臭氧氧化降解微囊藻毒素-LR的动力学研究

Study on Kinetics of Microcystin-LR Degradation by Ozonation

采用臭氧对微囊藻毒素-LR(MC-LR)进行降解试验,研究其反应动力学.取自无锡太湖流域蓝藻藻华提取藻毒素,研究了臭氧投加量、MC-LR的初始质量浓度、pH值及一些阴离子作用对降解速率的影响.结果表明,臭氧氧化能有效降解MC-LR,且符合准一级动力学反应.降解速率不受MC-LR初始质量浓度的影响.当臭氧投加量由0.31mg.L-1增加到1.35 mg.L-1时,MC-LR的降解速率由0.0103 min-1提高到0.0407 min-1.当pH值由3.08升高到10.08时,MC-LR的降解速率由0.2528 min-1降低到0.0099 min-1.在酸性条件下,pH值的变化对降解速率的影响程度更大.在阴离子影响方面,NO3-有利于MC-LR的降解,CO32-阻碍降解,SO42-和Cl-对降解速率的影响不明显,其反应速率常数由大到小的次序是:NO3-,Cl-,SO42-,CO32-.

A study was made of the degradation of microcystin-LR （MC-LR） by ozonafion and its kinetics. The microcystins were extracted in cyanobacteria blooms from Taihu Lake in Wuxi, China. An investigation was also conducted on the effects of ozone dose, MC-LR initial concentration, pH value and some anions. The results indicate that MC-LR can be effectively degraded by ozonation and the reaction fits well with the first-order kinetics. The rate constant is invariable with different MC-LR initial concentrations. However, when the dosage of ozone changes from 0.31mg·L^-1 to 1.35mg·L^-1, the rate constant increases from 0.010 3 min^-1 to 0. 040 7 min^-1. The rate constant decreases from 0.252 8 min^- 1 to 0.009 9 min^- 1 with pH value from 3.08 to 10. 08. Under acidic condition, the degradation of MC-LR is more sensitive to pH value. NO3^- has positive effect on the degradation of MC - LR while CO3^ 2- has negative effect on it,and the effects of SO4^2- and Cl^- on it are not obvious. According to their effects on the degradation rate, the four anions can be arranged as NO3^-, Cl^-, SO4^2- ,CO3^2-.