The effect of liquid phase plasma for photocatalytic degradation of bromothymol blue

Advanced oxidative degradation of a textile dye derivative, bromothymol blue, has been investigated by liquid phase plasma process with titanium dioxide. A bipolar pulsed power supply was used to generate discharges in the aqueous solution. Properties of generated plasma were investigated by electrical and optical emission spectroscopy methods. The comparison of properties of the discharge operated with and without oxygen gas bubbling is shown. The results of electrical-discharge degradation of bromothymol blue showed that the decomposition rate increased with the applied voltage, pulse width, and frequency. While appropriate oxygen gas bubbling enhanced the decomposition efficiency, excessive bubbling deteriorated the decomposition efficiency by inhibiting the generation of plasma. The bromothymol blue decomposition rate was shown to increase with the TiO₂ particle dosage.