title: Characteristic transformation of humic acid during photoelectrocatalysis process and its subsequent disinfection byproduct formation potential.
abstract: In this study, degradation of humic acid (HA) via photoelectrocatalysis (PEC) process and corresponding disinfection byproduct formation potential (DBPFP) were investigated. Particularly, structure variation and subsequent DBPFP of HA during PEC treatment were correlated. The PEC process was found to be effective in reducing dissolved organic carbon concentration by 75.0% and UV absorbance at 254 nm by 92.0%. Furthermore, 90.3% of haloacetic acids formation potential and 89.8% of trihalomethanes formation potential were reduced within 180 min. Based on molecular weight and resin fraction results, it was demonstrated that HA with large aromatic, hydrophobic and long aliphatic chain organics were transformed into small and hydrophilic organics during PEC process. Combined with the fourier transform infrared spectra and (13)C nuclear magnetic resonance spectra analysis of HA fractions, it was concluded that phenolic hydroxyl and conjugated double bonds tended to be attacked by hydroxyl radicals during PEC process; these groups were reactive with chlorine to produce disinfection byproducts (DBP), especially trihalomethane and trichloroacetic acid. By contrast, amino, carboxyl and alcoholic hydroxyl groups were relatively difficult to be oxidized during PEC process; these groups had the potential to form dichloroacetic acid during chlorination. Results of these studies confirmed that PEC process was a safe and effective technique to decrease DBP formation significantly in water treatment plant.
authors.affiliation: State key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Angzhen
authors.initials: A
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Zhao
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liu
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
mesh_terms: D002244:Carbon / Q000032:analysis; D002384:Catalysis / Q000528:radiation effects; D005591:Chemical Fractionation; D004203:Disinfection; D004563:Electrochemistry / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D006812:Humic Substances / Q000032:analysis*; D057927:Hydrophobic and Hydrophilic Interactions / Q000528:radiation effects; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction / Q000528:radiation effects; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D006812:Humic Substances; D002244:Carbon