title: Oxidation products and degradation pathways of 4-chlorophenol by catalytic ozonation with MnOx/γ-Al2O3/TiO2 as catalyst in aqueous solution.
abstract: To identify the intermediates of 4-chlorophenol (4-CP) and bring forward the degradation pathways in the process of catalytic ozonation of 4-CP, 4-CP was ozonated with MnOx/γ-Al2O3/TiO2 (MAT) catalyst, and 4-CP was almost decomposed within 30 min, the mineralization reaching above 94.1% at 100 min. The evident reduction of the degradation with the addition of the radical scavenger tert-butanol (TBA) and the stronger spin-adduct signals of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) indicated that 4-CP was oxidized primarily by hydroxyl radical (·OH). Analysis of GC-MS, HPLC and IC confirmed that aromatic compounds and carboxylic acids were predominant oxidative organic intermediates of 4-CP in catalytic ozonation.The main degradation steps were hydroxylation of 4-CP and the formation of hydroquinone, 4-chlororesorcinol and 4-chlorocatechol. The low molecular weight (LMW) acids, such as malic, malonic, oxalic, acetic, and formic acid, were formed from the further oxidation of the intermediates.
authors.affiliation: a State Key Laboratory of Urban Water Resource and Environment , Harbin Institute of Technology , Harbin , P. R. China.
authors.forename: Lili
authors.initials: L
authors.lastname: Qi
authors.forename: Jie
authors.initials: J
authors.lastname: Yao
authors.forename: Hong
authors.initials: H
authors.lastname: You
authors.forename: Ran
authors.initials: R
authors.lastname: Zhang
authors.forename: Chunhui
authors.initials: C
authors.lastname: Feng
authors.forename: Sjack
authors.initials: S
authors.lastname: Van Agtmaal
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002384:Catalysis; D002733:Chlorophenols / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D012996:Solutions; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002733:Chlorophenols; D017895:Manganese Compounds; D010087:Oxides; D012996:Solutions; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D017665:Hydroxyl Radical; C029107:4-chlorophenol; C027424:manganese oxide; D010126:Ozone; D014025:Titanium; D000537:Aluminum Oxide