Phototransformation of ibuprofen and ketoprofen in aqueous solutions

► Degradation of ibuprofen and ketoprofen was studied using UV and UV/VUV irradiation. ► Dissolved molecular oxygen changes the degradation mechanism of ibuprofen. ► The VUV irradiation accelerated the decomposition of ibuprofen only. ► Mineralization was about 60%, suggesting formation of stable aliphatic by-products. ► New by-products were identified using GC-MS and HPLC-MS. The UV (254nm) and UV/VUV (254/185nm) photolysis of two anti-inflammatory drugs, ibuprofen and ketoprofen, have been studied in aqueous solutions as a possible process for the removal of non-biodegradable compounds. We have examined the effects of dissolved oxygen and initial target concentration. Upon irradiation at 254nm, the decomposition rate of ketoprofen is almost forty times higher as it of ibuprofen whilst VUV irradiation only increased the ibuprofen decomposition rate. The presence of dissolved oxygen accelerated the photodegradation of ibuprofen, whereas no effect was observed on the degradation of ketoprofen. The maximum quantum yield for the phototransformation was 0.2. The rate of mineralization in both cases was ∼60%, even after 1h of treatment and this suggests the formation of stable by-products which were identified using GC-MS and HPLC-MS, respectively.