Different types of Y zeolites（HY, USY and Na Y） containing various amounts of cerium（Ce） were prepared with the method of liquid ion exchange and characterized by X-ray diffraction（XRD）, intelligent gravimetric ...Different types of Y zeolites（HY, USY and Na Y） containing various amounts of cerium（Ce） were prepared with the method of liquid ion exchange and characterized by X-ray diffraction（XRD）, intelligent gravimetric analyzer（IGA）, and a molecular simulation technology（grand canonical Monte Carlo simulation, GCMC）. A novel calculation method of desorption index（DI） was proposed and the influence of cerium cationic species on the processes of adsorption-desorption of hydrocarbon molecules（n-octane） on the cerium modified Y zeolites（Ce Y） was studied. The results indicated that Ce ion species played a key role in reducing desorption activation energy of n-octane on Y type zeolites, leading to an improvement of the desorption ability of the Ce Y and the regulation of the adsorption state of n-octane from aggregation to decentralization. These findings are essential factors for enhancing the product selectivity of light hydrocarbon component and the catalytic activity of rare earth modified Y zeolites（REY） catalysts in fluid catalytic cracking（FCC） process.展开更多
The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to captur...The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to capture the six exhaust gases.In this work, we performed grand canonical ensemble Monte Carlo(GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites.The simulation results showed that, H_2S, NO, NO_2, CO and NH_3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m^2·g^(-1) and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO_2 is well-adsorbed by zeolites containing larger accessible surface area(1700–2700 m^2·g^(-1)) and pore diameter(0.7–1.4 nm) at room temperature and an atmospheric pressure.However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases.Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry.展开更多
基金Project supported by the National Natural Science Foundation of China(21376114)
文摘Different types of Y zeolites（HY, USY and Na Y） containing various amounts of cerium（Ce） were prepared with the method of liquid ion exchange and characterized by X-ray diffraction（XRD）, intelligent gravimetric analyzer（IGA）, and a molecular simulation technology（grand canonical Monte Carlo simulation, GCMC）. A novel calculation method of desorption index（DI） was proposed and the influence of cerium cationic species on the processes of adsorption-desorption of hydrocarbon molecules（n-octane） on the cerium modified Y zeolites（Ce Y） was studied. The results indicated that Ce ion species played a key role in reducing desorption activation energy of n-octane on Y type zeolites, leading to an improvement of the desorption ability of the Ce Y and the regulation of the adsorption state of n-octane from aggregation to decentralization. These findings are essential factors for enhancing the product selectivity of light hydrocarbon component and the catalytic activity of rare earth modified Y zeolites（REY） catalysts in fluid catalytic cracking（FCC） process.
基金Supported by the National Natural Science Foundation of China(21406172)the Natural Science Foundation of Hubei Province,China(2016CFB388 and 2013CFA091)
文摘The exhaust gases, including SO_2,NH_3, H_2S, NO_2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment.Zeolites have been considered as good absorbent candidates to capture the six exhaust gases.In this work, we performed grand canonical ensemble Monte Carlo(GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites.The simulation results showed that, H_2S, NO, NO_2, CO and NH_3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m^2·g^(-1) and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO_2 is well-adsorbed by zeolites containing larger accessible surface area(1700–2700 m^2·g^(-1)) and pore diameter(0.7–1.4 nm) at room temperature and an atmospheric pressure.However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases.Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry.
