SOHIO Process Legacy Waste Treatment: Antimony(V) Removal from Sulfate Media Using Organic Polymeric Ion Exchange Resins

The feasibility of employing an ion-exchange resin for the recovery of antimony(V) from an industrial waste effluent has been investigated. The source of the effluent is a treatment process designed to reduce the volume of a spent uranium-antimony catalyst prior to its immobilisation and disposal in South Korea; known as the SENSEI Process. Commercial macroporous-type cation (Strong acid cation, Mitsubishi DIAION PK216) and anion (Strong base anion Type I, Mitsubishi DIAION PA316; Strong base anion Type II, Mitsubishi DIAION PA418) exchange resins, as well as macroporous-type chelation resins (Aminophosphonic acid, Lanxess LEWATIT TP260; Sulfonic-phosphonic acid, Purolite MTS957) have undergone batchwise screening. LEWATIT TP260 showed the best antimony removal from sulfuric acid solutions across the entire [H+] range tested (0.01 mM – 2 M) and showed no loss of removal performance as a function of increasing sulfate concentration at high [H+]. The Hill isotherm model produced the best fit for antimony binding to LEWATIT TP260 (Adj. R2 = 0.9969), corresponding to an equilibrium adsorption capacity of 160.55 mg g−1. Second order kinetics (Adj. R2 = 0.9808) best described the kinetic uptake of antimony onto the TP260 resin indicating a chemisorption mechanism. The presence of phosphate [PO43−] had a negligible impact on antimony removal by TP260, however, the presence of molybdate [MoO42−] and silica, both found in the SENSEI effluent stemming from the original catalyst, significantly reduced the performance of TP260.