KINETIC AND THERMODYNAMICS STUDIES OF AS (III) ADSORPTION ONTOIRON NANOPARTICLES ENTRAPPED CA-ALGINATE BEADS

Iron nanoparticles (Fe2O3) have been successfully entrapped in biopolymer viz. calcium (Ca)-alginate beads. The scanning electron microscopy images indicate that, the alginate gel acts as a bridge that binds the nanoparticles together. The adsorption of As (III) ions from the aqueous solution using Iron nanoparticle entrapped Ca-alginate as an adsorbent has been investigated. Kinetic studies with 0.50, 1.0, and 2.0 and 3.0 mg As (III)/ L indicates that 83-98% Arsenic removal was achieved with entrapped Fe2O3 nanoparticle as compared with bare Ca-alginate beads over a one hour period. The influences of the initial pH, temperature, contact time and dosage of the adsorbent on adsorption performance have been experimentally verified by column method. The equilibrium data were fitted to the Langmuir and Freundlich isotherm equations. From the effect of temperature, thermodynamic parameters like ΔG°, ΔH°, and ΔS° were calculated. The mechanism of adsorption for metal ions onto nanoparticle entrapped Ca-alginate was investigated by using the experimental results. Results suggested that Arsenic adsorption on iron nanoparticle entrapped Ca-alginate was spontaneous and endothermic process. The obtained results showed that iron oxide impregnated calcium alginate can be used to remove Arsenic from aqueous solutions even at low concentration. This work suggests that Fe2O3 nanoparticles offer a promising method for toxic heavy metal removal especially Arsenic, which is reported to causing severe health problems in the state of West Bengal and countries such as Bangladesh ,Taiwan , Mexico etc.