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

Abstract

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.

Keywords:

• KFeP₂O₇/SiO₂ adsorbent
• Cd²⁺ adsorption
• kinetics
• isotherms
• thermodynamics

Acknowledgement

This work was supported by the Department of Chemistry of ININ, México, through project No. CB-207 stages I and II. The authors are grateful to Marcelino Villa-Tomasa for technical help and ININ for providing necessary instrumentation facilities and financial support.