Promoted Photocatalytic Activity of Green Titanium Oxide-Clay Nanocomposite Toward Polychlorinated Biphenyl Degradation in Actual Samples

This study elucidates the synthesis of an eco-friendly titanium dioxide -(TiO2)-clay nanocomposite derived from naturally occurring carbohydrates. The monosaccharide glucose and soluble starch function as both reducing and stabilizing agents in the course of the reaction. The synthesis of -TiO2-clay nanocomposites was empirically ascertained through ultraviolet-visible (UV-vis) spectroscopy, in which a discernable absorption peak at a wavelength of 360 nm and an optical band gap value of 4.3 eV was observed. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) results show an anatase phase of spherical -TiO2-clay with an average crystal size of 18.36 nm. By using energy-dispersive X-ray (EDX) and X-ray fluorescence (XRF) techniques, the detection of titanium and oxygen peaks, as well as -TiO2 compounds (58 wt%), were confirmed. Additionally, the elemental composition of the clay was analyzed, yielding insights into the production of -TiO2-clay nanomaterials. The results obtained for the BET values pertaining to the specific surface area, mean pore diameter and pore volume are 47.48-m(2) g(-1), 17.39 nm, and 0.19 cm(3) -g(-1), respectively. -TiO2-clay nanocomposite demonstrated superior photocatalytic efficiency toward photodegradation of poly polychlorinated biphenyl pollutants owing to high amounts of turnover number, the turnover frequency, and the proficient photogenerated electron-hole separation caused by wider bandgap energy. In the real samples of industrial wastewater, the degradation rate of 2,2',5,5'-tetrachlorobiphenyl (PCB-52) pollutant by TiO2-clay was 98.32%, greater than 18%, and 25.72% compared to bare TiO2 NPs and pristine clay material, respectively. It is found that catalytic activity of TiO2-clay nanocatalyst maintain up to 93% after six photodegradation cycles. Immobilization of optical TiO2 nanoparticles (NPs) on clay minerals significantly improves the recovery and photocatalytic activity of TiO2 NPs. The mechanism of photocatalytic performance of clay-supported TiO2 was also discussed.

Automated summary

This study demonstrates the synthesis and characterization of an eco-friendly titanium dioxide (TiO2)-clay nanocomposite derived from naturally occurring carbohydrates. The nanocomposite shows a discernable absorption peak in the UV-vis spectrum and an anatase phase in the TEM and XRD results. The TiO2-clay nanocomposite exhibits superior photocatalytic efficiency for the degradation of PCB-52 pollutant compared to bare TiO2 NPs and pristine clay material, and maintains high catalytic activity after multiple photodegradation cycles.