Preparation, characterization and application of polyurethane foam functionalized with α-naphthol for preconcentration and determination of trace amounts of nickel and copper in cast iron and granite

Polyurethane foam functionalized with α-naphthol was synthesis by covalently linking them through an N N group. The characterization of 1-naphthol bonded to polyurethane foam (1-Nap–PUF) and the sorption behaviour of Ni 2+ and Cu 2+ on 1-Nap–PUF have been investigated. The optimum pH ranges for quantitative sorption were 6–10. The kinetics of sorption of the metal ions by the 1-Nap–PUF were found to be fast, reaching equilibrium in few minutes (5–10 min) and followed a first-order rate equation with an overall rate constant k in the range 0.16–0.22 min −1. The numerical values of thermodynamics parameters enthalpy (Δ H), entropy (Δ S) and Gibbs free energy (Δ G) indicated the exothermic and spontaneous nature of sorption. The sorption data followed Freundlich and Dubinin–Radushkevich (D–R) type sorption isotherms. The average value of the sorption free energy Δ E = 9.84 kJ mol −1 indicating ion exchange or chelations type chemisorption. The capacities of 1-Nap–PUF were 0.22 and 0.2 mmol g −1 for Ni 2+ and Cu 2+, respectively. The 1-Nap–PUF was used to determine these metal ions in iron, granite. On the basis of these parameters, the sorption mechanism was discussed.