A comparative analysis of a TiO2 nanoparticle dispersion in various biological extracts

Abstract

Chemical surfactants are used for efficient dispersion of nanoparticles (NPs) but they also cause a hazard to the environment. Therefore, research is required to replace such chemicals with eco-friendly ones. In the present study, the dispersion of TiO₂ NPs in various biologically originating extracts was investigated and compared with that of sodium dodecyl sulphate (SDS), a chemical surfactant. The adsorption of extract components on TiO₂ NPs was checked and confirmed by UV-vis spectroscopy and Fourier transform infrared spectroscopy (FT-IR). Dynamic light scattering was used to analyze the particle size distribution (PSD) and zeta potential (ZP) of the TiO₂ NPs. The ANOVA test suggests that there was no difference in the PSD and ZP of the various dispersions, indicative of similar dispersion behavior. Turbiscan analysis was used to measure the stability of TiO₂ NPs in biological dispersions, which was found to be equivalent to the dispersion stability in SDS. The biodegradability of dispersions was compared using chemical oxygen demand (COD) on day 1 and 15 after inoculation with sludge in both aerobic and anaerobic conditions. The maximum biodegradability achieved among the biological extracts was 92% while the SDS showed the least biodegradability (<5%) after 15 days of incubation. Our results demonstrate the suitability of biological compounds as NP stabilizers, and strongly recommend further research work for complete replacement of chemical surfactants for environmental safeguard.