Biosorption of Cr⁶⁺ from aqueous solution by sugarcane bagasse

Abstract

The biosorption characteristics of Cr⁶⁺ from aqueous solution using sugarcane bagasse (SCB) were investigated. Experimental parameters affecting the biosorption process, such as pH, contact time, initial metal concentration, and temperature were studied. The equilibrium nature of Cr⁶⁺ biosorption at different temperatures was described by the Freundlich, Langmuir, Sips, and Dubinin–Radushkevich isotherms. The biosorption isotherm of SCB for Cr⁶⁺ followed the Langmuir model, and the maximum biosorption capacity of Cr⁶⁺ obtained was 1.76 mg/g at 25°C. The biosorption kinetics of Cr⁶⁺ onto SCB followed the pseudo-second-order model. The calculated thermodynamic parameters (ΔG, ΔH, and ΔS) showed that the biosorption of Cr⁶⁺ ions were feasible, spontaneous (ΔG = −21.52 kJ·mol⁻¹), and exothermic (ΔH = −6.364 kJ·mol⁻¹) at the temperature range of 25–65°C.

Keywords:

• Sugarcane bagasse
• Biosorption
• Heavy metals
• Equilibrium isotherm
• Kinetic

Acknowledgment

The authors are grateful to the alpha BIOPROAM Program Contract No. AML/190901/06/18414/II-0548-FC-FA.