Sensors made with polysulfide nanocomposites to detect mercury

• Grant number: 23/08862-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2024
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Osvaldo Novais de Oliveira Junior
• Grantee: Stella Fortuna do Valle
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis, AP.TEM

Abstract

Mercury (Hg) contamination affects the environment and human health, which makes Hg detection essential. Elemental sulfur (S8), an abundant residue with affinity for Hg, can be used in the detection. However, it has low conductivity and is difficult to process. The inverse vulcanization technique of S8 with alkenes, proposed in this project, circumvents these issues, producing versatile and functional polymers. Polysulfides have been studied in Hg adsorption, but not in sensors. For its effective use, there are challenges such as the residual S8 content in the materials and the limited choice of alkenes for the reaction. In this project, an optical and electrochemical sensor with polysulfides will be developed to detect Hg. A synthesis route of polymeric nanocomposites will be used from the inverse vulcanization of S8 with alkenes linked to conductive nanoparticles of MoS2. This strategy allows the incorporation of properties to the polysulfides and reprocessability of the nanocomposite without segregation of the nanoparticles. For electrochemical sensors, the nanocomposites will be deposited by casting or spin-coating on FTO working electrodes and tested by different voltammetric techniques. In optical sensors, the colorimetric effects will be analyzed by UV-Vis spectroscopy.