Simultaneous removal of thallium and chloride from a highly saline industrial wastewater using modified anion exchange resins

•Simultaneous removal of Tl and Cl− by modified anion exchange resins was effective.•Tl removal was based on the exchange of chlorocomplex formed under saline conditions.•The operation had a broad flow rate and pH range.•Elution and regeneration of the resins suggest good potential for practice application. Simultaneous removal of thallium (Tl) and chloride from a highly saline industrial wastewater was investigated using modified anion ion exchange resins. The removal of thallium was mainly driven by the exchange of Tl-chlorocomplex (TlCl4−) formed in the oxidation of thallous (Tl (I)) to thallic ion (Tl (III)) by hydrogen peroxide (H2O2) under saline conditions. Over 97% of thallium and chloride removal was achieved using the modified resins, with a wide optimal conditions found to be H2O2 dosage 1.0–25.0mL/L, pH 1.6–4.3, and flow rate 0.5–4.7mL/L. The modified resins had an exchange capacity of 4.771mg Tl/g dry resins for thallium and 1800mg Cl/g dry resins for chloride. Stable regeneration could be achieved with the modified resins: over 97% of thallium and 90% of chloride can be eluted using Na2SO3 solution and alternating hot (60°C) H2SO4 and cold (25°C) water, and over 98% removal of thallium and chloride was achieved after five consecutive regeneration cycles.