Removal of As(V) from aqueous solution by using cement-porous hematite composite granules as adsorbent

Abstract

The potential of using Portland cement-porous hematite composite granules (CHG) as a new adsorbent for the adsorption of As(V) from aqueous solution was investigated in this study. This research was performed through the measurements of adsorption isotherm, adsorption kinetics, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), scanning electron microscope (SEM) and energy dispersive X-ray detector (EDX). The pore structure of CHG was extraordinary developed with the porosity, the total pore volume and the average pore diameter being 45.48%, 0.3586 mL/g and 62.7 nm, respectively. From the adsorption batch of As(V) on porous hematite and CHG, CHG exhibited a high adsorption capacity of 9.84 mg/g for As(V), slightly lower than the porous hematite adsorbent. It was observed that CHG kept greater than 83% adsorption capacity of the porous hematite. However, CHG was convenient in solid-liquid separation after adsorption benefited from its high mechanical strength, stability in solutions and big size, which could be separated directly from the water without any other equipment and technology. As a result, this work provides a theoretical basis for the practical application of granular adsorbents to the actual As(V) sewage. Keywords: Porous hematite, Portland cement, Granule, As(V) adsorption, Solid-liquid separation