Biosorption of Pb(II) and Ni(II) ions by chemically modified Eclipta alba stem powder: Kinetics and equilibrium studies

ABSTRACT

Biosorption of Pb(II) and Ni(II) ions onto the Eclipta alba stem powder (EAS) was investigated in a batch system. The biosorbent was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and elemental analysis. Adsorption influencing factors like pH, adsorbent dose, initial metal ion concentration and contact time were investigated. The adsorption mechanism of Pb(II) and Ni(II) followed the pseudo-second-order kinetic model (R² > 0.998). The Langmuir isotherm model fitted well and the maximum monolayer adsorption capacity of the sorbent for Pb(II) and Ni(II) was found to be 66.2 ± 1.9 mg g⁻¹and 62.5 ± 1.8 mg g^−1, respectively. Desorption and recovery were carried out using dilute HCl solution.

KEYWORDS:

• Biosorption
• CAEAS
• lead
• nickel
• kinetics
• isotherms

Funding

The authors are thankful for the financial assistance from the Board of Research in Nuclear Sciences, Mumbai, under the Project BRNS (No: 2011/37C/31/BRNS/2480).

Additional information

Funding

The authors are thankful for the financial assistance from the Board of Research in Nuclear Sciences, Mumbai, under the Project BRNS (No: 2011/37C/31/BRNS/2480).