Performance evaluation of metal impregnated activated carbon composite for removal of fluoride under varying solution chemistry Available to Purchase

The objectives of this study are to optimize the synthesis conditions of metals such as aluminum (Al), iron (Fe) and cerium (Ce) impregnated activated carbon composites (AC-M) for fluoride removal and to evaluate the sorption behavior of fluoride by the composite under varying solution chemistry. To achieve the objectives, several composites were prepared with different combinations of Al, Ce and Fe at different temperatures. The fluoride removal by different composites was evaluated, and the best performing composite was selected for further study. Equilibrium sorption experiments and kinetic tests were carried out. The effect of pH and the presence of different co-ions on the removal of fluoride were assessed. Based on the performances, the composites can be ranked as AC-Ce > AC-AlCe > AC-CeFe > AC-AlCeFe > AC-AlFe. The maximum sorption capacity by the AC-Ce composites is in the range of 4.1–4.6 mg/g. The equilibrium sorption follows the Freundlich isotherm model whereas the kinetics is better explained by a pseudo-second-order kinetics model (0.018–0.029 g/mg/min). The presence of bicarbonate and phosphate has a significant effect on fluoride removal efficiency. The novel AC-Ce composites have a strong buffering effect under a wide range of pH, which can make it suitable for treating drinking water.