Carbon-Enhanced Aluminum-Based Adsorbent for Highly Efficient Removal of Fluoride Contamination from Water

Abstract Excessive fluoride presence in water poses significant environmental and public health risks, necessitating the development of effective remediation techniques. Conventional aluminum-based adsorbents face inherent limitations such as limited pH range and low adsorption capacity. To overcome these challenges, we present a facile solvent-thermal method for synthesizing a carbon-doped aluminum-based adsorbent (CDAA). Extensive characterization of CDAA reveals remarkable features including substantial carbon-containing groups, unsaturated aluminum sites, and a high point of zero charge (pH pzc ). CDAA demonstrates superior efficiency and selectivity in removing fluoride contaminants, surpassing other adsorbents. It exhibits exceptional adaptability across a broad pH spectrum from 3 to 12, with a maximum adsorption capacity of 637.4 mg/g, more than 110 times higher than alumina. The applicability of the Langmuir isotherm and pseudo-second-order models effectively supports these findings. Notably, CDAA exhibits rapid kinetics, achieving near-equilibrium within just 5 minutes. Detailed analyses employing FTIR and XPS provide profound insights into the underlying mechanisms governing the adsorption process, which is facilitated by the active involvement of carbon-containing functional groups. The exceptional attributes of CDAA establish its immense potential as a transformative solution for the pressing challenge of fluoride removal from water sources.