Synthesis, characterization of iron-doped TiO2(B) nanoribbons for the adsorption of As(III) from drinking water and evaluating the performance from the perspective of physical chemistry

Abstract

In this study, iron-doped TiO2(B) nanoribbons (Fe-TiO2(B) NR) have been synthesized using the anatase TiO2 as a precursor. The formation of TiO2(B) with the monoclinic crystal system was confirmed by HRTEM, SAED pattern, and XRD analyses. The ESR and XPS analyses further revealed the presence of Ti3+ and oxygen vacancies in Fe-TiO2(B) NR. The Fe-TiO2(B) NR, as an adsorbent, exhibited a fantastic performance in adsorbing As(III) from potable water at near-neutral pH. More than 94% of removal efficacy was observed for all the studied As(III) concentrations (50, 100, 250, 500, 750, and 1000 ppb) at 1 g L−1 dose at 30, 40, and 50 °C temperatures in dark condition. Irradiation with visible light, however, diminished the removal efficacy to ~88%. The Sips, the Toth, and the D-A isotherm model-based approximate site energy distributions had taken the unimodal quasi-normal distribution pattern. Nevertheless, the density functional theory (DFT) calculations showed that the adsorption of H3AsO3 is highly favourable on the (001) crystal plane of monoclinic TiO2(B). Moreover, the DFT calculations meticulously suggested the exothermic nature of the adsorption process and the chances of oxidation of H3AsO3 on the (001) crystal plane of monoclinic TiO2(B), which was further vindicated by XPS analysis.