Diploma Thesis Defense by Mrs. Marias Sotiropoulou
Thesis Title: ««Photolysis of nicotine in leachates produced from used and unused tobacco products»
Friday 11 December 2020, at: 13:00,
Link: https://tuc-gr.zoom.us/j/86453405267?pwd=ZTBQN0w2aHI2Sy9GeEpYNjZPcTRnZz09
Examination Committee
- Professor Elia Psillakis (advisor)
- Associate Professor Danae Venieri
- Professor Nicolas Kalogerakis
Abstract
Nicotine is an emerging contaminant widely detected in the aquatic environment. The main sources of nicotine are human excretions and leaching from discarded tobacco product waste. To this end, cigarette butts are the most commonly littered item in urban areas, coasts and shorelines. In this study, the fate of nicotine in natural water and leachates produced from conventional cigarettes (CCs) and the new generation heat-not-burn (HnBs) tobacco products is examined. The effect of UV254 irradiation on nicotine depletion in ultrapure water was initially studied. The reaction was pseudo first-order with respect to nicotine concentration at low concentrations and shifted to lower order at higher concentrations, an effect associated to absorption saturation. The chemical structures of transformation intermediates were derived by means of liquid and gas chromatography coupled to mass spectrometry. The photodegradation kinetics was found to depend on pH and faster kinetics were recorded when the monoprotonated form of nicotine was dominant (pH=5-8). Leachates from used HnBs and smoked CCs were also submitted to UV254 irradiation and direct photolysis was found to proceed in only slightly slower kinetics despite the complexity of these matrices. Tobacco product waste leachates were also submitted to simulated solar irradiation and the conversion of nicotine was monitored for 260 min. These experiments confirmed the importance of indirect photolysis under sunlit conditions even in highly complex matrices. We take advantage of these investigations and report the leaching behavior of nicotine form HnBs and CCs. These studies highlight the importance of safely disposing tobacco product waste after operation to prevent nicotine leaching.
