Study on Kinetics of MicrocystinLR Degradation by Ozonation

Abstract:

A study was made of the degradation of microcystinLR (MCLR) by ozonation 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，MCLR initial concentration，pH value and some anions.The results indicate that MCLR can be effectively degraded by ozonation and the reaction fits well with the firstorder kinetics.The rate constant is invariable with different MCLR initial concentrations.However,when the dosage of ozone changes from 0.31 mg·L-1 to 1.35 mg·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 MCLR 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 NO-3,Cl-,SO2-4,CO2-3.