It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,...It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).展开更多
This study systematically conducted preparation optimization and performance investigations on Co-modified Ce/TiO_(2) catalysts,with a focus on examining how preparation methods and Co loading regulate the catalyst’s...This study systematically conducted preparation optimization and performance investigations on Co-modified Ce/TiO_(2) catalysts,with a focus on examining how preparation methods and Co loading regulate the catalyst’s low-temperature denitrification activity.After identifying optimal preparation parameters via condition screening,multiple characterization techniques-including BET,XRD,XPS,H_(2)-TPR and in situ DRIFTS-were employed to deeply analyze the catalyst’s physicochemical properties and reaction mechanism.Results demonstrated that compared to the impregnation and co-precipitation methods,the Ce-Co_(0.025)/TiO_(2)-SG catalyst(prepared by the sol-gel method with a Co/Ti mass ratio of 0.025)exhibited significantly superior denitrification activity:NO conversion remained stably above 95%in the 225−350℃ temperature range,and it displayed high N_(2) selectivity.Characterization analysis revealed that abundant surface oxygen vacancies,a high proportion of Ce^(3+) species,and prominent acidic sites collectively contributed to enhancing its low-temperature denitrification performance.This work provides reference value for the development of highly efficient low-temperature denitrification catalysts.展开更多
To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
文摘It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).
基金Supported by the National Key Research and Development Program of China (2023YFB4102903)。
文摘This study systematically conducted preparation optimization and performance investigations on Co-modified Ce/TiO_(2) catalysts,with a focus on examining how preparation methods and Co loading regulate the catalyst’s low-temperature denitrification activity.After identifying optimal preparation parameters via condition screening,multiple characterization techniques-including BET,XRD,XPS,H_(2)-TPR and in situ DRIFTS-were employed to deeply analyze the catalyst’s physicochemical properties and reaction mechanism.Results demonstrated that compared to the impregnation and co-precipitation methods,the Ce-Co_(0.025)/TiO_(2)-SG catalyst(prepared by the sol-gel method with a Co/Ti mass ratio of 0.025)exhibited significantly superior denitrification activity:NO conversion remained stably above 95%in the 225−350℃ temperature range,and it displayed high N_(2) selectivity.Characterization analysis revealed that abundant surface oxygen vacancies,a high proportion of Ce^(3+) species,and prominent acidic sites collectively contributed to enhancing its low-temperature denitrification performance.This work provides reference value for the development of highly efficient low-temperature denitrification catalysts.
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
