Study On Preparation And Adsorption Properties Of Global Chitosan Furfural Resin

Chitosan is a deacetylated derivative of chitin,a naturally occurring polymer. It is widely studied in many fields because of its biodegradability, its biocompatibility and its interesting structural properties (presence of amino and hydroxyl groups).The work reported in the present dissertation mainly concerns the preparation of chitosan beads which is influenced by the concentration of chitosan solution, the proportion of NaOH and CH₃OH,the size of beads.Global chitosan furfural resins had been synthesized and the effects of various conditions,such as reaction time,the ratio of furfural and chitosan beads,the amounts of HAc and the microwave irradiation were investigated.Adsorption properties of the resin on Cu²⁺, Ni²⁺ Co²⁺ and physical properties have been studied as well.The structure of the resin has been characterized by Fourier transform infrared(FT-IR) and X-ray diffraction.According to the study,the optimum conditions for preparation of chitosan beads were as follows:the concentration of chitosan is 2%, the ratio of NaOH and CH₃OH is 20%/20%, and the guage is 0.7#.The synthesis of global chitosan furfural resin under the action of microwave power of 225 W gave excellent results with the amounts of 0.7mL HAc at the ratio of 4:1 after reaction of 6h.This kind of resin presented a higher specific surface area and lesser crystallinity with higher mesoporosity than before and stability in acid enviroment. Selectivity of adsorption on metal ions was enhanced after the physical and chemical modification.The order of adsorption capacity was followed by Cu²⁺>Ni²⁺>Co²⁺.The sorption capability of Cu²⁺ on global chitosan furfural was superior to chitosan powder, and the sorption capability of Ni²⁺ was almost equal to it,while the sorption capability of Co²⁺took the inverse. The uptake performance of metal could be described with the mechanism of chemistry sorption.The metals were coordinated with intermediate amino groups,the residual amino groups and C₃ hydroxyl groups of the chitosan and furan ring.The resin was employed by physical and chemical modification to obtain the well-praticed product which showed higher adsorption in this paper.This would enhance the application of traditional forestry products and meet with the demands of green chemistry. And this kind of process has been highlightened by its simple operation,few-pollution and low-cost.The structure of the resin was characterized by modern instrumental analysis and the thermodynamic analysis was also exerted on interpreting the adsorption mechanism of the resin on metal ions...