UV photodegradation and kinetics experiments of ofloxacin in water

This research analyzes how direct UV photolysis and advanced oxidation processes remove fluoroquinolones from water in treatment plants. The presence of ofloxacin in water can cause environmental effects or health problems to humans and animals. This research explores a possible treatment technology that will help remove pharmaceuticals at a lower cost than reverse osmosis. It was hypothesized that when treating water samples containing the fluoroquinolone by using Advanced oxidation processes (AOP) the fluoroquinolone is removed more effectively. For this experiment, 0.5mM aqueous samples of ofloxacin were prepared. Samples were irradiated for 30 minutes using a UV lamp with a light of 280 nm. Direct UV photolysis and indirect photolysis experiments involving ferrous sulfate heptahydrate and hydrogen peroxide were done on the samples. The presence of ferrous sulfate heptahydrate caused a faster degradation in the pharmaceutical. The k value for the direct photolysis on ofloxacin was 0.0011 and for the indirect photolysis using ferrous sulfate heptahydrate the k value was 0.0262. AOPs appear to be efficient in removing fluoroquinolones in water. It was observed that direct photolysis degraded ofloxacin at a slower rate than indirect photolysis. Indirect photolysis transforms a molecule or sensitizer by radiation. Consequently, causing changes or degradations in the pharmaceutical of interest through the transmission of energy that occurs. Kinetic experiments were done to measure the production of oxygen singlet and hydroxyl radical. It was concluded after several runs with terephthalic acid that the reaction does not produce hydroxyl radical. However, singlet oxygen is present in the water after being radiated with UV light. Singlet oxygen is a reactive species in AOPs. In addition, future experiments will be done in different water matrices to see what conditions cause a faster and more effective degradation of the pharmaceutical. This research emphasizes on finding a way to help remove or degrade the concentration of these pharmaceuticals in order to prevent health and environmental damage.