| Summary: | Biosorption of Zn(II) using rice bran biomass immobilized in Ca-alginate beads was performed. NaOH has been used for activating rice bran biomass. This biosorption process was performed in order to determine the ability of biosorbent to adsorb Zn (II) ion. Ca-alginate-rice bran beads were produced by adding drop wise Na-alginate-rice bran solutions into CaCl2 solutions. Biosorption parameters include the effects of biosorbent mass, pH and contact time were studied. Zn(II) ions has been desorbed by two methods, sequential desorption method and direct desorption method. The concentration of Zn(II) ion was analyzed using atomic absorption spectrophotometer (AAS). Results showed that optimum conditions for biosorption of Zn(II) ions were found at biosorbent mass 3 g, pH 4 and contact time 120 min. The adsorption kinetics followed the pseudo-second order model with adsorption rate constant was 4,9�10-2 g·mg-1·min-1. Biosorption of Zn(II) ion followed the Langmuir isotherm, with adsorption capacity 2.03 mg·g-1 of adsorbent. Sequential desorption showed that the adsorption process followed ion exchange mechanism, whereas the direct desorption showed recovery percentage was 76.56% with HCl 0.1 M as desorption agent for 1 hour.
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