Silver Nanoparticle Entrapped Calcium-Alginate Beads for Fe(II) Removal via Adsorption

Silver nanoparticle entrapped calcium-alginate beads (AgNP-CAB) were successfully synthesized as adsorbent for effective removal of Fe(II) ions from aqueous solution. The adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Batch adsorption experiments were used to determine the adsorption capacity. The influence of various factors (such as temperature, pH, adsorbent dosage and contact time) on adsorption behaviour was investigated. The adsorbent thus developed showed higher uptake at pH 4, and adsorption the capacity decreased with increasing temperature. The kinetic results for the adsorption process were interpreted using pseudo-first order and pseudo-second order rate equations, as well as Elovich and intra-particle diffusion models. A good correlation with the pseudo-second order rate kinetics (R-2=0.998) could be observed. Adsorption isotherms were fitted to Langmuir, Freundlich, Temkin and Harkins-Jura isotherms whereby the experimental data was found to best fitted for the Langmuir model. The maximum adsorption capacity of adsorbent was found to be 236.40mg/g.