The Efficiency And Mechanism Of Removal Of Microcystis Aeruginosa By Electrocatalytic Oxidation

With the continuous development of society,the phenomenon of water bloom caused by eutrophication is more and more frequent,which has greatly affected the natural environment and human life.Therefore,it is of great significance to study a kind of economic and effective technology to remove algal bloom.Electrocatalytic oxidation is a kind of advanced oxidation technology,which is called"environmental friendly technology",and has been paid more and more attention by researchers in recent years.In this paper,the carbon nanotubes and Bi modified PbO₂ electrodes were prepared,and the efficiency and mechanism of electroch-emical oxidation were studied.The PbO₂ electrode was prepared by electrodeposition method,and the modified PbO₂electrode was prepared by adding carbon nanotubes and Bi to the electrodeposition solution.The surface morphology,crystal structure and electrochemical properties of the electrode were analyzed.The results showed that the grain size of PbO₂ electrode was reduced and the specific surface area increased with the modification of carbon nanotubes and Bi.The electrochemical active area of the modified PbO₂ electrode was increased,the electrochemical activity was improved,and the life of the electrode was prolonged,which was 1.54 times of that of the PbO₂ electrode.The factors of electrolyte,current,electrolyte concentration,time and initial concentra-tion of algal cells were studied on the electrocatalytic oxidation removal efficiency of algae and the results showed that the best treatment effect could be received by adding electrolyte of Na₂SO₄ with NaCl.The removal efficiency increased with the increase of current（or current density）,electrolyte ion concentration,electrolysis time and initial concentration of algae cells.Using carbon nanotubes and Bi modified PbO₂ electrode for electrocatalytic oxidation of algae removal,the optimal current size was 100mA,the best reaction time was 45min,the concentration of algae was 4.1994×10⁹/L.By electrocatalytic oxidation treatment of Microcystis aeruginosa,the enzyme system of algal cells was destroyed,which reduced superoxide dismutase activity in cells and the ability of scavenging active oxygen was decreased,with the accumulation of active oxygen and the destruction of cell structure.The removal rate of the modified PbO₂ electrode was 1.315 times of that of the PbO₂ electrode.Electrocatalytic Performance of PbO₂ electrode modified by carbon nanotubes and Bi.By means of orthogonal test and variance analysis,the influence of five factors on the removal of algae by electro catalytic oxidation was investigated.The influence of the five factors was as follows,Current size>reaction time>initial concentration>ion concentra-tion>electrolyte type.The current size had a significant effect on the removal of Microcystis aeruginosa,and the reaction time had a great influence on the removal of Microcystis aeruginosa.The effects of initial concentration,ion concentration and electrolyte on the removal of Microcystis aeruginosa were less.