UV/H2O2降解2,4,6-三氯苯甲醚动力学及产物研究

摘要

The degradation of 2,4,6-trichloroanisole (TCA) in UV/H2O2 process was investigated in the present study. Effects of water matrix (i.e., natural organic matter (NOM), carbonate/bicarbonate (HCO3-/CO32-), chloride ions (Cl-)), TCA concentration, and H2O2 dosage were evaluated. The second order rate constant of TCA react with HO? was determined to be 5.1×109L/(mol·s). The degradation efficiency of TCA was increased with increasing H2O2 dosage. The increase of TCA initial concentration (0.5~200nmol/L) and Cl- concentration (0.5~10mmol/L) had slight negative effects on TCA degradation. The removal of TCA was significantly inhibited in the presence of NOM or HCO3-/CO32-. Further, the main degradation products, including 2,4,6-trichlorophenol, 2,6-dichloro-1,4-benzoquinone and two aromatic ring-opening products, were detected in the reaction of TCA with HO?, and thus a tentative pathway was proposed.%对UV/H2O2降解水体中2,4,6-三氯苯甲醚(TCA)的效能进行了系统研究,并且对其氧化产物进行测定.考察了自然水体中存在的天然有机物、碳酸根、氯离子以及TCA初始浓度和H2O2投加量对TCA去除效率的影响.结果表明HO?能够有效的降解TCA,HO?与TCA的二级反应速率常数为5.1×109L/(mol·s).H2O2投加量的增加能够有效促进TCA的降解,TCA初始浓度(0.5~200nmol/L)和氯离子浓度(0.5~10mmol/L)的增加对TCA降解效率影响不大,而水体中NOM和碳酸根的存在却能够显著抑制TCA的降解.HO?氧化TCA的主要产物是2,4,6-三氯苯酚、2,6-二氯-1,4苯醌和2种开环产物,据此推测TCA在UV/H2O2体系中的降解路径.