Photochemical Reactions of Naproxen, Ibuprofen and Tylosin

He,Yang. M.S.E., Purdue University, December, 2013. Photochemical reactions of Naproxen, Ibuprofen and Tylosin. Major Professor: Inez Hua. Pharmaceuticals and personal care products (PPCPs) include a wide range of compounds that are used extensively and sometimes daily by people. Some PPCPs have been detected in surface water (streams, rivers, lakes) due to incomplete removal in wastewater treatment plants. The water contaminated by PPCPs is harmful to aquatic organisms and human. Naproxen (NXP), ibuprofen (IBP) and tylosin (TYL) are chosen as representative PPCPs in the current research, because they are consumed in large quantities throughout the world and there is limited data about photodegradation of these compounds in aqueous solution at the wavelength of 254 nm. The combination of ultraviolet light (UV254nm) and hydrogen peroxide (H2O2) (UV/H2O2) degraded greater than 90% of the initial concentration of NXP and IBP within 3 min (k = 0.018 sec-1, k = 0.023 sec-1 for NXP and IBP, respectively). Under direct photolysis (UV254nm) and at pH = 7, 20 min of treatment was required to obtain 90% degradation (k = 0.0028 sec-1 for NXP, k = 0.0023 sec-1 for IBP). Under the same conditions, molar absorptivity (Ɛ) and quantum yield (ɸ) of each compound were determined (for NXP, Ɛ = 4240 M-1cm-1 and ɸ = 0.008; for IBP, Ɛ =299 M-1cm-1 and ɸ = 0.098). Overall, degradation rate constants increased with increasing initial H2O2 level (0 mM, 1mM and 3