Surface sensitization of TiO2 via Pd/Rb2O cocatalysts: Mechanistic insights to the arsenic elimination from ground drinking water

In order to abide the regulations put forth by World Health Organization (WHO), it is imperative to employ innovative technique that can eliminate arsenic from ground drinking water. The effective sorbents are desperately needed to remove arsenic from the water. In this work, rutile TiO2 surfaces were tuned with nominal ratios of palladium and rubidium oxide cocatalysts via co-precipitation method. Firstly, As (III) contents were converted to As (V) by photooxidation reaction (POR) and then As (V) contents were removed by adsorption over Pd/Rb2O@TiO2 surfaces. The morphology, optical characteristics and structural features were obtained by XRD, Raman, UV-Vis/DRS, SEM, PL and TGA analysis. The surface characteristics and chemical compositions of Pd/Rb2O@TiO2 were obtained using TEM and XPS analysis. Arsenic contaminated water samples were collected from Hasilpur Tehsil (Punjab/Pakistan). The mechanism of As (III) to As (V) conversion, adsorption kinetic for pseudo-second-order (R2꞊0.99919), and the Langmuir adsorption isotherm kinetic model (R2꞊0.98906) provided the significant clarification. Spontaneous arsenic adsorption has been determined (ΔG=−12.52 KJ/mol), which addressed the substantial columbic interactions between adsorbate and substrate. Due to non-toxic nature, dual feautres (photocatalysis and adsorption), easy accesability and low cost, the utilization of titania based sorbents appear to be viable options for arsenic removal technologies. The results of this study depict that, Pd/Rb2O@TiO2 can effectively remove 99% arsenic from contaminated water. [Display omitted] •Modified rutile TiO2 surfaces with nominal ratios of Pd/Rb2O cocatalysts via co-precipitation technique.•Influence of Pd/Rb2O loading over TiO2 surfaces were characterized by XRD, Raman, UV-Vis/DRS, SEM,TEM, XPS, and TGA.•As (III) contents were converted to As (V) by photooxidation reaction.•Adsorption of As (V) was examined by adsorption-isotherm models.•Langmuir isotherm model (R2 = 0.98906) and pseudo-second-order (R2꞊0.99919) provided significant clarifications.