Application of Porous Geopolymer Composite 1 Based on Metakaolin and Activated 2 Carbon for Removal of Hg2+ from Aqueous Solution.

Abstract

This paper reviews the application of a geopolymer composite using an easy synthesis route based on the activation of metakaolin (MK) as aluminosilicate source, and activated carbon (AC) as a porous agent, to improve porosity and adsorption capacity. The main goal of this work is to evaluate the ability of the obtained geopolymer to remove Hg²⁺ from aqueous solutions, for comparison purposes a geopolymer sample was fully synthesized with metakaolin aluminosilicates. Samples were investigated by X-ray fluorescence (XRF), Fourier transformation infrared spectroscopy (FTIR), compressive strength test, and scanning electron microscopy (SEM). The respective removal of Hg²⁺ from aqueous solutions was quantified using an inductively coupled plasma optical emission spectroscopy (ICP-OES). The pH of the solution affected significantly the adsorption of Hg²⁺ ions onto the geopolymer surface. The maximum removal efficiency of the composite was 87.6 % at room temperature and pH 5. These results suggest the use of geopolymer with activated carbon as a successfully alternative adsorbent of Hg²⁺ ions from water.