用于燃烧前CO2捕集的微孔Nb2O5膜的制备及其水热稳定性能

以五正丁氧基铌为前驱体,通过溶胶-凝胶法制备出稳定的Nb₂O₅聚合溶胶,详细考察了溶胶制备过程参数(体系酸度、水解比、反应温度、反应时间和螯合剂用量)对溶胶尺寸、稳定性以及制备重复性的影响。采用平均粒径为4.8 nm的Nb₂O₅溶胶,通过浸浆法在平均孔径为3 nm的γ-Al₂O₃中孔膜上制备出Nb₂O₅微孔膜。利用TG、XRD、NH₃吸附-脱附、CO₂吸附、吡啶吸附傅里叶变换红外光谱(Py-IR)和单组分气体渗透实验等手段对Nb₂O₅粉体及微孔膜的性能进行了表征,结果表明:在200℃、0.3 MPa条件下,350℃烧成的微孔Nb₂O₅膜对H₂的渗透率和H₂/CO₂的理想分离因子分别为3.1×10^-9 mol·m^-2·s^-1·Pa^-1和21。此外,微孔Nb₂O₅膜经150 kPa的水蒸气处理8 h后,膜的渗透性能以及H₂/CO₂理想选择性基本保持不变。

Fabrication and hydrothermal stability of microporous Nb2O5 membrane for pre-combustion capture of CO2

Polymeric Nb₂O₅ sols were successfully synthesized via sol-gel process by using niobium penta(n)butoxide as a precursor.Effects of synthesis parameters,including pH of system,hydrolysis ratio,reaction temperature,reaction time and chelating agent,on the state and size of Nb₂O₅ sols were investigated in detail.Microporous Nb₂O₅ membranes were deposited on defect-free γ-alumina membranes with an average pore size of ca.3 nm,by using polymeric Nb₂O₅ sol with an average size of 4.8 nm.The properties of Nb₂O₅ powder and the supported Nb₂O₅ membranes were characterized by TG,XRD,NH₃ adsorption-desorption,CO₂ adsorption,Fourier-transform infrared spectroscopy of pyridine adsorption(Py-IR)and single gas permeance test.Results showed that the single hydrogen permeance and H₂/CO₂ permselectivity of 350℃-calcined microporous Nb₂O₅ membrane were 3.1×10^-9 mol·m^-2·s^-1·Pa^-1 and 21,respectively,measured at 200℃ and 0.3 MPa.The single gas permeance and H₂/CO₂ permselectivity of the membrane remained fairly stable after in-situ exposure to 150 kPa steam for 8 h.