| The main objectives of this project were to design, characterize and optimize a gas-liquid atmospheric pressure dielectric barrier discharge (DBD) reactor and to investigate its potential to degrade an aqueous pharmaceutical compound. The liquid was sandwiched inside a parallel plate semi-batch DBD reactor and thus, directly exposed to the plasma-forming region. The application of 10 kV (17.5 kHz) at low peak current (55 mA) between the high-voltage electrode, resting on an alumina plate, and the solution induced microdischarges in the gas phase and agitated the solution. The dissipated power (55 W on average) was monitored from the measure of Lissajous figures on a customized LabVIEW(TM) interface. Atomic oxygen was detected by optical emission spectroscopy when oxygen was used as the feed gas. An optimization of the operating conditions was performed by monitoring the absorbance at 600 run (UV-visible) of blue solutions composed of an indigo dye. The effects of solution volume (42-55 mL) or discharge gap, gas flow rate (15-70 cc/min), treatment time (3-9 minutes), and gas type (pure oxygen or air) were investigated. Some of the optimum values for the operating parameters, which led to a discoloration efficiency of the indigo solution of 99%, were used to degrade an antibiotic, sulfamethoxazole (SMX) diluted in water. |
