Removal and recovery of cadmium from aqueous solutions using magnetic nanoparticle-modified sawdust: kinetics and adsorption isotherm studies

Abstract

Removal and recovery of Cd(II) was studied on sawdust modified with magnetic nanoparticles, Fe₃O₄ (MNP), from aqueous solution. MNP were prepared, loaded on sawdust, and characterized using scanning electron microscopy and surface area analyzer. The parameters for removal percentage of Cd(II) from aqueous solutions were studied such as pH, contact time, and concentration of Cd(II). Results for kinetics studies revealed that Cd(II) removal followed pseudo-second-order kinetics and the q_e calculated values (22.17 mg g⁻¹) were in close agreement with experimental values (22.45 mg g⁻¹) with a high value of correlation coefficient (R² = 0.9994). The adsorption isotherm data were followed by Langmuir isotherm model adsorption studies. The adsorption capacity (Q_o) was found to be 1,000 mg g⁻¹, 588.5 mg g⁻¹, and 403.7 mg g⁻¹ for SD-MNP, MNP, and SD, respectively.

Keywords:

• Sawdust
• Magnetic nanoparticles
• Cd(II)
• Adsorption kinetics
• Adsorption isotherm