Removal of Ni(II), Zn(II) and Pb(II) from aqueous solutions using cation-exchange resin in fixed-bed column

Abstract

Breakthrough curves for the removal of Ni(II), Zn(II), and Pb(II) from aqueous solutions using cation exchange resin (Dowex 50W) were determined at dynamic conditions in a fixed-bed column under ambient temperature. The experiments and data obtained were designed and analyzed using response surface methodology, respectively. Three operating parameters: flow rate (15–25 mL min⁻¹), pH (3–9), and bed height (3–5 cm) were investigated. Fixed-bed adsorption models namely Thomas model and Bohart–Adam model were adopted to describe the dynamics of metal adsorption in the column. The obtained experimental data were fitted to these models based on the kinetic constant k_BA (mg min cm⁻³), k_TH (cm³ mg⁻¹ min), the maximum amount of metal exchange N₀ (mg cm⁻³), and the maximum adsorption capacities q_tm (mg), accordingly. The Thomas model was found to best fit all the experimental conditions studied with correlation coefficients of 0.91, 0.97, and 0.92 for Ni(II), Zn(II), and Pb(II), respectively.

Keywords:

• Cation exchange resins
• Heavy metal
• Bohart–Adam model
• Thomas model

Acknowledgment

The authors wish to acknowledge the financial support for this research from the Malaysian Ministry of Science, Technology, and Innovation (MOSTI) (Vot No. 79283), the Ministry of Higher Education (MOHE) (Vot No. 78400), and the Universiti Teknologi Malaysia (Vot No. 00L16).