Al-Impregnated Granular Activated Carbon for Removal of Fluoride from Aqueous Solution: Batch and Fixed-Bed Column Study

Fluoride pollution in water has been reported in many regions and countries. Adsorption is the most commonly used process for treating fluoride-containing water. For industrial applications, the treatment of a pollutant is normally performed in continuous column mode. In this work, batch and lab-scale column studies were conducted by applying modified granular activated carbon (MGAC) to remove fluoride (F−) from an aqueous solution. MGAC was prepared by a wet impregnation method and characterized using SEM and FTIR. Batch studies presented the adsorption of F− onto MGAC following the Freundlich model and the pseudo-second-order model, indicating the dominant adsorption was a multilayer adsorption and chemisorption process. The breakthrough time, exhaustion time, adsorption capacity, and adsorption efficiency in breakthrough curves were evaluated under varying influent F− concentrations, flow rates, and bed heights. Thomas, Yoon-Nelson, and Yan models were employed to describe the whole breakthrough behavior, showing their suitability to predict the features of the breakthrough curves of the MGAC continuous flow system.