Enhancement of the Catalytic Ozonation Process by Using TiO₂/ZrO₂ Nanoparticles

Abstract

In this study, we employed synthesized titanium oxide/zirconium oxide (TiO2/ZrO2) nanoparticles as activated catalysts to enhance the ozonation process during hydroxyl radical (OH°) generation using atrazine (ATZ) as a pollutant. The TiO2/ZrO2 nanoparticles were synthesized using the coprecipitation digestion method and were characterized using scanning and transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller theory, and energy dispersive X-ray spectroscopy. The experiments were conducted under different initial pH conditions (3, 7, and 10), with an initial ATZ concentration of 4.64 × 10−6 M, initial TiO2/ZrO2 nanocatalyst concentrations of 100, 200, and 300 ppm, and initial ozone (O3) concentrations of 1.35 × 10−4, 1.55 × 10−4, and 2.27 × 10−4 M, respectively. The key operational parameters were optimized, and the optimal OH° results were obtained at pH 10, 200 ppm TiO2/ZrO2 concentration, 4.64 × 10−6 M ATZ concentration, and 1.55 × 10−4 M O3 concentration. The potential of TiO2/ZrO2 nanoparticles to enhance OH° generation during catalytic ozonation was demonstrated. The catalytic ozonation mechanism using TiO2/ZrO2 nanoparticles was governed by the optimal formation of OH° radicals at about 1 × 10−11 mol/L and an excellent nanocatalytic activity with an Rct value of 2.83 × 10−8.