Evaluation of sol-gel-modified activated alumina adsorbent for arsenic removal from drinking water

In this research work, the feasibility of using sol-gel-activated alumina (sol-gel AA) for arsenic (As) removal from drinking water was evaluated. The sol-gel AA was modified by incorporating calcium oxide (CaO-AA) and zinc oxide (ZnO) nanoparticles (nanogel AA) and by drying it with supercritical carbon dioxide (CO2) (aerogel AA). Equilibrium adsorption studies were conducted to evaluate the As removal efficiency of the prepared and modified AA adsorbents. Results on As adsorption demonstrated that nanogel AA provides better adsorption performance. The high As adsorption capacity of nanogel AA is attributed to the enhanced pore textural and surface properties and to the pH independence of the adsorbent. The Freundlich adsorption isotherm fitted well to As adsorption on the AA adsorbents tested. Breakthrough column studies conducted in the laboratory suggested that sol-gel AA will treat a total of about 80,000 BV (736 liters of water) before reaching column saturation. Among the adsorbents prepared, nanogel AA emerged as a promising material for the removal of As from acidic and basic natural water environments.