Study of the Structural, Electronic and Morphological Properties of Silver Nanoparticles for the Nano-Detection and Remediation of Heavy Metal Ions in Water

Nanotechnology is a rapidly advancing field that has seen significant developments in recent decades, leading to the creation of nanoscale materials with unique properties. Among these, nanomaterials (NMs), especially nanoparticles (NPs), have attracted considerable attention due to their distinctive physicochemical characteristics, such as a high surface-to-volume ratio, quantum properties, and their ability to interact with a wide range of compounds. These attributes make NPs suitable for diverse applications across various sectors, including medicine, electronics, environmental science, and industry. One of the key challenges in utilizing NPs effectively, especially in medical and environmental applications, is the fine-tuning of their surface properties. Functionalization of NPs through surface modification allows for the control of their behavior in different environments, influencing aspects such as stability, aggregation, and reactivity. In particular, metal nanoparticles (MNPs) such as silver nanoparticles (AgNPs) have been identified as promising candidates for applications in sensing and environmental remediation due to their unique optical properties and ease of synthesis. This PhD research focuses on the development of functionalized AgNP based systems for the detection and remediation of heavy metal pollutants in water. The project aims to achieve precise control over the stability and functionality of AgNPs by using organic ligands as capping agents. These functional molecules not only stabilize the nanoparticles, preventing aggregation, but also serve to tailor their properties for specific applications, such as the selective detection of heavy metals. In particular, AgNPs were synthesized and functionalized with ligands such as sodium citrate, L-cysteine, and glutathione, which were chosen for their ability to enhance the stability of the nanoparticles and improve their biocompatibility. The study investigates the structural, electronic, and morphological properties of these functionalized AgNPs using advanced spectroscopic techniques, including UV-visible absorption, FT-IR, DLS, X-ray photoelectron spectroscopy (XPS), and synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS). These techniques provide in-depth insights into the nature of the interactions between the metal surface and capping agents, the stability of the systems, and the adsorption behavior of metal ions, particularly cadmium (Cd(II)) and iron (Fe(III)). A key aspect of the project was the design of hybrid systems composed of functionalized AgNPs embedded in poly(ethylene glycol) diacrylate (PEGDA) membranes. These systems were investigated for their potential use as devices for water decontamination, specifically targeting mercury (Hg(II)) ions. The results showed that the functionalized AgNPs remained effective within the PEGDA matrix, highlighting the potential of these hybrid materials for practical applications in environmental monitoring and pollutant removal. This research provides valuable contributions to the field of nanomaterials, particularly in the context of water purification and pollutant detection. The findings suggest that functionalized AgNPs, when integrated into hybrid systems, could serve as effective, safe, and cost-efficient solutions for addressing water contamination, particularly with heavy metal pollutants. The study demonstrates the feasibility of designing nanomaterials that can selectively interact with contaminants, laying the groundwork for the development of next-generation devices for environmental restoration.