| Start Date: | 3 октомври 2026 |
| End Date: | |
| Project Leader: | Hristo Kolev |
| Budget: | 350 000,00 лв. |
Abstract
The provision of clean and safe water is one of the major environmental and societal challenges of the present day. Persistent organic pollutants, including dyes released by the textile industry, antibiotics and their metabolites, may adversely affect aquatic organisms even at very low residual concentrations. Their removal by conventional physicochemical and biological treatment methods is difficult because of their low concentrations, chemical stability and inhibitory effects on biological wastewater-treatment processes. Tribocatalysis is an emerging mechano-electrochemical advanced oxidation process in which mechanical energy is used to generate triboelectric charges and reactive oxygen species. These species can participate directly or indirectly in the oxidation and complete mineralisation of organic pollutants into CO₂ and H₂O. The process may be performed under mild conditions in aqueous media, including optically dense systems in which the application of photocatalytic methods is limited. The main objective of the project is to investigate the tribocatalytic activity and reaction mechanisms of ZnO-based nanocomposites during the removal and complete mineralisation of model organic pollutants, particularly antibiotics and organic dyes. The possibility of developing highly efficient tribocatalysts by doping or surface-functionalising ZnO with rare-earth ions and/or oxides will be examined. The ZnO-based materials will be prepared by sol-gel, hydrothermal, mechanochemical and sonochemical methods to obtain materials with different morphologies, crystallinities and defect structures. Two rare-earth modification strategies will be compared: incorporation of rare-earth ions into the ZnO bulk and surface deposition of rare-earth oxides. The planned modifying elements include La, Ce, Eu, Sm and Nd, while the Ln/Zn ratio will be systematically varied. The prepared materials will be comprehensively characterised using XRD, Raman spectroscopy, SEM-EDS, TEM, XPS, EPR, UV/Vis, fluorescence and infrared spectroscopy, electrochemical impedance spectroscopy and measurements of the piezoelectric coefficient d₃₃. These investigations will reveal the relationships between synthesis method, morphology, phase and chemical composition, electronic and piezoelectric properties, and tribocatalytic activity. Tribocatalytic efficiency will be evaluated by monitoring the degradation of model organic dyes and antibiotics in aqueous media under dark conditions and mechanical stimulation. The planned model pollutants include methylene blue, rhodamine B, methylene green, doxycycline, sulfamethoxazole and ciprofloxacin. The roles of tribogenerated electrons and holes, reactive species such as •OH and O₂•⁻, reaction intermediates and rate-determining steps will be investigated. The effects of practically relevant parameters, including pH, temperature, water hardness, inorganic salts and the intensity of mechanical stimulation, will also be evaluated. The stability of the tribocatalysts during repeated use and possible changes in their phase and surface chemical composition will be examined. The expected results will provide a deeper understanding of the fundamental mechanisms governing tribocatalysis and support the development of sustainable ZnO-based materials for the removal of organic pollutants from water. The project also envisages the construction of a specialised electrochemical cell for measuring triboelectric potentials under mechanical stimulation in aqueous media.Назад...
