Preparation And Perfomance Study Of Silver Ion Imprinted Chitosan Gel Beads

The separation and selective enrichment of silver ions have important significance on the environmental protection and resource reclamation. Adsorption method has many excellences just like low-consumed, no secondary pollution and have observed effect on the separation of trace amount silver ions, which compared to conventional method. But the adsorption method still has many problems, just like the difficulty of sorbing material preparation, high priced and low reusability. So, it was badly in need of new material preparation, which have simple method to prepared, low priced and high reusability.This article was directed to those problems, silver ion imprinted chitosan hydrogel beads (Ag-ICHB) and silver ion imprinted chitosan gel beads (Ag-ICGB) were prepared using Ag(Ⅰ) as template, chitosan hydrogel beads as functional materials. Researched into the effect of chitosan (CTS) quantity, Ag(Ⅰ) quantity, concentration of coagulating bath, temperature of coagulating bath, concentration of eluant and elution time on the mass loss rate, moisture content and adsorption capacity of Ag-ICHB. Studied the effect of chitosan quantity, Ag(Ⅰ) quantity, concentration of coagulating bath, temperature of coagulating bath, temperature of heat treatment, concentration of eluant and elution time on the swelling rate and adsorption capacity of Ag-ICGB.The research shows that the Ag-ICHB would have higher adsorption capacity, lower mass loss rate and lower moisture content when the concentration of chitosan was 2.0%, CTS: Ag(Ⅰ) was 1:0.1, the concentration of coagulation was 22%, the temperature of coagulation was 90℃, the concentration of eluant was 6.0g/L and the elution time were 2h. The Ag-ICGB would have lower swelling rate and higher adsorption capacity when the concentration of chitosan was 2.0%, CTS: Ag(Ⅰ) was 1:0.1, the concentration of coagulation was 22%, the temperature of coagulation was room temperature, the heat treatment temperature was 60℃, the concentration of eluant was 8.0g/L and the elution time were 4h. Spectrum of FI-IR shows that bonding are formed between triethanolamine and the primary hydroxyl of CTS, and Ag(Ⅰ) could coordinate with CTS, it also shows that the Ag(Ⅰ) could be imprinted and could be eluted as well. DSC curve shows that two kinds of acting force for adsorption of Ag(Ⅰ) appears in the adsorption between Ag-ICGB and Ag(Ⅰ). SEM images show the structure of Ag-ICGB could be altered when the Ag(Ⅰ) went inside of it.Perfomance study shows the adsorption capacity of Ag-ICHB and Ag-ICGB could approach the best when the concentration of initial solution was 10g/L. The adsorption capacity of Ag-ICHB was much higher than which of Ag-ICGB in the same solution concentration. The Ag-ICHB could meet the adsorption equilibrium for 200min as the adsorption capacity was 382mg/g, and the Ag-ICGB could meet the adsorption equilibrium for 600min as the adsorption capacity was 231mg/g. Kinetic study shows that the granular internal diffusion is control step for Ag-ICGB, and liquid film diffusion is control step for Ag-ICHB in adsorption process. The optimum range of pH value for Ag-ICHB and Ag-ICGB were 5.0～5.5. The temperature of adsorption solution has very low effect on the adsorption capacity of Ag-ICHB and Ag-ICGB. Both of Ag-ICHB and Ag-ICGB have effect of selective adsorption and recognition on silver ions, and the selectivity of Ag-ICGB was much better than Ag-ICGB. The alkali resistance of Ag-ICHB and Ag-ICGB were much better than acid resistance. The Ag-ICGB has high reusability.Result display, this material was simple to prepared, which also has low priced and high reusability. So it has good application foreground.