Photoactive multi-component nanosystems for the degradation of organic pollutants in wastewater
Our goal is to synthesize functional nanostructured materials as efficient photocatalysts for the degradation of target molecules (e.g.: dyes and drugs) in wastewater. We seek systems meeting the requirements for a good photocatalyst such as low-cost, ease of synthesis, ability to exploit solar light, good stability, and recoverability. We analyze and identify their properties, their activity and stability by performing photocatalytic tests under UV and simulated solar light.
In our field of research, we are moving to solve one of the most pressing issues: water contamination. Several technologies can be used for wastewater treatment, based on physical, biological, and chemical methods, that bring to a complete oxidation or degradation of contaminants. Among all chemical treatments, there are the so-called advanced oxidation processes (AOPs) which appear to be the most promising due to their several advantages. Based on the reaction conditions, AOPs include different class of processes among which photocatalytic oxidation and photo-Fenton oxidation processes, being investigated by our research group.
Mention should also be made of heterogeneous photocatalysis, that is based on the redox capability of a catalyst when irradiated with light. Generally, semiconductor materials are used as photocatalysts in aqueous solution to degrade pollutants. In fact, their peculiarity is to have a suitable band gap that can be easily activated by light, bringing to the formation of excitons (e- — h+ pairs). This is a crucial step: the higher the production of excitons, the higher the creation of radicals, the latter fundamental for the degradation of pollutants. In this regard, many aspects and parameters may impair the efficiency of a photocatalysts, hence the need to develop highly stable and easily recoverable photocatalysts with appropriate optical properties, catalytic activity and selectivity.
To overcome these challenges, it is essential to rationally design a photocatalyst. Therefore, we are working on the synthesis and the development of hierarchical and shape-selected nanomaterials as new photocatalyst prototypes. To achieve this, we employ different methods to optimize the overall efficiency of the system, such as creation of homo- and hetero-junctions, doping, and structural modulation. We combine different synthesis techniques among which: hard-template sol-gel method, solvo/hydrothermal synthesis, and vacuum and physical deposition techniques (e.g.: CVD and magnetron sputtering).
Currently, we are investigating the photocatalytic oxidation and photo-Fenton oxidation reactions in the presence of Methylene Blue, Methyl Orange, Rhodamine B, Ciprofloxacin, Metrodinazole, Tetracycline, Carbamazepine, and Ibuprofen. Our aim is to investigate and identify the most important properties and to achieve mechanistic understanding by using different characterization techniques.