One-step removal of thallium (I) from groundwater by electrocoagulation using an aluminum anode

Abstract

Thallium (Tl) contamination in groundwater is a widespread issue, and the development of an efficient treatment process is of strong interest. We present, herein, a one-step Tl(I) removal method using electrocoagulation systems. Using this method, 86.4% ± 1.0% of total Tl was removed within 60 min by an aluminum anode, with an initial Tl(I) concentration of 10 mg/L and current density of 10 mA/cm2. The Tl removal efficiency increased with increasing current density. However, Tl removal efficiency increased first and then decreased with increasing pH in alkaline pH range. Tl(I) was partly oxidized to Tl(III) and both species precipitated with function of synchronously produced coagulants. X-ray photoelectron spectroscopy was used to analyze the recovered precipitate as well as to confirm the generation of Tl(III) and simultaneous adsorption of Tl(I). This study provides an efficient alternative for one-step Tl removal from groundwater via electrocoagulation.