Removal of Cd(II) onto Raphanus sativus peels biomass: equilibrium, kinetics, and thermodynamics

Abstract

Raphanus sativus peels (RSP) biomass for the adsorptive removal of Cadmium (II) has been studied. The effect of different experimental parameter like pH, temperature, contact time, and initial concentration has been reported. The equilibrium adsorption data were subjected to different adsorption isotherms (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Flory-Huggins isotherm, and Brunauer, Emmet and Teller isotherms), for kinetic studies pseudo-first-order, pseudo-second-order, Banghams’s model, and intraparticle diffusion kinetic models were applied. The experimental results indicated that the adsorption of Cd(II) followed monolayer adsorption model and pseudo-second-order kinetics. The change in thermodynamic parameters like free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) was also evaluated. It was found that the RSP exhibits good adsorption capacity for Cadmium (II) from aqueous solution.

Keywords:

• Raphanus sativus
• Bioadsorbent
• Kinetics
• Thermodynamics
• Equilibrium
• Cadmium (II)

Acknowledgments

The authors highly acknowledge the financial assistance from Higher Education Commission, Pakistan for the present work. Some of the research facilities were utilized from Department of Geology and University of Malaya Centre for Ionic Liquids (UMCiL), through research grant HIR UM-MOHE F00004-21001.