Photocatalytic treatment of 4-chlorophenol in aqueous ZnO suspensions: Intermediates, influence of dosage and inorganic anions

JOURNAL OF HAZARDOUS MATERIALS

卷:168

Article

Gaya, Umar Ibrahim¹  Abdullah, Abdul Halim^1,2  Zainal, Zulkarnain¹  Hussein, Mohd Zobir^1,2 

[1] Univ Pertanian Malaysia, Fac Sci, Dept Chem, Serdang 43400, Selangor De, Malaysia

[2] Univ Pertanian Malaysia, Inst Adv Technol, Adv Mat & Nanotechnol Lab, Serdang 43400, Selangor De, Malaysia

关键词: 4-Chlorophenol;    ZnO photocatalysis;    Intermediate;    Anion;   

DOI  :  10.1016/j.jhazmat.2009.01.130

来源: Elsevier

【 摘 要 】

The photocatalytically driven removal of eco-persistent 4-chlorophenol from water using ZnO is reported here. Kinetic dependence of transformation rate on operating variables such as initial 4-chlorophenol concentration and photocatalyst doses was investigated. A complete degradation of 4-chlorophenol at 50 mg L-1 levels was realised in 3 h. Analytical profiles on 4-chlorophenol transformation were consistent with the best-line fit of the pseudo zero-order kinetics. The addition of small amounts of inorganic anions as SO42-, HPO4-, S2O82- and Cl- revealed two anion types: active site blockers and rate enhancers. Fortunately. Cl- and SO42- commonly encountered in contaminated waters enhanced the rate of 4-chlorophenol degradation. The reaction intermediates and route to 4-chlorophenol mineralisation were elucidated by combined RP-HPLC and GC-MS methods. In addition to previously reported pathway products of 4-chlorophenol photo-oxidation catechol was detected. A radical mechanism involving o-hydroxylation is proposed to account for the formation of catechol. (C) 2009 Elsevier B.V. All rights reserved.

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