title: Treatment of atrazine by integrating photocatalytic and biological processes.
abstract: This research examines the degradation of atrazine by photocatalytic oxidation (PCO) under different experimental conditions. Deisopropylatrazine, deethylatrazine and deethyldeisopropylatrazine were formed as major intermediates based on gas chromatography-mass spectrometry. The reaction mixture was found to be toxic towards two bioassays, i.e. the Microtox and amphipods survival tests even when atrazine was completely degraded by PCO within 2 h under optimized conditions. The results indicate that adding H2O2 could significantly enhance the degradation of atrazine by PCO. Ammeline, ammelide and cyanuric acid (CA) became the major intermediates/products as detected by high performance liquid chromatography from 6th to the 40th h of PCO treatment. After 72 h PCO treatment, only CA was detectable in the reaction mixture. Further degradation of CA was carried out by a newly isolated CA-degrading bacterium, Sphingomonas capsulata. The photochemical pretreatment integrated with microbial degradation lead to the complete degradation and detoxification of atrazine.
authors.affiliation: Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
authors.forename: C Y
authors.initials: CY
authors.lastname: Chan
authors.forename: S
authors.initials: S
authors.lastname: Tao
authors.forename: R
authors.initials: R
authors.lastname: Dawson
authors.forename: P K
authors.initials: PK
authors.lastname: Wong
mesh_terms: D000818:Animals; D001280:Atrazine / Q000737:chemistry*; D001673:Biodegradation, Environmental; D006540:Herbicides / Q000737:chemistry*; D008027:Light; D010084:Oxidation-Reduction; D020578:Sphingomonas / Q000378:metabolism; D018675:Toxicity Tests; D018508:Water Purification / Q000379:methods*
chemical_list: D006540:Herbicides; D001280:Atrazine