Preparation Of Chitosan Composite Membrane And Its Removal Of Pollutants From Water

A dual network composite membrane was prepared using chitosan,gasification slag,and coal gangue as the basic materials using a water bath method and through crosslinking agents and freeze-thaw cycles.The prepared composite membrane has a three-dimensional structure,with an increase in specific surface area and pore size distribution.The adsorption performance and mechanism of chitosan/gasification residue composite membrane were further studied with hexavalent chromium ion and rhodamine B as target pollutants.Then,taking Escherichia coli and Staphylococcus aureus as the target bacteria,the antibacterial performance of chitosan/coal gangue composite membrane in water was studied,and the antibacterial process and mechanism were analyzed.This study can not only remove water pollutants,but also promote the recycling of solid waste.The main content of the study is divided into two parts.(1)Under the coordination of cross-linking agents,chitosan and gasification slag were uniformly mixed,and then further crosslinked to finally prepare chitosan/gasification slag composite membrane.According to the relevant characterization,the water absorption and tensile properties of the composite film are significantly enhanced,and SEM can see that the gasification slag is distributed in the surface and internal structure of chitosan.The composite membrane has a good adsorption effect on hexavalent chromium solution of different concentrations.This is because the gasification slag increases the specific surface area of the composite membrane and makes it difficult to lose amino acid,which also promotes the reuse of the composite membrane.The composite membrane complexes hexavalent chromium through NH2,thus removing hexavalent chromium from the solution.At the same time,the gasification slag will also remove hexavalent chromium through physical adsorption.The adsorption of RhB by chitosan/gasification slag composite membrane is mainly physical adsorption,which depends on the surface and internal pores in the gasification slag to achieve the removal effect.At the same time,the gasification slag is negatively charged,and RhB is a cationic dye,so both can achieve the removal effect through the action of electric charge.The chitosan/gasification residue composite membrane prepared by the research can not only effectively remove hexavalent chromium ions in water,but also well adsorb RhB,which can be applied to the adsorption and removal of metal ions and dye mixed wastewater in the future.(2)Chitosan/coal gangue composite membrane was prepared by blending chitosan with coal gangue in the presence of crosslinking agent.The successful preparation of the composite membrane was proved by SEM,FTIR and XRD characterization of the composite membrane.The water content,swelling rate,water solubility and thickness of the composite film were tested.Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were selected as the research objects,and the bacteriostatic effect of the composite membrane on these two bacteria was studied by the bacteriostatic ring method and the shaking flask bacteriostatic method respectively.Under the joint action of chitosan and coal gangue,chitosan/coal gangue composite membrane can inhibit Escherichia coli by nearly 100%,The bacteriostatic effect of single coal gangue or chitosan film was greatly improved.In the study,the antibacterial mechanism of the composite membrane in Escherichia coli solution was preliminarily explored.The loading of coal gangue not only changed the physical properties of chitosan,but also enhanced the bacteriostasis of the composite mold to a certain extent.The bacteriostasis of the composite membrane against Staphylococcus aureus is not obvious compared with that of Escherichia coli.It may be that the cell membrane of Staphylococcus aureus is too thick.This study provides a new idea for the antibacterial research of chitosan/coal gangue composite.