Removing lead from aqueous solutions using different low-cost abundant adsorbents

Abstract

The removal of Pb(II) ions from synthetically prepared solutions by different low-cost adsorbents (waste polyurethane foam, Slovak bentonite, and zeolite) was investigated. The adsorption experiments were carried out under a batch process with the concentration of Pb(II) ions, amount of adsorbent, pH, and time as the variables. Adsorption was strongly dependent on the pH of the medium, with the uptake of Pb(II) increasing as the pH increased from pH 1.5 to 5.0, after which the experiments could not be continued due to the decreasing solubility of Pb(II). The adsorption was very fast at low coverage, and equilibrium was approached within 60 min. The results best fitted the second-order kinetic model, with the rate constant in the range of 3.0 × 10⁻²–2.9 g/mg min. The Langmuir maximum adsorption capacity of the waste polyurethane foam, zeolite, and bentonite was found to be 14.1, 43.9, and 48.1 mg/g, respectively.

Keywords:

• Bentonite
• Zeolite
• Waste polyurethane foam
• Adsorption
• Lead

Acknowledgment

This work was supported by the Slovak Grant Agency VEGA [1/0538/15].