Anodic oxidation of ketoprofen—an anti-inflammatory drug using boron doped diamond and platinum electrodes

Journal of Hazardous Materials 180 (2010) 753–758

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Journal of Hazardous Materials
journal homepage: www.elsevier.com/locate/jhazmat

Anodic oxidation of ketoprofen—An anti-inflammatory drug using boron doped diamond and platinum electrodes
M. Murugananthan a,∗ , S.S. Latha a , G. Bhaskar Raju a , S. Yoshihara b
a b

National MetallurgicalLaboratory Madras Centre, CSIR Madras Complex, Taramani, Chennai 600 113, India Department of Advanced Interdisciplinary Science, Graduate School of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585, Japan

a r t i c l e

i n f o

a b s t r a c t
The mineralization of ketoprofen (KP) by anodic oxidation was studied by employing boron doped diamond (BDD) and Ptelectrodes. The redox behavior of KP molecule, fouling of electrodes, generation of oxygen and active chlorine species were studied by cyclic voltammetry. The effect of electrolyte, pH of aqueous medium and applied current density on the mineralization behavior of KP was also investigated. The degradation and mineralization were monitored by UV–vis spectrophotometer and total organic carbon analyzer,respectively. The results were explained in terms of in situ generation of hydroxyl radical (• OH), peroxodisulfate (S2 O8 2− ), and active chlorine species (Cl2 , HOCl, OCl− ). The physisorbed • OH on BDD was observed to trigger the combustion of KP in to CO2 and H2 O. The poor mineralization at both BDD and Pt anodes in the presence of NaCl as supporting electrolyte was ascribed to the formation ofchlorinated organic compounds which are refractory. Complete mineralization of KP molecule was achieved using Na2 SO4 as supporting electrolyte. © 2010 Elsevier B.V. All rights reserved.

Article history: Received 6 January 2010 Received in revised form 7 April 2010 Accepted 4 May 2010 Available online 8 May 2010 Keywords: Boron doped diamond Ketoprofen Hydroxyl radicals Active chlorine speciesMineralization current efficiency

1. Introduction In recent years, some ingested pharmaceutical compounds and their metabolites were detected in the surface and ground water situated near the sewage water treatment plants (STP) [1]. The non-steroidal anti-inflammatory drugs (NSAID) are special group of pharmaceuticals that are prescribed for muscle pain and inflammatory rheumatic disorders. Theusage of these drugs is expected to increase in future [2]. The NSAID drugs are generally polar compounds because of carboxylic acid moiety. Due to their polar structure, these molecules are easily soluble in ground water instead of remaining adsorbed in subsoil [3]. Ketoprofen (KP), one of the non-steroidal anti-inflammatory drugs, is categorized as a pharmaceutically active compound. Its chemicalstructure is very complex and resists both the abiotic and biotic degradation [4]. The KP was present in the sewage water to the extent of 3.0 g L−1 [5]. The sample collected from the drinking water treatment plant located near the STP was found to contain several ng L−1 of KP [6]. Prolonged exposure to these chemicals is expected to affect the health [7]. Biological methods are extensively adoptedfor the treatment of wastewater containing pharmaceutically active compounds [8]. Various treatment methods explored by previous investigators have indicated that the option of biological treatment may not be

∗ Corresponding author. Tel.: +91 44 22542077; fax: +91 44 22541027. E-mail address: muruga.chem@gmail.com (M. Murugananthan). 0304-3894/$ – see front matter © 2010 Elsevier B.V. Allrights reserved. doi:10.1016/j.jhazmat.2010.05.007

suitable because of the inhibitory effect of chloride on microbial growth [9]. The incomplete removal of KP in STPs was attributed to its stable microbial metabolite [10]. Advanced oxidation process (AOP) was attempted to remove the NSAID compounds but their degradation was observed to be only partial [5]. Thus, there is an urgent need to develop...