Preparation And Properties Of Hydrogel Materialsfor Microbial In Situ Soil Remediation

Hydrogel is a new kind of functional polymer material formed by various physical and chemical crosslinking of polymer monomer.The material can absorb a large amount of water while swelling but not dissolving,and because of its unique cross-linked three-dimensional network structure,hydrogels,as a macromolecular hydrophilic network material that has developed rapidly in recent years,not only have strong hydrophilicity,but also have unique physical and chemical properties such as anti-fatigue,anti-swelling,high elasticity.Soil microbial remediation technology is to reduce the activity of toxic and harmful pollutants in soil by utilizing the metabolism of microorganisms with specific functions.The main content of this work is to prepare high-strength,multi-aperture hydrogel as a good carrier of microorganisms,and use it in situ remediation of soil contaminated by chlorpyrifos accumulation.Firstly,polyacrylic acid(PAA),chitosan(CS),gum acacia(AG)and other raw materials were mixed.In the absence of any crosslinking agent,a high strength composite PCA hydrogel was prepared by in-situ synthesis method through heat initiation.The tensile test of the hydrogel proved that it has excellent recovery rate and mechanical strength.The pore size structure of PCA hydrogel was observed by high resolution thermal field emission scanning electron microscopy after freeze-drying.PCA hydrogel material was immersed in different solutions to investigate the interaction between the internal forces of the material.Soaking PCA hydrogel in deionized water proved its swelling resistance.PCA hydrogel material was air-dried under natural conditions to explore the water retention capacity of the hydrogel material.These results indicate that the PCA hydrogels have good application potential as microbial in situ soil remediation materials.Secondly,PCA hydrogel material was used as the carrier,and microbial bacteria(AY-1)were fixed in the pore structure of PCA hydrogel material in the swelling step during the preparation of PCA hydrogel material,and the adsorption and release ability of PCA hydrogel material to microorganisms was investigated.When PCA hydrogel material containing specific microorganisms was immersed in chlorpyrifos solution with a certain concentration,the concentration of chlorpyrifos was significantly reduced after a period of time.It was proved that PCA hydrogel,as a good carrier of microbial community,could improve the efficiency of microbial in-situ soil remediation.That is,PCA hydrogels have good application potential as in situ soil remediation materials for microorganisms.In summary,it can be seen that the PCA hydrogel material has the properties of reversible swelling,high strength and fatigue resistance,which can realize repeated swelling use and greatly reduce the use cost.The material overcomes the weakness of soft and fragile hydrogel,and has the advantages of high tensile strength,free cutting,convenient transportation and use.PCA hydrogel,as a good carrier of microbial community,can provide suitable temperature,humidity,permeability and other conditions for microorganisms.The formation of "microbial medium for soil repair" can significantly increase the rate of microbial reproduction and reduce the mortality rate,thus greatly improving the efficiency of microbial in situ soil repair.