Adsorption of Silver (I) from Aqueous Solution Using Chitosan/Montmorillonite Composite Beads

Abstract

Chitosan/montmorillonite (CTS-MMT) composite beads were used as adsorbents for the removal of silver ion (Ag+) from aqueous solution. Equilibrium adsorption was achieved within 150 min at 3% MMT of chitosan solution. The optimum pH value for Ag+ removal was found to be 6-7. The maximum adsorbent dosage for Ag+ removal was 5 g/L. Under above maximum conditions the Ag+ removal was 95.7%. The maximum adsorption capacities of CTS and CTS-MMT composite beads as obtained from Langmuir isotherm were found to be 38.46 and 43.48 mg/g, respectively. The adsorption kinetic agrees well with the pseudo second order model. The Ag+ desorption of CTS-MMT composite bead was 17.39% at pH=4. SEM/EDX images confirm that after adsorption the Ag+ were dispersed onto the composite bead surface. The adsorption and desorption experiment demonstrated that the CTS-MMT composite beads can be used as an effective adsorbents for removal of Ag+ from aqueous solution.