Preparation of Pseudoboehmite with a Large Pore Volume and a Large Pore Size by Using a Membrane-Dispersion Microstructured Reactor through the Reaction of CO2 and a NaAlO2 Solution

Abstract

In this work, a membrane-dispersion microstructured reactor was specially designed to prepare PB (pseudoboehmite) with a large pore volume and a large pore size through the reaction of CO2 and an aqueous solution of NaAlO2. Tiny crystals of PB and a suitable template are necessary for generating large pore diameter and large pore volume. In this reactor, the tiny crystals could be obtained by increasing the mass transfer rate between the gas phase and the liquid phase through dispersing the CO2 gas into many microbubbles, and these microbubbles could act as a template to increase the pore volume. The effects of the final pH of the aqueous solution, the concentrations of raw materials, and the flow rate of the gas phase on pore properties of products were investigated. The results showed that when the final pH of the aqueous solution was between 10.5 and 9.4, pure PB could be obtained, and the crystal size of PB was about 2.3 nm. In addition, the specific surface area, the pore volume, and the average pore...