Alsyouri Hatem M, Lin Jerry Y S
Department of Chemical Engineering, University of Cincinnati, Cincinnati, Ohio 45221, USA.
J Phys Chem B. 2005 Jul 21;109(28):13623-9. doi: 10.1021/jp0509764.
Pore and surface diffusion of carbon dioxide (CO(2)) and ethylene (C(2)H(4)) in the nanopores of ordered mesoporous silica fibers about 200 microm in length was measured by the transient gravimetric method. The experimentally determined pore diffusivity data, coupled with the porosity, pore size, and fiber length, are used to obtain the actual length of the nanopores in silica fibers. These measurements reveal a structure of the ordered nanopores whirling helically around the fiber axis with a spiral diameter of about 15 microm and a pitch value of 1.6 microm. At room temperature the surface diffusion contributes about 10% to the total diffusional flux for these two gases in the nanopores of the ordered mesoporous silica fibers. The surface diffusion coefficients for the ordered mesoporous silica fibers are about 1 order of magnitude larger than the non-ordered mesoporous alumina or silica with similar pore size.
采用瞬态重量法测量了长度约为200微米的有序介孔二氧化硅纤维纳米孔中二氧化碳（CO₂）和乙烯（C₂H₄）的孔隙扩散和表面扩散。实验测定的孔隙扩散率数据，结合孔隙率、孔径和纤维长度，用于获得二氧化硅纤维中纳米孔的实际长度。这些测量揭示了有序纳米孔围绕纤维轴螺旋状旋转的结构，螺旋直径约为15微米，螺距值为1.6微米。在室温下，表面扩散对这两种气体在有序介孔二氧化硅纤维纳米孔中的总扩散通量贡献约10%。有序介孔二氧化硅纤维的表面扩散系数比具有相似孔径的无序介孔氧化铝或二氧化硅大大约1个数量级。
