ClO2杀灭拟柱孢藻过程中毒素释放行为与释放机理

试验考察了二氧化氯(ClO_2)杀灭拟柱孢藻过程中不同条件下柱孢藻毒素(CYN)随时间的释放规律,对释放量与时间数据进行曲线方程拟合,并以透射电镜观察不同反应时间拟柱孢藻细胞形态,对柱孢藻毒素的释放机理进行分析。结果表明,反应初期5 min内CYN释放率随时间延长快速提高,随后增长缓慢,30 min后趋于稳定。ClO_2投加量影响了CYN释放速率,1.0 mg/L ClO_2投加量时CYN释放率要高于0.5 mg/L和0.7 mg/L时,但在反应2 h后不同ClO_2投加量的CYN释放率趋于接近。拟柱孢藻初始浓度对CYN释放率的影响不明显。CYN释放率在酸性条件下高于中性和碱性条件。随反应温度升高,CYN释放率逐渐升高。各种反应条件下CYN释放量与反应时间的关系可以用曲线方程来表示。藻细胞形态随反应时间延长发生变化。ClO_2投加量增大,藻细胞结构的破坏程度加剧。在反应初期CYN释放是通过扩散作用而并非由细胞壁的破裂而致。

Release behavior and mechanism of cylindrospermopsin in killing Cylindrospermopsis raciborskii via chlorine dioxide

The paper has done an experimental investigation for the release regularity of cylindrospermopsin with time at different dosages of ClO2,and the corresponding conditions of the initial concentrations of Cylindrospermopsis raciborskii,pH value and temperature changes in the process of crushing Cylindrospermopsis raciborskii by ClO2.At the same time,we have also made careful observations of the experimental data and traced the relation between the release amount and the reaction time,which should be fit for the curve,meanwhile analyzed the cell morphology of Cylindrospermopsis raciborskii after different reaction time by using the transmission electron microscopy (TEM) and the release mechanism of cylindrospermopsin.The results of our investigation have shown that,in the early stages of the reaction,say,for the first 5 min,the cylindrospermopsin releasing rate tends to increase abruptly with time,and,then,the releasing rate turns to rise slowly and may turn to cease till the rising process lasts about 30 min.What is more,the releasing rate of cylindrospermopsin has been found influenced by the dosage of ClO2.Or,more specifically speaking,the releasing rate of cylindrospermopsin can be kept higher at the dosage of ClO2 1.0 mg/L than that at 0.5 mg/L and 0.7 mg/L,but seems to be close no matter what the dosages of ClO2 can be made to vary after 2 h.Besides,no obvious impact can be found with the initial concentration change of Cylindrospermopsis raciborskii on the releasing rate of cylindrospermopsin.As for pH value,higher releasing rate can be found for cylindrospermopsin in the acidic condition than in the neutral and alkaline ones.On the other hand,the releasing rate of cylindrospermopsin can be found increasing with the increase of the reaction temperature.Thus,we have found that there must exist a proper inherent relation between the release amount and reaction time under the following reaction conditions,such as different initial concentrations of Cylindrospermopsis raciborskii,different dosages of ClO2,in addition to different pH values and temperature,which can be properly represented in a curve equation,with each coefficient in the equation being gained by the experiments.In addition,the cell morphology of Cylindrospermopsis raciborskii tends to change with reaction time,till the moment of 60 min coming,the cell walls of Cylindrospermopsis raciborskii tend to break promptly.The increase of ClO2 dosage tends to lead to more intensive or vigorous damage to the algal cell structures.For,in the early reaction stage,the releasing rate of cylindrospermopsin has been mainly caused by the diffusion effect rather than by the splitting of the cell structure of the algae walls due to the oxidation intensification promoted by ClO2.