Abstract
Boron selective resin is a crucial material used for extracting boron from salt lake brine, but the adsorption capacity of resin remains to be improved. In this work, a boron selective resin with high adsorption capacity was created by modifying branched poly (ethylene imine) (PEI) on chloromethyl polystyrene resin, followed by reacting with D-(+)-gluconic acid δ-lactone. The influence of surface hydroxyl content on adsorption capacity of the resin was investigated by varying molecular weights of PEI during modification. The adsorption mechanism of boric acid was explored by changing pH and composition of solution, and by analyzing the adsorption thermodynamic and kinetic behaviors. Furthermore, the selectivity of resin was assessed by the effects of coexisting ions on the adsorption rate of boric acid. The results show that PEI modification effectively increases the content of hydroxyl on the surface of the resin so as to enhance the adsorption capacity of the resin towards boric acid up to 39.4 mg/g. Also, the adsorption rate can still reach up to 75 % even in the presence of 400 times coexisting ion, showing a good selectivity. Furthermore, the adsorption of boric acid is primarily driven by boronate affinity rather than an anion exchange in alkaline solution. Finally, the dynamic extraction of boric acid was carried out, and gives an enrichment factor of up to 39.6 on fixed bed, demonstrating a potential of the resin in the field of boron extraction.
Published Version
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