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.

Factors that have an effect on degradation of diclofenac in aqueous solution by gamma ray irradiation

“…Therefore, as effective technologies, advanced oxidation processes (AOPs) represent a good method for wastewater treatment. Different chemical oxidation methods for degrading diclofenac have recently been described, such as Fenton reactions, sonolysis in the presence of catalysts, ultrasound in the presence of photocatalysts, and UV-light irradiation in the presence of H 2 O 2 or ozone (Ravina et al 2002;Huber et al 2003;Vogna et al 2004;Leónidas et al 2005;Pérez-Estrada et al 2005;Hartmann et al 2008;Vincenzo et al 2009;Madhavan et al 2010;Güyer and Ince 2011). As an AOP, gamma ray irradiation is an effective way for degrading organic compounds due to its high penetrating power and the isothermal character (Yamazaki et al 1983;Kimura et al 2006;Zhang et al 2008b;Ito et al 2009;Choi et al 2010).…”

An overview on the advanced oxidation processes applied for the treatment of water pollutants defined in the recently launched Directive 2013/39/EU

“…Concerning these compounds, there are several works reporting AOPs to treat diclofenac (Calza et al, 2006;Guyer and Ince, 2011;Martínez et al, 2011;Michael et al, 2014;Naddeo et al, 2010;Naddeo et al, 2009;Pérez-Estrada et al, 2005;Rizzo et al, 2009;Zhang et al, 2011) as well as both hormones (Dimitroula et al, 2012;Frontistis et al, 2012;Frontistis et al, 2011;Pereira et al, 2012). Data regarding these particular compounds can be consulted in article reviews that have been published in the last few years and that already encompass a lot of information dealing with the removal of these compounds from water by using AOPs Kanakaraju et al, 2014;Klavarioti et al, 2009;Liu et al, 2009;Luo et al, 2014;Rivera-Utrilla et al, 2013;Silva et al, 2012).…”

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

“…Efficient degradation and mineralization of diclofenac were achieved by using ultrasound in the presence of various catalytic iron species like iron superoxide nanoparticles, reactive divalent iron and reactive zero-valent iron (Güyer and Ince 2011;Ziylan et al 2013). The sonochemical degradation of carbamazepine is compared by introducing the UV light into the reaction system, and it was found that the introduction of the UV light enhanced the degradation rate from 0.28 to 0.329 min -1 .…”