Selective separation of aluminum from biological and environmental samples using glyoxal-bis(2-hydroxyanil) functionalized amberlite XAD-16 resin: Kinetics and equilibrium studies

A new glyoxal-bis(2-hydroxyanil) anchored Amberlite XAD-16 chelating resin was synthesized and characterized by elemental analyses and scanning electron microscopy along with energy dispersive X-ray spectroscopy (SEM/EDAX), infrared spectral, and thermal studies. The resin was found to selectively bind aluminum in aqueous medium over a large number of competitive cations, at pH 9. Experimental conditions, for effective sorption of Al(III) were optimized systematically and were found to have fast kinetics (t_1/2 10 min), high preconcentration flow rate (5.0 mL min^-1), very high sorption capacity (24.28 mg g^-1), regenerability up to 66 sample loading/elution cycles, and low preconcentration limit (3.3 ppb) from test solutions of different interferent to analyte ratio. The chemisorption and identical, independent binding site behavior were evaluated by Dubinin-Radushkevich isotherm and Scatchard plot analysis. Equilibrium data fit well to Langmuir adsorption isotherms (r² = 0.998) indicating a typical monolayer sorption. We confirmed the analytical reliability of the method by the analysis of standard reference materials (SRMs), recovery experiments, and precision expressed as coefficient of variation (<5%). The applicability of the proposed method was demonstrated by preconcentration of trace Al(III) in dialysis fluid, packaged drinking water, rum, and soft drink samples.