Surface Modified Organic-inorganic Hybrid Microporous Silica Membranes for Hydrogen Separation

Organic-inorganic hybrid silica membranes were prepared by sol-gel method with bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane,BTESE] and phenyltriethoxysilane(PTES) as precursors.The pore structure and hydrophobic property of the hybrid silica membranes were characterized by N2 adsorption,contact angle meter,TG and FTIR.The hydrogen permeation and separation performance was also investigated.The results show that the modified hybrid silica membranes possess a desirable microporous structure with a pore width centered at 0.4—0.6 nm.Such a pore structure can be retained after aging for 30 d under a temperature of 40 ℃ and a relative humidity of 70%—80%.The hybrid silica membranes become hydrophobic after modification,with a water contact angle of(125±0.4)° at a PTES/BTESE molar ratio of 0.6.The transportation of hydrogen in the hybrid silica membranes complies with the activated diffusion mechanism,with a permeance of 8.71×10-7mol·m-2·Pa-1·s-1 and a H2/CO2 permselectivity of 5.53.