Abstract:
Multi-wall carbon nanotubes functionalized with 3-Amino-5a, 10a-dihydroxybenzo indeno furan-10-one (ADIF), (MWCNT-ADIF), were used as the adsorbent to remove lead ions (Pb
2+) from aqueous solutions. The samples were characterized by FT-IR, SEM, TGA and DTG. Effects of pH, initial Pb
2+ concentration, adsorbent dosage and contact time on adsorption kinetics and equilibrium were investigated in a batch mode. Adsorption isotherms of Pb
2+ ions were investigated using four two-parameter models (Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich) and six three-parameter models (Redlich-Peterson, Khan, Sips, Radke-Prausnitz, Toth, Hill). Adsorption kinetics were investigated by the pseudo first-order kinetic model, the pseudo second-order kinetic model and the intra-particle diffusion model. Three error analysis methods, correlation coefficient, chi-square test and average relative errors, were used to determine the best fitted isotherm. Results indicated that adsorption kinetics was best described by the pseudo second-order kinetic model. Error analysis indicated that three-parameter models described the Pb
2+ sorption data better than the two-parameter models. The isotherm data were best fitted by the Langmuir, Hill and Sips models. Pb
2+ ions could be desorbed from MWCNT-ADIF up to 92% at pH=3 and the recycled MWCNT-ADIF could be reused for 5 regeneration cycles.