A dense SERS substrate of the AgNPs@GO compound film for detecting homocysteine molecules.

This study focuses on the development of a highly sensitive surface-enhanced Raman scattering (SERS) sensor for detecting homocysteine (Hcy) molecules. The Hcy sensor was created by depositing silver nanoparticles (AgNPs) onto the surface of graphene oxide (GO) film to form a dense AgNPs@GO composite film. The AgNPs on the composite film interacted with sulfur atoms (S) of Hcy molecules to form Ag-S bonds, which boosted the chemisorption of Hcy molecules and enabled them to be specifically recognized. The SERS sensor exhibited a maximum enhancement factor of up to 1.1 × 104, with a reliable linear response range from 1 to 60 ng mL-1. The limit of detection (LOD) for Hcy molecules was as low as 1.1 × 10-9 M. Moreover, Hcy molecules were successfully distinguished in a mixed solution of γ-aminobutyric acid and Hcy molecules. In this study, a simple preparation process of SERS substrate and a novel detection method for Hcy molecules provided a new pathway for the rapid and effective detection of Hcy molecules in the food and biomedicine fields.

Microemulsion extraction: An efficient way for simultaneous detoxification and resource recovery of hazardous wastewater containing V(V) and Cr(VI).

Vanadium (V) metallurgy industry produces significant amount of ammonium polyvanadate (APV) wastewater containing V(V) and Cr(VI), thereby polluting the ecological environment and adversely affecting human health and wasting natural resources. Herein, an efficient method for separating V and chromium (Cr) from APV wastewater is proposed based on an artful pretreatment of the selective transformation of Cr(VI) using microemulsion extraction to realize harmless treatment of the wastewater and recycling of V and Cr resources. The influence of various factors on the V and Cr extraction efficiencies has been investigated, including the extractant concentration, aqueous phase-to-microemulsion volume ratio, contact time, and temperature. Furthermore, the principle of Cr transformation and microemulsion extraction and stripping has been illustrated and the recyclability of the microemulsion has been evaluated. Under optimum conditions, 96.29 % of V(V) and 95.56 % of Cr(VI) were separately recovered from the AVP wastewater, confirming the efficient separation and recovery of V and Cr. This study highlights a new approach for the separate recovery of V(V) and Cr(VI) from hazardous wastewater and provides new insights into the simultaneous detoxification and resource utilization of industrial hazardous wastes.