电活化过硫酸盐去除铜绿微囊藻的效果及机理研究

Removal Performance and Mechanisms of Microcystis aeruginosa by Electro-Activated Persulfate

为了开发微藻及藻类有机物的高效去除技术,采用电活化过硫酸盐(EC/PS)体系处理含铜绿微囊藻的水样.通过藻细胞密度和叶绿素a含量测定以及扫描电镜观察,研究了EC/PS体系的除藻特性及影响因素;采用荧光区域积分法定量分析了除藻过程中胞内有机物(IOM)和胞外有机物(EOM)的变化特征;利用电子顺磁共振波谱仪测定了EC/PS体系中的自由基类别,并分析了EC/PS体系的除藻机理.结果表明:①在初始藻细胞密度为1.24×10^(7)~1.30×10^(7) cells/mL,电压为7 V,初始pH为6,初始PS浓度为4 mmol/L的条件下,当EC/PS体系处理60 min时,藻细胞和叶绿素a的去除率分别达90.80%和98.41%,明显优于单独EC体系和单独PS体系;当EC/PS体系处理10 min时,IOM的总荧光响应值降低了77.39%.在处理过程中,以腐殖酸类物质为主的胞内有机物会大量释放.②EC/PS体系中电化学作用对除藻的平均贡献率为54.63%;同时,除藻过程可产生大量的SO4−·和·OH,且其随处理时间的增加而增加.研究显示,EC/PS体系能有效去除铜绿微囊藻及藻类有机物,反应体系中的SO4−·和·OH发挥了重要作用.

In order to develop a technology for efficient removal of microalgae and algal organic matter,an electro-activated persulfate(EC/PS)system was used to treat water samples containing Microcystis aeruginosa.The characteristics and influencing factors of the EC/PS system for Microcystis aeruginosa removal were studied through determination of cell density and chlorophyll-a and scanning electron microscopy.Fluorescence regional integration method was used to quantitatively analyze the fluorescence intensity of each region,and the changes of intracellular organic matter(IOM)and extracellular organic matter(EOM)associated with Microcystis aeruginosa during the EC/PS treatment were studied.The free radicals in EC/PS system were determined by electron paramagnetic resonance and the mechanism of algae removal was analyzed.The results showed that:(1)After 60 min of EC/PS treatment,the removal rates of algal cells and chlorophyll-a reached 90.80%and 98.41%,respectively,under the conditions of initial algal density of 1.24×10^(7)-1.30×10^(7) cells/mL,the voltage of 7 V,the initial pH of 6,and the PS concentration of 4 mmol/L.It was better than a separate EC system and a separate PS system;The total fluorescence response value of IOM decreased by 77.39%after 10 min of EC/PS treatment,and a large number of intracellular organic matters dominated by humic acids were released during treatment processing.(2)In EC/PS system,the average contribution rate of electrochemical action to algae removal was 54.63%;At the same time,a large amount of SO4−·and·OH were produced during the algae removal process,which increased with the increase of treatment time.This study showed that algae and their organic matters could be effectively removed by EC/PS system,in which SO4−·and·OH played an important role.