Membrane-based vapor permeation(VP) is regarded as a highly efficient technology,featuring low energy consumption and free salt fouling.In this study,we have demonstrated upscaling chabazite(CHA) zeolite membranes on ...Membrane-based vapor permeation(VP) is regarded as a highly efficient technology,featuring low energy consumption and free salt fouling.In this study,we have demonstrated upscaling chabazite(CHA) zeolite membranes on the 19-channel α-Al_(2)O_(3) monolithic supports synthesized from high-silica gel(SiO_(2)/Al_(2)O_(3) ratio of 200) for the dehydration of acetic acid by VP.The monolithic membrane presents higher surface-to-volume ratio and a-tenfold greater mechanical strength compared to tubular ones.The micromorphology and crystallinity of the monolithic CHA zeolite membranes were characterized by scanning electron micrographs and X-ray diffraction analysis.The single-gas permeation test and the effects of temperature,feed water content and feed flow rate on the VP separation performance of monolithic CHA zeolite membrane for dehydration of acetic acid were investigated.Moreover,the stability test of monolithic CHA zeolite membranes was carried out.The 19-channel monolithic membrane achieved a comparable separation performance(water flux of 0.63 kg m^(-2)·h^(-1) and selectivity of 369 at 393 K) with the reported small-area zeolite membranes in water/acetic acid mixtures.It is demonstrated that the monolithic CHA zeolite membranes could be transformative candidates for industrial dehydration of acetic acid under harsh environments.展开更多
Reducing pollution and carbon emissions is an important step toward peaking CO_(2)emissions before 2030 and reaching carbon neutrality before 2060,and heavy diesel vehicle pollution,particularly nitrogen oxides(NOx)em...Reducing pollution and carbon emissions is an important step toward peaking CO_(2)emissions before 2030 and reaching carbon neutrality before 2060,and heavy diesel vehicle pollution,particularly nitrogen oxides(NOx)emissions,is an essential part.CuSAPO-34 is a CHA-type small pore molecular sieve with excellent ammonia(NH_(3))selective catalytic reduction(NH_(3)-SCR)catalytic activity,but it cannot be stored or applied because of severe degradation caused by low-temperature hydrothermal aging.To improve the hydrothermal stability,TiO_(2)was coated on the surface of Cu-SAPO-34 by the ALD method to form a uniform nanolayer.Though this ultrathin TiO_(2)nanolayer has little effect on NH_(3)-SCR catalytic activity of Cu-SAPO-34,the resistance to low-temperature hydrothermal aging in liquid water at 80℃for 24 h has greatly been improved.A study carried out by SEM,XRD,NH_(3)-TPD,and EPR,showed that the ultra-thin TiO_(2)nanolayers were covered uniformly and hydrolysis of frameworks silicon and the migration of Cu^(2+)was retarded.This method has some implications for the future preparation of highly robust Cu-SAPO-34 catalysts for industrial applications.This research could inspire the development of highly robust CuSAPO-34 catalysts to control the NOx emissions from diesel engines.展开更多
基金financially supported by the National Key Research and Development Program of China (2023YFB3810700)the National Natural Science Foundation of China (22378189,U22A20414 and 22378188)+1 种基金the Natural Science Foundation of Jiangsu Provincial Department of Science and Technology(BK20232010 and BG2024018)National State Key Laboratory of Material-oriented Chemical Engineering (SKL-MCE-22A02 and SKL-MCE23B14)。
文摘Membrane-based vapor permeation(VP) is regarded as a highly efficient technology,featuring low energy consumption and free salt fouling.In this study,we have demonstrated upscaling chabazite(CHA) zeolite membranes on the 19-channel α-Al_(2)O_(3) monolithic supports synthesized from high-silica gel(SiO_(2)/Al_(2)O_(3) ratio of 200) for the dehydration of acetic acid by VP.The monolithic membrane presents higher surface-to-volume ratio and a-tenfold greater mechanical strength compared to tubular ones.The micromorphology and crystallinity of the monolithic CHA zeolite membranes were characterized by scanning electron micrographs and X-ray diffraction analysis.The single-gas permeation test and the effects of temperature,feed water content and feed flow rate on the VP separation performance of monolithic CHA zeolite membrane for dehydration of acetic acid were investigated.Moreover,the stability test of monolithic CHA zeolite membranes was carried out.The 19-channel monolithic membrane achieved a comparable separation performance(water flux of 0.63 kg m^(-2)·h^(-1) and selectivity of 369 at 393 K) with the reported small-area zeolite membranes in water/acetic acid mixtures.It is demonstrated that the monolithic CHA zeolite membranes could be transformative candidates for industrial dehydration of acetic acid under harsh environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.22072141,22176185,and 22002150)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2018263)+1 种基金the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDRW-CN-2021-3)the Self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(Grant No.E055C003)。
文摘Reducing pollution and carbon emissions is an important step toward peaking CO_(2)emissions before 2030 and reaching carbon neutrality before 2060,and heavy diesel vehicle pollution,particularly nitrogen oxides(NOx)emissions,is an essential part.CuSAPO-34 is a CHA-type small pore molecular sieve with excellent ammonia(NH_(3))selective catalytic reduction(NH_(3)-SCR)catalytic activity,but it cannot be stored or applied because of severe degradation caused by low-temperature hydrothermal aging.To improve the hydrothermal stability,TiO_(2)was coated on the surface of Cu-SAPO-34 by the ALD method to form a uniform nanolayer.Though this ultrathin TiO_(2)nanolayer has little effect on NH_(3)-SCR catalytic activity of Cu-SAPO-34,the resistance to low-temperature hydrothermal aging in liquid water at 80℃for 24 h has greatly been improved.A study carried out by SEM,XRD,NH_(3)-TPD,and EPR,showed that the ultra-thin TiO_(2)nanolayers were covered uniformly and hydrolysis of frameworks silicon and the migration of Cu^(2+)was retarded.This method has some implications for the future preparation of highly robust Cu-SAPO-34 catalysts for industrial applications.This research could inspire the development of highly robust CuSAPO-34 catalysts to control the NOx emissions from diesel engines.
