Cross-linked amidoxime porous resin for selective gallium separation in Bayer solutions: Reaction mechanism and kinetic study

Low-cost, high-performance adsorbent materials have been developed to recover high-value Ga elements from aluminum extraction wastewater, and realize resourceful waste utilization. [Display omitted] •A novel process for preparing amidoxime resin using acrylonitrile as a monomer.•The preparation procedure is more efficient than commercial LSC600 resins.•DFT combined with characterization to determine the adsorption model.•Revealing the dynamic adsorption model through column experiments. The commercial resin suffers from slow diffusion rates and long mass transfer times, limiting its practical application in gallium extraction in Bayer solution. A novel amidoxime grafted polyacrylonitrile-styrene–divinylbenzene (A-PSD) resin was prepared by suspension acrylonitrile-styrene–divinylbenzene resins and subsequent electrophilic addition of hydroxylamine hydrochloride with amidoxime. Adsorption sites and mechanism study proved that the Ga3+ reacted with the amidoxime groups (CNOH) on the A-PSD resins. The A-PSD resins for Ga3+ adsorption followed the Langmuir model and exhibited excellent adsorption performance in Bayer solution with a Ga3+ capacity of 14.67 mg/g at 25 °C. The kinetic adsorption experiment showed that the adsorption process was controlled by chemical reaction and followed the pseudo-second-order kinetic model. The penetration curves of the column experiments indicate the possibility of industrial application of A-PSD resins, which may lay the groundwork for a new alternative to Ga3+ adsorption resins.