Catalysts using α-FeOOH nanoparticles as the active ingredient were testedby a microreactor-chromatography assessing apparatus at atmospheric pressure between 25 and 60 ℃with a gas hourly space velocity of 10,000 h^...Catalysts using α-FeOOH nanoparticles as the active ingredient were testedby a microreactor-chromatography assessing apparatus at atmospheric pressure between 25 and 60 ℃with a gas hourly space velocity of 10,000 h^(-1), while the removal performance of H_2S withcatalysts was investigated using the thermal gravimetric method. The results show that the catalystsare highly active for COS hydrolysis at low temperatures (≤60 ℃) and high gas hourly spacevelocity, and the highest activity can reach 100%. The catalyst is particularly stable for 12 h, andno deactivation is observed. Nanoparticle α-FeOOH prepared using hydrated iron sulfate showshigher COS hydrolysis activity, and the optimum calcination temperature for the catalyst is 260 ℃.In addition, the catalysts can remove COS and H_2S simultaneously, and 60 ℃ is favorable for theremoval of H_2S. The compensation effect exists in nanoparticle-based catalysts.展开更多
A series of ZnO/SiO_(2) adsorbents were prepared by a sol-gel method using tetraethyl orthosilicate,ethylene glycol(EG)and nitrates as precursors.The effect of gel drying temperature on the structure and desulfurizati...A series of ZnO/SiO_(2) adsorbents were prepared by a sol-gel method using tetraethyl orthosilicate,ethylene glycol(EG)and nitrates as precursors.The effect of gel drying temperature on the structure and desulfurization performance of the adsorbents were investigated in detail.It is found that the low drying temperature led to a weak interaction among EG,Si AOH/H_(2)O and the nitrates in the gel system,which caused the oxidation of EG by NO3-and formed zinc glyoxylate complex during the gel calcination process,whereas this oxidation process also occurred at a high drying temperature during the gel drying process.The formed zinc glyoxylate complex promoted the generation of monodentate carbonate on the surface of Zn O,which resulted in the inferior desulfurization performance of adsorbents despite they have smaller Zn O nanoparticles.The gel dried at 120°C formed the hydrogen bonds between EG and Si AOH/H_(2)O and a strong interaction between zinc oxo-clusters and NO3-was also found in the gel system,which avoided the oxidation of EG by NO3-during the preparation process and the Zn O nanoparticles with sizes of 6 nm were formed by a combustion method.The adsorbent affords a highest sulfur capacity of 104.9 mg·g^(-1) in this case.In addition,the gel drying temperature has a significant influence on the textural properties of the adsorbents except their surface area.展开更多
Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial...Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.展开更多
Upgrading biogas into biomethane not only improves the biogas utilization as vehicle fuel or natural gas substitute,but also reduces the greenhouse gases emissions.Considering the principle of engineering green energy...Upgrading biogas into biomethane not only improves the biogas utilization as vehicle fuel or natural gas substitute,but also reduces the greenhouse gases emissions.Considering the principle of engineering green energy process,the renewable aqueous ammonia(RAA)solution obtained from biogas slurry was used to remove H_(2)S and CO_(2) simultaneously in the hollow fiber membrane contactor.RAA was mimicked in this study using the ammonia aqueous solution mixed with some typical impurities including ethanol,acetic acid,propionic acid,butyric acid and NH4HCO_(3).Compared with the typical physical absorption(i.e.,pure water)removing 48%of H_(2)S from biogas,RAA with 0.1 mol·L^(−1) NH_(3) could remove 97%of H_(2)S.Increasing the NH3 concentration from 0.1 to 0.5 mol·L^(−1) could elevate the CO_(2) absorption flux from 0.97 to 1.72 mol·m^(−2)·h^(−1) by 77.3%.Among the impurities contained in RAA,ethanol has a less impact on CO_(2) absorption,while other impurities like CO_(2) and acetic acid have significant negative impacts on CO_(2) absorption.Fortunately,the impurities have a less influence on H_(2)S removal efficiency,with more than 98%of H_(2)S could be removed by RAA.Also,the influences of operating parameters on acid gases removal were investigated to provide some engineering suggestions.展开更多
A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sor...A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory.The effect of H_(2)S on Hg^(0)adsorption was also investigated.The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon.In the absence of H_(2)S at a low temperature(≤100℃),the Hg^(0)removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%.This value is significantly higher than that of coconut shell activated carbon,which is approximately 45%.H_(2)S significantly enhanced the Hg^(0)removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures(100–180℃).The hierarchical porous structure facilitated the diffusion and adsorption of H_(2)S and Hg^(0),while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H_(2)S,contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent.The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg^(0)temperature-programmed desorption tests.Density functional theory was employed to elucidate the adsorption and transformation of Hg^(0)on the sorbent surface.H_(2)S adsorbed and dissociated on the sorbent surface,generating active sulfur species that reacted with gaseous Hg^(0)to form HgS.展开更多
Poisonous gases,such as H_(2)S and PH3,produced by industrial production harm humans and damage the environment.In this study,H_(2)S and PH3 were simultaneously removed at low temperature by modified activated carbon ...Poisonous gases,such as H_(2)S and PH3,produced by industrial production harm humans and damage the environment.In this study,H_(2)S and PH3 were simultaneously removed at low temperature by modified activated carbon fiber(ACF)catalysts.We have considered the active metal type,content,precursor,calcination,and reaction temperature.Experimental results exhibited that ACF could best perform by loading 15%Cu from nitrate.The optimized calcination temperature and reaction temperature separately were 550℃ and 90℃.Under these conditions,the most removal capacity could reach 69.7 mg/g and 132.1 mg/g,respectively.Characterization results showed that moderate calcination temperature(550℃)is suitable for the formation of the copper element on the surface of ACF,lower or higher temperature will generate more cuprous oxide.Although both can exhibit catalytic activity,the role of the copper element is significantly greater.Due to the exceptional dispersibility of copper(oxide),the ACF can still maintain the advantages of larger specific surface area and pore volume after loading copper,which is the main reason for better performance of related catalysts.Finally,increasing the copper loading amount can significantly increase the crystallinity and particle size of copper(oxide)on the ACF,thereby improving its catalytic performance.In situ IR found that the reason for the deactivation of the catalyst should be the accumulation of generated H_(2)PO_(4)^(-) and S0_(4)^(2-)(H_(2)0)^(6) which could poison the catalyst.展开更多
文摘Catalysts using α-FeOOH nanoparticles as the active ingredient were testedby a microreactor-chromatography assessing apparatus at atmospheric pressure between 25 and 60 ℃with a gas hourly space velocity of 10,000 h^(-1), while the removal performance of H_2S withcatalysts was investigated using the thermal gravimetric method. The results show that the catalystsare highly active for COS hydrolysis at low temperatures (≤60 ℃) and high gas hourly spacevelocity, and the highest activity can reach 100%. The catalyst is particularly stable for 12 h, andno deactivation is observed. Nanoparticle α-FeOOH prepared using hydrated iron sulfate showshigher COS hydrolysis activity, and the optimum calcination temperature for the catalyst is 260 ℃.In addition, the catalysts can remove COS and H_2S simultaneously, and 60 ℃ is favorable for theremoval of H_2S. The compensation effect exists in nanoparticle-based catalysts.
基金financially supported by the National Natural Science Foundation of China(22078223 and 21878209)Shanxi Province Science Foundation for Youths(20210302123065)。
文摘A series of ZnO/SiO_(2) adsorbents were prepared by a sol-gel method using tetraethyl orthosilicate,ethylene glycol(EG)and nitrates as precursors.The effect of gel drying temperature on the structure and desulfurization performance of the adsorbents were investigated in detail.It is found that the low drying temperature led to a weak interaction among EG,Si AOH/H_(2)O and the nitrates in the gel system,which caused the oxidation of EG by NO3-and formed zinc glyoxylate complex during the gel calcination process,whereas this oxidation process also occurred at a high drying temperature during the gel drying process.The formed zinc glyoxylate complex promoted the generation of monodentate carbonate on the surface of Zn O,which resulted in the inferior desulfurization performance of adsorbents despite they have smaller Zn O nanoparticles.The gel dried at 120°C formed the hydrogen bonds between EG and Si AOH/H_(2)O and a strong interaction between zinc oxo-clusters and NO3-was also found in the gel system,which avoided the oxidation of EG by NO3-during the preparation process and the Zn O nanoparticles with sizes of 6 nm were formed by a combustion method.The adsorbent affords a highest sulfur capacity of 104.9 mg·g^(-1) in this case.In addition,the gel drying temperature has a significant influence on the textural properties of the adsorbents except their surface area.
基金the financial supports from the National Natural Science Foundation of China(No.51904052)the Chongqing Research Program of Basic Research and Frontier Technology,China(No.cstc2020jcyjmsxm X0476)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission,China(No.KJQN201901508)the Graduate Science and Technology Innovation Training Program of Chongqing University of Science and Technology,China(No.YKJCX2020201)。
文摘Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.
基金supports from the Natural Science Foundation of Hubei Province of China(2020CFA107,2020CFB209)the National Natural Science Foundation of China(32002222,52076101)the Fundamental Research Funds for the Central Universities(2662021JC004).
文摘Upgrading biogas into biomethane not only improves the biogas utilization as vehicle fuel or natural gas substitute,but also reduces the greenhouse gases emissions.Considering the principle of engineering green energy process,the renewable aqueous ammonia(RAA)solution obtained from biogas slurry was used to remove H_(2)S and CO_(2) simultaneously in the hollow fiber membrane contactor.RAA was mimicked in this study using the ammonia aqueous solution mixed with some typical impurities including ethanol,acetic acid,propionic acid,butyric acid and NH4HCO_(3).Compared with the typical physical absorption(i.e.,pure water)removing 48%of H_(2)S from biogas,RAA with 0.1 mol·L^(−1) NH_(3) could remove 97%of H_(2)S.Increasing the NH3 concentration from 0.1 to 0.5 mol·L^(−1) could elevate the CO_(2) absorption flux from 0.97 to 1.72 mol·m^(−2)·h^(−1) by 77.3%.Among the impurities contained in RAA,ethanol has a less impact on CO_(2) absorption,while other impurities like CO_(2) and acetic acid have significant negative impacts on CO_(2) absorption.Fortunately,the impurities have a less influence on H_(2)S removal efficiency,with more than 98%of H_(2)S could be removed by RAA.Also,the influences of operating parameters on acid gases removal were investigated to provide some engineering suggestions.
基金supported by National Natural Science Foundation of China(Grant Nos.51976108 and U1906232)Shihezi University Self Funded Support Project(ZZZC2023069).
文摘A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory.The effect of H_(2)S on Hg^(0)adsorption was also investigated.The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon.In the absence of H_(2)S at a low temperature(≤100℃),the Hg^(0)removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%.This value is significantly higher than that of coconut shell activated carbon,which is approximately 45%.H_(2)S significantly enhanced the Hg^(0)removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures(100–180℃).The hierarchical porous structure facilitated the diffusion and adsorption of H_(2)S and Hg^(0),while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H_(2)S,contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent.The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg^(0)temperature-programmed desorption tests.Density functional theory was employed to elucidate the adsorption and transformation of Hg^(0)on the sorbent surface.H_(2)S adsorbed and dissociated on the sorbent surface,generating active sulfur species that reacted with gaseous Hg^(0)to form HgS.
基金supported by the National Natural Science Foundation of China(Nos.51968034,41807373 and 22006058)the National Key R&D Program of China(No.2018YFC0213400)the Science and Technology Program of Yunnan Province(No.2019FB069).
文摘Poisonous gases,such as H_(2)S and PH3,produced by industrial production harm humans and damage the environment.In this study,H_(2)S and PH3 were simultaneously removed at low temperature by modified activated carbon fiber(ACF)catalysts.We have considered the active metal type,content,precursor,calcination,and reaction temperature.Experimental results exhibited that ACF could best perform by loading 15%Cu from nitrate.The optimized calcination temperature and reaction temperature separately were 550℃ and 90℃.Under these conditions,the most removal capacity could reach 69.7 mg/g and 132.1 mg/g,respectively.Characterization results showed that moderate calcination temperature(550℃)is suitable for the formation of the copper element on the surface of ACF,lower or higher temperature will generate more cuprous oxide.Although both can exhibit catalytic activity,the role of the copper element is significantly greater.Due to the exceptional dispersibility of copper(oxide),the ACF can still maintain the advantages of larger specific surface area and pore volume after loading copper,which is the main reason for better performance of related catalysts.Finally,increasing the copper loading amount can significantly increase the crystallinity and particle size of copper(oxide)on the ACF,thereby improving its catalytic performance.In situ IR found that the reason for the deactivation of the catalyst should be the accumulation of generated H_(2)PO_(4)^(-) and S0_(4)^(2-)(H_(2)0)^(6) which could poison the catalyst.
