title: Degradation of diclofenac in water by homogeneous and heterogeneous sonolysis.
abstract: The study is about the degradation of a widely used anti-inflammatory drug-diclofenac (DCF) by high frequency ultrasound to select the operating conditions and to improve the process efficiency by the addition of iron species. The initial concentration, pH and frequency of operation that rendered maximum degradation of the drug were 30 μM, 3.0 and 861 kHz, respectively. The efficacy (EF) of each additive was expressed by a "yield factor" defined as the change in DCF concentration in 1-h sonication per unit mass of Fe in the reactor. Estimated values of EF were 41.54, 1.65 and 0.02 μM mg(-1), respectively for non-reactive iron superoxide nanoparticles (NPI), reactive divalent iron (DVI) and reactive zero-valent iron (ZVI). The remarkably high yield in presence of NPI was attributed to the synergy of nanotechnology and ultrasound; i.e. combined effects of massive surface area, excess cavitation nuclei, enhanced mass transfer and continuous cleaning of the metal surface. Total mineralization after 90 min sonication of DCF in the presence of 8.9 mM ZVI, 0.01 mM DVI and 0.001 mM NPI were 22%, 43% and 30%, respectively. Although DVI provided a larger degree of mineralization, the efficiency of NPI was still higher owing to its 10-fold lower effective dose.
authors.affiliation: Fatih University, Department of Environmental Engineering, 34500 Istanbul, Turkey.
authors.forename: Gökce Tezcanlı
authors.initials: GT
authors.lastname: Güyer
authors.forename: Nilsun H
authors.initials: NH
authors.lastname: Ince
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D004008:Diclofenac / Q000737:chemistry*; D015394:Molecular Structure; D014465:Ultrasonics; D014867:Water / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D014867:Water; D004008:Diclofenac