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

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.