Utilization of an amidoxime resin waste to prepare solvent-impregnated resins (CA−12/SIRs) for the extraction of Ga(III) from acid solutions

Solvent-impregnated resins (CA−12/SIRs) have been prepared by using amidoxime resin waste as a polymeric support. The process of gallium (Ga) adsorption onto CA− 12/SIRs from a hydrochloric acid solution was examined in a batch experiment. It was found that CA− 12/SIRs exhibits excellent adsorbent properties with a saturated adsorption capacity of up to 31.2 mg·g−1 (318 K). In addition, CA− 12/SIRs showed an outstanding separation ability for Ga(Ⅲ), with a partition coefficient as high as above 2500 mL·g−1. The optimum pH value was found to be 2.75. Moreover, CA− 12/SIRs maintained an excellent adsorption performance for Ga(III), even after ten adsorption-elution cycles. For practical applications, the adsorption percentage of Ga(III) onto CA− 12/SIRs reached more than 99 % when using hydrochloric acid and sulfuric acid solutions. Thus, a low-cost adsorbent has been developed in the present study by which it is possible to purify gallium. Moreover, this study has provided a new direction for also other types of waste resins in the preparation of impregnated resins.