Aluminium-iron-amended activated bamboo charcoal (AIAABC) for fluoride removal from aqueous solutions

In this study, the adsorption potential of aluminium-iron-amended activated bamboo charcoal (AIAABC), prepared from waste bamboo, for defluoridation of drinking water was investigated. The adsorbent (AIAABC) in which ABC was impregnated in AlCl3/FeCl3 solution and treated at 400 °C showed higher fluoride uptake capacity. The samples obtained were characterized and tested in batch mode. Inorganic particles were dispersed on the surface of carbon as indicated by SEM images and EDS. The main elements found in AIAABC were carbon, oxygen, aluminium, iron, sodium, and sulfur. Fluoride was associated with the aluminium hydro(oxide) (AO) particles in the pore spaces of ABC after adsorption. Specific surface area (SSA) was reduced from 80.5 to 3.7 m2/g, when ABC was impregnated with AO, indicating that the AO particles might cover the surface or pore spaces found in ABC. Maximum adsorption occurred at pH range from 5 to 9. The adsorption data were well fitted to Langmuir isotherm model with a maximum adsorption capacity of 21.1 mg/g. The adsorption process obeyed a pseudo-second-order rate equation. The adsorbent was effectively regenerated (85.7%) by 0.1% NaOH. Due to its high adsorption capacity compared to commercially available aluminium hydroxide-based adsorbents, AIAABC is a highly promising material for defluoridation of drinking water.