Adsorption Properties of Magnetic Ca-alginate-chitosan Gel Bead for La(III) Ions
Magnetic Ca-alginate-chitosan gel bead was prepared by using direct and indirect methods and its adsorption properties were investigated in a batch system.The result indicated that the pH value,contact time,temperature,adsorbent dose and the initial metal ion concentration have significant effect on adsorption.Under the condition of 0.05 g adsorbent dose and optimum pH value of 4.0,the reaction attained equilibrium at 5 h,and fitted to second-order kinetic equation.The maximum adsorption capacity calculated to be 208.3 mg/g for S1 and 232.6 mg/g for S2.Thermodynamic parameters were determined and the adsorption process was found to be exothermic.The adsorption mechanism was cation exchange and superficial chelation.The carboxyl group in alginate played a major role in the progress of adsorption.Furthermore,column breakthrough curves indicated that the magnetic beads can be reused.