Efficient removal of bismuth with supersoluble amorphous antimony acids: An insight into synthesis mechanism and Sb(V)-Bi(III) interaction behaviors

Abstract

• Supersoluble amorphous antimony acid was prepared by controllable hydrolysis. • Phases and structures of A-SbA with different hydrolysis ratios were determined. • Hydrolysis and polymerization mechanism during A-SbA synthesis was investigated. • The maximum Bi(III) removal capacity by A-SbA can reach 300 mg g −1 . • Selective removal of Bi, Sb and As in H 2 SO 4 solution was achieved. The commonly used electrodeposition method for copper electrorefining electrolyte purification is actually suffered from the complicated process, expensive energy cost and the potential arsine hazard. This work synthesized a kind of submicro-sized amorphous antimonic acids (A-SbA) with ultrahigh solubilities in strong acid aqueous solution and evaluated their environment-friendly application in removing the problematic impurity bismuth (Bi). By controlling the hydrolysis ratio and aging time the crystalline structures and dissolution behaviors of A-SbA materials can be varied. The effects of hydrolysis ratio, aging time, temperature, acidity, initial Bi concentration and co-existing ions on Bi(III) removal efficiencies by A-SbA were systemically studied. The results show that the A-SbA prepared at a hydrolysis ratio of 1:2 without aging treatment has the highest solubility and the maximum Bi(III) removal capacity can reach 300.2 mg g −1 . The Sb(V)-Bi(III) reactions follow a pseudo-second-order kinetics model and the apparent activation energy of reaction process is calculated to be 32.14 kJ mol −1 . The Bi(III) removal efficiencies of over 99% can be achieved under the coexistence of Cu 2+ , Ni 2+ , Na + and Sb(III), while As(III,V) ions can also be partially precipitated together with Bi(III). This work gives an insight into the hydrolysis of antimony pentachloride and the polymerization of monomer HSb(OH) 6 as well as the Sb(V)-Bi(III)-As(III,V) interaction behaviors.