Oxidative removal of bisphenol A by manganese dioxide: efficacy, products, and pathways.
Bisphenol A (BPA) is a ubiquitous environmental contaminant with endocrine disruption potential. In this study, exploiting the outstanding oxidative capacity of manganese dioxide (delta-MnO2), we explored forthe firsttime the efficacy and mechanisms of BPA removal by MnO2. In aqueous solutions, MnO2 demonstrated an extremely efficient capacity to remove BPA. Nearly all BPA (>99%) was eliminated in 6 min in a pH 4.5 solution initially containing 800 microM MnO2 and 4.4 microM BPA. While humic acid showed negligible inhibition on BPA removal, coexisting metal ions such as Mn2+, Ca2+, Mg2+, and Fe3+ displayed suppressive effects and the inhibitive capacityfollowed the order Mn2+ > Ca2+ > Mg2+ approximately Fe3+. A total of 11 products or intermediates were indentified and a detailed reaction scheme was suggested. The products could be ascribed to a suite of reactions of radical coupling, fragmentation, substitution, and elimination, triggered by the BPA radical formed through electron transfers to MnO2. The exceptional efficiency of MnO2 in removing BPA represents a potential use of MnO2 to treat waters containing phenolic compounds and also suggests a potentially important role of oxide-facilitated abiotic transformations in BPA attenuation in natural soil and sediment environments.
Lin
Kunde
K
Department of Environmental Sciences, University of California, Riverside, California 92521, USA. kunde@ucr.edu
Liu
Weiping
W
Gant
Jay
J
D001559:Benzhydryl Compounds; D004777:Environment; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010636:Phenols / Q000302:isolation & purification*; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D006812:Humic Substances; D017895:Manganese Compounds; D008670:Metals; D010087:Oxides; D010636:Phenols; D012996:Solutions; C006780:bisphenol A; D000098826:Bisphenol A Compounds; C016552:manganese dioxide