Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperatur...Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect. Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.展开更多
The behavior of antimony oxidation in the solution of sodium thioantimonite was studied in the presence of catalytic agents. The catalytic effects of the respective addition of cupric sulfate, sodium tartrate, potassi...The behavior of antimony oxidation in the solution of sodium thioantimonite was studied in the presence of catalytic agents. The catalytic effects of the respective addition of cupric sulfate, sodium tartrate, potassium permanganate, phenol, 1,2 dihydroxybenzene and their combination on the oxidation of sodium thioantimonite were investigated. A pilot test was carried out. The results show that the respective use of sodium tartrate, cupric sulfate, potassium permanganate, phenol and 1,2 dihydroxybenzene have little catalytic effect on the oxidation of sodium thioantimonite. However there exists obvious catalytic oxidation by the combination of 0.25 g/L 1,2 dihydroxybenzene, 0.5 g/L potassium permanganate and 1.0 g/L phenol. Moreover, high blast intensity, the increase of temperature and NaOH concentration favor the oxidation of antimony. The oxidation process of antimony has such advantages as quick reaction and low operation costs. The results of the pilot test are consistent with those of laboratory experiments.展开更多
A novel process, microwave assisted catalytic wet air oxidation(MW-CWO), was applied for the degradation of H-acid(1-amino-8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon(GAC)...A novel process, microwave assisted catalytic wet air oxidation(MW-CWO), was applied for the degradation of H-acid(1-amino-8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon(GAC), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC.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) 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
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 kinetics of Fe3O4 formation by air oxidation of slightly acidic suspension of Fe（OH）2 was studied. The effects of initial concentration of Fe（Ⅱ）, temperature, partial pressure of oxygen, air flow rate and sti...The kinetics of Fe3O4 formation by air oxidation of slightly acidic suspension of Fe（OH）2 was studied. The effects of initial concentration of Fe（Ⅱ）, temperature, partial pressure of oxygen, air flow rate and stirring rate on the oxidation rate were investigated. The results show that Fe3O4 formation is composed of two-step reaction, the first step is the formation of Fe（OH）+2 by oxidation of Fe（OH）+ complex ions, the second step is the formation of magnetite by dehydration and deprotonation of Fe（OH）+ and Fe（OH）+2. The oxidation reaction is zero-order with respect to the concentration of Fe（Ⅱ） and around 0.5-order with respect to partial pressure of oxygen, and oxygen transfer process is rate-limiting step of oxidation reaction with apparent activation energy of 2.74 kJ·mol-1.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
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
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
Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of...Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of catalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removed by wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperature of 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited high catalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCr was removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had better catalytic activity for the degradation of o-chlorophenol in wastewater.展开更多
Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control po...Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide （SO2） control policy during the llth Five Year Plan period （2006-2010） had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate （SO42-） concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides （NOx） control policy during the 12th Five Year Plan period （2011-2015） targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide （NO2）, nitrate （NO3-）, 1-hr maxima ozone （03） concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%--4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3-, 1-hr maxima 03 concentrations and total nitrogen deposition by 2%-4%, 1%-%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.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
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
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
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
By screening the copper catalysts,ligands,and the reaction conditions,a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful...By screening the copper catalysts,ligands,and the reaction conditions,a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful nitriles by an aerobic oxidation reaction of primary amines using air as an advantageous oxidant under mild conditions.展开更多
This paper presents the effect of reaction factors on wet air oxidation(WAO) of H acid wastewater. Higher COD Cr removal were observed at low initial pH, high reaction temperature and no addition of Na 2SO 4. I...This paper presents the effect of reaction factors on wet air oxidation(WAO) of H acid wastewater. Higher COD Cr removal were observed at low initial pH, high reaction temperature and no addition of Na 2SO 4. Initial oxygen pressure P O 2 should be consistent with the initial H acid concentration. The changes of some indexes were also studied. A significant initial (about 10 min) rapid reduction in COD Cr was observed at 200℃ and 250℃. The decline of pH and the increase of SO 2- 4 concentration were found in all the experiments. Some formic acid and large amount of acetic acid were detected in the treated solution in this study. The analysis of off gas indicated undetectable amount of SO 2 and nitrogen oxides. The biodegradability of H acid solution was greatly improved after WAO treatment. The ratio of BOD 5/COD Cr increased from initial 3 4% to 33 3% after one hour reaction at 160℃ and 3 MPa initial oxygen pressure(initial H acid concentration:10 g/L, mixing speed:300 r/min). The result of WAO of H acid production wastewater was similar to that of WAO of H acid pure compound in distilled water.展开更多
The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was investigated.According to the X-ray diffraction (XRD),scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and X-...The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was investigated.According to the X-ray diffraction (XRD),scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis results of the product,it was shown that the introduction of MnSO_(4)in the form of solution would generate Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O with strong catalytic oxidation ability in the aerobic alkaline solution,whereas the catalytic effect of the other product MnOOH is not satisfactory.Under the optimal reaction conditions of temperature 90℃,As/Mn molar ratio 12.74:1,air flow rate1.0 L/min,and stirring speed 300 r/min,As(Ⅲ) can be completely oxidized after 2 hr reaction.The excellent catalytic oxidation ability of MnSO_(4)on As(Ⅲ) was mainly attributed to the indirect oxidation of As(Ⅲ) by the product Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O.This study shows a convenient and efficient process for the oxidation of As(Ⅲ) in alkali solutions,which has potential application value for the pre-oxidation of arsenic-containing solution or the detoxification of As(Ⅲ).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
文摘Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect. Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.
文摘The behavior of antimony oxidation in the solution of sodium thioantimonite was studied in the presence of catalytic agents. The catalytic effects of the respective addition of cupric sulfate, sodium tartrate, potassium permanganate, phenol, 1,2 dihydroxybenzene and their combination on the oxidation of sodium thioantimonite were investigated. A pilot test was carried out. The results show that the respective use of sodium tartrate, cupric sulfate, potassium permanganate, phenol and 1,2 dihydroxybenzene have little catalytic effect on the oxidation of sodium thioantimonite. However there exists obvious catalytic oxidation by the combination of 0.25 g/L 1,2 dihydroxybenzene, 0.5 g/L potassium permanganate and 1.0 g/L phenol. Moreover, high blast intensity, the increase of temperature and NaOH concentration favor the oxidation of antimony. The oxidation process of antimony has such advantages as quick reaction and low operation costs. The results of the pilot test are consistent with those of laboratory experiments.
基金The Hi Tech Research and Development Program(863) of China(No. 2002AA649090) and the National Basic Research Program(973) of China(No.2003CB415006)
文摘A novel process, microwave assisted catalytic wet air oxidation(MW-CWO), was applied for the degradation of H-acid(1-amino-8-naphthol-3, 6-disulfonic acid) in aqueous solution. Ni-loaded granular activated carbon(GAC), prepared by immersion-calcination method, was used as catalyst. The results showed that the MW-CWO process was very effective for the degradation of H-acid in aqueous solution under atmospheric pressure with 87.4% TOC (total organic carbon) reduction in 20 min. Ni on GAC existed in the form of NiO as specified by XRD. Loss of Ni was significant in the initial stage, and then remained almost constant after 20 min reaction. BET surface area results showed that the surface property of GAC after MW-CWO process was superior to that of blank GAC.
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.
文摘The kinetics of Fe3O4 formation by air oxidation of slightly acidic suspension of Fe（OH）2 was studied. The effects of initial concentration of Fe（Ⅱ）, temperature, partial pressure of oxygen, air flow rate and stirring rate on the oxidation rate were investigated. The results show that Fe3O4 formation is composed of two-step reaction, the first step is the formation of Fe（OH）+2 by oxidation of Fe（OH）+ complex ions, the second step is the formation of magnetite by dehydration and deprotonation of Fe（OH）+ and Fe（OH）+2. The oxidation reaction is zero-order with respect to the concentration of Fe（Ⅱ） and around 0.5-order with respect to partial pressure of oxygen, and oxygen transfer process is rate-limiting step of oxidation reaction with apparent activation energy of 2.74 kJ·mol-1.
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).
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.
基金Supported by the Returnee Fourndation of China Ministry of Education.
文摘Catalytic wet air oxidation (CWAO) was investigated in laboratory-scale experiments for the treatment of o-chlorophenol in wastewater. Experimental results showed that wet air oxidation (WAO) process in the absence of catalyst was also effective for o-chlorophenol in wastewater treatment. Up to 80% of the initial CODCr was removed by wet air oxidation at 270℃ with twice amount of the required stoichiometric oxygen supply. At temperature of 150℃, the removal rate of CODCr was only 30%. Fe2(SO4)3, CuSO4, Cu(NO3)2 and MnSO4 exhibited high catalytic activity. Higher removal rate of CODCr was obtained by CWAO. More than 96% of the initial CODCr was removed at 270℃ and 84.6%-93.6% of the initial CODCr was removed at 150℃. Mixed catalysts had better catalytic activity for the degradation of o-chlorophenol in wastewater.
基金supported by the Science Fund for Creative Research Groups of the Natural Science Foundation of China (No. 21221004)the Special Fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control (No. 12L05ESPC)+1 种基金the MEP’s Special Funds for Research on Public Welfares (No. 201309009, 2011467003)supported by the Program for New Century Excellent Talents in University (No. NCET-10-0532) and the China Scholarship Council
文摘Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide （SO2） control policy during the llth Five Year Plan period （2006-2010） had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate （SO42-） concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides （NOx） control policy during the 12th Five Year Plan period （2011-2015） targets the reduction of the national NOx emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NOx emission will reduce the ambient nitrogen dioxide （NO2）, nitrate （NO3-）, 1-hr maxima ozone （03） concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%--4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3-, 1-hr maxima 03 concentrations and total nitrogen deposition by 2%-4%, 1%-%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.
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.
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.
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.
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.
基金NNSFC(Nos.51502174,21672163)ZJNSF(No.LR14B020002)+2 种基金Postdoctoral Science Foundation of China(Nos.2015 M582401,2016M592520)for financial supportpartially supported by Science and Technology Project of Shenzhen(Nos.JCYJ20150324141711616,JCYJ20150626090504916)Science and Technology Planning Project of Guangdong Province(No.2016B050501005)
文摘By screening the copper catalysts,ligands,and the reaction conditions,a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful nitriles by an aerobic oxidation reaction of primary amines using air as an advantageous oxidant under mild conditions.
文摘This paper presents the effect of reaction factors on wet air oxidation(WAO) of H acid wastewater. Higher COD Cr removal were observed at low initial pH, high reaction temperature and no addition of Na 2SO 4. Initial oxygen pressure P O 2 should be consistent with the initial H acid concentration. The changes of some indexes were also studied. A significant initial (about 10 min) rapid reduction in COD Cr was observed at 200℃ and 250℃. The decline of pH and the increase of SO 2- 4 concentration were found in all the experiments. Some formic acid and large amount of acetic acid were detected in the treated solution in this study. The analysis of off gas indicated undetectable amount of SO 2 and nitrogen oxides. The biodegradability of H acid solution was greatly improved after WAO treatment. The ratio of BOD 5/COD Cr increased from initial 3 4% to 33 3% after one hour reaction at 160℃ and 3 MPa initial oxygen pressure(initial H acid concentration:10 g/L, mixing speed:300 r/min). The result of WAO of H acid production wastewater was similar to that of WAO of H acid pure compound in distilled water.
基金supported by the National Key R&D Program of China (No.SQ2019YFC190179)National Natural Science Foundation of China (Nos.51864019 and 52004111)+2 种基金the Distinguished Professor Program of Jinggang Scholars in institutions of higher learning,Jiangxi Provincethe Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technologythe Jiangxi Province Natural Science Foundation of China (No.20181BAB206019)。
文摘The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was investigated.According to the X-ray diffraction (XRD),scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis results of the product,it was shown that the introduction of MnSO_(4)in the form of solution would generate Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O with strong catalytic oxidation ability in the aerobic alkaline solution,whereas the catalytic effect of the other product MnOOH is not satisfactory.Under the optimal reaction conditions of temperature 90℃,As/Mn molar ratio 12.74:1,air flow rate1.0 L/min,and stirring speed 300 r/min,As(Ⅲ) can be completely oxidized after 2 hr reaction.The excellent catalytic oxidation ability of MnSO_(4)on As(Ⅲ) was mainly attributed to the indirect oxidation of As(Ⅲ) by the product Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O.This study shows a convenient and efficient process for the oxidation of As(Ⅲ) in alkali solutions,which has potential application value for the pre-oxidation of arsenic-containing solution or the detoxification of As(Ⅲ).
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.
