The diversified mechanism of adsorption and electro-adsorption technologies by using Ti3AlC2 for removing fluoride

Fluoride is a common pollutant from nature, normal life, and production. Adsorption, electro-adsorption, and precipitation are dominant mechanisms corresponding to the adsorption and electro-adsorption technologies for removing fluoride. This paper presents Ti 3 AlC 2 as an effective reagent for removing fluoride under acidic conditions. The adsorption mechanisms of adsorption and electro-adsorption were compared to sedimentation at pH 2 and 1, leading to a higher removal rate of adsorption by pH 2 than at pH 1. The adsorptive behavior of Ti 3 AlC 2 with fluoride includes both multilayer sorption and chemisorption. Furthermore, the precipitation reaction induced a partial change of Ti 3 AlC 2 to MXene. Notably, electro-adsorption was more effective rather than sedimentation at pH 1 in capacitive deionization technology. The Al adsorption sites made it easier to combine fluoride than Ti, and aluminum fluoride was easier to produce than titanium (III) fluoride. These adsorption and electro-adsorption experiments were carried out to elucidate and delineate the performance of Ti 3 AlC 2 for removing fluoride. A molecular model of Ti 3 AlC 2 was also built to calculate adsorption using the density functional theory. Hence, the Ti 3 AlC 2 molecular model combined with XPS and other characterizations of materials provided an effective, easy-to-understand combinative mechanism for removing fluoride.