Structural, morphological, and adsorption properties of titanium dioxide doped with Fluorine

This work is devoted to synthesizing titanium dioxide doped with Fluorine and investigating its structural, morphological, and adsorption properties. By sol-gel synthesis, samples of TiO2 from 2, 4, and 8 wt. mass of Fluorine, labeled as 2F-TiO2, 4F-TiO2, and 8F-TiO2, were created. To obtain these samples, NaF was injected into an aqueous solution of titanium aqua-complex [Ti(OH2)6]3+‧3Cl- with a pH of ~ 0.5÷1.5. XRD, IR spectrometry, low-temperature N2 adsorption-desorption isotherms, and pH of point of zero charges of as-synthesized samples were performed. A description of the structure-forming process is also given. The adsorption capacity of 2F-TiO2, 4F-TiO2, and 8F-TiO2 samples toward strontium cations was investigated. The adsorption kinetics, equilibrium adsorption, and the effect of the solution's acidity on this process were measured. It was found that 8F-TiO2 has the most potent adsorption properties toward strontium cations. The paper concludes that as the mass fraction of Fluorine atoms in TiO2 increases, the number of acid adsorption centers ≡TiOHδ+ increases. Compared to the basic sample of a-TiO2, the number of adsorption centers in the 8F-TiO2 sample increases by 3.5 times.