In this study,advanced oxidation processes(AOPs) such as anodic oxidation(AO),UV/H_2O_2 and Fenton processes(FP) were investigated for the degradation of salicylic acid(SA) in lab-scale experiments.Boron-doped diamond...In this study,advanced oxidation processes(AOPs) such as anodic oxidation(AO),UV/H_2O_2 and Fenton processes(FP) were investigated for the degradation of salicylic acid(SA) in lab-scale experiments.Boron-doped diamond(BDD) film electrodes using Ta as substrates were employed for AO of SA.In the case of FP and UV/H_2O_2,most favorable experimental conditions were determined for each process and these were used for comparing with AO process.The study showed that the FP was the most effective process under ...展开更多
Treatment to crystallization mother liquor containing high concentration of organic and inorganic substances is a challenge in zero liquid discharge of industrial wastewater.Acid precipitation coupled membrane-dispers...Treatment to crystallization mother liquor containing high concentration of organic and inorganic substances is a challenge in zero liquid discharge of industrial wastewater.Acid precipitation coupled membrane-dispersion advanced oxidation process(MAOP)was proposed for organics degradation before salt crystallization by evaporation.With acid-MAOP treatment CODCrin mother liquor of pulping wastewater was eliminated by 55.2%from ultrahigh initial concentration up to 12,500 mg·L^-1.The decolorization rate was 96.5%.Recovered salt was mainly NaCl(83.3 wt%)having whiteness 50 brighter than industrial baysalt of whiteness 45.The oxidation conditions were optimized as CO3=0.11 g·L^-1 and CH2O2=2.0 g·L^-1 with dispersing rate 0.53 ml·min^-1 for 100 min reaction toward acidified liquor of p H=2.Acidification has notably improved evaporation efficiency during crystallization.Addition of H2O2 made through membrane dispersion has eliminated hydroxyl radical"quench effect"and enhanced the degradation capacity,in particular,the breakage of carbon-chloride bonds(of both aliphatic and aromatic).As a result,the proposed coupling method has improved organic pollutant reduction so as the purity of salt from the wastewater mixture which can facilitate water and salt recycling in industry.展开更多
Studies to decompose persistent organic pollutants in wastewater from chemical factories by using Advanced Oxidation Processes (AOPs) have recently been performed. Oxidation reactions involving ozone and •OH ...Studies to decompose persistent organic pollutants in wastewater from chemical factories by using Advanced Oxidation Processes (AOPs) have recently been performed. Oxidation reactions involving ozone and •OH radicals and cleavage caused by UV are the main decomposition reactions that occur in AOPs using ozone and UV. The mechanisms through which organic compounds are decomposed in AOPs are complicated and difficult to understand because various decomposition reactions occur simultaneously. The Total Organic Carbon (TOC) removal efficiencies achieved in several different AOPs were evaluated in this study. The TOC removal efficiencies were different for organic compounds with different chemical structures. The TOC was more effectively removed when aromatic compounds were treated using the O<sub>3</sub>-UV-TiO<sub>2</sub> process than when using the other AOPs, and the TOC was removed more effectively by the O<sub>3</sub>-UV process than by the UV-TiO<sub>2</sub> process. However, the TOC was removed more effectively when open-chain compounds were treated using the UV-TiO<sub>2</sub> process than using the O<sub>3</sub>-UV process, and the UV-TiO<sub>2</sub> and O<sub>3</sub>-UV-TiO<sub>2</sub> processes resulted in similar TOC removal efficiencies. Therefore, it is necessary to use the O<sub>3</sub>-UV-TiO<sub>2</sub> process to decompose aromatic compounds as quickly as possible. On the other hand, the UV-TiO<sub>2</sub> process degraded the open-chain compounds most effectively, and the O<sub>3</sub>-UV-TiO<sub>2</sub> process did not need to decompose open-chain compounds. Moreover, the TOC of aromatic compounds was removed more slowly than that of open-chain compounds. The TOC removal efficiency increased with decreasing the number of carbon atoms in the molecule. The TOC removal efficiencies increased in order of the organic compounds containing methyl groups, aldehyde groups and carboxyl groups. The removal of the TOC when organic compounds were treated using the O<sub>3</sub>-UV-TiO<sub>2</sub> process followed pseudo-zero-order kinetics.展开更多
Hospital sewage contains various harmful pharmaceutical contaminants(e.g.,antibiotics,anti-inflammatory agents,and painkillers)and pathogens(e.g.,bacteria,viruses,and parasites),whose direct discharge into the environ...Hospital sewage contains various harmful pharmaceutical contaminants(e.g.,antibiotics,anti-inflammatory agents,and painkillers)and pathogens(e.g.,bacteria,viruses,and parasites),whose direct discharge into the environment will induce diseases and pose a powerful threat to human health and safety,and environmental ecology.In recent years,advanced oxidation processes(AOPs),particularly photocatalysis,electrocatalysis,and ozone catalysis have been developed as widespread and effective techniques for hospital sewage treatments.However,there is a lack of systematic comparison and review of the prior studies on hospital sewage treatment using AOPs systems.This review elaborates on the mechanisms,removal efficiencies,and advantages/disadvantages of these AOPs systems for hospital wastewater decontamination and disinfection.Meanwhile,some novel and potential technologies such as photo-electrocatalysis,electro-peroxone,Fenton/Fenton-like,and piezoelectric catalysis are also included and summarized.Moreover,we further summarize and compare the capacity of these AOPs to treat the actual hospital wastewater under the impact of the water matrix and pH,and estimate the economic cost of these technologies for practical application.Finally,the future development directions of AOPs for hospital wastewater decontamination and disinfection have been prospected.Overall,this study provides a comparison and overview of these AOP systems in an attempt to raise extensive concerns about hospital wastewater decontamination and disinfection technologies and guide researchers to discover the future directions of technologies optimization,which would be a crucial step forward in the field of hospital sewage treatment.展开更多
Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is...Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation efficiency.Fortunately,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its reactivity.Herein,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other support.The activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical pathways.The effects of pH,inorganic ions,and natural organic matter on degradation reactions are also discussed.Finally,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.展开更多
This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced ...This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI fraction.In terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of HPI.The specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI content.UV/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based AOPs.Results from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.展开更多
As important emerging contaminants, antibiotics have caused potential hazards to the ecological environment and human health due to their extensive production and consumption. Among various techniques for removing ant...As important emerging contaminants, antibiotics have caused potential hazards to the ecological environment and human health due to their extensive production and consumption. Among various techniques for removing antibiotics from wastewater, H_(2)O_(2)-based advanced oxidation processes(AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability. Hence this review critically discusses:(i) Recent research progress of AOPs with the addition of H_(2)O_(2) for antibiotics removal through different methods of H_(2)O_(2) activation;(ii) recent advances in AOPs that can in-situ generate and activate H_(2)O_(2) for antibiotics removal;(iii) H_(2)O_(2)-based AOPs as a combination with other techniques for the degradation and mineralization of antibiotics in wastewater. Future perspectives about H_(2)O_(2)-based AOPs are also presented to grasp the future research trend in the area.展开更多
In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of ...In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of cobalt ions with cyanoimino NNIs, acetamiprid(ACE) and thiacloprid(THI), could promote peroxymonosulfate and Ru(bpy)_(3)^(2+) to produce strong CL, but no CL occurred with nitro-involved NNIs as alternatives. Experimental dada from UV absorption spectra and chemiluminescence spectra suggested that new cyclic compounds might be formed during the reaction. Based on the results of free radical scavenging experiment and mass spectra, a new degradation and reaction mechanism of cyanoiminocontaining NNIs was proposed. ACE or THI were first attacked by SO_(4)^(·-) to form benzyl radicals, which in turn reacted with the carbon atoms of cyano group through electrophilic addition reaction in the formation of intramolecular ring. Then a redox reaction between Ru(bpy)_(3)^(3+) and imino group immediately took place with CL emission(610 nm). The new mechanistic knowledge would be meaningful for other contaminants for their interactions with PMS.展开更多
Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and...Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and Ce-based catalysts have exhibited excellent performance.Recently,the development and application of Ce-based catalysts in various AOPs have been reported.Our study conducts the first review in this rapid growing field.This paper clarifies the variety and properties of Ce-based catalysts.Their applications in different AOP systems (catalytic ozonation,photodegradation,Fenton-like reactions,sulfate radicalbased AOPs,and catalytic sonochemistry) are discussed.Different Ce-based catalysts suit different reaction systems and produce different active radicals.Finally,future research directions of Ce-based catalysts in AOP systems are suggested.展开更多
Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing at...Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing attentions and various technologies have been developed,among which advanced oxidation processes(AOPs)are more effectively and promising.Progresses on five representative types of AOPs,including Fenton(like)oxidation,electrochemical oxidation,photocatalytic oxidation,ozonation and discharge plasma oxidation for heavy metal complexe s degradation are summarized in this review.Their rationales,advantages,applications,challenges and prospects are introduced independently.Combinations among these AOPs,such as electrochemical Fenton oxidation and photoelectrocatalytic oxidation,are also comprehensively highlighted.Future efforts should be made to reduce acid requirement and scale up for practical applications of AOPs for heavy metal complex degradation efficiently and cost-effectively.展开更多
Herein,we prepa red novel three-dimensional(3D)gear-s haped Co3O4@C(Co3O4 modified by amorphous carbon)and sheet-like SnO2/CC(SnO2 grow on the carbon cloth)as anode and cathode to achieve efficient removal of 4-nitrop...Herein,we prepa red novel three-dimensional(3D)gear-s haped Co3O4@C(Co3O4 modified by amorphous carbon)and sheet-like SnO2/CC(SnO2 grow on the carbon cloth)as anode and cathode to achieve efficient removal of 4-nitrophenol(4-NP)in the presence of peroxymonosulfate(PMS)and simultaneous electrocatalytic reduction of CO2,respectively.In this process,4-NP was mineralized into CO2 by the Co3O4@C,and the generated CO2 was reduced into HCOOH by the sheet-like SnO2/CC cathode.Compared with the pure Co0.5(Co3O4 was prepared using 0.5 g urea)with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP(60 mL,10 mg/L)increased from 74.5%-85.1%in 60 min using the Co0.5 modified by amorphous carbon(Co0.5@C).Furthermore,when the voltage of 1.0 V was added in the anodic system of Co0.5@C with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP increased from 85.1%-99.1%when Pt was used as cathode.In the experiments of 4-NP degradation coupled with simultaneous electrocatalytic CO2 reduction,the degradation efficiency of 4-NP was 99.0%in the anodic system of Co0.5@C with addition of PMS(30 mg,0.5 g/L),while the Faraday efficiency(FE)of HCOOH was 24.1%at voltage of-1.3 V using the SnO2/CC as cathode.The results showed that the anode of Co3O4 modified by amorphous carbon can markedly improve the degradation efficiency of 4-NP,while the cathode of SnO2/CC can greatly improve the FE and selectivity of CO2 reduction to HCOOH and the stability of cathode.Finally,the promotion mechanism was proposed to explain the degradation of organic pollutants and reduction of CO2 into HCOOH in the process of electrocatalysis coupled with advanced oxidation processes(AOPs)and simultaneous CO2 reduction.展开更多
In recent years,with the emergence of new pollutants,the effective treatment of wastewater has become very important.Persulfate-based advanced oxidation processes have been successfully applied to the treatment of was...In recent years,with the emergence of new pollutants,the effective treatment of wastewater has become very important.Persulfate-based advanced oxidation processes have been successfully applied to the treatment of wastewater,such as wastewater containing antibiotics,pharmaceuticals and personal care products,dyes,endocrine-disrupting chemicals,chlorinated organic pollutants,and phenolics,for the degradation of refractory organic contaminants.This paper summarizes the production of sulfate radicals,which can be generated by the activation of persulfate via conventional and emerging approaches.The existing problems of persulfate-based advanced oxidation processes were analyzed in detail,including residual sulfates,coexisting factors(coexisting inorganic anions and natural organic matter),and energy consumption.This paper proposes corresponding possible solutions to the problems mentioned above,and this paper could provide a reference for the application of persulfate-based advanced oxidation processes in actual wastewater treatment.展开更多
In the field of advanced oxidation processes(AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species(ROS) to...In the field of advanced oxidation processes(AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species(ROS) to decompose refractory pollutants. Perovskite oxide, an emerging catalyst in the field of AOPs, has been extensively studied in wastewater treatment. Nevertheless, the application of perovskite in AOP systems still faces some problems, such as leaching of metal ions, a small surface area, a low number of active sites, etc. Herein, this critical review comparatively examines the activation mechanisms of peroxymonosulfate, hydrogen peroxide, and peroxydisulfate. Furthermore, the formation pathways of oxidizing species based on recent advances in experimental and theoretical studies were evaluated. In addition, the impacts of water parameters and constituents such as initial p H, oxidant concentration, catalyst dosage,natural organic matter, halide, phosphate, and carbonate were discussed. Finally, a critical discussion and prospects of mechanism exploration and possible materials development are proposed to confront the existing challenges in the application of perovskite oxides in AOPs.展开更多
Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated site...Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated sites usually contain abundant inorganic ions, like the chloride ion (Cl−), which significantly affectAOPs, but their influence on MG-activated AOPs still remains unclear. Through the study of three commonly used oxidants, hydrogen peroxide (H_(2)O_(2)), peroxydisulfate (PDS), and peroxymonosulfate (PMS), theeffect of Cl− on the FeSiB-catalyzed process of degradation of the typical azo dye Orange Ⅱ was investigated. Evidence indicates that the addition of Cl− resulted in the monotonous inhibition of the degradation process when the H_(2)O_(2)/FeSiB and PDS/FeSiB systems were employed, but promoted effect wasdetected with the PMS/FeSiB system, which is different from the previously observed dual effect of Cl−.It is closely relative with FeSiB induced unique variety of degradation pathways, including radicals, nonradicals (^(1)O_(2)), and direct reduction degradation. Moreover, the presence of Cl− significantly affected thesystems’ absorbable organic halogen content and the amount of Fe leached into the solution. The resultsof this work will provide essential references for Fe-based MG used as AOP catalysts in field applicationsand the development of advanced MGs with excellent adaptability to complex environments.展开更多
This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced ...This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced oxidation processes(AOP).Iron,copper,and two different cobalt-based catalysts were prepared and evaluated.The catalysts were supported on a biochar obtained from the pyrolysis of woody pruning wastes.They were characterized by C,H,and N elemental analysis,X-Ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).The metal content in each catalyst was determined by means of atomic absorption spectroscopy(AAS).The degradation reac-tions of benzoic acid(BA),catechol(C),and cinnamic acid(CA)were carried out in a lab scale batch glass reactor and were followed by UV-Visible spectroscopy(UV-Vis).A colorimetric technique was employed to verify the presence of oxidant during the reaction progress.The catalyst/oxidant optimal ratio was determined for the cobalt catalysts.The mineralization degree of the pollutants after the degradations was verified by means of total organic carbon(TOC)content in the residual liquids.After 4 h of reaction,the maximum mineralization was reached when C was treated with a cobalt-based catalyst(>80%),and its stability was evaluated through successive cycles of use.展开更多
The degradation of the anti-inflammatory ibuprofen(IBP)was evaluated by several advanced oxidation processes.IBP was treated by single ozonation and oxidation with hydrogen peroxide(H_(2)O_(2)),as well as a combinatio...The degradation of the anti-inflammatory ibuprofen(IBP)was evaluated by several advanced oxidation processes.IBP was treated by single ozonation and oxidation with hydrogen peroxide(H_(2)O_(2)),as well as a combination of these treatments.In order to improve the efficiency,the presence of catalysts such as original carbon nanotubes,labelled as CNT,and iron oxide supported on carbon nanotubes,named as Fe/CNT sample,was considered.The evolution of IBP degradation,mineralization and toxicity of the solutions was assessed.The formation of intermediates was also monitored.In the non-catalytic processes,IBP was faster removed by single ozonation,whereas no significant total organic carbon(TOC)removal was achieved.Oxidation with H_(2)O_(2) did not present satisfactory results.When ozone and H_(2)O_(2) were combined,a higher mineralization was attained(70%after 180 min of reaction).On the other hand,in the catalytic processes,this combined process allowed the fastest IBP degradation.In terms of mineralization degree,the presence of Fe/CNT increases the removal rate in the first hour of reaction,achieving a TOC removal of 85%.Four compounds were detected as by-products.All treated solutions presented lower toxicity than the initial solution,suggesting that the released intermediates during applied processes are less toxic.展开更多
TiO_(2)has demonstrated outstanding performance in electrochemical advanced oxidation processes(EAOPs)due to its structural stability and high oxygen overpotential.However,there is still much room for improving its el...TiO_(2)has demonstrated outstanding performance in electrochemical advanced oxidation processes(EAOPs)due to its structural stability and high oxygen overpotential.However,there is still much room for improving its electrochemical activity.Herein,narrow bandgap manganese oxide(MnO_(x))was composited with TiO_(2)nanotube arrays(TiO_(2)NTAs)that in-situ oxidized on porous Ti sponge,forming the MnO_(x)-TiO_(2)NTAs anode.XANES and XPS analysis further proved that the composition of MnO_(x)is Mn2O3.Electrochemical characterizations revealed that increasing the composited concentration of MnO_(x)can improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnO_(x)-TiO_(2)NTAs anode.Meanwhile,the optimal degradation rate of benzoic acid(BA)was achieved using MnO_(x)-TiO_(2)NTAs with a MnO_(x)concentration of 0.1 mmol L^(-1),and the role of MnO_(x)was proposed based on DFT calculation.Additionally,the required electrical energy(EE/O)to destroy BA was optimized by varying the composited concentration of MnO_(x)and the degradation voltage.These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.展开更多
The degradation of metoprolol(MTP)by the UV/sulfite with oxygen as an advanced reduction process(ARP)and that without oxygen as an advanced oxidation process(AOP)was comparatively studied herein.The degradation of MTP...The degradation of metoprolol(MTP)by the UV/sulfite with oxygen as an advanced reduction process(ARP)and that without oxygen as an advanced oxidation process(AOP)was comparatively studied herein.The degradation of MTP by both processes followed the first-order rate law with comparable reaction rate constants of 1.50×10^(-3)sec^(−1)and 1.20×10^(-3)sec^(−1),respectively.Scavenging experiments demonstrated that both e^(−)_(aq)and H·played a crucial role in MTP degradation by the UV/sulfite as an ARP,while SO_(4)^(·−)was the dominant oxidant in the UV/sulfite AOP.The degradation kinetics of MTP by the UV/sulfite as an ARP and AOP shared a similar pH dependence with a minimum rate obtained around pH 8.The results could be well explained by the pH impacts on the MTP speciation and sulfite species.Totally six transformation products(TPs)were identified from MTP degradation by the UV/sulfite ARP,and two additional ones were detected in the UV/sulfite AOP.The benzene ring and ether groups of MTP were proposed as the major reactive sites for both processes based on molecular orbital calculations by density functional theory(DFT).The similar degradation products of MTP by the UV/sulfite process as an ARP and AOP indicated that e^(−)_(aq)/H·and SO_(4)^(·−)might share similar reaction mechanisms,primarily including hydroxylation,dealkylation,and H abstraction.The toxicity of MTP solution treated by the UV/sulfite AOP was calculated to be higher than that in the ARP by the Ecological Struc-ture Activity Relationships(ECOSAR)software,due to the accumulation of TPs with higher toxicity.展开更多
The characteristics of the slaughterhouse effluents and current wastewater treatment practices in the province of Ontario, Canada are analyzed. Meat processing plants are found to produce large amounts of wastewater d...The characteristics of the slaughterhouse effluents and current wastewater treatment practices in the province of Ontario, Canada are analyzed. Meat processing plants are found to produce large amounts of wastewater due to the slaughtering process and cleaning of their facilities. Furthermore, the composition of the wastewater varies according to the type and number of animals slaughtered and the water requirements of the process. However, the slaughterhouse wastewater usually contains high levels of organics and nutrients. Several slaughterhouses in Ontario discharge their wastewater into the municipal sewer system after primary pretreatment at the meat processing plant. Therefore, due to the high-strength characteristics of the slaughterhouse effluents, an extensive treatment for a safe discharge into the environment is required. Thus, the combination of biological processes and advanced oxidation technologies for slaughterhouse wastewater treatment is evaluated in this study. Results show that the application of combined biological and advanced oxidation processes is recommended for on-site slaughterhouse wastewater treatment.展开更多
Currently, landfills are the main method used for the final disposal of urban solid waste. The degradation processes that waste goes through in these sites, alongside rainwater that percolates through them, generate h...Currently, landfills are the main method used for the final disposal of urban solid waste. The degradation processes that waste goes through in these sites, alongside rainwater that percolates through them, generate highly polluting liquids (leachate). In the treatment of leachate, advanced oxidation processes (AOP) can significantly reduce the concentrations of different pollutants. Due to the high documented potential around AOPs, in this study, the effectiveness of anodic oxidation in the removal of the remaining organic load in leachates pretreated in a biological system was evaluated. Graphite electrodes were used as anode and cathode. The efficiency of anodic oxidation, in terms of the removal of chemical oxygen demand (COD) and color, was evaluated under different current densities (7, 12, 17 and 22 mA/cm2) and pH values (3, 4.5 and 6). Under the best conditions found (22 mA/cm2 and pH of 6) and with an oxidation time of 5 hours, a maximum removal of 68% in COD and 91% in color was achieved, which represented a quality in the final effluent of 271 mg/L and 151 Pt-Co in COD and color, respectively. Therefore, considering that graphite is an economic and widely available material, the results obtained show anodic oxidation, with the use of graphite electrodes, as a technically viable alternative as a final purification stage for pretreated leachates.展开更多
文摘In this study,advanced oxidation processes(AOPs) such as anodic oxidation(AO),UV/H_2O_2 and Fenton processes(FP) were investigated for the degradation of salicylic acid(SA) in lab-scale experiments.Boron-doped diamond(BDD) film electrodes using Ta as substrates were employed for AO of SA.In the case of FP and UV/H_2O_2,most favorable experimental conditions were determined for each process and these were used for comparing with AO process.The study showed that the FP was the most effective process under ...
基金Financial supports from the Prospective Joint Research Project of Jiangsu Province(BY2014005-06)National Natural Science Foundation of China(U1510202)the Jiangsu National Synergistic Innovation Center for Advanced Materials(SICAM)。
文摘Treatment to crystallization mother liquor containing high concentration of organic and inorganic substances is a challenge in zero liquid discharge of industrial wastewater.Acid precipitation coupled membrane-dispersion advanced oxidation process(MAOP)was proposed for organics degradation before salt crystallization by evaporation.With acid-MAOP treatment CODCrin mother liquor of pulping wastewater was eliminated by 55.2%from ultrahigh initial concentration up to 12,500 mg·L^-1.The decolorization rate was 96.5%.Recovered salt was mainly NaCl(83.3 wt%)having whiteness 50 brighter than industrial baysalt of whiteness 45.The oxidation conditions were optimized as CO3=0.11 g·L^-1 and CH2O2=2.0 g·L^-1 with dispersing rate 0.53 ml·min^-1 for 100 min reaction toward acidified liquor of p H=2.Acidification has notably improved evaporation efficiency during crystallization.Addition of H2O2 made through membrane dispersion has eliminated hydroxyl radical"quench effect"and enhanced the degradation capacity,in particular,the breakage of carbon-chloride bonds(of both aliphatic and aromatic).As a result,the proposed coupling method has improved organic pollutant reduction so as the purity of salt from the wastewater mixture which can facilitate water and salt recycling in industry.
文摘Studies to decompose persistent organic pollutants in wastewater from chemical factories by using Advanced Oxidation Processes (AOPs) have recently been performed. Oxidation reactions involving ozone and •OH radicals and cleavage caused by UV are the main decomposition reactions that occur in AOPs using ozone and UV. The mechanisms through which organic compounds are decomposed in AOPs are complicated and difficult to understand because various decomposition reactions occur simultaneously. The Total Organic Carbon (TOC) removal efficiencies achieved in several different AOPs were evaluated in this study. The TOC removal efficiencies were different for organic compounds with different chemical structures. The TOC was more effectively removed when aromatic compounds were treated using the O<sub>3</sub>-UV-TiO<sub>2</sub> process than when using the other AOPs, and the TOC was removed more effectively by the O<sub>3</sub>-UV process than by the UV-TiO<sub>2</sub> process. However, the TOC was removed more effectively when open-chain compounds were treated using the UV-TiO<sub>2</sub> process than using the O<sub>3</sub>-UV process, and the UV-TiO<sub>2</sub> and O<sub>3</sub>-UV-TiO<sub>2</sub> processes resulted in similar TOC removal efficiencies. Therefore, it is necessary to use the O<sub>3</sub>-UV-TiO<sub>2</sub> process to decompose aromatic compounds as quickly as possible. On the other hand, the UV-TiO<sub>2</sub> process degraded the open-chain compounds most effectively, and the O<sub>3</sub>-UV-TiO<sub>2</sub> process did not need to decompose open-chain compounds. Moreover, the TOC of aromatic compounds was removed more slowly than that of open-chain compounds. The TOC removal efficiency increased with decreasing the number of carbon atoms in the molecule. The TOC removal efficiencies increased in order of the organic compounds containing methyl groups, aldehyde groups and carboxyl groups. The removal of the TOC when organic compounds were treated using the O<sub>3</sub>-UV-TiO<sub>2</sub> process followed pseudo-zero-order kinetics.
基金the National Natural Science Foundation of China(Nos.52170088 and 52070133)China Postdoctoral Science Foundation(No.2021M690844)Sichuan Science and Technology Program(No.2021JDRC0027)for financially supporting this study.
文摘Hospital sewage contains various harmful pharmaceutical contaminants(e.g.,antibiotics,anti-inflammatory agents,and painkillers)and pathogens(e.g.,bacteria,viruses,and parasites),whose direct discharge into the environment will induce diseases and pose a powerful threat to human health and safety,and environmental ecology.In recent years,advanced oxidation processes(AOPs),particularly photocatalysis,electrocatalysis,and ozone catalysis have been developed as widespread and effective techniques for hospital sewage treatments.However,there is a lack of systematic comparison and review of the prior studies on hospital sewage treatment using AOPs systems.This review elaborates on the mechanisms,removal efficiencies,and advantages/disadvantages of these AOPs systems for hospital wastewater decontamination and disinfection.Meanwhile,some novel and potential technologies such as photo-electrocatalysis,electro-peroxone,Fenton/Fenton-like,and piezoelectric catalysis are also included and summarized.Moreover,we further summarize and compare the capacity of these AOPs to treat the actual hospital wastewater under the impact of the water matrix and pH,and estimate the economic cost of these technologies for practical application.Finally,the future development directions of AOPs for hospital wastewater decontamination and disinfection have been prospected.Overall,this study provides a comparison and overview of these AOP systems in an attempt to raise extensive concerns about hospital wastewater decontamination and disinfection technologies and guide researchers to discover the future directions of technologies optimization,which would be a crucial step forward in the field of hospital sewage treatment.
基金the National Natural Science Foundation of China(Nos.52170088 and 52070133)for financial support。
文摘Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation efficiency.Fortunately,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its reactivity.Herein,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other support.The activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical pathways.The effects of pH,inorganic ions,and natural organic matter on degradation reactions are also discussed.Finally,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.
基金supported by the “Central leading local” Science and Technology Development Fund Project of Shandong Province (No.YDZX202037 00001642)the Key Research and Development Plan of Shandong Province(NO.2020CXGC011406),the Natural Science Foundation of Shandong Province (No.ZR2021ME166)the Special Project of Taishan Scholar Construction Engineering (No.ts201712084)。
文摘This study examined the effectiveness for degradation of hydrophobic (HPO),transphilic(TPI) and hydrophilic (HPI) fractions of natural organic matter (NOM) during UV/H_(2)O_(2),UV/TiO_(2)and UV/K2S2O8(UV/PS) advanced oxidation processes (AOPs).The changing characteristics of NOM were evaluated by dissolved organic carbon (DOC),the specific UV absorbance (SUVA),trihalomethanes formation potential (THMFP),organic halogen adsorbable on activated carbon formation potential (AOXFP) and parallel factor analysis of excitation–emission matrices (PARAFAC-EEMs).In the three UV-based AOPs,HPI fraction with low molecular weight and aromaticity was more likely to degradate than HPO and TPI,and the removal efficiency of SUVA for HPO was much higher than TPI and HPI fraction.In terms of the specific THMFP of HPO,TPI and HPI,a reduction was achieved in the UV/H_(2)O_(2)process,and the higest removal rate even reached to 83%.UV/TiO_(2)and UV/PS processes can only decrease the specific THMFP of HPI.The specific AOXFP of HPO,TPI and HPI fractions were all able to be degraded by the three UV-based AOPs,and HPO content is more susceptible to decompose than TPI and HPI content.UV/H_(2)O_(2)was found to be the most effective treatment for the removal of THMFP and AOXFP under given conditions.C1 (microbial or marine derived humic-like substances),C_(2) (terrestrially derived humic-like substances)and C_(3) (tryptophan-like proteins) fluorescent components of HPO fraction were fairly labile across the UV-based AOPs treatment.C_(3) of each fraction of NOM was the most resistant to degrade upon the UV-based AOPs.Results from this study may provide the prediction about the consequence of UV-based AOPs for the degradation of different fractions of NOM with varied characteristics.
基金financially supported by National Natural Science Foundation of China(Nos.21976096,52170085 and 21773129)Tianjin Development Program for Innovation and Entrepreneurship+2 种基金Key Project of Natural Science Foundation of Tianjin(No.21JCZDJC00320)Tianjin Post-graduate Students Research and Innovation Project(No.2021YJSB013)Fundamental Research Funds for the Central Universities,Nankai University。
文摘As important emerging contaminants, antibiotics have caused potential hazards to the ecological environment and human health due to their extensive production and consumption. Among various techniques for removing antibiotics from wastewater, H_(2)O_(2)-based advanced oxidation processes(AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability. Hence this review critically discusses:(i) Recent research progress of AOPs with the addition of H_(2)O_(2) for antibiotics removal through different methods of H_(2)O_(2) activation;(ii) recent advances in AOPs that can in-situ generate and activate H_(2)O_(2) for antibiotics removal;(iii) H_(2)O_(2)-based AOPs as a combination with other techniques for the degradation and mineralization of antibiotics in wastewater. Future perspectives about H_(2)O_(2)-based AOPs are also presented to grasp the future research trend in the area.
基金financial supports from the National Natural Science Foundation of China(Nos.81960600and 81760601)the Natural Science Foundation of Jiangxi Province(Nos.20192BAB205089 and 20192BAB205091)。
文摘In this study, we proposed a novel method to investigate the advanced oxidation process of neonicotinoids(NNIs) from the perspective of concomitant chemiluminescence(CL) reaction. It was found that in the presence of cobalt ions with cyanoimino NNIs, acetamiprid(ACE) and thiacloprid(THI), could promote peroxymonosulfate and Ru(bpy)_(3)^(2+) to produce strong CL, but no CL occurred with nitro-involved NNIs as alternatives. Experimental dada from UV absorption spectra and chemiluminescence spectra suggested that new cyclic compounds might be formed during the reaction. Based on the results of free radical scavenging experiment and mass spectra, a new degradation and reaction mechanism of cyanoiminocontaining NNIs was proposed. ACE or THI were first attacked by SO_(4)^(·-) to form benzyl radicals, which in turn reacted with the carbon atoms of cyano group through electrophilic addition reaction in the formation of intramolecular ring. Then a redox reaction between Ru(bpy)_(3)^(3+) and imino group immediately took place with CL emission(610 nm). The new mechanistic knowledge would be meaningful for other contaminants for their interactions with PMS.
基金supported by National Water Pollution Control and Treatment Science and Technology Major Project (No.2018ZX07110003)the National Natural Science Foundation of China (No.51779068)。
文摘Refractory organic pollutants in water threaten human health and environmental safety,and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants.Catalysts play vital role in AOPs,and Ce-based catalysts have exhibited excellent performance.Recently,the development and application of Ce-based catalysts in various AOPs have been reported.Our study conducts the first review in this rapid growing field.This paper clarifies the variety and properties of Ce-based catalysts.Their applications in different AOP systems (catalytic ozonation,photodegradation,Fenton-like reactions,sulfate radicalbased AOPs,and catalytic sonochemistry) are discussed.Different Ce-based catalysts suit different reaction systems and produce different active radicals.Finally,future research directions of Ce-based catalysts in AOP systems are suggested.
基金the National Natural Science Foundation of China(NSFC)(No.41672237)the Beijing Natural Science Foundation(No.8192040)。
文摘Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries,which are mo re stable and refracto ry than free heavy metal ions.Their re movals from wastewater draw increasing attentions and various technologies have been developed,among which advanced oxidation processes(AOPs)are more effectively and promising.Progresses on five representative types of AOPs,including Fenton(like)oxidation,electrochemical oxidation,photocatalytic oxidation,ozonation and discharge plasma oxidation for heavy metal complexe s degradation are summarized in this review.Their rationales,advantages,applications,challenges and prospects are introduced independently.Combinations among these AOPs,such as electrochemical Fenton oxidation and photoelectrocatalytic oxidation,are also comprehensively highlighted.Future efforts should be made to reduce acid requirement and scale up for practical applications of AOPs for heavy metal complex degradation efficiently and cost-effectively.
基金the National Natural Science Foundation of China(Nos.51878325,51868050,51622806,51378246 and 51720105001)the Natural Science Foundation of Jiangxi Province(Nos.20162BCB22017,20165BCB18008,20171ACB20017,20133ACB21001 and 20171BAB206049)the Graduate Innovation Fund of Jiangxi Province(No.YC2018-S360)。
文摘Herein,we prepa red novel three-dimensional(3D)gear-s haped Co3O4@C(Co3O4 modified by amorphous carbon)and sheet-like SnO2/CC(SnO2 grow on the carbon cloth)as anode and cathode to achieve efficient removal of 4-nitrophenol(4-NP)in the presence of peroxymonosulfate(PMS)and simultaneous electrocatalytic reduction of CO2,respectively.In this process,4-NP was mineralized into CO2 by the Co3O4@C,and the generated CO2 was reduced into HCOOH by the sheet-like SnO2/CC cathode.Compared with the pure Co0.5(Co3O4 was prepared using 0.5 g urea)with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP(60 mL,10 mg/L)increased from 74.5%-85.1%in 60 min using the Co0.5 modified by amorphous carbon(Co0.5@C).Furthermore,when the voltage of 1.0 V was added in the anodic system of Co0.5@C with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP increased from 85.1%-99.1%when Pt was used as cathode.In the experiments of 4-NP degradation coupled with simultaneous electrocatalytic CO2 reduction,the degradation efficiency of 4-NP was 99.0%in the anodic system of Co0.5@C with addition of PMS(30 mg,0.5 g/L),while the Faraday efficiency(FE)of HCOOH was 24.1%at voltage of-1.3 V using the SnO2/CC as cathode.The results showed that the anode of Co3O4 modified by amorphous carbon can markedly improve the degradation efficiency of 4-NP,while the cathode of SnO2/CC can greatly improve the FE and selectivity of CO2 reduction to HCOOH and the stability of cathode.Finally,the promotion mechanism was proposed to explain the degradation of organic pollutants and reduction of CO2 into HCOOH in the process of electrocatalysis coupled with advanced oxidation processes(AOPs)and simultaneous CO2 reduction.
基金the National Natural Science Foundation of China(No.51678185)Talents of High Level Scientific Research Foundation of Qingdao Agricultural University(No.6651120004).
文摘In recent years,with the emergence of new pollutants,the effective treatment of wastewater has become very important.Persulfate-based advanced oxidation processes have been successfully applied to the treatment of wastewater,such as wastewater containing antibiotics,pharmaceuticals and personal care products,dyes,endocrine-disrupting chemicals,chlorinated organic pollutants,and phenolics,for the degradation of refractory organic contaminants.This paper summarizes the production of sulfate radicals,which can be generated by the activation of persulfate via conventional and emerging approaches.The existing problems of persulfate-based advanced oxidation processes were analyzed in detail,including residual sulfates,coexisting factors(coexisting inorganic anions and natural organic matter),and energy consumption.This paper proposes corresponding possible solutions to the problems mentioned above,and this paper could provide a reference for the application of persulfate-based advanced oxidation processes in actual wastewater treatment.
基金financial support from National Key R&D Program of China (No.2019YFD1100200)National Natural Science Foundation of China (Nos.51878431,51961145106)+2 种基金Shanghai Rising-Star Program (No.20QC1401200)Shanghai Science and Technology Committee (No.19DZ1208400)State Key Laboratory of Pollution Control and Resource Reuse Foundation,(No.PCRRE20002)。
文摘In the field of advanced oxidation processes(AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species(ROS) to decompose refractory pollutants. Perovskite oxide, an emerging catalyst in the field of AOPs, has been extensively studied in wastewater treatment. Nevertheless, the application of perovskite in AOP systems still faces some problems, such as leaching of metal ions, a small surface area, a low number of active sites, etc. Herein, this critical review comparatively examines the activation mechanisms of peroxymonosulfate, hydrogen peroxide, and peroxydisulfate. Furthermore, the formation pathways of oxidizing species based on recent advances in experimental and theoretical studies were evaluated. In addition, the impacts of water parameters and constituents such as initial p H, oxidant concentration, catalyst dosage,natural organic matter, halide, phosphate, and carbonate were discussed. Finally, a critical discussion and prospects of mechanism exploration and possible materials development are proposed to confront the existing challenges in the application of perovskite oxides in AOPs.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52101195,51871120)the Natural Science Foundation of Jiangsu Province(Nos.BK20190480,BK20200019)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.30920021156,30920010004)the GuangdongHong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology。
文摘Fe-based metallic glasses (Fe–MGs) are potential candidate catalysts for advanced oxidation processes(AOPs) for recalcitrant organic pollutant degradation. However, industrial wastewater and natural contaminated sites usually contain abundant inorganic ions, like the chloride ion (Cl−), which significantly affectAOPs, but their influence on MG-activated AOPs still remains unclear. Through the study of three commonly used oxidants, hydrogen peroxide (H_(2)O_(2)), peroxydisulfate (PDS), and peroxymonosulfate (PMS), theeffect of Cl− on the FeSiB-catalyzed process of degradation of the typical azo dye Orange Ⅱ was investigated. Evidence indicates that the addition of Cl− resulted in the monotonous inhibition of the degradation process when the H_(2)O_(2)/FeSiB and PDS/FeSiB systems were employed, but promoted effect wasdetected with the PMS/FeSiB system, which is different from the previously observed dual effect of Cl−.It is closely relative with FeSiB induced unique variety of degradation pathways, including radicals, nonradicals (^(1)O_(2)), and direct reduction degradation. Moreover, the presence of Cl− significantly affected thesystems’ absorbable organic halogen content and the amount of Fe leached into the solution. The resultsof this work will provide essential references for Fe-based MG used as AOP catalysts in field applicationsand the development of advanced MGs with excellent adaptability to complex environments.
基金funded by SGCyT-UNS M24/Q075,PICTO COVIAR 2017-0112Agregando Valor VT42-UNS11738 research Grants.
文摘This study focuses on the synthesis of metal-based biochar catalysts and their catalytic activation of peroxymonosulfate(PMS,HSO5−)for the degradation of three different wastewater model pollutants employing advanced oxidation processes(AOP).Iron,copper,and two different cobalt-based catalysts were prepared and evaluated.The catalysts were supported on a biochar obtained from the pyrolysis of woody pruning wastes.They were characterized by C,H,and N elemental analysis,X-Ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).The metal content in each catalyst was determined by means of atomic absorption spectroscopy(AAS).The degradation reac-tions of benzoic acid(BA),catechol(C),and cinnamic acid(CA)were carried out in a lab scale batch glass reactor and were followed by UV-Visible spectroscopy(UV-Vis).A colorimetric technique was employed to verify the presence of oxidant during the reaction progress.The catalyst/oxidant optimal ratio was determined for the cobalt catalysts.The mineralization degree of the pollutants after the degradations was verified by means of total organic carbon(TOC)content in the residual liquids.After 4 h of reaction,the maximum mineralization was reached when C was treated with a cobalt-based catalyst(>80%),and its stability was evaluated through successive cycles of use.
基金financially supported by Base Funding–UIDB/50020/2020 of the Associate Laboratory LSRE-LCM–funded by national funds through FCT/MCTES(PIDDAC)Project PTDC/EAM-AMB/31337/2017–POCI-01-0145-FEDER-031337–funded by FEDER funds through COMPETE2020–Programa Operacional Competitividade e Internacionalização(POCI)+4 种基金with financial support of FCT/MCTES through national funds(PIDDAC)by NORTE-01-0247-FEDER-069836co-funded by the European Regional Development Fund(ERDF),through the North Portugal Regional Operational Programme(NORTE2020),under the PORTUGAL 2020 Partnership AgreementFCT funding under DL57/2016 Transitory Norm ProgrammeFCT funding under the Scientific Employment Stimulus–Institutional Call CEECINST/00049/2018
文摘The degradation of the anti-inflammatory ibuprofen(IBP)was evaluated by several advanced oxidation processes.IBP was treated by single ozonation and oxidation with hydrogen peroxide(H_(2)O_(2)),as well as a combination of these treatments.In order to improve the efficiency,the presence of catalysts such as original carbon nanotubes,labelled as CNT,and iron oxide supported on carbon nanotubes,named as Fe/CNT sample,was considered.The evolution of IBP degradation,mineralization and toxicity of the solutions was assessed.The formation of intermediates was also monitored.In the non-catalytic processes,IBP was faster removed by single ozonation,whereas no significant total organic carbon(TOC)removal was achieved.Oxidation with H_(2)O_(2) did not present satisfactory results.When ozone and H_(2)O_(2) were combined,a higher mineralization was attained(70%after 180 min of reaction).On the other hand,in the catalytic processes,this combined process allowed the fastest IBP degradation.In terms of mineralization degree,the presence of Fe/CNT increases the removal rate in the first hour of reaction,achieving a TOC removal of 85%.Four compounds were detected as by-products.All treated solutions presented lower toxicity than the initial solution,suggesting that the released intermediates during applied processes are less toxic.
基金the support from the Brook Byers Institute for Sustainable Systems,Hightower ChairGeorgia Research Alliance at the Georgia Institute of Technology。
文摘TiO_(2)has demonstrated outstanding performance in electrochemical advanced oxidation processes(EAOPs)due to its structural stability and high oxygen overpotential.However,there is still much room for improving its electrochemical activity.Herein,narrow bandgap manganese oxide(MnO_(x))was composited with TiO_(2)nanotube arrays(TiO_(2)NTAs)that in-situ oxidized on porous Ti sponge,forming the MnO_(x)-TiO_(2)NTAs anode.XANES and XPS analysis further proved that the composition of MnO_(x)is Mn2O3.Electrochemical characterizations revealed that increasing the composited concentration of MnO_(x)can improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnO_(x)-TiO_(2)NTAs anode.Meanwhile,the optimal degradation rate of benzoic acid(BA)was achieved using MnO_(x)-TiO_(2)NTAs with a MnO_(x)concentration of 0.1 mmol L^(-1),and the role of MnO_(x)was proposed based on DFT calculation.Additionally,the required electrical energy(EE/O)to destroy BA was optimized by varying the composited concentration of MnO_(x)and the degradation voltage.These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.
基金This study was supported by the Guangdong introducing innovative and entrepreneurial teams(No.2019ZT08L213)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0403)+2 种基金the National Natural Science Foundation of China(Nos.51979044 and 42177045)the Young Talent Project of Beijing Normal University at Zhuhai(No.310432101)We also thank the support received from China Scholarship Council(CSC)for providing a graduate fellowship to Y.C.(No.202006120356).
文摘The degradation of metoprolol(MTP)by the UV/sulfite with oxygen as an advanced reduction process(ARP)and that without oxygen as an advanced oxidation process(AOP)was comparatively studied herein.The degradation of MTP by both processes followed the first-order rate law with comparable reaction rate constants of 1.50×10^(-3)sec^(−1)and 1.20×10^(-3)sec^(−1),respectively.Scavenging experiments demonstrated that both e^(−)_(aq)and H·played a crucial role in MTP degradation by the UV/sulfite as an ARP,while SO_(4)^(·−)was the dominant oxidant in the UV/sulfite AOP.The degradation kinetics of MTP by the UV/sulfite as an ARP and AOP shared a similar pH dependence with a minimum rate obtained around pH 8.The results could be well explained by the pH impacts on the MTP speciation and sulfite species.Totally six transformation products(TPs)were identified from MTP degradation by the UV/sulfite ARP,and two additional ones were detected in the UV/sulfite AOP.The benzene ring and ether groups of MTP were proposed as the major reactive sites for both processes based on molecular orbital calculations by density functional theory(DFT).The similar degradation products of MTP by the UV/sulfite process as an ARP and AOP indicated that e^(−)_(aq)/H·and SO_(4)^(·−)might share similar reaction mechanisms,primarily including hydroxylation,dealkylation,and H abstraction.The toxicity of MTP solution treated by the UV/sulfite AOP was calculated to be higher than that in the ARP by the Ecological Struc-ture Activity Relationships(ECOSAR)software,due to the accumulation of TPs with higher toxicity.
文摘The characteristics of the slaughterhouse effluents and current wastewater treatment practices in the province of Ontario, Canada are analyzed. Meat processing plants are found to produce large amounts of wastewater due to the slaughtering process and cleaning of their facilities. Furthermore, the composition of the wastewater varies according to the type and number of animals slaughtered and the water requirements of the process. However, the slaughterhouse wastewater usually contains high levels of organics and nutrients. Several slaughterhouses in Ontario discharge their wastewater into the municipal sewer system after primary pretreatment at the meat processing plant. Therefore, due to the high-strength characteristics of the slaughterhouse effluents, an extensive treatment for a safe discharge into the environment is required. Thus, the combination of biological processes and advanced oxidation technologies for slaughterhouse wastewater treatment is evaluated in this study. Results show that the application of combined biological and advanced oxidation processes is recommended for on-site slaughterhouse wastewater treatment.
文摘Currently, landfills are the main method used for the final disposal of urban solid waste. The degradation processes that waste goes through in these sites, alongside rainwater that percolates through them, generate highly polluting liquids (leachate). In the treatment of leachate, advanced oxidation processes (AOP) can significantly reduce the concentrations of different pollutants. Due to the high documented potential around AOPs, in this study, the effectiveness of anodic oxidation in the removal of the remaining organic load in leachates pretreated in a biological system was evaluated. Graphite electrodes were used as anode and cathode. The efficiency of anodic oxidation, in terms of the removal of chemical oxygen demand (COD) and color, was evaluated under different current densities (7, 12, 17 and 22 mA/cm2) and pH values (3, 4.5 and 6). Under the best conditions found (22 mA/cm2 and pH of 6) and with an oxidation time of 5 hours, a maximum removal of 68% in COD and 91% in color was achieved, which represented a quality in the final effluent of 271 mg/L and 151 Pt-Co in COD and color, respectively. Therefore, considering that graphite is an economic and widely available material, the results obtained show anodic oxidation, with the use of graphite electrodes, as a technically viable alternative as a final purification stage for pretreated leachates.
