In this work, the biological enrichment of TiO 2 nanoparticles (NPs) by Salvinia natans was studied, and the EDXRF technology was used to evaluate the ability of Salvinia natans to enrich TiO 2 NPs. At the same time, with the accumulation of TiO 2 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 TiO 2 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 TiO 2 NPs concentration (20 mg/L) to saturation. By calculating the bioconcentration factors (BCF), the enrichment ability of TiO 2 NPs in S. natans was evaluated. It was found that the enrichment effect of Salvinia natans on TiO 2 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 TiO 2 NPs have a positive effect on the growth and development of Salvinia natans. Besides, the reduction of Fe might indicate that the absorption of TiO 2 NPs affects the bioaccumulation of metal ions in Salvinia natans.
The current study aimed to determine the major and minor elements in different algal species using energy dispersive x-ray fluorescence (EDXRF). Eight microalgae were isolated, and the dry powder of biomass was pressed for EDXRF. The results showed all chemical compositions in each of the isolates. The major elements were detected as Ca, K, Cl, Si, Mg, and Mn, respectively, with high concentrations in percentages for most algal species including Chara hispida, Chara spp , Chlorella vulgaris, Chlorella spp , Chlorella spp , and Spirogyra turfosa. The minor elements with low percentages were detected as Mn, S, Fe, Al, P and Sr. Whereas the major elements for Spirulina platensis and Nostoc punctiforme were detected as Fe, K, S, the minor elements were seen to include Ca, Cl, Si, Mg, and Mn. There are very few studies that determine the elements in microalgae with EDXRF, which is a rapid, easy method to determine what components and in what quantities they are contained to be used (no chemical pre-treatments are required). Algae contain elements like iron, and calcium, which are vital microelements for dietary intake and metabolism in humans. Algae could be useful if further studies are done on the efficiency of microalgae for calcium and iron absorption in human subjects.
The silicon-aluminum ratio of the molecular sieves is a crucial control index for the quality of synthetic molecular sieves. Here a fast, simple and reliable sample preparation method, referred to as pouring and curing method, is described for determining the silicon-aluminum ratio of high silicon molecular sieves by energy dispersive x-ray fluorescence (EDXRF). Resin is used as the carrier with the addition of a curing agent, so that the sample powder is embedded in the resin matrix. By measuring sixteen random positions of the same cured sample, the homogeneity of the sample was evaluated to ensure the stability of the results. A double logarithmic calibration curve of the analysis line ratio and the corresponding concentration ratio of silicon and aluminum was established according to the binary ratio method. The results by EDXRF and inductively coupled plasma-optical emission spectrometer (ICP-OES) were compared with a relative standard error from 2.934 to 6.777%. The good precision shows that the pouring and curing method is a suitable for measuring the silicon-aluminum ratio of molecular sieves.
危险品化学品经营许可证（带存储）