Photodegradation of acetaminophen on titania fibers prepared by electrospinning

The presence of pharmaceutical emerging pollutants in water can result in severe negative consequences on the environment and animal and human health. Among the different technologies to degrade these organic compounds, advanced oxidation techniques have attracted great interest in the scientific community, with special remark to solar photocatalysis which can be applied directly with solar light and without any addition of chemical compounds. In the current study, the photodegradation of acetaminophen, as model pharmaceutical emerging pollutant, under simulated solar irradiation was investigated using titania-based fibers prepared by the electrospinning technique, this offers an operational advantage considering its ease of separation from the reaction medium once the contaminant is degraded. The fibers were calcined at two different temperatures, 350 and 500 degrees C, which resulted in substantial differences in their physicochemical properties. Characterization revealed that the fibers calcined at the lower temperature exhibited higher porosity (A(BET) > 75 m(2)/g), a carbon-rich surface composition (ca. 20 % measured by XPS) and a distinct crystallographic structure. The photocatalytic activity of the calcined fibers was assessed, showing how the carbon content and the rutile-anatase ratio directly influenced the photocatalytic activity of the fibers. In this sense, the fibers treated at lower temperature presented a higher pseudo-first order kinetic constant (0.048 min(-1)) for the acetaminophen photodegradation. The remarkable photocatalytic activity of fibers with higher carbon and anatase content in their structure was exploited for their novel use in continuous reaction systems, including both stirred tank and plug flow reactor configurations. High stability over extended reaction times was demonstrated for the fibers, further underlining their suitability for these types of applications.