超声辐照降解MC-RR动力学的影响因素

Influence factors in kinetics during degradation of MC-RR by ultrasonic irradiation process

利用超声辐照技术降解水中微囊藻毒素-RR(MC-RR),考察MC-RR初始质量浓度、超声频率、初始pH值、声能密度以及水中几种典型阴离子对降解效果的影响并探讨其动力学机理。HPLC检测结果表明:超声辐照能有效降解MC-RR且与初始质量浓度无关;超声频率改变水中空化泡分布和特性,影响反应速率;pH值改变MC-RR存在形态和亲疏水性,pH从1.90到12.21变化时,降解速率常数k由0.400min-1降至0.082min-1;CO32-能阻碍MC-RR的降解,但NO3-,SO42-和Cl-对其无影响,其反应速率常数由大到小为:CO32-,NO3-,Cl-,SO24-;声能密度的提高对去除有利;反应符合准一级动力学。

The process and kinetics of microcystin-RR （MC-RR） degradation by ultrasonic irradiation were studied. The effects of initial concentration of MC-RR, ultrasonic frequency, initial pH value, energy density and several typical anions were investigated. The concentration of MC-RR was detected by HPLC and results show that the rate constant （k） is invariable with different MC-RR initial concentrations. Different ultrasonic frequencies can change the distribution and characteristic of vapour cavity, while pH value changes the structure and hydrophilic property of MC-RR and finally affects the reaction. When pH changes from 1.90 to 12.21, the rate constant decreases from 0.400 min^-1 to 0.082 min^-1. The degradation of MC-RR is inhibited by CO3^2- but NO3^-, SO3^2- and Cl^- can be omitted, while the sequence of influence from large to small is CO3^2-, NO3^-, Cl^-, SO4^2-. When sound-energy density increases, the rate constant increases. The degradation of MC-RR by ultrasonic followed a pseudo first-order kinetics.