Adsorption profile of preheated Cr(III)-SCN complexes on polyurethane foam

Abstract

The accumulation of preheated chromium(III)-thiocyanate complexes onto polyurethane foam (PUF) has been studied. The maximum sorption of Cr(III) (7.01.10-5M) is occurred at pH 2 from 1.2M thiocyanate solution in 10 minute agitation time using 7.25 mg/ml PUF. The sorption data have been investigated by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The Freundlich parameters 1/n = 0.31 and of KF = 9.7.10-4 mol.g-1, Langmuir constants M = 7.03.10-5 mol.g-1 and of b = 1.5.105 l.mol-1 and of D-R constants, Cm = 1.91.10-4 mol.g-1, affinity coefficient b = -0.0023 mol2.kJ-2 and sorption energy E = 14.7 kJ.mol-1 have been evaluated. Thermodynamic parameters of enthalpy, entropy and Gibbs free energy suggest the endothermic and spontaneous adsorption of Cr(III)-SCN complex onto PUF at higher temperature. The influence of common anions and cations on the accumulation of chromium-thiocyanate on PUF and possible sorption mechanism of [Cr(SCN)4]- species on PUF is discussed.