Removal of analgesic drugs from the aquatic environment using photochemical methods

The occurrence of analgesics in the environment can be explained by the fact that they are very popular and in common use, for example: to treat the symptoms of colds, aches and pains or for the treatment of painful diseases of rheumatic and non-rheumatic origin. Analgesic drugs are only partly removed from wastewater using the biological wastewater treatment processes. The photochemical methods are mentioned as a useful tool for the removal of analgesic medicines from the aquatic environment. The elimination of three analgesic drugs: diclofenac, naproxen and ibuprofen from the aquatic environment using UV- and UV/H₂O₂-processes was the aim of the study. All experiments were performed in the water with the presence and the absence of the urea as the main urine component. With the presence of urea the values of photo-oxidation rate constants (in the UV/H₂O₂-process) varied from 0.22 min^-1 (ibuprofen) to 0.39 min^-1 (diclofenac). The values of the photodegradation rate constants in the solution without urea (in the UV/H₂O₂-process) varied from 0.25 min^-1 (ibuprofen) to 0.45 min^-1 (diclofenac). The study showed that naproxen, ibuprofen and diclofenac may be effectively removed from the aquatic environment (e.g. from the urine) by means of photochemical methods.