title: A novel mechanism of bisphenol A removal during electro-enzymatic oxidative process: chain reactions from self-polymerization to cross-coupling oxidation.
abstract: The catalyzed removal of bisphenol A (BPA) by a horseradish peroxidase (HRP) cathode in the presence of humic acid (HA) was investigated. At an optimal condition, the removal of BPA achieved 100% within 2min reaction. In the electro-enzymatic process, products were analyzed by high performance liquid chromatography with diode array detector (HPLC-DAD) and high performance size exclusion chromatography (HPSEC). HPLC-DAD results showed that BPA was oxidized into self-polymers and then self-polymers as important intermediate products decreased and disappeared. HPSEC results showed the order of molecular weight (MW): HA+BPA cross-coupling products>HA self-coupling products>initial HA. According to above results, a novel mechanism of BPA transformation in the presence of HA was proposed in electro-enzymatic process. In summary, under oxidation of in situ hydrogen peroxide on HRP electrode, the BPA first are polymerized into self-polymers, and then, the polymers may be incorporated into HA matrix and finally larger MW of BPAn-HA might be formed. The presence of HA can provide chain reactions from BPA self-polymerization to cross-coupling oxidation. Therefore, in the presence of HA, the electro-enzymatic oxidation is an effective way to improve BPA removal.
authors.affiliation: National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190, China.
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
authors.forename: He
authors.initials: H
authors.lastname: Zhao
authors.forename: Chenming
authors.initials: C
authors.lastname: Liu
authors.forename: Yuping
authors.initials: Y
authors.lastname: Li
authors.forename: Hongbin
authors.initials: H
authors.lastname: Cao
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D001559:Benzhydryl Compounds / Q000302:isolation & purification* / Q000378:metabolism; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D052244:Endocrine Disruptors / Q000302:isolation & purification* / Q000378:metabolism; D004867:Equipment Design; D006735:Horseradish Peroxidase / Q000378:metabolism; D006812:Humic Substances / Q000032:analysis; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010636:Phenols / Q000302:isolation & purification* / Q000378:metabolism; D058105:Polymerization; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D006735:Horseradish Peroxidase; D006812:Humic Substances; D010636:Phenols; D014874:Water Pollutants, Chemical; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Bisphenol A; Cross-coupling oxidation; Electro-enzymatic catalysis; Endocrine disrupting chemicals; Humic acid