氯化和UVC灭活铜绿微囊藻的机理

Inactivation Mechanism of Microcystis aeruginosa by Chlorination and UVC Irradiation

采用荧光光谱矩阵(EEM)法探讨了铜绿微囊藻胞内外溶解性有机物的荧光特征,并结合蓝藻生化指标(总蛋白含量、藻蓝蛋白含量、叶绿素a含量以及藻毒素(MC-LR)含量)研究了氯化和短波紫外线照射(UVC)处理铜绿微囊藻的机理.结果表明,与铜绿微囊藻相关的EEM荧光物质主要有类蛋白质物质(位于峰A和B)与类腐殖质物质(位于峰C和D).UVC的灭活机理主要包括光降解和高级氧化,UVC处理60min后胞内类蛋白质物质被降解并转化为胞外类腐殖质物质,120 min后残留较少;30 min内藻蓝蛋白和MC-LR的去除率分别达到83.55%和94.70%,总蛋白和叶绿素a去除率较低.氯化处理主要依靠HClO穿透进入藻细胞内部进行化学破坏和降解,处理60 min后胞内外类蛋白质物质减少,而胞外类腐殖质物质增加且有明显的残留;30min内藻蓝蛋白和总蛋白去除率分别达到96.44%和60.36%,MC-LR和叶绿素a去除率较低.比较发现:中等强度UVC灭藻及有机物降解效果显著;HClO能有效灭藻,但对水中溶解性有害有机物的控制效果不佳.

In this paper,the fluorescent characteristics of intracellular and extracellular dissolved organic matters of Microcystis aeruginosa were investigated by means of the EEM（Excitation Emission Matrix） fluorescence spectro-scopy,and the inactivation mechanism of Microcystis aeruginosa by chlorination and UVC irradiation was analyzed according to the cyanobacterial biochemical indexes such as the contents of total protein,phycocyanin,chlorophyll-a and microcystin-LR.The results indicate that（1） the characteristic materials associated with Microcystis aeruginosa are mainly protein-like matters corresponding to peaks A and B and humic-like matters corresponding to peaks C and D;（2） the inactivation of Microcystis aeruginosa by UVC irradiation is mainly due to the photodegradation and advanced oxidation;（3） after a UVC irradiation for 60min,the intracellular protein-like matters are transformed into extracellular humic-like ones,and few residuals are found after 120min;（4） the removals of phycocyanin and microcystin-LR respectively reach 83.55% and 94.70% after 30min,while the removals of total protein and chlorophyll-a are relatively low;（5） the inactivation of Microcystis aeruginosa by chlorination is mainly due to the chemical ablation and degradation of cyanobacteria cells by the permeated HClO;（6） after a chlorination for 60 min,both the intracellular and the extracellular protein-like matters decline with significant remain of extracellular humic-like matters;（7） the removals of phycocyanin and total protein respectively reach 96.44% and 60.36% after 30min,while the removals of microcystin-LR and chlorophyll-a are relatively low;（8） the UVC irradiation with medium intensity is effective in the removal of cyanobacteria and the purification of dissolved organic matters;and（9） the HClO permeated into cyanobacteria cells is also effective in the removal of cyanobacteria but is ineffective in the purification of dissolved organic matters.