REMOVAL OF Zn2+, Cd2+ AND Pb2+ FROM AQUEOUS SOLUTION BY CHEMICALLY MODIFIED POTATO (Solanum tuberosum) PEEL

Abstract

In the present study potato, peel was used as a bio-sorbent for removal of heavy metal ions from aqueous solutions. The bio-sorption tendency of Pb2+, Cd2+ and Zn2+ ions onto modified and unmodified potato peel was significantly affected by the parameters including pH, adsorbent dose, initial concentration and contact time. Bio-sorption was highly pH dependents and the optimum pH for the investigated metals was obtained at pH 5 for modified and 6 for unmodified. Fourier transform infrared (FTIR) spectroscopy was used to determine the participating functional groups of potato peel adsorbent for Pb2+, Cd2+ and Zn2+ adsorption. The broad and strong band in the range of 3401-3426 cm-1 were due to (OH-) of phenols, hydroxyl and carboxylic acid. The adsorption equilibrium was achieved with in 60 min. The adsorption isotherm of Lead cadmium and zinc fitted to Freundlich model with R2 values of 0.997 = unmodified, 0.978 = modified and 0.988 = unmodified, 0.996 = modified, respectively. Cadmium fitted both freundlich and Langmuir models. The R2 value of 0.999 for unmodified and 0.998 for modified. For all the three metals were described by the pseudo second order kinetic models. Based on the results observed in the present study, potato peel can be taken as good adsorbent for the removal of heavy metals from aqueous solution.