Treatment Of Microcystis Aeruginosa By Novel Advanced Oxidation Technology

The problem of water pollution is becoming more and more serious,which affects people’s production and life.In China,the outbreak of cyanobacteria blooms has become a serious problem of water pollution.The inhibition of cvanobacterial bloomings should not be neglected.In recent years,novel advanced oxidation technology has developed rapidly,and it has good application prospects in water treatment.This article mainly introduces two systems to treat Microcystis aeruginosa.The main contents of the research are as follows:For the first time,the inactivation of Microcystis aeruginosa using sono-Fenton process at low frequency high intensity(20 kHz,0.42 W/mL)and high frequency low intensity(800 kHz,0.07 W/mL)was investigated,re-spectively.20 kHz sono-Fenton treatment successfully reduced cyanobacterial cell number from 4.19 × 106 cells/mL to 0.45 X 106 cells/mL within 5 min treatment.Alternatively,efficient performance of 800 kHz sono-Fenton process was observed to decrease Microcystis cell number to 2.33 X 10 6 cells/mL after 5 min inactivation,with lower energy cost.It was found that powerful 20kHz sonication induced pore formation on the cell wall,leading to extracellular damage,while 800kHz irradiation with low intensity triggered in-tracellular uptake of chemicals,suggesting endocytosis effects.Furthermore,sono-Fenton Processes were found to be affected by the concentrations of Fenton s reagent,and pre-sonication time.Although solo Fenton treat-ment released microcystins in water,the degradation of microcystin-LR were achieved using 20 and 800kHz sono-Fenton processes,respectively.The results of this work showed that severe extracellular oxidation is the vital inactivation mechanism of 20 kHz sono-Fenton process,while the internal oxidation caused by in-tracellularly delivered Fenton reagents is suggested to be the main cause of 800kHz sono-Fenton inactivation,leading to much lower energy cost.In the presence of modified nanodiamonds,persulfate can effectively oxidize and coagulate Microcystis cells,so that the removal efficiency reaches more than 99.9%.Through the free radical quenching experiment,EPR detection and cell SEM detection,only in the N-AND/PS system,a clear signal with a specific pattern was observed.The EPR spectrum signal measured by the system is the signal of DMPO being oxidized;further passed SEM analysis was carried out,and only large-scale aggregation or agglomeration of cells was found in N-AND/PS,and a large amount of N-AND material was attached to the cell surface.These results together indicate that the oxidative coagulation system may be a special reaction system composed of Microcystis aeruginosa,N-AND and PS.This new mechanism is important for the removal of Microcystis aeruginosa:the oxidation process occurs in The biological interface is thus targeted.These works provides alternative methods to control harmful cyanobacteria in water towards effective treatment.