title: Oxidation of nonylphenol and octylphenol by manganese dioxide: kinetics and pathways.
abstract: Due to their potent estrogenicity and ubiquitous occurrence, non-ionic surfactant metabolites nonylphenol (NP) and octylphenol (OP) are of significant concern. Abiotic chemical oxidation by naturally abundant metal oxides may be an important route of their environmental attenuation, but is poorly understood. We investigated the reaction kinetics and pathways of NP and OP with MnO2. At pH 5.5 and 100 mg/L δ-MnO2, 92, 84 and 76% of 4-n-NP, 4-tert-OP and technical nonylphenol (tNP) was transformed in 90 min, respectively. A further experiment using a Mn-containing soil and Mn-removed soil confirmed that soil MnO2 caused NP removal. Multiple reaction products, including hydroquinone, hydroxylated products, dimers and trimers were identified through fragmentation analysis by GC-MS/MS and UPLC-MS/MS, allowing the construction of tentative pathways. This study suggested that abiotic oxidation by MnO2 may contribute to the dissipation of tNP, 4-n-NP, 4-tert-OP and their analogues in the natural environment.
authors.affiliation: Department of Environmental Sciences, University of California, Riverside, CA 92521, USA. zhijiang.lu@email.ucr.edu
authors.forename: Zhijiang
authors.initials: Z
authors.lastname: Lu
authors.forename: Jay
authors.initials: J
authors.lastname: Gan
mesh_terms: D052918:Environmental Restoration and Remediation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D010636:Phenols; D012989:Soil Pollutants; C016552:manganese dioxide
keywords: Manganese oxides; Natural attenuation; Nonylphenol; Surfactant metabolites