EDXRF analysis of TiO2 nanoparticles bioaccumulation in aquatic plant, Salvinia natans

In this work, the biological enrichment of TiO2 nanoparticles (NPs) by Salvinia natans was studied, and the EDXRF technology was used to evaluate the ability of Salvinia natans to enrich TiO2 NPs. At the same time, with the accumulation of TiO2 Nps in Salvinia natans, the changes of nutrient elements (P, S, Ca, Fe, and Zn) in its leaves and root tissues of Salvinia natans were observed simultaneously. The experimental results indicate that the Salvinia natans showed a strong potential to enrich the TiO2 NPs. It had accumulated about 14.9 mg/g and 2.2 mg/g of titanium in roots and leaves when they were cultured in the highest TiO2 NPs concentration (20 mg/ L) to saturation. By calculating the bioconcentration factors (BCF), the enrichment ability of TiO2 NPs in S. natans was evaluated. It was found that the enrichment effect of Salvinia natans on TiO2 NPs showed negative correlation with the culture concentration. As to nutrient elements, the contents of P, S, and Ca in the roots and leaves were significantly increased with the increase of Ti enrichment. It might mean that the TiO2 NPs have a positive effect on the growth and development of Salvinia natans. Besides, the reduction of Fe might indicate that the absorption of TiO2 NPs affects the bioaccumulation of metal ions in Salvinia natans.