Acidified Water + Surfactant Synthesis and Diffusion Properties of Ordered Nanoporous Silica Membranes with Controlled Macroscopic Morphology Jerry Y.S. Lin, Dept of Chemical Engineering, Arizona State University, Tempe, AZ 85260 Oxygen permeance of CDSA silica membranes (at 298 K) and porosimetry results Membrane Support Permeance (10-6 mol/m2.Pa.s)* O2 Permeance (10-6 mol/m2.Pa.s) d100 spacing Wall thickness (nm) Pore Volume (cm3/g) BET Surface Area (m2/g) BJH Pore Size (nm) Method A (H>>>h) 120 1.4 - 0.20 312 3.1 Method B (H>h) ** 5.3 4.2 2.1 0.26 379 2.7 Method C (H=h) 3.7 4.25 0.60 990 Silicon source Support Acidified Water + Surfactant * Theoretical permeance,** Sample mass too low to get an accurate estimate for Surface area and Pore volume Silica grown inside the support pores in Methods A, B and C Permeance decreases by about 100 times after growth of silica with surfactant SEM shows plug morphology is typical of MCM-41 fibers XRD shows ordered pattern for Method B and Method C Nitrogen sorption studies shows ordered mesoporous nature of plugs with high surface area and pore volume Typical Nitrogen Adsorption Desorption isotherm for the silica plugs Inset-BJH pore size