title: Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates.
abstract: Removal of nonylphenol ethoxylates (NPEOs) in aqueous solution by Fenton oxidation process was studied in a laboratory-scale batch reactor. Operating parameters, including initial pH temperature, hydrogen peroxide, and ferrous ion dosage, were thoroughly investigated. Maximum NPEOs reduction of 84% was achieved within 6 min, under an initial pH of 3.0, 25°C, an H2O2dosage of 9.74×10-3M, and a molar ratio of [H2O2]/[Fe2+] of 3. A modified pseudo-first-order kinetic model was found to well represent experimental results. Correlations of reaction rate constants and operational parameters were established based on experimental data. Results indicated that the Fenton oxidation rate and removal efficiency were more dependent on the dosage of H2O2than Fe2+, and the apparent activation energy (ΔE) was 17.5 kJ/mol. High-performance liquid chromatography and gas chromatograph mass spectrometer analytical results indicated degradation of NPEOs obtained within the first 2 min stepwise occurred by ethoxyl (EO) unit shortening. Long-chain NPEOs mixture demonstrated a higher degradation rate than shorter-chain ones. Nonylphenol (NP), short-chain NPEOs, and NP carboxyethoxylates were identified as the primary intermediates, which were mostly further degraded.
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China . ; College of Resources & Environment, Hunan Agricultural University , Changsha, China .
authors.forename: Kai
authors.initials: K
authors.lastname: Cui
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China .
authors.forename: Hao
authors.initials: H
authors.lastname: Yi
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China . ; College of Resources & Environment, Hunan Agricultural University , Changsha, China .
authors.forename: Zi-Jian
authors.initials: ZJ
authors.lastname: Zhou
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China .
authors.forename: Qiong-Fang
authors.initials: QF
authors.lastname: Zhuo
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China .
authors.forename: Yong-Xin
authors.initials: YX
authors.lastname: Bing
authors.affiliation: South China Institute of Environmental Sciences , Ministry of Environmental Protection, Guangzhou, China .
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Guo
authors.affiliation: College of Resources & Environment, Hunan Agricultural University , Changsha, China .
authors.forename: Zhen-Cheng
authors.initials: ZC
authors.lastname: Xu
keywords: Fenton's reagent; intermediates; kinetics; nonylphenol ethoxylates