Indian Journal of Science and Technology

Abstract

2-((3-silylpropylimino) methyl) phenol chemically bonded silica gel were successfully applied for the enrichment of trace amount of Fe(III), Pb(II), Cu(II), Ni(II), Co(II) and Zn(II) ion prior to their determination by Flame Atomic Absorption Spectroscopy (FAAS). The influences of the analytical parameters including pH, amount of ligand and solid phase, type and condition of eluent and sample volume on the metal ions recoveries were investigated. The method has high sorption– preconcentration efficiency even in the presence of various interfering ions with the low limit of detection (1.4 - 2.6 µg L-1 ), the enrichment factor of 25.3, 28.2, 24.6, 20.1, 28.2 and 18.6 respectively for Ni2+, Zn2+, Ni2+, Pb2+, Cu2+ and Fe3+ ions, and relative standard deviation less than 4.0%, especially for their determination in real samples. Graphical correlation of various adsorption isotherm models like, Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich have been carried out. The adsorption of these metal ions has been found endothermic and feasible in nature and various thermodynamic parameters such as Gibb’s free energy, entropy and enthalpy of the on-going adsorption process has been calculated. The kinetic studies suggest the process following pseudo second order kinetics and involvement of particle diffusion mechanism.
Keywords: Trace metal enrichment, Silica gel, 2-((3-silylpropylimino) methyl) phenol, Atomic absorption spectrometry, Solid phase extraction