Integrated Photocatalytic-Biological Treatment of Triazine-Containing Organic Compounds
Invited conference paper presented and published in conference proceedings



摘要The degradation of triazine-containing compounds including three herbicides (Atrazine, Simazine, Terbuthylazine), an anti-fouling agent (Irgarol® 1051) and an azo dye (Reactive Brilliant Red K-2G) by photocatalytic oxidation (PCO) was investigated. The effects of the concentrations of TiO2 and hydrogen peroxide (H2O2), initial pH of the reaction mixture and UV intensity on PCO treatment efficiency were examined. Complete decolorization of K-2G required 60 min, while only 15 min was required to completely degrade triazine-containing herbicides and Irgarol® 1051 under respective optimized conditions. HPLC, GC/MS and IC were employed to determine and identify the PCO degradation intermediates and products. Three main dealkylated intermediates (i.e. CEAT, CIAT and CAAT) of triazine-containing herbicides were detected by GC/MS in the initial phase of PCO. Dechlorination, desulfuration and dealkylation processes were preceded faster than the deamination process. Complete mineralization could not be achieved for all triazine-containing compounds even after prolonged UV irradiation (>72h) due to the presence of a PCO resistant end product, cyanuric acid (CA). The toxicities of different compounds before and after PCO treatment were monitored by using the Microtox® test.
In addition, a CA-degrading bacterium was isolated from polluted marine sediment and further identified as Klebsiella pneumoniae by comparing the substrate utilization pattern (BiologTM microplate), fatty acid composition (in term of FAMEs by MIDI) and 16S rRNA gene sequencing. K. pneumoniae utilized CA from 1 to 2,000 mg/L as a good nitrogen source and complete CA removal was observed within 4 to 24 h of incubation. The effects of incubation temperature, agitation rate, medium pH as well as the CA and glucose interactions were investigated and optimized. Biuret and urea, the CA biodegradation metabolites were identified by HPLC during the biodegradation process.
This study demonstrates that the biodegradability of triazine pollutants was significantly improved by using the PCO pre-treatment, and this proposed photocatalytic-biological integrated system showed a promising feasibility to treat various classes of triazine pollutants.
著者WONG Po Keung
會議名稱1st International Conference on Ecotechnologies for Controlling Non-point Source Pollution and Protecting Aquatic Ecosystem
頁次1 - 2
關鍵詞Photocatalysis, Biodegradation, Triazine Compounds

上次更新時間 2018-22-01 於 05:54