial concentration of xylene.展开更多
Methotrexate(MTX)is one of the most consumed anti-cancer drugs in the pharmaceutical market around the world.The widespread occurrence of MTX in aquatic environment through hospital effluent has attracted increasing c...Methotrexate(MTX)is one of the most consumed anti-cancer drugs in the pharmaceutical market around the world.The widespread occurrence of MTX in aquatic environment through hospital effluent has attracted increasing concern due to its potential to induce water pollution.In the present study,the degradation of MTX in aqueous medium was investigated by UV-activated peroxymonosulfate(PMS).A significant improvement in degradation rate by increasing UV intensity and PMS concentration while the decrease in degradation efficiency with the increase of solution p H and initial concentration of MTX was observed.The proposed UV/PMS process could achieve more than 90%MTX degradation in 30 min with a good mineralization degree(65%).A pseudofirst order kinetic model was employed and successfully predicted the degradation of MTX.The effect of other operational parameters such as the initial concentration of the targeted compound,dosage of oxidant(PMS),solution p H and UV intensity on the degradation rate were investigated.At the last,the main transform intermediates were identified using LC–MS and possible degradation pathways were proposed.The results show that UV/PMS can be used as an efficient technology to treat pharmaceuticals such as methotrexate containing water and wastewater.展开更多
The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' ...The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' recombination rate,as well as wider and stronger visible light absorption capacity.Since the synergistic effect between g-C_(3 )N_(4) and MnFe_(2) O_(4),the photogene rated electron could transfer from g-C3 N4 to MnFe_(2) O_(4),which could promote the migration of electrons as well as enhance the photocatalytic activity and peroxymonosulfate(PMS) activation efficiency.Mn/G/D-5% composite displayed the excellent degradation performance of bisphenol A(BPA) with the removal efficiency of 99.9% under PMS/Vis system,which was approximately 2.47 and 63.8 times as high as that of the Mn/G/D-5%/PMS and Mn/G/D-5%/Vis system,respectively.Moreover,negative electricity derived from diatomite surface also promoted the photogenerated carriers' migration,and the degradation rate constant was around 2.4 times higher than that of MnFe_(2) O_(4)/g-C_(3) N_(4)(Mn/G).In addition,quenching experiments showed that both radical pathway(h^(+),·OH,·O_(2)^(-)and SO_(4)·^(-)) and non-radical pathway(^(1) O_(2)) were responsible for the degradation of BPA.展开更多
Metal-based perovskite oxides have contributed significantly to the advanced oxidation processes(AOPs)due to their diverse active sites and excellent compositional/structural flexibility.In this study,we specially des...Metal-based perovskite oxides have contributed significantly to the advanced oxidation processes(AOPs)due to their diverse active sites and excellent compositional/structural flexibility.In this study,we specially designed a perovskite oxide with abundant oxygen vacancies,SrCo_(0.8)Fe_(0.2)O_(3)(SCF),and firstly applied it as a catalyst in peroxymonosulfate(PMS) activation towards organic pollutants degradation.The result revealed that the prepared SCF catalyst exhibited excellent performance on organic compounds degradation.Besides,SCF showed much better activity than La_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3)(LSCF) in terms of reaction rate and stability for the degradation of the organic compounds.Based on the analysis of scanning electron microscope,transmission electron microscope,X-ray diffraction,N_(2) adsorption-desorption,X-ray photoelectron spectroscopy and electron paramagnetic resonance,it was confirmed that the perovskite catalysts with high content of Sr doping at A-site could effectively create a defect-rich surface and optimize its physicochemical properties,which was responsible for the excellent heterogeneous catalytic activity of SCF.SCF can generate three highly active species:~1 O_(2),SO_(4)^(-)· and ·OH in PMS activation,revealing the degradation process of organic compounds was a coupled multiple active species in both radical and nonradical pathway.Moreover,it was mainly in a radical pathway in the degradation through PMS activation on SCF and SO_(4)^(-)· radicals produced were the dominant species in SCF/PMS system.This study demonstrated that perovskite-type catalysts could enrich OVs efficiently by doping strategy and regulate the PMS activation towards sulfate radical-based AOPs.展开更多
Sulfate radical-advanced oxidation processes(SR-AOPs)are promising technologies for organic pollutants elimination.Heterogeneous metal-based catalysis has been widely studied and applied to activate peroxymonosulfate(...Sulfate radical-advanced oxidation processes(SR-AOPs)are promising technologies for organic pollutants elimination.Heterogeneous metal-based catalysis has been widely studied and applied to activate peroxymonosulfate(PMS)for producing sulfate radicals.Developing highly efficient catalysts is crucial for future extensive use.Importantly,the catalytic activity is mainly determined by mass and electron transfer.This paper aims to overview the recent enhancement strategies for developing heterogeneous metalbased catalysts as effective PMS activators.The main strategies,including surface engineering,structural engineering,electronic modulation,external energy assistance,and membrane filtration enhancement,are summarized.The potential mechanisms for improving catalytic activity are also introduced.Finally,the challenges and future research prospects of heterogenous metal-based catalysis in SR-AOPs are proposed.This work is hoped to guide the rational design of highly efficient heterogenous catalysts in SR-AOPs.展开更多
β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by ...β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by loading carbon dots(CDs)onto rod-like CoFe_(2)O_(4)(CFO),which can effectively degrade amoxicillin(AMX)by photocata lytic/peroxy mono sulfate(PMS)activation under visible light irradiation.The degradation results exhibits that the optimal degradation efficiency with 97.5%within 80 min is achievd by the CDs-CFO-5 composite.Such enhanced activity is ascribed to the introduction of CDs that effectively improves the separation efficiency of photogenerated electron pairs and creates new active sites as electron bridges that improve the photocata lytic performance.More importantly,a strong synergistic between CDs and photo-induced electrons generated from CFO can further activiate PMS to provide more SO4-·and·OH radicals for boosting the degradation ability towards AMX.The present study aims to elucidate positive role of CDs in photocata lytic/peroxy monosulfate activation during the degradation reaction.展开更多
Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and struc...Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/Co-ZIFs).Results show that Co doping amount could mediate the transformation of the activation pathway of PMS over CoN/C.When Co doping amount was less than 10%,the constructed x Co-N/C/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing Co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet oxygen.Furthermore,the nitrogen-coordinated Co(Co-NX)sites could serve as main catalytically active sites to generate singlet oxygen.While excess Co doping amount caused the formation of Co nanoparticles from which leached Co ions were responsible for the generation of sulfate radicals and high-valent cobalt.Compared to undoped N/C,Co doping could significantly enhance the catalytic performance.The 0.5%Co-N/C could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated Co-N/C catalysts,which was superior to most of previously reported catalysts.In addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation behaviors.This study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.展开更多
Photocatalytic activation of peroxymonosulfate (PMS) has garnered a lot of interest in the field of wastewater treatment. Herein, a plasmonic Ag nanoparticles decorated MIL-101(Fe) hybrid was synthesized through a pho...Photocatalytic activation of peroxymonosulfate (PMS) has garnered a lot of interest in the field of wastewater treatment. Herein, a plasmonic Ag nanoparticles decorated MIL-101(Fe) hybrid was synthesized through a photodeposition process. Upon light irradiation, the Ag/MIL-101(Fe) exhibit reinforced photocatalytic activities for elimination of bisphenol A (BPA) with PMS. The optimized 2.0% Ag/MIL-101(Fe) composite presented the highest photocatalytic activity with kinetic constant k of 0.102 min-1, which was about 10-fold of the pristine MIL-101(Fe). Loading of plasmonic Ag into MIL-101(Fe) boosts photoinduced carrier separation and accelerates PMS activation to generate strong oxidative radicals. Photoelectrochemical tests and multiple spectroscopic studies confirmed the promoted charge carrier separation and transfer capability of Ag/MIL-101(Fe). Combining the results of radical trapping experiments and electron spin resonance (ESR), the formed SO4·-, ·OH, ·O2- and 1O2 had a significant role in the photocatalytic process. According to intermediate study, the degradation pathway was studied, and the possible mechanism was proposed.展开更多
The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitril...The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitrile(PAN)nanofibers by electrospinning.The introduction of INA destroys theπ-πconjugated stack structure in phthalocyanine molecules and exposes more active sites.The FeMATNPc-INA structure is characterized by X-ray photoelectron spectroscopy and UV-visible absorption spectrum,and the FeMATNPcINA/PAN structure is characterized by Fourier transform infrared spectroscopy and X-ray diffraction.The FeMATNPc-INA/PAN can effectively activate peroxymonosulfate(PMS)to eliminate carbamazepine(CBZ)within 40 minutes(PMS 1.5 mmol/L)in the dark.The effects of catalyst dosage,PMS concentration,pH and inorganic anion on the degradation of CBZ are investigated.It has been confirmed by electron paramagnetic resonance,gas chromatography–mass spectroscopy and free radical capture experiments that the catalytic system is degraded by·OH,SO4^(·-)and Fe(IV)=O are the major active species,the singlet oxygen(^(1)O_(2))is the secondary active species.The degradation process of CBZ is analyzed by ultra-high performance liquid chromatography-mass spectrometry and the aromatic compounds have been degraded to small molecular acids.展开更多
Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics degradation.Compared with MoS_(2)-SS powder/PMS...Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics degradation.Compared with MoS_(2)-SS powder/PMS system(0.37 g/(m^(2)/min)),4.3-fold higher k_(FLO)/S_(BET)value was obtained in 3DP MoS_(2)-SS/PMS system(1.60 g/(m^(2)/min),resulting from the superior utilization of active sites.We observed that 3DP MoS_(2)-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active sites.Moreover,Mo^(4+)facilitated the Fe^(2+)/Fe^(3+)cycle,resulting in the rapid degradation of florfenicol(FLO).Quenching experiments and electron paramagnetic resonance spectra indicated that·OH,SO_(4)·^(-),O_(2)·^(-)and^(1)O_(2)were involved in the degradation of FLO.The effect of influencing factors on the degradation of FLO were evaluated,and the optimized degradation efficiency of 98.69%was achieved at 1 mM PMS and pH of 3.0.Six degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds,dechlorination,hydrolysis,defluorination and hydroxylation.In addition,3DP MoS_(2)-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol,acetaminophen,ibuprofen and carbamazepine.This study provided deep insights into the MoS_(2)-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.展开更多
Fast Fe(III)/Fe(II)circulation in heterogeneous peroxymonosulfate(PMS)activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation processes.Herein,we proposed a facile ammon...Fast Fe(III)/Fe(II)circulation in heterogeneous peroxymonosulfate(PMS)activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation processes.Herein,we proposed a facile ammonia reduction strategy and synthesized a novel FeVO3-x catalysts to activate PMS for the degradation of a typical pharmaceutical,carbamazepine(CBZ).Rapid CBZ removal could be achieved within 10 min,which outperforms most of the other iron or vanadium-based catalysts.Electron paramagnetic resonance analysis and chemical probe experiments revealed SO_(4)^(·-),·OH,O_(2)^(·-)and high valent iron(Fe(IV))were all generated in this system,but SO4·-and Fe(IV)primarily contributed to the degradation of CBZ.Besides,X-ray photoelectron spectroscopy and X-ray adsorption spectroscopy indicated that both the generated low-valent V provides and oxygen vacancy acted as superior electron donors and accelerated internal electron transfer via the unsaturated V-O-Fe bond.Finally,the proposed system also exhibited satisfactory performance in practical applications.This work provides a promising platform in heterogeneous PMS activation.展开更多
A novel N, O modified Mn_(3)O_(4)@porous carbon catalyst(NOC-Mn_(3)O_(4)) was prepared by direct carbonization using the manganese-metal organic framework(Mn-MOF) and covalent organic framework(COF) as precursors to a...A novel N, O modified Mn_(3)O_(4)@porous carbon catalyst(NOC-Mn_(3)O_(4)) was prepared by direct carbonization using the manganese-metal organic framework(Mn-MOF) and covalent organic framework(COF) as precursors to activate peroxymonosulfate(PMS) for the degradation of bisphenol A(BPA) and rhodamine B(Rh B). Benefiting from the N and O co-doping of COF, larger specific surface area, faster electron transfer and Mn cycling, the optimum 1NOC-Mn_(3)O_(4)could significantly improve the degradation performance of BPA and Rh B(92.1% and 96.9% within 30 min) as compared to C-Mn_(3)O_(4)without COF doping. In addition, 1NOC-Mn_(3)O_(4) showed good reusability and strong anti-interference ability. Radical quenching experiments, X-ray photoelectron spectroscopy(XPS), Electron paramagnetic resonance spectrometer(EPR) and electrochemical tests showed that the 1NOC-Mn_(3)O_(4)/PMS system degraded BPA and Rh B by both radical and non-radical pathways. Moreover, the possible degradation pathways of BPA and Rh B were proposed by liquid chromatography-mass spectrometry(LC-MS). Except for that, the toxicity of BPA, Rh B and their intermediates were evaluated. This study opens up a new prospect for the design of COF-doped PMS catalysts.展开更多
In this study,the cobalt-nickel layered double hydroxides(CoNi LDH)were synthesized with a variety of Co/Ni mass ratio,as CoxNiyLDHs.In comparison,Co1Ni3LDH presented the best peroxymonosulfate(PMS)activation efficien...In this study,the cobalt-nickel layered double hydroxides(CoNi LDH)were synthesized with a variety of Co/Ni mass ratio,as CoxNiyLDHs.In comparison,Co1Ni3LDH presented the best peroxymonosulfate(PMS)activation efficiency for 2,4-dichlorophenol removal.Meanwhile,CoNi LDH@Nickel foam(CoNi LDH@NF)composite membrane was constructed for enhancing the stability of catalytic performance.Herein,CoNi LDH@NF-PMS system exerted high degradation efficiency of 99.22%within 90 min for 2,4-DCP when[PMS]_(0)=0.4 g/L,Co^(1)Ni^(3)LDH@NF=2 cm×2 cm(0.2 g/L),reaction temperature=298 K.For the surface morphology and structure of the catalyst,it was demonstrated that the CoNi LDH@NF composite membrane possessed abundant cavity structure,good specific surface area and sufficient active sites.Importantly,·OH,SO_(4)·^(-)and^(1)O_(2)played the primary role in the CoNi LDH@NF-PMS system for 2,4-DCP decomposition,which revealed the PMS activation mechanism in CoNi LDH@NF-PMS system.Hence,this study eliminated the stability and adaptability of CoNi LDH@NF composite membrane,proposing a new theoretical basis of PMS heterogeneous catalysts selection.展开更多
Biochar-based transition metal catalysts have been identified as excellent peroxymonosulfate(PMS)activators for producing radicals used to degrade organic pollutants.However,the radical-dominated pathways for PMS acti...Biochar-based transition metal catalysts have been identified as excellent peroxymonosulfate(PMS)activators for producing radicals used to degrade organic pollutants.However,the radical-dominated pathways for PMS activation severely limit their practical applications in the degradation of organic pollutants from wastewater due to side reactions between radicals and the coexisting anions.Herein,bimetallic Fe/Mn-loaded hydroxyl-rich biochar(FeMn-OH-BC)is synthesized to activate PMS through nonradical-dominated pathways.The as-prepared FeMn-OH-BC exhibits excellent catalytic activity for degrading tetracycline at broad pH conditions ranging from 5 to 9,and about 85.0%of tetracycline is removed in 40 min.Experiments on studying the influences of various anions(HCO_(3)^(−),NO_(3)^(−),and H_(2)PO_(4)^(−))show that the inhibiting effect is negligible,suggesting that the FeMn-OHBC based PMS activation is dominated by nonradical pathways.Electron paramagnetic resonance measurements and quenching tests provide direct evidence to confirm that 1O2 is the major reactive oxygen species generated from FeMn-OH-BC based PMS activation.Theoretical calculations further reveal that the FeMn-OH sites in FeMn-OH-BC are dominant active sites for PMS activation,which have higher adsorption energy and stronger oxidative activity towards PMS than OH-BC sites.This work provides a new route for driving PMS activation by biochar-based transition metal catalysts through nonradical pathways.展开更多
Wastewater containing an azo dye Orange G(OG)causes massive environmental pollution,thus it is critical to develop a highly effective,environmental-friendly,and reusable catalyst in peroxymonosulfate(PMS)activation fo...Wastewater containing an azo dye Orange G(OG)causes massive environmental pollution,thus it is critical to develop a highly effective,environmental-friendly,and reusable catalyst in peroxymonosulfate(PMS)activation for OG degradation.In this work,we successfully applied a magnetic MnFe_(2)O_(4)/α-MnO_(2) hybrid fabricated by a simple hydrothermal method for OG removal in water.The characteristics of the hybrid were investigated by Xray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,Brunauer–Emmett–Teller method,vibrating sample magnetometry,electron paramagnetic resonance,thermogravimetric analysis,and X-ray photoelectron spectroscopy.The effects of operational parameters(i.e.,catalytic system,catalytic dose,solution pH,and temperature)were investigated.The results exhibited that 96.8% of OG degradation was obtained with MnFe_(2)O_(4)/α-MnO2(1:9)/PMS system in 30 min regardless of solution pH changes.Furthermore,the possible reaction mechanism of the coupling system was proposed,and the degradation intermediates of OG were identified by mass spectroscopy.The radical quenching experiments and EPR tests demonstrated that SO_(4)•̶,O_(2)•̶,and 1O2 were the primary reactive oxygen species responsible for the OG degradation.The hybrid also displayed unusual stability with less than 30%loss in the OG removal after four sequential cycles.Overall,magnetic MnFe2O4/α-MnO2 hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.展开更多
Fe-N co-doped coral-like hollow carbon shell (Fe-N-CS) was synthesized via a simply impregnation-pyrolysis method.The Fe-N-CS showed an excellent ability for activating peroxymonosulfate (PMS),which could degrade abou...Fe-N co-doped coral-like hollow carbon shell (Fe-N-CS) was synthesized via a simply impregnation-pyrolysis method.The Fe-N-CS showed an excellent ability for activating peroxymonosulfate (PMS),which could degrade about 93.74%tetracycline (20 mg/L) in 12 min.The Fe-N-CS/PMS system exhibited a good anti-interference capacity of various pH,inorganic anions,HA and different water qualities.More importantly,the Fe nanoparticles were anchored uniformly in the carbon layer,effectively limiting the metal leaching.The quenching tests and electron spin resonance (ESR) manifested that non-radical singlet oxygen (1O_(2))was the main reactive oxygen species (ROS) for TC degradation.The mechanism study showed that Fe nanoparticles,defect and graphite N played a key role in activating PMS to produce ROS.Moreover,three probable degradation pathways were proposed by using LC-MS measurements.Generally,this work had a new insight for the synthesis of heterogeneous Fe-N-C catalysts in the advanced oxidation process based on PMS.展开更多
The Z-scheme heterostructure for photocatalyst can effectively prolong the lifetime of photogenerated carriers and retain a higher conduction/valence band position,promoting the synergistic coupling of photocatalysis ...The Z-scheme heterostructure for photocatalyst can effectively prolong the lifetime of photogenerated carriers and retain a higher conduction/valence band position,promoting the synergistic coupling of photocatalysis and peroxymonosulfate(PMS) activation.In order to fully utilize the luminous energy and realize the efficient activation of PMS,this work achieved successful construction of NiCo_(2)O_(4)/BiOCl/Bi_(24)O_(31)Br_(10) ternary Z-scheme heterojunction by simultaneously synthesizing BiOCl and NiCo_(2)O_(4) with NiCl_(2) and CoCl_(2) as the precursors.The intercalated BiOCl could serve as a carrier migration ladder to further achieve the spatial separation of electron-hole pairs,so that the oxidation and reduction processes separately occurred in different regions.Compared with the reported catalysts,the as-prepared composites exhibited the enhanced removal efficiency for tetracycline hydrochloride(TCH) in the visible light/PMS system,with a degradation efficiency of 85.30%in 2 min,and possessed good stability.Z-scheme heterojunction was shown to be beneficial for maximizing the superiority of photo-assisted Fenton-like reaction system.The experimental and characterization results confirmed that both non-radicals(^(1)O_(2)) and radicals(SO_(5)^(·-) and SO_(4)^(·-)) were involved in the reaction process and the SO_(5)^(·-)generated by the oxidation of PMS played a crucial role in the TCH degradation.The possible reaction mechanism was finally proposed.This study provided new insight into the Z-scheme heterostructure to promote the photo-assisted Fenton-like reaction.展开更多
Bisphenol A(BPA)has received increasing attention due to its long-term industrial application and persistence in environmental pollution.Iron-based carbon catalyst activation of peroxymonosulfate(PMS)shows a good pros...Bisphenol A(BPA)has received increasing attention due to its long-term industrial application and persistence in environmental pollution.Iron-based carbon catalyst activation of peroxymonosulfate(PMS)shows a good prospect for effective elimination of recalcitrant contaminants in water.Herein,considering the problem about the leaching of iron ions and the optimization of heteroatoms doping,the iron,nitrogen and sulfur co-doped tremellalike carbon catalyst(Fe-NS@C)was rationally designed using very little iron,S-C_(3)N_(4) and low-cost chitosan(CS)via the impregnation-calcination method.The as-prepared Fe-NS@C exhibited excellent performance for complete removal of BPA(20 mg/L)by activating PMS with the high kinetic constant(1.492 min^(−1))in 15 min.Besides,the Fe-NS@C/PMS system not only possessed wide pH adaptation and high resistance to environmental interference,but also maintained an excellent degradation efficiency on different pollutants.Impressively,increased S-C_(3)N_(4) doping amount modulated the contents of different N species in Fe-NS@C,and the catalytic activity of Fe-NS@C-1-x was visibly enhanced with increasing SC_(3)N_(4) contents,verifying pyridine N and Fe-Nx as main active sites in the system.Meanwhile,thiophene sulfur(C-S-C)as active sites played an auxiliary role.Furthermore,quenching experiment,EPR analysis and electrochemical test proved that surface-bound radicals(·OH and SO_(4)^(·−))and non-radical pathways worked in the BPA degradation(the former played a dominant role).Finally,possible BPA degradation route were proposed.This work provided a promising way to synthesize the novel Fe,N and S co-doping carbon catalyst for degrading organic pollutants with low metal leaching and high catalytic ability.展开更多
基金gratefully acknowledge the financial support of the National Natural Science Foundation of China(22108145 and 21978143)the Shandong Province Natural Science Foundation(ZR2020QB189)+1 种基金State Key Laboratory of Heavy Oil Processing(SKLHOP202203008)the Talent Foundation funded by Province and Ministry Co-construction Collaborative Innovation Center of Eco-chemical Engineering(STHGYX2201).
文摘The novel Fe-N co-doped ordered mesoporous carbon with high catalytic activity in m-cresol removal was prepared by urea-assisted impregnation and simple pyrolysis method.During the preparation of the Fe-NC catalyst,the complexation of N elements in urea could anchor Fe,and the formation of C3N4during urea pyrolysis could also prevent migration and aggregation of Fe species,which jointly improve the dispersion and stability of Fe.The FeN4sites and highly dispersed Fe nanoparticles synergistically trigger the dual-site peroxymonosulfate (PMS) activation for highly efficient m-cresol degradation,while the ordered mesoporous structure of the catalyst could improve the mass transfer rate of the catalytic process,which together promote catalytic degradation of m-cresol by PMS activation.Reactive oxygen species (ROS) analytic experiments demonstrate that the system degrades m-cresol by free radical pathway mainly based on SO_(4)^(-)·and·OH,and partially based on·OH as the active components,and a possible PMS activation mechanism by 5Fe-50 for m-cresol degradation was proposed.This study can provide theoretical guidance for the preparation of efficient and stable catalysts for the degradation of organic pollutants by activated PMS.
基金supported by the National Natural Science Foundation of China (21806115)Sichuan Science and Technology Program (2020YJ0149)+1 种基金the Power Construction of China (P42819,DJ-ZDXM-2019-42)the Supported by Sichuan Science and Technology Program (2021ZDZX0012)。
文摘Among the numerous transition metal catalysts,manganese-based compounds are considered as promising peroxymonosulfate(PMS)catalysts due to their low cost and environmental friendliness,such as cryptomelane manganese oxide(K_(2-x)Mn_(8)O_(16):abbreviation KMnO).However,the limited catalytic performance of KMnO limits its practical application.In this work,iron-doped KMnO(Fe-KMnO)was prepared by one-step hydrothermal method to optimize its catalytic performance.Compared with KMnO/PMS system,Fe-KMnO/PMS system possessed more excellent removal efficiency of tetracycline(TC).Meanwhile,the Fe-KMnO/PMS system also exhibited good practical application potential and excellent stability.The mechanism of Fe-KMnO activation of PMS was further analyzed in detail.It was found that Fe participated in the redox of high-valent Mn,which promoted the activation of PMS.Moreover,The Fe site as an adsorption site enhanced the TC enrichment ability of the catalyst,reducing the mass transfer resistance and further enhancing the TC removal ability of Fe-KMnO/PMS system.This work not only provides an excellent PMS catalyst,but also offers new insights into the mechanism of PMS activation by bimetallic manganese-based catalysts.
基金Supported by Guigang City Science Research and Technology Development Plan Project(GUIKEJI2203014).
文摘Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation rule of xylene under different conditions such as the ORP value of the spray liquid, pH value of the spray liquid, liquid-gas ratio of the spray liquid, residence time of xylene, and initial concentration of xylene was investigated. The results showed that at a low concentration, the pH value of the spray liquid had little effect on the degradation rate of xylene. The degradation rate of xylene rose with the increase of the ORP value of the spray liquid, the liquid-gas ratio of the spray liquid, the residence time of xylene, and the initial concentration of xylene.
基金the financial support of research grants from the Hong Kong Polytechnic University(Q67H)and Higher Education Commission(HEC),Pakistan for the financial support during IRSIP。
文摘Methotrexate(MTX)is one of the most consumed anti-cancer drugs in the pharmaceutical market around the world.The widespread occurrence of MTX in aquatic environment through hospital effluent has attracted increasing concern due to its potential to induce water pollution.In the present study,the degradation of MTX in aqueous medium was investigated by UV-activated peroxymonosulfate(PMS).A significant improvement in degradation rate by increasing UV intensity and PMS concentration while the decrease in degradation efficiency with the increase of solution p H and initial concentration of MTX was observed.The proposed UV/PMS process could achieve more than 90%MTX degradation in 30 min with a good mineralization degree(65%).A pseudofirst order kinetic model was employed and successfully predicted the degradation of MTX.The effect of other operational parameters such as the initial concentration of the targeted compound,dosage of oxidant(PMS),solution p H and UV intensity on the degradation rate were investigated.At the last,the main transform intermediates were identified using LC–MS and possible degradation pathways were proposed.The results show that UV/PMS can be used as an efficient technology to treat pharmaceuticals such as methotrexate containing water and wastewater.
基金the financial support provided by the Beijing Natural Science Foundation (2202044)the Fok Ying Tung Education Foundation, China (171042)+1 种基金the National Postdoctoral Program for Innovative Talents (BX20190370)the Fundamental Research Funds for the Central Universities (2021JCCXHH04)。
文摘The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this study.The Mn/G/D possessed higher specific surface area,lower electron-hole pairs' recombination rate,as well as wider and stronger visible light absorption capacity.Since the synergistic effect between g-C_(3 )N_(4) and MnFe_(2) O_(4),the photogene rated electron could transfer from g-C3 N4 to MnFe_(2) O_(4),which could promote the migration of electrons as well as enhance the photocatalytic activity and peroxymonosulfate(PMS) activation efficiency.Mn/G/D-5% composite displayed the excellent degradation performance of bisphenol A(BPA) with the removal efficiency of 99.9% under PMS/Vis system,which was approximately 2.47 and 63.8 times as high as that of the Mn/G/D-5%/PMS and Mn/G/D-5%/Vis system,respectively.Moreover,negative electricity derived from diatomite surface also promoted the photogenerated carriers' migration,and the degradation rate constant was around 2.4 times higher than that of MnFe_(2) O_(4)/g-C_(3) N_(4)(Mn/G).In addition,quenching experiments showed that both radical pathway(h^(+),·OH,·O_(2)^(-)and SO_(4)·^(-)) and non-radical pathway(^(1) O_(2)) were responsible for the degradation of BPA.
基金supported by the National Key Research and Development Program of China (Project No.2018YFB1502903)。
文摘Metal-based perovskite oxides have contributed significantly to the advanced oxidation processes(AOPs)due to their diverse active sites and excellent compositional/structural flexibility.In this study,we specially designed a perovskite oxide with abundant oxygen vacancies,SrCo_(0.8)Fe_(0.2)O_(3)(SCF),and firstly applied it as a catalyst in peroxymonosulfate(PMS) activation towards organic pollutants degradation.The result revealed that the prepared SCF catalyst exhibited excellent performance on organic compounds degradation.Besides,SCF showed much better activity than La_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3)(LSCF) in terms of reaction rate and stability for the degradation of the organic compounds.Based on the analysis of scanning electron microscope,transmission electron microscope,X-ray diffraction,N_(2) adsorption-desorption,X-ray photoelectron spectroscopy and electron paramagnetic resonance,it was confirmed that the perovskite catalysts with high content of Sr doping at A-site could effectively create a defect-rich surface and optimize its physicochemical properties,which was responsible for the excellent heterogeneous catalytic activity of SCF.SCF can generate three highly active species:~1 O_(2),SO_(4)^(-)· and ·OH in PMS activation,revealing the degradation process of organic compounds was a coupled multiple active species in both radical and nonradical pathway.Moreover,it was mainly in a radical pathway in the degradation through PMS activation on SCF and SO_(4)^(-)· radicals produced were the dominant species in SCF/PMS system.This study demonstrated that perovskite-type catalysts could enrich OVs efficiently by doping strategy and regulate the PMS activation towards sulfate radical-based AOPs.
基金financially supported by the National Natural Science Foundation of China(21938009)。
文摘Sulfate radical-advanced oxidation processes(SR-AOPs)are promising technologies for organic pollutants elimination.Heterogeneous metal-based catalysis has been widely studied and applied to activate peroxymonosulfate(PMS)for producing sulfate radicals.Developing highly efficient catalysts is crucial for future extensive use.Importantly,the catalytic activity is mainly determined by mass and electron transfer.This paper aims to overview the recent enhancement strategies for developing heterogeneous metalbased catalysts as effective PMS activators.The main strategies,including surface engineering,structural engineering,electronic modulation,external energy assistance,and membrane filtration enhancement,are summarized.The potential mechanisms for improving catalytic activity are also introduced.Finally,the challenges and future research prospects of heterogenous metal-based catalysis in SR-AOPs are proposed.This work is hoped to guide the rational design of highly efficient heterogenous catalysts in SR-AOPs.
基金founding support from the National Natural Science Foundation of China(Nos.21906072,22006057 and 31971616)the Natural Science Foundation of Jiangsu Province(BK20190982)+4 种基金“Doctor of Mass Entrepreneurship and Innovation”Project in Jiangsu Province,Henan Postdoctoral Foundation(202003013)Doctoral Scientific Research Foundation of Jiangsu University of Science and Technology(China)(1062931806 and 1142931803)the Science and Technology Research Project of the Department of Education of Jilin Province(JJKH20200039KJ)the Science and Technology Research Project of Jilin City(20190104120,201830811)the Project of Jilin Provincial Science and Technology Development Plan(20190201277JC,20200301046RQ,YDZJ202101ZYTS070)。
文摘β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by loading carbon dots(CDs)onto rod-like CoFe_(2)O_(4)(CFO),which can effectively degrade amoxicillin(AMX)by photocata lytic/peroxy mono sulfate(PMS)activation under visible light irradiation.The degradation results exhibits that the optimal degradation efficiency with 97.5%within 80 min is achievd by the CDs-CFO-5 composite.Such enhanced activity is ascribed to the introduction of CDs that effectively improves the separation efficiency of photogenerated electron pairs and creates new active sites as electron bridges that improve the photocata lytic performance.More importantly,a strong synergistic between CDs and photo-induced electrons generated from CFO can further activiate PMS to provide more SO4-·and·OH radicals for boosting the degradation ability towards AMX.The present study aims to elucidate positive role of CDs in photocata lytic/peroxy monosulfate activation during the degradation reaction.
基金supported by the National Natural Science Foundation of China(Nos.52100081,51978178,and 51521006)the Department of Science and Technology of Guangdong Province of China(Nos.2021A1515011797,2023A1515012062,2019A1515012044,and 2022A1515010226)+4 种基金the Department of Education of Guangdong Province of China(No.2021KTSCX078)the Program for Innovative Research Teams of Guangdong Higher Education Institutes of China(No.2021KCXTD043)Maoming Municipal Department of Science and Technology of Guangdong Province of China(No.2018S0013)the Key Laboratory of Petrochemical Pollution Control of Guangdong Higher Education Institutes(No.2017KSYS004)the Startup Fund of GDUPT(Nos.2018rc63 and 2020rc041)。
文摘Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/Co-ZIFs).Results show that Co doping amount could mediate the transformation of the activation pathway of PMS over CoN/C.When Co doping amount was less than 10%,the constructed x Co-N/C/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing Co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet oxygen.Furthermore,the nitrogen-coordinated Co(Co-NX)sites could serve as main catalytically active sites to generate singlet oxygen.While excess Co doping amount caused the formation of Co nanoparticles from which leached Co ions were responsible for the generation of sulfate radicals and high-valent cobalt.Compared to undoped N/C,Co doping could significantly enhance the catalytic performance.The 0.5%Co-N/C could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated Co-N/C catalysts,which was superior to most of previously reported catalysts.In addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation behaviors.This study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.
基金Natural Science Foundation of Hebei Province, China (No. B2020202044)the Open Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering, MOE, China (No. KLIEEE-21-04).
文摘Photocatalytic activation of peroxymonosulfate (PMS) has garnered a lot of interest in the field of wastewater treatment. Herein, a plasmonic Ag nanoparticles decorated MIL-101(Fe) hybrid was synthesized through a photodeposition process. Upon light irradiation, the Ag/MIL-101(Fe) exhibit reinforced photocatalytic activities for elimination of bisphenol A (BPA) with PMS. The optimized 2.0% Ag/MIL-101(Fe) composite presented the highest photocatalytic activity with kinetic constant k of 0.102 min-1, which was about 10-fold of the pristine MIL-101(Fe). Loading of plasmonic Ag into MIL-101(Fe) boosts photoinduced carrier separation and accelerates PMS activation to generate strong oxidative radicals. Photoelectrochemical tests and multiple spectroscopic studies confirmed the promoted charge carrier separation and transfer capability of Ag/MIL-101(Fe). Combining the results of radical trapping experiments and electron spin resonance (ESR), the formed SO4·-, ·OH, ·O2- and 1O2 had a significant role in the photocatalytic process. According to intermediate study, the degradation pathway was studied, and the possible mechanism was proposed.
基金supported by National Natural Science Foundation of China (No.22006136)。
文摘The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitrile(PAN)nanofibers by electrospinning.The introduction of INA destroys theπ-πconjugated stack structure in phthalocyanine molecules and exposes more active sites.The FeMATNPc-INA structure is characterized by X-ray photoelectron spectroscopy and UV-visible absorption spectrum,and the FeMATNPcINA/PAN structure is characterized by Fourier transform infrared spectroscopy and X-ray diffraction.The FeMATNPc-INA/PAN can effectively activate peroxymonosulfate(PMS)to eliminate carbamazepine(CBZ)within 40 minutes(PMS 1.5 mmol/L)in the dark.The effects of catalyst dosage,PMS concentration,pH and inorganic anion on the degradation of CBZ are investigated.It has been confirmed by electron paramagnetic resonance,gas chromatography–mass spectroscopy and free radical capture experiments that the catalytic system is degraded by·OH,SO4^(·-)and Fe(IV)=O are the major active species,the singlet oxygen(^(1)O_(2))is the secondary active species.The degradation process of CBZ is analyzed by ultra-high performance liquid chromatography-mass spectrometry and the aromatic compounds have been degraded to small molecular acids.
基金supported by the Guangdong Province Enterprise Science and Technology Commissioner Project (No.GDKTP2021048000)the National Natural Science Foundation of China (No.41907292)+2 种基金the Guangdong Basic and Applied Basic Research Foundation (No.2019A1515110497)the Key-Area Research and Development Program of Guangdong Province (No.2020B090923002)the Guangdong Basic and Applied Basic Research Foundation (No.2019B1515130005)。
文摘Herein,a novel MoS_(2)-stainless steel composite material was first synthetized via a 3D printing method(3DP MoS_(2)-SS)for peroxymonosulfate(PMS)activation and organics degradation.Compared with MoS_(2)-SS powder/PMS system(0.37 g/(m^(2)/min)),4.3-fold higher k_(FLO)/S_(BET)value was obtained in 3DP MoS_(2)-SS/PMS system(1.60 g/(m^(2)/min),resulting from the superior utilization of active sites.We observed that 3DP MoS_(2)-SS significantly outperformed the 3DP SS due to the enhanced electron transfer rate and increased active sites.Moreover,Mo^(4+)facilitated the Fe^(2+)/Fe^(3+)cycle,resulting in the rapid degradation of florfenicol(FLO).Quenching experiments and electron paramagnetic resonance spectra indicated that·OH,SO_(4)·^(-),O_(2)·^(-)and^(1)O_(2)were involved in the degradation of FLO.The effect of influencing factors on the degradation of FLO were evaluated,and the optimized degradation efficiency of 98.69%was achieved at 1 mM PMS and pH of 3.0.Six degradation products were detected by UPLC/MS analyses and several possible degradation pathways were proposed to be the cleavage of C-N bonds,dechlorination,hydrolysis,defluorination and hydroxylation.In addition,3DP MoS_(2)-SS/PMS system also demonstrated superior degradation performance for 2-chlorophenol,acetaminophen,ibuprofen and carbamazepine.This study provided deep insights into the MoS_(2)-SS catalyst prepared by 3DP technology for PMS activation and FLO-polluted water treatment.
基金the Shanghai Tongji Gao Tingyao Environmental Science&Technology Development Foundation.Additionally,the authors acknowledge the staff at beamline 1WB at the Beijing Synchronic Radiation Facility(BSRF)for their assistance during the XAS measurements.And the authors would like to acknowledge the financial support from National Natural Science Foundation of China(Nos.52070133,2022NSFSC0972)Sichuan Science and Technology Program:Key Research and Development Program(Nos.2019YFG0314,2017SZ0180 and 2019YFG0324).
文摘Fast Fe(III)/Fe(II)circulation in heterogeneous peroxymonosulfate(PMS)activation remains as a bottleneck issue that restricts the development of PMS based advanced oxidation processes.Herein,we proposed a facile ammonia reduction strategy and synthesized a novel FeVO3-x catalysts to activate PMS for the degradation of a typical pharmaceutical,carbamazepine(CBZ).Rapid CBZ removal could be achieved within 10 min,which outperforms most of the other iron or vanadium-based catalysts.Electron paramagnetic resonance analysis and chemical probe experiments revealed SO_(4)^(·-),·OH,O_(2)^(·-)and high valent iron(Fe(IV))were all generated in this system,but SO4·-and Fe(IV)primarily contributed to the degradation of CBZ.Besides,X-ray photoelectron spectroscopy and X-ray adsorption spectroscopy indicated that both the generated low-valent V provides and oxygen vacancy acted as superior electron donors and accelerated internal electron transfer via the unsaturated V-O-Fe bond.Finally,the proposed system also exhibited satisfactory performance in practical applications.This work provides a promising platform in heterogeneous PMS activation.
基金the Fundamental Research Funds for the Central Universities (No.lzujbky-2022-59)National Natural Science Foundation of China (No.51978319)。
文摘A novel N, O modified Mn_(3)O_(4)@porous carbon catalyst(NOC-Mn_(3)O_(4)) was prepared by direct carbonization using the manganese-metal organic framework(Mn-MOF) and covalent organic framework(COF) as precursors to activate peroxymonosulfate(PMS) for the degradation of bisphenol A(BPA) and rhodamine B(Rh B). Benefiting from the N and O co-doping of COF, larger specific surface area, faster electron transfer and Mn cycling, the optimum 1NOC-Mn_(3)O_(4)could significantly improve the degradation performance of BPA and Rh B(92.1% and 96.9% within 30 min) as compared to C-Mn_(3)O_(4)without COF doping. In addition, 1NOC-Mn_(3)O_(4) showed good reusability and strong anti-interference ability. Radical quenching experiments, X-ray photoelectron spectroscopy(XPS), Electron paramagnetic resonance spectrometer(EPR) and electrochemical tests showed that the 1NOC-Mn_(3)O_(4)/PMS system degraded BPA and Rh B by both radical and non-radical pathways. Moreover, the possible degradation pathways of BPA and Rh B were proposed by liquid chromatography-mass spectrometry(LC-MS). Except for that, the toxicity of BPA, Rh B and their intermediates were evaluated. This study opens up a new prospect for the design of COF-doped PMS catalysts.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01C733)the Open Project of Key Disciplines of Physics(No.XJZDXKphy202309)the Research and Innovation Team Cultivation Program of Yili Normal University(No.CXZK2021004)。
文摘In this study,the cobalt-nickel layered double hydroxides(CoNi LDH)were synthesized with a variety of Co/Ni mass ratio,as CoxNiyLDHs.In comparison,Co1Ni3LDH presented the best peroxymonosulfate(PMS)activation efficiency for 2,4-dichlorophenol removal.Meanwhile,CoNi LDH@Nickel foam(CoNi LDH@NF)composite membrane was constructed for enhancing the stability of catalytic performance.Herein,CoNi LDH@NF-PMS system exerted high degradation efficiency of 99.22%within 90 min for 2,4-DCP when[PMS]_(0)=0.4 g/L,Co^(1)Ni^(3)LDH@NF=2 cm×2 cm(0.2 g/L),reaction temperature=298 K.For the surface morphology and structure of the catalyst,it was demonstrated that the CoNi LDH@NF composite membrane possessed abundant cavity structure,good specific surface area and sufficient active sites.Importantly,·OH,SO_(4)·^(-)and^(1)O_(2)played the primary role in the CoNi LDH@NF-PMS system for 2,4-DCP decomposition,which revealed the PMS activation mechanism in CoNi LDH@NF-PMS system.Hence,this study eliminated the stability and adaptability of CoNi LDH@NF composite membrane,proposing a new theoretical basis of PMS heterogeneous catalysts selection.
基金This work was financially supported by the talent starting-up project of research development fund of Zhejiang Agriculture and Forestry University(No.2034020103)the Overseas Expertise Introduction Project for Discipline Innovation(No.111 Project D18008).
文摘Biochar-based transition metal catalysts have been identified as excellent peroxymonosulfate(PMS)activators for producing radicals used to degrade organic pollutants.However,the radical-dominated pathways for PMS activation severely limit their practical applications in the degradation of organic pollutants from wastewater due to side reactions between radicals and the coexisting anions.Herein,bimetallic Fe/Mn-loaded hydroxyl-rich biochar(FeMn-OH-BC)is synthesized to activate PMS through nonradical-dominated pathways.The as-prepared FeMn-OH-BC exhibits excellent catalytic activity for degrading tetracycline at broad pH conditions ranging from 5 to 9,and about 85.0%of tetracycline is removed in 40 min.Experiments on studying the influences of various anions(HCO_(3)^(−),NO_(3)^(−),and H_(2)PO_(4)^(−))show that the inhibiting effect is negligible,suggesting that the FeMn-OHBC based PMS activation is dominated by nonradical pathways.Electron paramagnetic resonance measurements and quenching tests provide direct evidence to confirm that 1O2 is the major reactive oxygen species generated from FeMn-OH-BC based PMS activation.Theoretical calculations further reveal that the FeMn-OH sites in FeMn-OH-BC are dominant active sites for PMS activation,which have higher adsorption energy and stronger oxidative activity towards PMS than OH-BC sites.This work provides a new route for driving PMS activation by biochar-based transition metal catalysts through nonradical pathways.
文摘Wastewater containing an azo dye Orange G(OG)causes massive environmental pollution,thus it is critical to develop a highly effective,environmental-friendly,and reusable catalyst in peroxymonosulfate(PMS)activation for OG degradation.In this work,we successfully applied a magnetic MnFe_(2)O_(4)/α-MnO_(2) hybrid fabricated by a simple hydrothermal method for OG removal in water.The characteristics of the hybrid were investigated by Xray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,Fourier transform infrared spectroscopy,Brunauer–Emmett–Teller method,vibrating sample magnetometry,electron paramagnetic resonance,thermogravimetric analysis,and X-ray photoelectron spectroscopy.The effects of operational parameters(i.e.,catalytic system,catalytic dose,solution pH,and temperature)were investigated.The results exhibited that 96.8% of OG degradation was obtained with MnFe_(2)O_(4)/α-MnO2(1:9)/PMS system in 30 min regardless of solution pH changes.Furthermore,the possible reaction mechanism of the coupling system was proposed,and the degradation intermediates of OG were identified by mass spectroscopy.The radical quenching experiments and EPR tests demonstrated that SO_(4)•̶,O_(2)•̶,and 1O2 were the primary reactive oxygen species responsible for the OG degradation.The hybrid also displayed unusual stability with less than 30%loss in the OG removal after four sequential cycles.Overall,magnetic MnFe2O4/α-MnO2 hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.
基金supported by the Key R&D Program from the Department of Science and Technology of Sichuan Province(Nos.2019YFG0056,2019YFG0443 and 2019YFG0035)the Major special projects of science and Technology Department of Sichuan Province (No.2020ZDZX0020)。
文摘Fe-N co-doped coral-like hollow carbon shell (Fe-N-CS) was synthesized via a simply impregnation-pyrolysis method.The Fe-N-CS showed an excellent ability for activating peroxymonosulfate (PMS),which could degrade about 93.74%tetracycline (20 mg/L) in 12 min.The Fe-N-CS/PMS system exhibited a good anti-interference capacity of various pH,inorganic anions,HA and different water qualities.More importantly,the Fe nanoparticles were anchored uniformly in the carbon layer,effectively limiting the metal leaching.The quenching tests and electron spin resonance (ESR) manifested that non-radical singlet oxygen (1O_(2))was the main reactive oxygen species (ROS) for TC degradation.The mechanism study showed that Fe nanoparticles,defect and graphite N played a key role in activating PMS to produce ROS.Moreover,three probable degradation pathways were proposed by using LC-MS measurements.Generally,this work had a new insight for the synthesis of heterogeneous Fe-N-C catalysts in the advanced oxidation process based on PMS.
基金financially supported by the National Natural Science Foundation of China(Nos.52170079 and U20A20322)the Programme of Introducing Talents of Discipline to Universities,China(No.B16020)。
文摘The Z-scheme heterostructure for photocatalyst can effectively prolong the lifetime of photogenerated carriers and retain a higher conduction/valence band position,promoting the synergistic coupling of photocatalysis and peroxymonosulfate(PMS) activation.In order to fully utilize the luminous energy and realize the efficient activation of PMS,this work achieved successful construction of NiCo_(2)O_(4)/BiOCl/Bi_(24)O_(31)Br_(10) ternary Z-scheme heterojunction by simultaneously synthesizing BiOCl and NiCo_(2)O_(4) with NiCl_(2) and CoCl_(2) as the precursors.The intercalated BiOCl could serve as a carrier migration ladder to further achieve the spatial separation of electron-hole pairs,so that the oxidation and reduction processes separately occurred in different regions.Compared with the reported catalysts,the as-prepared composites exhibited the enhanced removal efficiency for tetracycline hydrochloride(TCH) in the visible light/PMS system,with a degradation efficiency of 85.30%in 2 min,and possessed good stability.Z-scheme heterojunction was shown to be beneficial for maximizing the superiority of photo-assisted Fenton-like reaction system.The experimental and characterization results confirmed that both non-radicals(^(1)O_(2)) and radicals(SO_(5)^(·-) and SO_(4)^(·-)) were involved in the reaction process and the SO_(5)^(·-)generated by the oxidation of PMS played a crucial role in the TCH degradation.The possible reaction mechanism was finally proposed.This study provided new insight into the Z-scheme heterostructure to promote the photo-assisted Fenton-like reaction.
基金This work was supported by the Major special projects of Science and Technology Department of Sichuan Province(No.2020ZDZX0020).
文摘Bisphenol A(BPA)has received increasing attention due to its long-term industrial application and persistence in environmental pollution.Iron-based carbon catalyst activation of peroxymonosulfate(PMS)shows a good prospect for effective elimination of recalcitrant contaminants in water.Herein,considering the problem about the leaching of iron ions and the optimization of heteroatoms doping,the iron,nitrogen and sulfur co-doped tremellalike carbon catalyst(Fe-NS@C)was rationally designed using very little iron,S-C_(3)N_(4) and low-cost chitosan(CS)via the impregnation-calcination method.The as-prepared Fe-NS@C exhibited excellent performance for complete removal of BPA(20 mg/L)by activating PMS with the high kinetic constant(1.492 min^(−1))in 15 min.Besides,the Fe-NS@C/PMS system not only possessed wide pH adaptation and high resistance to environmental interference,but also maintained an excellent degradation efficiency on different pollutants.Impressively,increased S-C_(3)N_(4) doping amount modulated the contents of different N species in Fe-NS@C,and the catalytic activity of Fe-NS@C-1-x was visibly enhanced with increasing SC_(3)N_(4) contents,verifying pyridine N and Fe-Nx as main active sites in the system.Meanwhile,thiophene sulfur(C-S-C)as active sites played an auxiliary role.Furthermore,quenching experiment,EPR analysis and electrochemical test proved that surface-bound radicals(·OH and SO_(4)^(·−))and non-radical pathways worked in the BPA degradation(the former played a dominant role).Finally,possible BPA degradation route were proposed.This work provided a promising way to synthesize the novel Fe,N and S co-doping carbon catalyst for degrading organic pollutants with low metal leaching and high catalytic ability.