In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnat...In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.展开更多
There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in cata...There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.展开更多
Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing...Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.展开更多
Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the T...Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the TOC and COD Cr removal rates were studied. The degradation kinetics of landfill leachate was also investigated and an exponential experiential model consisting of four influential factors was established to describe the reduction of the organic compounds in the landfill leachate. Meanwhile, the GC-MS technique was used to detect the components of the organic intermediates for the inference of the decomposition mechanisms of the organic compounds in landfill leachate. The results reveal that the reaction temperature and the catalyst dosage are the most important factors affecting the degradation reaction of the organic compounds and that the principal intermediates confirmed by GC-MS are organic acids at a percentage of more than 88% with no aldehydes or alcohols detected. The decomposition mechanisms of the organic compounds in landfill leachate were inferred based on the GC-MS information as follows: the activated gas phase O 2 captured the hydrogen of the organic pollutants to produce free radicals, which then initiated the catalytic reaction. So most of the organic compounds were oxidized into CO 2 and H 2O ultimately. In general, catalytic wet air oxidation over catalyst Co 3O 4/Bi 2O 3 was a very promising technique for the treatment of landfill leachate.展开更多
A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination t...A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination temperature, the initial pH of the feed solution anddegradation temperature on the activity of the RuO_2/γ-Al_2O_3 catalyst were investigated and thereaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO_2crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher atcalcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO_2crystallites were abundant at high calcination temperature of 500℃ The activity of the catalyst wasbetter in the acid solution than in the alkaline solution. Increasing degradation temperature andusing the catalyst could shorten the induction periods so that the phenol and COD removal wereincreased. For RuO_2/γ-Al_2O_3 catalyst, the phenol and COD removal were respectively 98% and 80%in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated thatRu/γ-Al_2O_3 catalyst had good activity.展开更多
The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD...The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50 2% and 55 0%, COD removals were 40 0% and 46 0%, and the ratio of BOD_5/COD was increased to 0 49 and 0 54 with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5/COD was increased to 0 45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO. HO_2· may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2/Al_2O_3 in WAO of apramycin wastewater.展开更多
Four metal oxide catalysts composed of copper(Cu), stannum(Sn), copper-stannum(Cu-Sn) and copper-cerium(Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al 2O 3) is selected as supp...Four metal oxide catalysts composed of copper(Cu), stannum(Sn), copper-stannum(Cu-Sn) and copper-cerium(Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al 2O 3) is selected as support. A first-order kinetics model was established to study the catalytic wet air oxidation of phenol at different temperature when these catalysts were used. The model simulations are good agreement with present experimental data. Results showed that the reaction rate constants can be significantly increased when catalysts were used, and the catalyst of 6% Cu—10%Ce/γ-Al 2O 3 showed the best catalytic activity. This is consistent with the result of catalytic wet air oxidation of phenol and the COD removal can be arrived at 98.2% at temperature 210℃, oxygen partial pressure 3 MPa and reaction time 30 min. The activation energies of each reaction with different catalysts are nearly equal, which is found to be about 42 kJ/mol and the reaction in this study is proved to be kinetics control.展开更多
FeO;supported on activated carbon(AC) has been shown to be an ideal catalyst for catalytic wet peroxide oxidation(CWPO) due to its high CWPO reaction activity and stability. Although there have been some studies on th...FeO;supported on activated carbon(AC) has been shown to be an ideal catalyst for catalytic wet peroxide oxidation(CWPO) due to its high CWPO reaction activity and stability. Although there have been some studies on the mechanism of Fe/AC catalysis in CWPO, the specific contribution of each component(surface oxygen groups and FeOxon AC) inside an Fe/AC catalyst and their corresponding reaction mechanism remain unclear, and the reaction stability of CWPO catalysts has rarely been discussed. Then the optimal CWPO catalyst in our laboratory, 3%Fe/AC, was selected.(1) By removing certain components on the AC through heat treatment, its contribution to the reaction and the corresponding reaction mechanism were investigated. With the aid of temperature-programmed desorption–mass spectrometry(TPD–MS) and the CWPO reaction, the normalized catalytic contributions of components were shown to be: 37.3%(carboxylic groups), 5.3%(anhydride), 19.3%(ether/hydroxyl),-71.4%(carbonyl groups) and 100%(FeOx),respectively. DFT calculation and EPR analysis confirmed that carboxylic groups and Fe_(2)O_(3) are able to activate the H_(2)O_(2) to generate·OH.(2) The catalysts at were characterized at different reaction times(0 h, 450 h, 900 h, 1350 h, and 1800 h) by TPD–MS and M?ssbauer spectroscopy. Results suggested that the number of carboxylic goups gradually increased and the size of paramagnetic Fe_(2)O_(3) particle crystallites gradually increased as the reactions progressed. The occurrence of strong interactions between metal oxides and AC was also confirmed. Due to these effects, the strong stability of 3%Fe/AC was further improved. Therefore, the reasons for the high activity and strong stability of 3%Fe/AC in CWPO were clearly shown. We believe that this work provides an idea of the removal of cresols from wastewater into the introduction to show the potential applications of CWPO.展开更多
The wet air oxidation(WAO) and catalytic WAO(CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO proce...The wet air oxidation(WAO) and catalytic WAO(CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO processes were carried out at the temperature from 433 K to 513 K, with initial oxygen pressure 1 2 MPa. It was found that homogeneous catalyst copper(Cu(NO_3)_2) had an fairly good catalytic activity for the WAO process, and the oxidation was catalyzed when the temperature was higher than 473 K. Moreover, several heterogeneous catalysts were proved to be effective for the WAO process. At the temperature 473 K, after 2 h reaction, WAO process could achieve about 75% COD removal and 66% TOC removal, while catalysts Cu/Al_2O_3 and Mn-Ce/Al_2O_3 elevated the COD removal up to 86%—89% and that of TOC up to 82%. However, complete elimination of COD and TOC was proved to be difficult even the best non-noble catalyst was used. Therefore, the effluent from WAO or CWAO process need to be further disposed. The bioassay proved that the effluent from WAO process was amenable to the biochemical method.展开更多
The International Space Station(ISS) employs catalytic wet oxidation carried out in a Volatile Reactor Assembly (VRA) for water recycling. Previous earth gravity experiments show that the VRA is very effective at ...The International Space Station(ISS) employs catalytic wet oxidation carried out in a Volatile Reactor Assembly (VRA) for water recycling. Previous earth gravity experiments show that the VRA is very effective at removing polar, low molecular weight organics. To compare the reactor performance under micro-gravity and Earth gravity conditions, a tracer study was performed on a space shuttle in 1999 by using 0.2% potassium carbonate as the chemical tracer. In this paper, the experimental data were analyzed and it is indicated that the reactor can be considered as a plug flow one under both micro-gravity and earth gravity experimental conditions. It has also been proved that dispersion is not important in the VRA reactor under the experimental conditions. Tracer retardation was observed in the experiments and it is most likely caused by catalyst adsorption. It is concluded that the following reasons may also have influence on the retardation of mean residence time : (1) the liquid can be held by appurtenances, which will retard the mean residence time; (2) the pores can hold the tracer, which can also retard the mean residence time.展开更多
Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of ...Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of preparation process of catalysts, assistants and reaction conditions on the removal rate of ammonia nitrogen were analyzed. The results show that the preparation process of catalysts and assistants had great effects on catalytic activity; when steeping fluid concentration was 2 mol/L and 0.01 mol/L cerium nitrate was used as an assistant, Fe-Ce/5A catalyst roasted for 3 h at 400 ~C had a good catalytic effect. As 10 g of Fe-Ce/5A catalyst was added to water sample, and landfill leachate pretreated by MBR reacted with 15 ml of H2 02 for 30 min at 60 ~C, the removal rate of ammonia nitrogen was up to 90.8%, that is, ammonia nitrogen concentra- tion decreased from 253 to 23 mg/L, reaching the national emission standard. Besides, the kinetic analysis of ammonia nitrogen removal reveals that the removal reaction of ammonia nitrogen conformed with pseudo first order kinetic equation. Thus, it is feasible to use this method to deeply treat landfill leachate pretreated by MBR.展开更多
A Cu–Fe–La/γ-Al_2O_3(CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron ...A Cu–Fe–La/γ-Al_2O_3(CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that the catalyst contained mostly Cu^(2+), Fe^(3+), and La^(3+)and a small amount of Cu^+, Fe^(2+), and La. The active components were uniformly distributed in the catalyst, and the particle size of the components was approximately 7.5 nm. The CFLA catalyst was used for the treatment of methyl orange(MO) solution by catalytic wet air oxidation(CWAO), and it exhibited a high catalytic activity. The catalytic reaction involved variable valence states of metals and free-radical reaction mechanism. The CWAO reaction of MO solution was fitted by a segmented first-order dynamic model, and the rapid reaction apparent activation energy was 13.9 k J·mol^(-1).展开更多
Two series of cobalt(Ⅲ)\|containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acet...Two series of cobalt(Ⅲ)\|containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acetic acid than those without dopant bismuth oxide. The catalysts were investigated by XRD,TEM,ESR,UV\|DRS and XPS,and the interaction between Co and Bi was studied as well. It has been found that nano\|sized bismuth oxide is paved on the surface of cobalt spinel crystal and the structures of cobalt(Ⅲ)\|containing spinel are still maintained. The shift of the binding energy of Bi\-\{\%4f\%\-\{7/2\}\} is related to the catalytic activity of these catalysts doped with bismuth oxide.展开更多
The catalytic wet air oxidation (CWAO) of H acid and phenol was investigated in the presence of Cu or Fe doped CeOsolid solutions, which were obtained by sol-gel method. The experiment results showed that the incorpor...The catalytic wet air oxidation (CWAO) of H acid and phenol was investigated in the presence of Cu or Fe doped CeOsolid solutions, which were obtained by sol-gel method. The experiment results showed that the incorporation of Cu or Fe into the fluorite lattice of CeOstrongly enhanced the oxidation activity of the catalyst. At 90 ℃ and 0.1 MPa, H acid conversion was 70% for the Ce0.9Fe0.1O2-δ and 60% for the Ce0.9Cu0.1O2-δ catalyst. For phenol removal, the conversion was 70% for the Ce0.9Cu0.1O2-δ catalyst, while for the Ce0.9Fe0.1O2-δ the conversion was 30%. The results indicated that Ce0.9Cu0.1O2-δ was suitable for the treatment of organic wastewaters while Ce0.9Fe0.1O2-δ was suitable for the removal of H acid. The 70% phenol removal rate with Ce0.9Cu0.1O2-δ catalyst was markedly increased to 90% with Ce0.8Cu0.2O2-δ catalyst. However, the phenol removal reduced from 30% to 15% with Fe content increasing from 10% to 20%. For the H acid, the increase of the content of Cu or Fe tended to obviously increase the original reaction rate while the COD removal changed little.展开更多
As one of the few renewable aromatic resources,the research of depolymerization of lignin into highvalue chemicals has attracted extensive attention in recent years.Catalytic wet aerobic oxidation(CWAO)is an effective...As one of the few renewable aromatic resources,the research of depolymerization of lignin into highvalue chemicals has attracted extensive attention in recent years.Catalytic wet aerobic oxidation(CWAO)is an effective technology to convert lignin like sodium lignosulfonate(SL),a lignin derivative,into aromatic aldehydes such as vanillin and syringaldehyde.However,how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge,and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically.In this work,we adopted the stirred tank reactor(STR)for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde.The effect of operating conditions including reaction time,oxygen partial pressure,reaction temperature,SL concentration,rotational speed,catalyst amount,and NaOH concentration on the yield of single phenolic compound was systematically investigated.The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield.Therefore,they should be regulated in an optimal value to obtain high yield of these aldehydes.More importantly,the reaction kinetics of the lignin oxidation was explored.This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.展开更多
Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and was...Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.展开更多
The development of highly active carbon material catalysts in catalytic wet air oxidation(CWAO)has attracted a great deal of attention. In this study different carbon material catalysts(multi-walled carbon nanotube...The development of highly active carbon material catalysts in catalytic wet air oxidation(CWAO)has attracted a great deal of attention. In this study different carbon material catalysts(multi-walled carbon nanotubes,carbon fibers and graphite) were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.展开更多
Catalytic wet air oxidation(CWAO)is one of the most promising technologies for pollution abatement.Developing catalysts with high activity and stability is crucial for the application of the CWAO process.The Mn/Ce com...Catalytic wet air oxidation(CWAO)is one of the most promising technologies for pollution abatement.Developing catalysts with high activity and stability is crucial for the application of the CWAO process.The Mn/Ce com-plex oxide catalysts for CWAO of high concentration phenol-containing wastewater were prepared by coprecipitation.The catalyst preparation conditions were optimized by using an orthogonal layout method and single-factor experimental analysis.The Mn/Ce serial catalysts were characterized by Brunauer-Emmett-Teller(BET)analysis and the metal cation leaching was measured by inductively coupled plasma torch-atomic emission spectrometry(ICP-AES).The results show that the catalysts have high catalytic activities even at a low temperature(80°C)and low oxygen partial pressure(0.5 MPa)in a batch reactor.The metallic ion leaching is comparatively low(Mn<6.577 mg/L and Ce<0.6910 mg/L,respectively)in the CWAO process.The phenol,COD_(Cr),and TOC removal efficiencies in the solution exceed 98.5%using the optimal catalyst(named CSP).The new catalyst would have a promising application in CWAO treatment of high concentration organic wastewater.展开更多
The Cu-Fe/AC catalyst was prepared by microwave-assisted synthesis, and its morphological characteristics were characterized. The degradation effect of phenol wastewater by catalytic wet peroxide oxidation(CWPO) was s...The Cu-Fe/AC catalyst was prepared by microwave-assisted synthesis, and its morphological characteristics were characterized. The degradation effect of phenol wastewater by catalytic wet peroxide oxidation(CWPO) was studied, and the response surface methodology(RSM) was used to analyze the influencing factors of the removal rate of COD. The experimental results showed that under the conditions of reaction temperature 80 ℃, reaction time 90 min, initial pH 3.1 and H_(2)O_(2)addition 2.2 g/L, the removal rate of COD reached 82%. The results of response surface methodology indicated that under the conditions of reaction temperature 100 ℃, reaction time 64 min, initial pH 3.3 and H_(2)O_(2)addition 2.7 g/L, the removal rate of COD was up to 86%. After Cu-Fe/AC catalyst was reused for 4 times, the removal rate of COD was still above 80%, revealing that the catalyst showed good catalytic performance.展开更多
The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. T...The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe203-CeO2-]]i203/qt-A1203 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ. mo1-1. Hydroperoxy radicals (HO2.) and superoxide radicals (O2-) appeared as the main reactive species upon the CWAO of cationic red GTL.展开更多
基金supported by the Key Research and Development Program of Shaanxi,China(2018GY-067).
文摘In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.
基金supported by National Natural Science Foundation of China(52100072,52100213)the Fundamental Research FundsfortheCentralUniversities(JZ2021HGTA0159,JZ2021HGQA0212)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21021101)the Scientific Research Common Program of Beijing Municipal Commission of Education(KM202010017006)the Beijing Natural Science Foundation(8214056)。
文摘There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.
基金support provided by the National Natural Science Foundation of China (21978143 and 21878164)。
文摘Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.
基金Program Foundation for Environmental Protection of 2 0 0 2 by Jilin Province Environm ental ProtectionBureau
文摘Catalytic wet air oxidation(CWAO) was employed to reduce the organic compounds in landfill leachate and the effects of temperature, oxygen pressure, catalyst dosage, and concentration of the organic compounds on the TOC and COD Cr removal rates were studied. The degradation kinetics of landfill leachate was also investigated and an exponential experiential model consisting of four influential factors was established to describe the reduction of the organic compounds in the landfill leachate. Meanwhile, the GC-MS technique was used to detect the components of the organic intermediates for the inference of the decomposition mechanisms of the organic compounds in landfill leachate. The results reveal that the reaction temperature and the catalyst dosage are the most important factors affecting the degradation reaction of the organic compounds and that the principal intermediates confirmed by GC-MS are organic acids at a percentage of more than 88% with no aldehydes or alcohols detected. The decomposition mechanisms of the organic compounds in landfill leachate were inferred based on the GC-MS information as follows: the activated gas phase O 2 captured the hydrogen of the organic pollutants to produce free radicals, which then initiated the catalytic reaction. So most of the organic compounds were oxidized into CO 2 and H 2O ultimately. In general, catalytic wet air oxidation over catalyst Co 3O 4/Bi 2O 3 was a very promising technique for the treatment of landfill leachate.
基金This project is supported by the Natural High Tech. R&D Program of China (No. 2002AA601260)
文摘A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination temperature, the initial pH of the feed solution anddegradation temperature on the activity of the RuO_2/γ-Al_2O_3 catalyst were investigated and thereaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO_2crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher atcalcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO_2crystallites were abundant at high calcination temperature of 500℃ The activity of the catalyst wasbetter in the acid solution than in the alkaline solution. Increasing degradation temperature andusing the catalyst could shorten the induction periods so that the phenol and COD removal wereincreased. For RuO_2/γ-Al_2O_3 catalyst, the phenol and COD removal were respectively 98% and 80%in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated thatRu/γ-Al_2O_3 catalyst had good activity.
文摘The pretreatment technology of wet air oxidation(WAO) and coagulation and acidic hydrolysis for apramycin wastewater was investigated in this paper. The COD, apramycin, NH^+_4 concentration, and the ratio of BOD_5/COD were analyzed, and the color and odor of the effluent were observed. WAO of apramycin wastewater, without catalyst and with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts, was carried out at degradation temperature of 200℃ and the total pressure of 4 MPa in a 1 L batch reactor. The result showed that the apramycin removals were respectively 50 2% and 55 0%, COD removals were 40 0% and 46 0%, and the ratio of BOD_5/COD was increased to 0 49 and 0 54 with RuO_2/Al_2O_3 and RuO_2-CeO_2/Al_2O_3 catalysts in catylytic wet air oxidation(CWAO) after the reaction of 150 min. With the pretreatment of coagulation and acidic hydrolysis, COD and apramycin removals were slight decreased, and the ratio of BOD_5/COD was increased to 0 45, and the effluents was not suitable to biological treatment. The color and odor of the wastewater were effectively controlled and the reaction time was obviously shortened with WAO. HO_2· may promote organic compounds oxidized in WAO of the apramycin wastewater. The addition of CeO_2 could promote the activity and stability of RuO_2/Al_2O_3 in WAO of apramycin wastewater.
文摘Four metal oxide catalysts composed of copper(Cu), stannum(Sn), copper-stannum(Cu-Sn) and copper-cerium(Cu-Ce) respectively were prepared by the co-impregnation method, and γ-alumina(γ-Al 2O 3) is selected as support. A first-order kinetics model was established to study the catalytic wet air oxidation of phenol at different temperature when these catalysts were used. The model simulations are good agreement with present experimental data. Results showed that the reaction rate constants can be significantly increased when catalysts were used, and the catalyst of 6% Cu—10%Ce/γ-Al 2O 3 showed the best catalytic activity. This is consistent with the result of catalytic wet air oxidation of phenol and the COD removal can be arrived at 98.2% at temperature 210℃, oxygen partial pressure 3 MPa and reaction time 30 min. The activation energies of each reaction with different catalysts are nearly equal, which is found to be about 42 kJ/mol and the reaction in this study is proved to be kinetics control.
基金funded by the National Natural Science Foundation of China (52100072)the Beijing Natural Science Foundation(8214056)+2 种基金the special fund of Beijing Key Laboratory of Clean Fuels and Efficient Catalytic Emission Reduction Technology,the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21021101)the National Key Research and Development Program of China (2019YFA0705803)Scientific Research Common Program of Beijing Municipal Commission of Education(KM202010017006)。
文摘FeO;supported on activated carbon(AC) has been shown to be an ideal catalyst for catalytic wet peroxide oxidation(CWPO) due to its high CWPO reaction activity and stability. Although there have been some studies on the mechanism of Fe/AC catalysis in CWPO, the specific contribution of each component(surface oxygen groups and FeOxon AC) inside an Fe/AC catalyst and their corresponding reaction mechanism remain unclear, and the reaction stability of CWPO catalysts has rarely been discussed. Then the optimal CWPO catalyst in our laboratory, 3%Fe/AC, was selected.(1) By removing certain components on the AC through heat treatment, its contribution to the reaction and the corresponding reaction mechanism were investigated. With the aid of temperature-programmed desorption–mass spectrometry(TPD–MS) and the CWPO reaction, the normalized catalytic contributions of components were shown to be: 37.3%(carboxylic groups), 5.3%(anhydride), 19.3%(ether/hydroxyl),-71.4%(carbonyl groups) and 100%(FeOx),respectively. DFT calculation and EPR analysis confirmed that carboxylic groups and Fe_(2)O_(3) are able to activate the H_(2)O_(2) to generate·OH.(2) The catalysts at were characterized at different reaction times(0 h, 450 h, 900 h, 1350 h, and 1800 h) by TPD–MS and M?ssbauer spectroscopy. Results suggested that the number of carboxylic goups gradually increased and the size of paramagnetic Fe_(2)O_(3) particle crystallites gradually increased as the reactions progressed. The occurrence of strong interactions between metal oxides and AC was also confirmed. Due to these effects, the strong stability of 3%Fe/AC was further improved. Therefore, the reasons for the high activity and strong stability of 3%Fe/AC in CWPO were clearly shown. We believe that this work provides an idea of the removal of cresols from wastewater into the introduction to show the potential applications of CWPO.
文摘The wet air oxidation(WAO) and catalytic WAO(CWAO) of the high strength emulsifying wastewater containing nonionic surfactants have been investigated in terms of COD and TOC removal. The WAO and homogeneous CWAO processes were carried out at the temperature from 433 K to 513 K, with initial oxygen pressure 1 2 MPa. It was found that homogeneous catalyst copper(Cu(NO_3)_2) had an fairly good catalytic activity for the WAO process, and the oxidation was catalyzed when the temperature was higher than 473 K. Moreover, several heterogeneous catalysts were proved to be effective for the WAO process. At the temperature 473 K, after 2 h reaction, WAO process could achieve about 75% COD removal and 66% TOC removal, while catalysts Cu/Al_2O_3 and Mn-Ce/Al_2O_3 elevated the COD removal up to 86%—89% and that of TOC up to 82%. However, complete elimination of COD and TOC was proved to be difficult even the best non-noble catalyst was used. Therefore, the effluent from WAO or CWAO process need to be further disposed. The bioassay proved that the effluent from WAO process was amenable to the biochemical method.
文摘The International Space Station(ISS) employs catalytic wet oxidation carried out in a Volatile Reactor Assembly (VRA) for water recycling. Previous earth gravity experiments show that the VRA is very effective at removing polar, low molecular weight organics. To compare the reactor performance under micro-gravity and Earth gravity conditions, a tracer study was performed on a space shuttle in 1999 by using 0.2% potassium carbonate as the chemical tracer. In this paper, the experimental data were analyzed and it is indicated that the reactor can be considered as a plug flow one under both micro-gravity and earth gravity experimental conditions. It has also been proved that dispersion is not important in the VRA reactor under the experimental conditions. Tracer retardation was observed in the experiments and it is most likely caused by catalyst adsorption. It is concluded that the following reasons may also have influence on the retardation of mean residence time : (1) the liquid can be held by appurtenances, which will retard the mean residence time; (2) the pores can hold the tracer, which can also retard the mean residence time.
基金Supported by the Project of Agricultural Key Programs for Science and Technology Development of Ningbo (2011C11006)Key Spark Program Project of Science and Technology Ministry (2012GA7010011)the Science and Technology Plan Project of Ningbo City,Zhejiang Province
文摘Active iron catalysts with 5A molecular sieve as the carrier were prepared firstly, and then were used in the treatment of ammonia nitrogen in landfill leachate pretreated by MBR by using CWPO, finally the effects of preparation process of catalysts, assistants and reaction conditions on the removal rate of ammonia nitrogen were analyzed. The results show that the preparation process of catalysts and assistants had great effects on catalytic activity; when steeping fluid concentration was 2 mol/L and 0.01 mol/L cerium nitrate was used as an assistant, Fe-Ce/5A catalyst roasted for 3 h at 400 ~C had a good catalytic effect. As 10 g of Fe-Ce/5A catalyst was added to water sample, and landfill leachate pretreated by MBR reacted with 15 ml of H2 02 for 30 min at 60 ~C, the removal rate of ammonia nitrogen was up to 90.8%, that is, ammonia nitrogen concentra- tion decreased from 253 to 23 mg/L, reaching the national emission standard. Besides, the kinetic analysis of ammonia nitrogen removal reveals that the removal reaction of ammonia nitrogen conformed with pseudo first order kinetic equation. Thus, it is feasible to use this method to deeply treat landfill leachate pretreated by MBR.
基金Supported by the Natural Science Foundation of Guangdong Province(2014A030312007)the China Postdoctoral Science Foundation(2014M552202)the Started Project for Professor of Hanshan Normal University(QD20140615)
文摘A Cu–Fe–La/γ-Al_2O_3(CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that the catalyst contained mostly Cu^(2+), Fe^(3+), and La^(3+)and a small amount of Cu^+, Fe^(2+), and La. The active components were uniformly distributed in the catalyst, and the particle size of the components was approximately 7.5 nm. The CFLA catalyst was used for the treatment of methyl orange(MO) solution by catalytic wet air oxidation(CWAO), and it exhibited a high catalytic activity. The catalytic reaction involved variable valence states of metals and free-radical reaction mechanism. The CWAO reaction of MO solution was fitted by a segmented first-order dynamic model, and the rapid reaction apparent activation energy was 13.9 k J·mol^(-1).
文摘Two series of cobalt(Ⅲ)\|containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acetic acid than those without dopant bismuth oxide. The catalysts were investigated by XRD,TEM,ESR,UV\|DRS and XPS,and the interaction between Co and Bi was studied as well. It has been found that nano\|sized bismuth oxide is paved on the surface of cobalt spinel crystal and the structures of cobalt(Ⅲ)\|containing spinel are still maintained. The shift of the binding energy of Bi\-\{\%4f\%\-\{7/2\}\} is related to the catalytic activity of these catalysts doped with bismuth oxide.
文摘The catalytic wet air oxidation (CWAO) of H acid and phenol was investigated in the presence of Cu or Fe doped CeOsolid solutions, which were obtained by sol-gel method. The experiment results showed that the incorporation of Cu or Fe into the fluorite lattice of CeOstrongly enhanced the oxidation activity of the catalyst. At 90 ℃ and 0.1 MPa, H acid conversion was 70% for the Ce0.9Fe0.1O2-δ and 60% for the Ce0.9Cu0.1O2-δ catalyst. For phenol removal, the conversion was 70% for the Ce0.9Cu0.1O2-δ catalyst, while for the Ce0.9Fe0.1O2-δ the conversion was 30%. The results indicated that Ce0.9Cu0.1O2-δ was suitable for the treatment of organic wastewaters while Ce0.9Fe0.1O2-δ was suitable for the removal of H acid. The 70% phenol removal rate with Ce0.9Cu0.1O2-δ catalyst was markedly increased to 90% with Ce0.8Cu0.2O2-δ catalyst. However, the phenol removal reduced from 30% to 15% with Fe content increasing from 10% to 20%. For the H acid, the increase of the content of Cu or Fe tended to obviously increase the original reaction rate while the COD removal changed little.
基金supported by the National Key Research and Development Program of China(2019YFA0210302)the National Natural Science Foundation of China(21878009).
文摘As one of the few renewable aromatic resources,the research of depolymerization of lignin into highvalue chemicals has attracted extensive attention in recent years.Catalytic wet aerobic oxidation(CWAO)is an effective technology to convert lignin like sodium lignosulfonate(SL),a lignin derivative,into aromatic aldehydes such as vanillin and syringaldehyde.However,how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge,and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically.In this work,we adopted the stirred tank reactor(STR)for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde.The effect of operating conditions including reaction time,oxygen partial pressure,reaction temperature,SL concentration,rotational speed,catalyst amount,and NaOH concentration on the yield of single phenolic compound was systematically investigated.The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield.Therefore,they should be regulated in an optimal value to obtain high yield of these aldehydes.More importantly,the reaction kinetics of the lignin oxidation was explored.This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.
基金supported by the Natural Science Foundation of Liaoning Province (No. 2020-BS-012)the National Natural Science Foundation of China (No. 51878643)+2 种基金the Dalian Institute of Chemical Physics & Qingdao Institute of Bioenergy and Bioprocess Technology (DICP&QIBEBT) (No. UN201809)the Scientific Research Common Program of Beijing Municipal Commission of Education (No. KM202010017006)Talents Project of Beijing Organization Department (No. 2018000020124G091)。
文摘Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.
基金supported by the National Natural Science Foundation of China (No.51078143)the Fundamental Research Funds for the Central Universities of China
文摘The development of highly active carbon material catalysts in catalytic wet air oxidation(CWAO)has attracted a great deal of attention. In this study different carbon material catalysts(multi-walled carbon nanotubes,carbon fibers and graphite) were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.
基金This work was supported by the National High-Tech Research and Development Program of China(Grant No.2002AA601260)。
文摘Catalytic wet air oxidation(CWAO)is one of the most promising technologies for pollution abatement.Developing catalysts with high activity and stability is crucial for the application of the CWAO process.The Mn/Ce com-plex oxide catalysts for CWAO of high concentration phenol-containing wastewater were prepared by coprecipitation.The catalyst preparation conditions were optimized by using an orthogonal layout method and single-factor experimental analysis.The Mn/Ce serial catalysts were characterized by Brunauer-Emmett-Teller(BET)analysis and the metal cation leaching was measured by inductively coupled plasma torch-atomic emission spectrometry(ICP-AES).The results show that the catalysts have high catalytic activities even at a low temperature(80°C)and low oxygen partial pressure(0.5 MPa)in a batch reactor.The metallic ion leaching is comparatively low(Mn<6.577 mg/L and Ce<0.6910 mg/L,respectively)in the CWAO process.The phenol,COD_(Cr),and TOC removal efficiencies in the solution exceed 98.5%using the optimal catalyst(named CSP).The new catalyst would have a promising application in CWAO treatment of high concentration organic wastewater.
文摘The Cu-Fe/AC catalyst was prepared by microwave-assisted synthesis, and its morphological characteristics were characterized. The degradation effect of phenol wastewater by catalytic wet peroxide oxidation(CWPO) was studied, and the response surface methodology(RSM) was used to analyze the influencing factors of the removal rate of COD. The experimental results showed that under the conditions of reaction temperature 80 ℃, reaction time 90 min, initial pH 3.1 and H_(2)O_(2)addition 2.2 g/L, the removal rate of COD reached 82%. The results of response surface methodology indicated that under the conditions of reaction temperature 100 ℃, reaction time 64 min, initial pH 3.3 and H_(2)O_(2)addition 2.7 g/L, the removal rate of COD was up to 86%. After Cu-Fe/AC catalyst was reused for 4 times, the removal rate of COD was still above 80%, revealing that the catalyst showed good catalytic performance.
文摘The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe203-CeO2-]]i203/qt-A1203 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ. mo1-1. Hydroperoxy radicals (HO2.) and superoxide radicals (O2-) appeared as the main reactive species upon the CWAO of cationic red GTL.