Removal of Pb(II) from aqueous solution using a new zeolite-type absorbent: Potassium ore leaching residue

Abstract

The ability of potassium ore leaching residue to adsorb Pb(II) from aqueous solution related to the wastewater from lead smelter was assessed. The X-ray diffraction pattern of the residue shows that it is a zeolite-type material and is mainly composed of faujasite and cancrinite. The characteristics of the Fourier-transform infrared spectra of the residue are consistent with those of zeolite. The pseudo-second-order kinetic model was found to describe Pb(II) adsorption kinetics well. The effects of contact time, residue dosage, and equilibrium pH on adsorption were investigated under batch test conditions. The adsorption process was relatively quick and equilibrium was achieved after 60 min of contact time. The maximum removal of Pb(II) (99.6%) was observed at an equilibrium pH of 7.3 with a residue dosage of 2.5 g L−1. The Langmuir model was found to describe the Pb(II) adsorption isotherm well. The maximum adsorption capacity (qm) of the residue was 25.88 mg g−1. Polyacrylamide was determined to be the optimum flocculant for the settling of the residue loaded with lead. The experimental results indicate that potassium ore leaching residue is a promising adsorbent for the treatment of Pb(II)-contaminated wastewater.