Adsorption of Pb2+, Cu2+ and Ni2+ from aqueous solutions by novel garlic peel adsorbent

The viability of garlic peel (GP) to remove Pb2+, Cu2+, and Ni2+ was evaluated in this paper. Characterization of prepared GP adsorbent was performed using scanning electron microscopy and Fourier-transform infrared spectrophotometer. Batch experiments were carried out to investigate the effects of pH, temperature, time, and initial metal ion concentration on the adsorption of single heavy metal ion by GP. Competitive adsorption of binary mixture (Pb2+/Cu2+ and Pb2+/Ni2+) by GP was also investigated. The results showed that the adsorption process could attain equilibrium within 20 min, and kinetics was found to fit pseudo-second-order equation. GP had remarkable higher adsorption affinity for Pb2+ than Cu2+ and Ni2+ with the maximum adsorption capacity as 209 mg/g. The adsorption efficiency and uptake capacity of one metal ion were reduced by the presence of the other metal ion. The adsorption mechanism was supposed to be ion exchange between Ca2+ of GP with heavy metal ions in the solution.