New insights on the UV/TiO2 photocatalytic treatment of thiomersal and its 2-sulfobenzoic acid product

Background: Thiomersal (TM), a complex between 2-mercaptobenzoic acid (2-MBA) and ethylmercury (C2H5Hg + ), is an antimicrobial preservative used in immunological, ophthalmic, cosmetic products, vaccines. Objective: TM has been treated by UV/TiO 2 photocatalysis the presence or absence of oxygen at acidic pH. C H 5 Hg , 2-MBA, 2-sulfobenzoic (2-SBA) were found as products. A 2-SBA photocatalytic treatment was undertaken to study sulfur evolution. Methods: Photocatalytic runs performed using UVA lamp (λmax = 352 nm), open air under N . suspension corresponding salt TiO prepared, pH adjusted. Suspensions stirred dark for 30 min then irradiated. TM, 2-SBA, quantified HPLC, TXRF, deposits on photocatalyst analyzed chemical reactions. The mineralization degree followed TOC. Sulfate determined BaCl 580 nm. Results: destruction total complete air, but degradation much faster air. evolution products pseudo-first-order kinetics. Conclusion: -photocatalytic suitable technique its In contrast other organomercurial compounds, O indicating that oxidative mechanism preferred pathway. significant (> 60%, NPOC S) obtained. more easily degraded than 2-SBA. final product.