Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic aci...Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8-6.7. Coexisting cations, such as Na＋, K＋, and Ca2＋, can enhance the adsorption of tannic acid on poly- aniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorp- tion process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 rag.g〈 at 35℃and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the ad- sorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.展开更多
Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combust...Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating system.The Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous combustion.Further research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.展开更多
A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continu...A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min 1,respectively.The phenolic treatment results in seven cases were compared：（a）O3 only,（b）fresh granular activated carbon（GAC）,（c） 1st reused GAC,（d）2nd reused GAC,（e）fresh GAC enhanced with O3,（f）1st reused GAC enhanced with O3,and （g）2nd reused GAC enhanced with O3.The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time.The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result.The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone.Fresh GAC could adsorb phenol better than reused GAC.All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics.Finally,a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3.The calculated results agree reasonably well with the experimental results.展开更多
CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highl...CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.展开更多
This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray te...This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray technique has a dual function containing Ni as a catalytic material and CaO as an adsorption material used in the ReSER process. The attrition characteristics of the catalytic complex are acceptable for the commercial used. The nano GaCO3 material used as a precursor of CaO showed a desirable durability with a CO2 sorption capacity of 0.6 mol CO2/kg after 10 repeating cycles under the carbonation temperature of 600 ℃, a CO2 partial pressure of 0.02 MPa, and a calcination temperature of 750 ℃ in N2 measured by a thermal gravimetric analyzer. The testing of the catalytic complex for ReSER showed a hydrogen yield of over 95 % （v/v） in the laboratory fixed fluidized bed reactor. The catalytic system has an attractive prospect in the ReSER process for hydrogen production, especially in the fluidized mode where reactor and regenerator combined in a cycling process.展开更多
Desulfurization experiments of CuO, γ-Al2O3 and CuO/γ-Al2O3 were made in simulated flue gas by means of thermogravimetric analysis. It is found that reaction activities of CuO supported on γ-Al2O3 could be highly i...Desulfurization experiments of CuO, γ-Al2O3 and CuO/γ-Al2O3 were made in simulated flue gas by means of thermogravimetric analysis. It is found that reaction activities of CuO supported on γ-Al2O3 could be highly improved. Desulfurization kinetics of CuO/γ-Al2O3 was studied in the temperature range of 250 °C-400 °C and SO2 concentration of 0.1%-0.9%. The experimental data were tested and compared with kinetics models of volume reaction model(VRM), grain size model(GSM), random pore model(RPM) and pore-blocking model(PBM). Correlation analysis shows that VRM and RPM models do not fit experimental data well. GSM contradicts with the changes in the physical and chemical properties of Cu O/γ-Al2O3 as the desulfurization proceeds. It is found that PBM is consistent with the change of pore structure of CuO/γ-Al2O3 sorbent during desulfurization process and predicts the conversion-time curves of the sorbent well. Meanwhile, kinetics parameters are obtained and discussed.展开更多
We deposited NiO via atomic layer deposition on mesoporous SiO2 particles with diameters of several hundred micrometers and a mean mesopore size of -14 nm.NiO was deposited within the shell region of mesoporous SiO2 p...We deposited NiO via atomic layer deposition on mesoporous SiO2 particles with diameters of several hundred micrometers and a mean mesopore size of -14 nm.NiO was deposited within the shell region of mesoporous SiO2 particles with a shell thickness of -11 mm.We annealed the as-prepared NiO/SiO2 at 450 and 600℃,respectively.These two samples were used as catalysts for the uptake of toluene molecules and their oxidative conversion to CO2.The sample annealed at450℃ was generally more reactive in toluene uptake and its subsequent conversion to CO2.When the NiO/SiO2 annealed at 450℃ was exposed to toluene vapor at 160℃ and then heated to 450℃,CO2 was emitted with almost no toluene desorption.We suggest that our catalysts can be used as building blocks for odor removal devices that operate below 200℃.These catalysts can be regularly regenerated at -450℃.展开更多
Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of th...Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of the dye was 150 mg/L, CODer was 432 mg/L and chrome was 2800 times, the appropriate conditions determined by the experiment were as follows： r（NaC10）--4.84 g/L, 25 min, pH=6, height of activated carbon fixed bed was 10 cm. Under these conditions, the decolorizing rate can come up to about 100% and total removed rate of CODer reached at 89.6%. Comparison of UV-Vis adsorption spectrums before and after treatment showed that decomposition effects of chemical oxidation and adsorption of activated carbon fixed bed on acidic black 10B dye wastewater were satisfactory.展开更多
基金supported by the National Natural Science Foundation of China(21173153)National High-Tech Research and Development Program of China(863)(2013AA065304)~~
基金Supported by the National Major Research Plan for Water Pollution Control and Treatment of China （2008ZX07010-003-002）, the National Natural Science Foundation of China （21107065） and the Scientific Research Program Funded by Shaanxi Pro- vincial Education DePartment （HJK0769）.
文摘Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8-6.7. Coexisting cations, such as Na＋, K＋, and Ca2＋, can enhance the adsorption of tannic acid on poly- aniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorp- tion process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 rag.g〈 at 35℃and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the ad- sorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.
基金conducted in the context of coal-shale spontaneous combustion in the eMalahleni coalfields, South Africa was financially sponsored by Coaltech
文摘Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating system.The Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous combustion.Further research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.
基金Supported by the National Nanotechnology Center(NANOTEC)(601003)the National Science and Technology Development Agency(NSTDA)
文摘A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min 1,respectively.The phenolic treatment results in seven cases were compared：（a）O3 only,（b）fresh granular activated carbon（GAC）,（c） 1st reused GAC,（d）2nd reused GAC,（e）fresh GAC enhanced with O3,（f）1st reused GAC enhanced with O3,and （g）2nd reused GAC enhanced with O3.The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time.The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result.The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone.Fresh GAC could adsorb phenol better than reused GAC.All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics.Finally,a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3.The calculated results agree reasonably well with the experimental results.
基金supported by US Army contract(W56HZV-05-C0686) at Auburn University administered through TARDEC
文摘CO self-poisoning and slow surface kinetics pose major challenges to a CO oxidation catalyst that should work at ambient temperature.Furthermore,the presence of moisture would cause passivation of the catalyst A highly active ceria promoted Pt catalyst（4%Pt-12%CeO_2/SiO_2;conversion≥99%at low（ 500 ppm） and high（ 2500 ppm） CO concentrations was developed for CO oxidation at ambient temperature in humid air.Catalyst preparation variables such as Pt and CeO_2 loading,ceria deposition method,drying and calcination conditions for the ceria and Pt precursors were optimized experimentally.The activity was correlated with surface properties using CO/H_2 chemisorption,O_2-H_2 titration,X-ray diffraction and BET surface area analysis.The method of CeO_2 deposition had a significant impact on the catalytic activity.CeO_2 deposition by impregnation resulted in a catalyst that was three times more active than that prepared by deposition precipitation or CeO_2grafting.O_2-H_2 titration results revealed that the close association of ceria and Pt in the case of CeO_2deposition by impregnation resulted in higher activity.The catalyst support used was also crucial as a silica supported catalyst was five times more active than an alumina supported catalyst.The particle size and pore structure of the catalyst support were also crucial as the reaction was diffusion controlled.The drying and calcination conditions of the ceria and Pt precursors also played a crucial role in determining the catalytic activity.The Pt-CeO_2/SiO_2 catalysts with Pt 2.5 wt%and CeO_2 15 wt%were highly active（TOF 0.02 s^（-1）） and stable（conversion 99%after 15 h） at ambient conditions.
基金supports from Sinopec of China and from National Science Foundation of China (NSFC) under contracts No.20676119supports from Sinopec of China and from National Science Foundation of China (NSFC) under contracts No. 20876142 respectively
文摘This paper describes the preparation and evaluation of a micro-sphere catalytic complex for the hydrogen production in a Reactive Sorption Enhanced Reforming （ReSER） process. The catalytic complex made by a spray technique has a dual function containing Ni as a catalytic material and CaO as an adsorption material used in the ReSER process. The attrition characteristics of the catalytic complex are acceptable for the commercial used. The nano GaCO3 material used as a precursor of CaO showed a desirable durability with a CO2 sorption capacity of 0.6 mol CO2/kg after 10 repeating cycles under the carbonation temperature of 600 ℃, a CO2 partial pressure of 0.02 MPa, and a calcination temperature of 750 ℃ in N2 measured by a thermal gravimetric analyzer. The testing of the catalytic complex for ReSER showed a hydrogen yield of over 95 % （v/v） in the laboratory fixed fluidized bed reactor. The catalytic system has an attractive prospect in the ReSER process for hydrogen production, especially in the fluidized mode where reactor and regenerator combined in a cycling process.
基金Projects(51264023,51364020,U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of ChinaProject(2014HA003)supported by the Yunnan Province Science and Technology Talents Program,China
文摘Desulfurization experiments of CuO, γ-Al2O3 and CuO/γ-Al2O3 were made in simulated flue gas by means of thermogravimetric analysis. It is found that reaction activities of CuO supported on γ-Al2O3 could be highly improved. Desulfurization kinetics of CuO/γ-Al2O3 was studied in the temperature range of 250 °C-400 °C and SO2 concentration of 0.1%-0.9%. The experimental data were tested and compared with kinetics models of volume reaction model(VRM), grain size model(GSM), random pore model(RPM) and pore-blocking model(PBM). Correlation analysis shows that VRM and RPM models do not fit experimental data well. GSM contradicts with the changes in the physical and chemical properties of Cu O/γ-Al2O3 as the desulfurization proceeds. It is found that PBM is consistent with the change of pore structure of CuO/γ-Al2O3 sorbent during desulfurization process and predicts the conversion-time curves of the sorbent well. Meanwhile, kinetics parameters are obtained and discussed.
基金supported by the National Research Council of Science and Technology(NST)through Degree and Research Center(DRC)Program(2015)
文摘We deposited NiO via atomic layer deposition on mesoporous SiO2 particles with diameters of several hundred micrometers and a mean mesopore size of -14 nm.NiO was deposited within the shell region of mesoporous SiO2 particles with a shell thickness of -11 mm.We annealed the as-prepared NiO/SiO2 at 450 and 600℃,respectively.These two samples were used as catalysts for the uptake of toluene molecules and their oxidative conversion to CO2.The sample annealed at450℃ was generally more reactive in toluene uptake and its subsequent conversion to CO2.When the NiO/SiO2 annealed at 450℃ was exposed to toluene vapor at 160℃ and then heated to 450℃,CO2 was emitted with almost no toluene desorption.We suggest that our catalysts can be used as building blocks for odor removal devices that operate below 200℃.These catalysts can be regularly regenerated at -450℃.
文摘Acidic black 10B dye wastewater was treated by chemical oxidation and adsorption of activated carbon fixed bed and all kinds of influential factors of removal CODcr were discussed. When the initial concentration of the dye was 150 mg/L, CODer was 432 mg/L and chrome was 2800 times, the appropriate conditions determined by the experiment were as follows： r（NaC10）--4.84 g/L, 25 min, pH=6, height of activated carbon fixed bed was 10 cm. Under these conditions, the decolorizing rate can come up to about 100% and total removed rate of CODer reached at 89.6%. Comparison of UV-Vis adsorption spectrums before and after treatment showed that decomposition effects of chemical oxidation and adsorption of activated carbon fixed bed on acidic black 10B dye wastewater were satisfactory.
