Uptake of lead(II) from water sample by 2-allyl-phenol-functionalized amberlite XAD-4: isotherm and thermodynamic study

A new polymeric sorbent is prepared by coupling Amberlite XAD-4 with phenol through an azo spacer, then modified by allyl bromide and characterized using FTIR, elemental analysis, and thermogravimetric analysis and evaluated for the preconcentration and determination of trace Pb(II) in human biological fluid and environmental water samples. The optimum pH value for sorption of the metal ion was 5.5. The sorption capacity of functionalized resin is 80 mg g-1. The modified sorbent can be reused for 20 cycles of sorption–desorption without any significant change in sorption capacity. A recovery of 89–95% was obtained for the metal ion with 0.5 mol L-1 nitric acid as eluting agent. The profile of lead uptake by this sorbent reflects good accessibility of the active sites in the Amberlite XAD-4-[2-(allyl-phenol)]. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Pb(II) on modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich–Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined to be 1.60, 44.00, and 51.83 at pH 5.5 and 20°C, respectively. The method was applied for lead ions determination from human plasma and sea water sample.