The Study On F/Ce-TiO₂ Photoelectric Catalytic Inactivation Of Microorganisms In Ballast Water

Ballast water carries a large number of microorganisms and pathogens.With the navigation of ships and foreign emissions,harmful organisms in ballast water are brought into the world.Since January 22,2019,the 2004 International Convention on the Control and Management of Ballast Water and Sediments for Ships has been formally implemented in China.The implementation of the D-2 standard in the Convention indicates that harmful organisms in ballast water must be treated before they can be discharged.The treatment of ballast water for ships has attracted more and more attention.In this paper,on the basis of in-depth investigation of current ballast water treatment technology,F/Ce-TiO2 was prepared by anodic oxidation method.Microorganisms in ballast water were inactivated by photoelectric catalysis technology,and the inactivation mechanism of microorganisms was deeply analyzed.The main research contents of this paper include the preparation of F/Ce-TiO2 catalysts,the efficiency analysis of photoelectric catalytic inactivation of microorganisms and the mechanism analysis of microbial inactivation.F/Ce-TiO2 catalysts were prepared by anodic oxidation.The effects of electrolyte concentration,oxidation time,oxidation voltage and Ce doping ratio on the catalytic performance of the catalysts were studied.Through response surface design experiments,the interaction between influencing factors was analyzed,and the optimum preparation parameters were obtained.The F/Ce-TiO2 catalyst prepared with the optimum parameters was characterized by SEM and EDS.It was confirmed that F and Ce elements were successfully doped and modified.The efficiency analysis of photoelectric catalytic inactivation of microorganisms mainly studied the inactivation effect of photocatalysis and photoelectric catalysis on microorganisms.Taking sterilization rate and algae-killing rate as indicators,the effects of voltage intensity,illumination intensity,temperature and pH value on the experimental process were investigated.The results showed that photoelectric catalysis had better inactivation effect on microorganisms than photocatalysis,and the effluent could reach the ship.Ballast water discharge standards for ships.The removal rate of E.coli decreased by only 0.42 log after 12 reuses of the catalyst,which proved that F/Ce-TiO2 catalyst had excellent reuse function.The mechanism analysis of microbial inactivation mainly investigated the lipidization of cell membrane,the change of superoxide oxidase activity,the leakage of intracellular substances and the change of chlorophyll a content in the process of microbial inactivation under different conditions.It was found that microbial cells were destroyed more severely in the photoelectric catalytic system.The results showed that cell wall(membrane)destruction,cell metabolism destruction and macromolecule leakage coexisted in the process of inactivation,which indicated that under the photoelectrocatalytic system,many factors contributed to the rapid death of microorganisms.The test results will provide theoretical basis and technical support for the establishment of ballast water efficient inactivation system in actual engineering.Photoelectrocatalysis technology can effectively solve the problem of ship ballast water treatment,which is of great significance for preventing marine ecosystem damage and environmental pollution.