Selective gallium adsorption and recovery from Bayer mother liquor using chitosan-based gallium -imprinted resin

Abstract

Gallium is an important scattered metal. Currently, Gallium recovery from Bayer mother liquor by adsorption has the problem of poor selectivity. For this reason, this article developed a novel chitosan gallium-imprinted resin for the recovery of gallium from Bayer mother liquor. Using chitosan as a carrier, Ga(OH)4- as a template, and glutaraldehyde as a cross-linking agent, a resin with specific recognition ability and good adsorption performance was prepared by optimizing the synthesis conditions. The resin has a rough and porous surface, as well as a large specific surface area and pore size distribution, which is conducive to improving the adsorption efficiency. The adsorption of gallium on the gallium-imprinted resin fit the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. The adsorption process involves monomolecular layer adsorption, which is mainly controlled by chemisorption, and the adsorption reaction is spontaneous. Elevating the temperature was conducive to the adsorption reaction. The saturated adsorption capacity was 8.93 mg·g -1. The selectivity coefficient K for Ga/V is 154.8, indicating excellent selectivity. Utilizing 2 mol/L hydrochloric acid as the eluent, the desorption efficiency of gallium reaches 87% after 60 minutes. After five cycles of adsorption and desorption, the resin retains 85% of its initial adsorption capacity, indicating excellent reusability.