Solar photocatalytic removal of arsenic from polluted water using carbon-modified titanium oxide nanoparticles supported on activated carbon

Abstract

Environmental contextContamination of water resources with arsenic is a serious environmental problem requiring efficient, viable and environmentally safe As removal processes. This study reports an arsenic remediation strategy using carbon modified titanium dioxide supported on activated carbon as a photocatalyst. The study highlights a practical process for efficient remediation of As-contaminated water under natural sunlight. AbstractCarbon-modified titanium oxide nanoparticles supported on activated carbon (C-TiO2/AC) were synthesised by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the crystal structure, surface morphology, and optical properties of the C-TiO2/AC nanoparticles. The performance of C-TiO2/AC was evaluated towards the photocatalytic oxidation of AsIII in simulated and real wastewater under illumination of both artificial UV and natural sunlight. Compared with activated carbon (AC), pure TiO2 and carbon-modified titanium oxide (C-TiO2), the combination of carbon modification of TiO2 and activated carbon (C-TiO2/AC) significantly enhanced the photocatalytic oxidation rate of AsIII. Complete removal of arsenic (2.66ppm) from wastewater was attained by using C-TiO2/AC after 150min under illumination of natural sunlight. However, the removal efficiency was declined remarkably to 58.4 and 37.3% for C-TiO2 and pure TiO2 respectively. The highest removal rate of AsIII was achieved at the optimised conditions of 1.0g L−1 of C-TiO2/AC and a solution pH of 9.