Nanotitania crystals induced efficient photocatalytic color degradation, antimicrobial and larvicidal activity

Textile industries release tonnes of harmful toxic dyes into the environment, causing severe effects on living organisms, including humans. Mosquitoes vectors spread important diseases which cause millions of human deaths worldwide. To control mosquitoes a number of synthetic mosquitocidal agents have been employed but all these pesticides pose harmful effects to human health and non-target species and also led to resistance development in treated vectors. Microbial strains are also developing resistance to the available antibiotics, this currently represents a major public health challenge. The current study is focused on the green synthesis of titanium dioxide nanoparticles (TiO₂ NPs) using aqueous leaf extracts of Euphorbia hirta. Results suggested an efficient remedy for the above mentioned problems using TiO₂ NPs against the dye degradation, mosquito larvae and bacterial pathogens. The fabrication of TiO₂ NPs was confirmed by UV-visible spectroscopy, the biomolecules involved in the synthesis process were evidenced by Fourier transform infra-red spectroscopy (FT-IR), the crystalline structure was observed by using X-ray powder diffraction (XRD) analysis. Spherical shaped TiO₂NPs were recorded using field emission scanning electron microscopy (FESEM). Energy dispersive X-ray spectroscopy (EDX) results showed the elemental composition of TiO₂ NPs. Enhanced rate of photocatalytic dye degradation efficacy was recorded in in methylene blue (95.8%) followed by crystal violet (86.7%). Antibacterial activity assays indicated growth inhibition was highest in Staphylococcus epidermidis and Proteus vulgaris. The LC₅₀ of TiO₂ NPs and E. hirta extract on Aedes aegypti larvae were 13.2mg/l and 81.2mg/l, while on Culex quinquefasciatus they were 6.89mg/l and 46.1mg/l respectively. Overall, based on the results of the present study, the green engineered nanotitania could be considered as novel and promising photocatalytic, antibacterial, and mosquitocidal agent.