Study Of Using Bentonite – Poly Ethylene Glycol Composite for Metal Removal from Water

Abstract

Direct polymerization of polyethylene glycol (PEG) in suspensions of Bentonite (Ben) was used for preparation of Ben-PEG composite. The prepared composite was characterized using field-effect scanning electron microscopy, surface area measurements, and X-ray diffraction. In the XRD pattern there is a change in peak intensity. But New peaks appeared. This may be due to high dispersion of particles of polymer in the Ben matrix or low concentration of the modifying agent. The crystallinity absence after loading the sorbent with cadmium and lead ions in the SEM measurement indicates that there was no crystalline phase after sorption. The optimal conditions for adsorption of Cd2+ and Pb2+ ions were found to be a PEG content of 0.2 % and a contact time of 150 min. The sorption experiments were performed under different operating variables, including, pH, adsorbent dose and initial concentration of metals. For both Cd2+ and Pb2+, Adsorption parameters were determined using both Langmuir and Freundlich isotherms, but the experimental data were better fitted to the Langmuir equation than to Freundlich equation. The adsorption equilibrium was described by the Langmuir model, which confirmed the presence of saturated mono-layer of adsorbent molecules on the adsorbent surface, that the energy of adsorption is constant. The potential of Ben-PEG composite for the removal of cadmium and lead from aqueous solution was substantiated.