AAS Study on Adsorption of Cadium(Ⅱ) Ion by Hollow Microspheres of Chitosan

Making use of the distinguishing features of large specific surface and coordination reaction of amino groups at its surface,the adsorption of Cd2+ ion by hollow microspheres of chitosan was studied.Especially,the microphenomena of structure of the microspheres of chitosan before and after the adsorption of Cd2+ ion was characterized.Optimum conditions,including acidity of the reaction medium,temperature for adsorption,adsorption capacity at equilibrium and interferences of Pb2+ and Zn2+ ions,were studied.It was found that at the optimum acidity of pH 7,adsorption equilibrium was attained when the concentration of Cd2+ ion was 1 000 mg·L-1,and the adsorption capacity calculated achieved to a value of 424 mg of Cd2+ per one gram of chitosan hollow microspheres,having the adsorption rate of 42.4%.Forty minutes were required to attain the adsorption equilibrium.Changes in temperature (15-50 ℃) for adsorption and size (75-250 μm) of the microspheres showed no significant effects on the adsorption.