Ibuprofen degradation by electrolysis under electric plasma high voltage and low current, with multielectrode system

Abstract

The drug Ibuprofen was degraded by electrolysis under high voltage and low current electric plasma. This electrolytic process is non-faradaic, where the plasma is sustained by discharges between the anode and the liquid electrolyte in its surroundings, causing varied physical and chemical effects, producing radical and molecular chemical species, all of which are highly reactive. In the electrochemical cell used, the platinum wire anodes are exposed about 1.5 mm in the solution while the spectroscopic graphite cathode is surrounded by a plastic tube with holes on the sides. The potential difference was maintained at 625 volts in the experiments of temporal measurements of H₂O₂ production, observing an exponential increase in the concentration as a function of the plasma application time, tending to stability after 40 minutes. The generation of H₂O₂ according to the number of anodes added is not linear, apparently due to small differences in the platinum anodes. To study the degradation of Ibuprofen a factorial design was carried out with the variables electrolyte, number of anodes and difference in potential. The degradation monitoring was performed by ultraviolet spectral scans, at 0, 30 and 60 minutes after plasma ignition. There was a substantial reduction in the ibuprofen absorption band at 222 nm. For solutions in which two electrodes were worked, an absorption band appeared at 210 nm. This band disappeared after 60 minutes of plasma application, apparently due to the existence of an easily degradable intermediate species, since the band does not appear when more electrodes are used. By the measurements of Total Organic Carbon, degradations above 90% were obtained after 60 minutes of plasma application, for some solutions, probably due to a synergistic effect, by the combination of variables of these solutions in the planning.