Preparation Of Chitosan-glutaraldehyde-tannic Acid Composite And Solid Bacteria Adsorption Property

In the treatment of heavy metals in water,biological treatment technology has the advantages of high efficiency,economy,environmental protection and so on.Relatively speaking,immobilized microbial technology can better solve the problem that microbial agents are easy to be affected by the environment and the treatment effect is unstable.It is more suitable for building a water purification system with less microbial loss,stable and reliable operation and low operation cost.At present,the application of immobilized microorganism technology is mainly limited by the economy and feasibility of carrier materials and immobilization technology.Based on microbial structural and activity,and the positive electricity,safety and innocuity of natural polymer adsorption material chitosan,the microbial membrane carrier was developed with chitosan as the base material,and the immobilization effect and adsorption performance of the membrane carrier were optimized by adjusting the membrane-forming components and process,and then the correlation of"membrane carrier structure-fixation effect-adsorption performance"was discussed.The main results are as follows:1.The film-forming property of chitosan is poor by spin coating method.The addition of glutaraldehyde and tannic acid could promote the cross-linking of chitosan molecules,thus improving the film-forming effect,but both reduce the adhesion of Chitosan on the glass slide.Compared with spin coating method,CS/GA/TA membrane prepared by casting method showed better stability and mechanical properties,which could be applied to a wider range of applications.2.The possibility of CS/GA/TA Composite Membrane as microbial membrane carrier was discussed.It was found that,in general,the preparation process of the base membrane material would affect the amount of bacteria fixed.When the preparation temperature was 80℃and the ratio of chitosan and glutaraldehyde was 15:1,the amount of bacteria grafted was the most.Accordingly,the removal effect of Mn²⁺was enhanced,which directly confirmed the relationship between the rate of bacteria fixation and the adsorption performance.However,the increase of film-forming temperature could increase the effect of bacteria fixation,but the removal effect of Mn²⁺was decreased,and its mechanism was not clear.At the same time,the adsorption effect of CS/GA/TA composite membrane was greatly affected by p H.3.In order to simplify the preparation process and expand the applicability of the material,cotton embryo cloth was selected as the base material to graft.The results showed that the grafting effect of chitosan on cotton embryo cloth was better than that of glass.The grafting time,reaction temperature,the mass ratio of chitosan to glutaraldehyde and the mass ratio of chitosan to tannic acid could affect the grafting effect of Chitosan on cotton embryo cloth.The CS/GA/TA graft copolymer should good immobilization effect on S.maltophilia.A large number of bacteria were observed on the surface of cotton embryo cloth by scanning electron microscope.The CS/GA/TA graft copolymer showed good Mn²⁺removal effect,and the effect could be further improved after immobilization.At the same time,the p H value of solution,adsorption time and Mn²⁺solution concentration will affect the effect of manganese removal.