Electrochemical treatment of anti-cancer drug carboplatin on mixed-metal oxides and boron doped diamond electrodes: Density functional theory modelling and toxicity evaluation

This study represents the electrooxidation of anti-cancer drug carboplatin (CrbPt) with different mixed metal oxide (MMO) and boron doped diamond (BDD) electrodes. The most effective anode was found as Ti/RuO2 with the complete degradation of CrbPt in just 5 min. The effect of applied current density, pH and electrolyte concentration on CrbPt degradation has been studied. The degradation of CrbPt significantly increased at the initial stages of the process with increasing current density. However, further increase in current density did not affect the degradation rate. While complete degradation of CrbPt was provided at pH 7, the degradation rates were 49% and 75% at pH 9 and 4, respectively. Besides, increasing supporting electrolyte (Na2SO4) concentration provided higher degradation rate but further increase in Na2SO4 concentration did not provide higher degradation rate due to excess amount of SO4−2. According to the DFT calculations, the formation of [Pt(NH3)2 (H2O)2]2+ and [Pt(NH3)2 (OH)2] takes place with molecular weights of 265 and 263 g mol−1, respectively. Toxicity of treated samples at BDD and Ti/RuO2 electrodes has been also evaluated in this study. The results showed that Ti/RuO2 anode provided zero toxicity at the end of the process.