Study of Structural Surface Modified Tin Oxide Membrane Prepared by Sol-Gel Route Sintered at 400°C

Abstract

This work describes the chemical modification by Tiron® molecules of the surface of SnO2 nanoparticles used to prepare nanoporous membranes. Samples prepared with Tiron® content between 1 and 20 wt% and fired at 400°C were characterised by X-Ray Powder Diffraction (XRPD), Extended X-ray Absorption Fine Structure (EXAFS), N2 adsorption isotherms analysis and permeation experiments. XRPD and EXAFS results show a continuous reduction of crystallite size by increasing the Tiron® contents until 7.5 wt%. The control exercised by Tiron® modifying agent in crystallite growth allows the fine tuning of the average pore size that can be screened from 0.4 to 4 nm as the amount of grafted molecules decreases from 10 to 0 wt%. In consequence, the membrane cut-off can be screened from 1500 to 3500 g · mol−1.