Remediation of methylene blue water solution with iodine doped TiO2 nanoparticles and their regeneration: For reuse and check phytotoxicity level of treated water

Abstract

Titanium dioxide (TiO2) is an essential metal-oxide semiconductor with unique features, such as low cost, photostability, nontoxicity, and abundance used as a photocatalyst. However, TiO2's photocatalytic activity is limited because it exclusively absorbs incoming light in the ultraviolet (UV) range. In present work, Iodine-doped TiO2 (IDT) photocatalysts were prepared employing solution-combustion process in various mol % of iodine (I), i.e., Ti1-xIxO2 (x = 0.00–0.05). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and UV–Vis Diffuse Reflectance spectroscopic (DRS) were used to characterise the synthesised IDT. DRS indicated that iodine doping increased the absorbance range while diminishing its bandgap energy. As the I doping concentration in TiO2 increased, there was a constant shift in absorbance towards the visible light area. The XRD demonstrated that the prepared photocatalysts were solely with the anatase phase of TiO2. The FTIR identified the functional groups in the prepared photocatalysts and numerous Ti–O lattice stretching and bending vibrational bands. Photocatalytic degradation of methylene blue (MB) dye was tested in a UV photochemical reactor. The 3 % IDT photocatalyst has the highest photodegradation efficiency amid all the prepared pristine and IDT photocatalysts. Regarding dye photodegradation, the synthesised TiO2 photocatalyst doped with 3 % Iodine outperformed the commercially available Aeroxide P-25 photocatalyst. Furthermore, the nanoparticles demonstrated excellent reusability in regeneration trials. A study on the germination of "Vigna Radiata" was done to determine phytotoxicity as part of the investigation into the potential use of photocatalytically treated water in irrigation. The phytotoxicity evaluation results show that the treated water has potential for use in irrigation.