Activated carbon based TiO2 nanocomposites (TiO2@AC) used simultaneous adsorption and photocatalytic oxidation for the efficient removal of Rhodamine-B (Rh–B)

Abstract

The availability of fresh water is limited compared to its huge consumption. Conversely, certain industries like dyes, textiles, paper, and tanning not only consume vast quantities of fresh water, but also generate significant amounts of wastewater that poses severe threats to living organisms. The present investigation focuses on the degradation of Rhodamine-B (Rh–B) as a model pollutant by using the nanocomposite based on waste scrap tire-derived activated carbon (AC) and titanium dioxide (TiO2). These nanostructures were fabricated using wet chemistry techniques. Analysis using scanning electron microscopy (SEM) revealed that the morphology of the structures remained largely unchanged even with a concentration of 6 mg of AC. X-ray diffraction (XRD) results confirmed the successful fabrication of rutile and anatase phases of TiO2@AC nanocomposite. The XPS results confirmed the presence of AC and TiO2 in the composite. Furthermore, the optical band gap of the nanocomposites decreased up to 17.17 % and 34.57 % through direct and indirect methods respectively, owing to the varying quantity of AC used. The narrowing of optical band gap and the increased surface oxygen vacancies were caused by the successive addition of AC during the synthesis of nanocomposites. This resulted in the efficient degradation of Rhodamine-B (Rh–B) using adsorption and photocatalytic oxidation. The findings demonstrate a significant influence of AC on the TiO2 catalyst in the removal of Rh–B dye. The maximum efficiency of dye removal, reaching up to 99.14 %, was achieved with the highest concentration of AC, thus demonstrating almost complete elimination of Rh–B dye. The findings suggest that the use of waste scrap tires can be effectively applied to design efficient photocatalysts for addressing the wastewater management issues.