Sorption-Catalytic Increase of Rhodamine B Dye Destruction Efficiency in Barrier Discharge Plasma by Zeolite NaX and Diatomite Granules with TiO2 Coating

This paper presents the results of studies of a combined process of plasma-photocatalytic destruction of aqueous solutions of Rhodamine B (RhB) with high concentrations (up to 40 mg/L) using two composite catalytic systems consisting of titanium dioxide fixed on zeolite NaX and diatomite granules. TiO₂ coating was applied by hydrothermal impregnation of carrier with solutions containing large-sized titanium hydroxocomplexes. The sorption and photocatalytic properties of impregnated granules were studied under static conditions. Contribution of sorption-catalytic processes to the efficiency of RhB decomposition was assessed in a plasma-chemical reactor of a dielectric barrier discharge. It was shown that the presence of both types of catalysts in the plasma leads to an increase in the rate of dye destruction by at least 20%. Maximum efficiency of decomposition in plasma is observed when using a TiO₂/zeolite catalyst and reaches 100% (2 g of catalyst in a reactor volume of 25 cm³ and a discharge power of 8.6 W/cm³) with a degree of mineralization of more than 80%, which indicates a high degree of oxidation processes.