Uniform macroporous amidoximated polyacrylonitrile monoliths for gallium recovery from Bayer liquor

Abstract

Efficient recovery of gallium from aqueous solution remains a problem to be solved in industry. Here a novel crosslinked monolith based on polyacrylonitrile/dimethyl sulfoxide (C-PAN) was prepared by thermally induced phase separation and supercritical CO 2 extraction drying technology. The influences of dissolution temperature and exchange solvents with different solubility parameters on the pore structure of C-PAN were systematically studied. It was found that the pore diameter decreased with the decrease of dissolution temperature and the increase of Δδ between exchange solvent and PAN. Meanwhile, the C-PAN with a small and dense pore structure showed better mechanical strength. Thereafter, the Ga 3+ adsorption ability of amidoximated monolith (C-PAO) in simulated Bayer liquor was determined by batch tests. In the case of using methanol as the exchange solvent, the kinetic and equilibrium inspection study illustrated that both physical and chemical adsorption are present due to the multiscale and interconnected structure and the amidoxime groups. The adsorption capacity of C-PAO monolith toward gallium was 15.8 mg/g, with the equilibrium time as fast as 140 min, which can meet the requirement for the rapid extraction of gallium from Bayer liquor. It is expected that our work can provide some new ideas for fabricating gallium adsorbents.