Diploma Thesis Defense by Mrs Eftathia Varkouta
Thesis Title « Photolysis of benzophenone-3 in the presence of dissolved salts and in real water samples »
Friday February 12 2021, at: 11:00, Venue: : Link Zoom Meeting
Link: https://tuc-gr.zoom.us/j/84147691203?pwd=bDZabHBUYStzZ3lMMWJpQ1l4WE9IUT09
Meeting ID: 841 4769 1203
Password: 458236
Examination Committee
- Professor Elia Psillakis (advisor)
- Associate Professor Danae Venieri
- Associate Professor Paraskevi Panagiotopoulou
Abstract
Benzophenone-3 (BP-3) belongs to a widely used class of organic UV filters, called benzophenones. The main feature of this compound is the high photostability it has and because of that it is incorporated in a wide variety of products that people use daily, such as sunscreens and other cosmetics. However, after dermal applications of these products, BP-3 is absorbed by the human body and this causes its detection mainly in urine but also in breast milk, placenta, blood plasma and semen. It has anti-androgenic and estrogenic activity in humans and it can also cause allergies. Besides that, it is metabolized in the human body, creating metabolites that in some cases are more toxic than BP-3. As for the surface waters, BP-3 has been detected in lakes, rivers, swimming pool and sea water. Consequently, it is bioaccumulated in several aquatic organisms and has serious consequences for them. In the present project the photodegradation of BP-3 in aqueous samples, which were irradiated with UV-C radiation (254 nm), was studied. Photolyzed samples were analyzed using a liquid chromatograph coupled to a mass spectrometer. The results of the experiments showed that change of the initial concentration affects the photodegradation rate of the compound, as concentration increase led to decrease in the rate. It was also found that the addition of sodium chloride in the aqueous solution resulted increase of the rate. Finally, the BP-3 photolysis experiments in river and sea water showed that the rate of its photodegradation in river water is slightly faster than that in ultra-pure water, while in seawater the decomposition of the compound takes place much faster. The chromatograms from the analysis using the liquid chromatograph showed more peaks other than those that correspond to the testing substance, which belong to by-products formed during the photolysis of the samples in some cases.
