Deep removal of trace arsenic from acidic SbCl₃ solution by in-situ galvanically coupled Cu₂Sb/Cu particles

Arsenic is a harmful associated element in antimony ore, which might bring out the risk of leakage during complex industrial production of high-purity antimony. Herein, we reported a novel and efficient way to remove the trace arsenic impurity from acidic SbCl₃ solution by utilizing copper-system bimetallic particles. Specifically, galvanically coupled Cu₂Sb/Cu was in-situ synthesized by introducing precursor copper powder to the specific SbCl₃ solution. DFT studies revealed that Sb(III) was easily reduced by Cu to form Cu₂Sb due to the strong adsorption of Sb(III) on Cu (111) crystal plane. The Cu₂Sb/Cu coupling exhibited excellent activity for As(III) reduction, over 99.4% arsenic were removed under optimal conditions and residual arsenic concentration dropped to only 2.7 mg L^-1. Crucially, Sb(III) concentration changes could be neglected. Besides, the dearsenization residues were extensively characterized to analyze the evolvement and cause in the reaction process. The results confirmed that the arsenic removal mechanisms by Cu₂Sb/Cu particles were multi-affected, including adsorption, displacement, and precipitation. And the strong electrostatic attraction of AsO⁺ under high HCl conditions was identified as a key step to achieving dearsenization. This research will provide a theoretical guidance for the green synthesis of high-purity antimony and related products.