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.