Nanoparticles of KFeP2O7 implanted on silica gel beads for Cd2+ ion adsorption.

Nanoparticles of iron and potassium diphosphate (KFeP2O7) implanted in silica gel beads (SiO2) have been investigated as an alternative adsorbent for removing Cd2+ ions from aqueous solutions. Batch adsorption experiments were conducted as a function of contact time, adsorbent dosage, initial cadmium ion concentration, solution pH, and temperature. Kinetic and thermodynamic studies on the cadmium adsorption onto KFeP2O7/SiO2 include a complete analysis and discussion. The equilibrium data were well described by the Freundlich isotherm model. The adsorption kinetic of cadmium on KFeP2O7/SiO2 followed a pseudo-first-order kinetic model obtained by using nonlinear regression analysis. Thermodynamic parameters (enthalpy change, free energy change, and entropy change) indicated that the Cd2+ adsorption process was spontaneous and exothermic in nature. The results showed that the studied KFeP2O7 nanomaterial implanted in silica is an effective adsorbent for cadmium ion removal from wastewater.