Exposure of Microcystis aeruginosa to Hydrogen Peroxide and Titanium Dioxide under Visible Light Conditions: Cell Lysis Microcystin Release and Degradation and Kinetic Modeling

摘要

Effects of H2O2 and Titanium dioxide (TiO2) on Microcystis aeruginosa and the subsequent release and degradation of microcystins (MCs) under visible light was investigated Four factors namely TiO2 H2O2 hydroxyl radical (·OH) and visible light were examined individually for their effects on cell integrity of Microcystis It was observed that the additive effect of H2O2 and visible light is significant on the reduction of Microcystis cell integrity The low concentration of ·OH produced in the experiments (10-14-10-15 M) is not able to influence the rate of cell rupture Nonetheless results of MCs concentration in the system indicate that ·OH is crucial for the degradation of MCs released from ruptured cells Higher concentrations of ·OH resulted in higher degradation rates of MCs A sequential model including one sub-model to simulate the kinetics for cell integrity of Microcystis and another one to describe the release and degradation of MCs was developed in this study Among the commonly used models for describing cell rupture the Modified Chick-Watson model gave best simulation for the change of cell integrity over time To further describe the concentration change of MCs in the system the Modified Chick-Watson model was combined with the degradation model for MCs in water The results show that the models are able to predict the observed MC concentrations in the water using input parameters either measured from separate experiments or obtained from literatures The developed sequential model is reasonable to describe the experimental systems and may have the potential to be used to evaluate the application of hydrogen peroxide and titanium dioxide in the control of cyanobacteria in fresh water bodies

獎項日期	2015 8月 26
原文	English
監督員	Tsair-Fuh Lin (Supervisor)