The Effect And Mechanisms Of Metal Organic Framworks On Inhibiting The Growth Of Hamful Algae

Harmful cyanobacteria blooms are becoming more and more frequentcy in all kinds of water bodies,which cause seious damage on the aquatic ecological environment and threaten the safety of water use.Metal organic frameworks?MOFs?is a new type of nanomaterial,due to its large surface area,high porosity,good thermal stability,easyly control of physicochemical properties,which has been widely used in fields of catalysis,adsorption,light,electricity,magnetism and environment,and so on.However,there is no research to be found on the application of MOFs in cyanobacteria bloom control.In view of the MOFs inhibiting toxic cyanobacteria growth effect and the mechanism is unknown,in this research,Microcystis aeruginosa was used as the research object,five kinds of MOFs were synthesized according to the algae characteristics,and the inhibitory effects of different kinds of MOFs on the growth of algae cells were studied.The physiological characteristics of MOFs,the interaction between MOFs and algae,revealing the mechanisms of algae inhibition by MOFs were systematically investigaeted to provides a new method for controlling cyanobacteria blooms.The results of algae inhibition by MOFs showed that when the concentration of MOFs in water reached a certain threshold,it could inhibit the growth of algae cells.Five kinds of MOFs,Cu-MOF-74 has the best algae inhibition performance.Inhibition of algae cells growth by Cu-MOF-74 conforms to pseudo second order kinetic model with good correlation,which R²=0.966.And the reaction rate constant is 0.0025 h^-1.Cu-MOF-74,the best algae inhibiting ability in five kinds of materials,was selected as the main material to study the physiological characteristics of algae.The results showed that 1-10 mg/L Cu-MOF-74 could destroy the chlorophyll-a.and phycobiliproteins,the ability of algae to capture light energy was decreased,the light quantum transport chain was cut off,and the damage degree of phycobiliproteins was greater than that of chlorophyll-a.At the same time,1-10 mg/L Cu-MOF-74 could destroy the integrity of cell membrane and reduce the total protein content of algae cells.By studying the mechanism of algae inhibition by Cu-MOF-74,it could be found that the Cu²⁺ dissolved by Cu-MOF-74 could inhibit the growth of algae cells.Moreover,Cu-MOF-74 could produce OH in aqueous solution,cause accumulation of intracellular ROS and oxidative damage,damage of antioxidant enzyme system,decrease of SOD content and increase of CAT content.Cu-MOF-74 could make the algae cells agglomerate.By observing the submicroscopic structure of algae cells,it can be found that the cell morphology has changed compared with the control group.In summary,Cu-MOF-74 is a potential algae removal material,which has good potential for removal of algae cells,and provides a new idea for cyanobacteria bloom control.