紫外线对微囊藻毒素-RR降解动力学拟合

Effect and Kinetic of Ultraviolet Degradation on Microcystin-RR

探讨了反应时间、初始pH值、紫外线(UV)辐射强度、温度及初始质量浓度等因素对UV去除微污染水体中微囊藻毒素-RR(MC-RR)效果的影响.研究表明:MC-RR的降解率随反应时间的延长及UV辐照度的增大而提高;pH对其降解具有重要作用,中性和弱酸性环境有利于MC-RR的降解,当pH值为5时,UV对MC-RR的降解效果最佳,强酸性和强碱性环境对UV降解MC-RR起抑制作用;UV对MC-RR的降解率随温度的升高而提高,且呈线性关系;从降解动力学角度考察,符合二级动力学模型,速率常数随MC-RR溶液初始质量浓度的降低而加快.在10℃、辐照度为153μW.cm-2的中性(pH=7.00)环境中,UV辐射时间在160min时可将初始质量浓度为251.7783μg.L-1的MC-RR溶液降解至0.8012μg.L-1,UV对MC-RR溶液的去除率可达99.68%.

The parameters, such as reaction time, pH value, UV light intensity, temperature and initial concentration are investigated on the degradation of MC- RR by ultraviolet （UV） radiation in micro-polluted water, respectively. The results show that the degradation rate of MC-RR is improved with the reaction time and higher UV intensity. The initial pH acted as a key factor to the degradation rate of MC-RR. The neutral and weak acidic solutions were more appropriate to the degradation of MC-RR, and the optimal pH value was 5 in this study. The strong acidic and alkaline solutions were inhibitory to the degradation of MC- RR. The relationship between degradation rate and temperature was linear.MC-RR was removed quickly in the lower concentration solution, and the processes conform to second-order kinetics model.At the UV light intensity 153 μW · cm^-2, the MC-RR concentration decreased from 251.778 3 μg · L^-1 to 0.801 2 μg · L^-1 within 160 min at pH 7.0 and 10 ℃ ,and the degradation rate was 99.68%.