Antimony(III/V) removal from industrial wastewaters: treatment of spent catalysts formally used in the SOHIO acrylonitrile process

• Published in: Water science and technology Vol. 80; no. 3; pp. 529 - 540
• Main Authors: Foster, Richard I, Oh, Maeng-Kyo, Yang, Dasom, Shon, Woo-Jung, Kim, Kwang-Wook, Lee, Keun-Young
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.08.2019
• Subjects: Acrylonitrile; Acrylonitrile - chemistry; Adsorption; Anions; Antimony; Antimony - analysis; Arsenic removal; Binding sites; Catalysts; Catalytic oxidation; Caustic soda; Effluents; Environmental science; Ferric Compounds; Hydrogen peroxide; Immobilization; Industrial wastewater; Iron; Kinetics; Organic chemistry; pH effects; Phosphates; Pollutants; Reaction kinetics; Regulatory approval; Removal; Uranium; Waste Disposal, Fluid - methods; Waste Water; Wastewater; Water Pollutants, Chemical - analysis; United States > US
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2019.299

A treatment and volume reduction process for a spent uranium-antimony catalyst has been developed. Targeted removal, immobilization and disposal of the uranium component has been confirmed, thus eliminating the radiological hazard. However, significant concentrations of antimony ([Sb] ≥ 25-50 mg L ) remain in effluent from the process, which require removal in compliance with Korean wastewater regulations. Antimony(III/V) removal via co-precipitation with iron has been considered with optimal pH, dose and kinetics being determined. The effect of selected anions - Cl , SO and PO - have also been considered, the latter present due to a prior uranium removal step. Removal of Sb(III) from both Cl and SO media and Sb(V) removal from Cl media to below release limits were found to be effective within 5 minutes at an iron dose of 8 mM (molar ratio, [Fe ]/[Sb] = 20) and a target pH of 5.0. However, Sb(V) removal from SO was significantly hampered requiring significantly higher iron dosages for the same removal performance. Phosphate poses significant challenges for the removal of Sb(V) due to competition between PO and Sb(OH) species for surface binding sites, attributed to similarities in chemistries and a shared preference for an inner vs outer binding mechanism.