Evaluation of TiO<sub>2</sub>, ZnO, CuO and Ga<sub>2</sub>O<sub>3</sub> on the Photocatalytic Degradation of Phenol Using an Annular-Flow Photocatalytic Reactor

Abstract

Even with rigorous environmental regulations, phenol still is a major contaminant. One possible solution is the use of heterogeneous photocatalysis due to low chemical addition, feasibility and reliability to be implanted on cost-effective industrial process. TiO 2 is the most employed photocatalyst because of its favorable (photo) chemical properties and ZnO is considered one of the best alternative for that. Other oxides were tested in lesser proportions, like CuO and Ga 2 O 3 . When the photocatalyst is dispersed as slurry, higher degradation rates are achieved due to high solid to liquid contact area when compared with supported form. The aim of this work was to develop a batch recirculating photocatalytic reactor and evaluate its efficiency when assisted by the photocatalysts TiO 2 P25, ZnO, CuO and β-Ga 2 O 3 . TiO 2 achieved 95% mineralization after 200 min reaction in an average degradation rate of 0.68 mg·L ). Ga 2 O 3 and CuO presented poor performance, mainly due to low surface area for the CuO syntesized and the absorption of the UV radiation by the reactor walls, decreasing Ga 2 O 3 activity. Degradation intermediates were detected in diverse concentrations and at different operational times for each oxide tested, which indicate different degradation mechanisms.

Visible Light Photocatalytic Activity of NaYF4:(Yb,Er)-CuO/TiO2 Composite

“…Although photo-degradation up to 40% is observed in the TiO 2 -coated composites, the NaYF 4 :(Yb,Er)-CuO degraded only 20% of MB solution. This is due to the higher oxidizing ability of TiO 2 as compared to CuO [46]. In contrast, the photocatalyst mixture with H 2 O 2 oxidant molecules showed an improvement in photocatalytic activity of the NaYF 4 :(Yb,Er)/TiO 2, NaYF 4 :(Yb,Er)-CuO and NaYF 4 :(Yb,Er)-CuO/TiO 2 .…”

Visible Light Photocatalytic Degradation of Methylene Blue Dye and Pharmaceutical Wastes over Ternary NiO/Ag/TiO2 Heterojunction

“…The catalyst’s capacity to generate electron–hole pairs is considered one of the crucial factors in determining the photocatalytic activity of the catalyst, which results in the production of free radicals that may cause further reactions . The most effective photocatalysis uses semiconducting nanoparticles to break down organic molecules, dangerous chemicals, bacteria, and viruses into CO 2 and H 2 O. Metal-oxide nanoparticles, such as TiO 2 , ZnO, CuO, and WO 3, are known for their excellent photocatalytic properties and have been widely used to degrade pollutants and microorganisms under UV irradiation. , …”

“… 13 The most effective photocatalysis uses semiconducting nanoparticles to break down organic molecules, dangerous chemicals, bacteria, and viruses into CO 2 and H 2 O. Metal-oxide nanoparticles, such as TiO 2 , ZnO, CuO, and WO 3, are known for their excellent photocatalytic properties and have been widely used to degrade pollutants and microorganisms under UV irradiation. 14 , 15…”

The Effects of Pt-Doped TiO2 Nanoparticles and Thickness of Semiconducting Layers at Photoanode in the Improved Performance of Dye-Sensitized Solar Cells

“…It is chemically stable and non-toxic. [3]. Compared with other MO-NPS such as, for example, Al 2 O 3 , CuO, CO 3 O 4 , Cr 2 O 3 , Fe 3 O 4 , La 2 O 3 , Mn 2 O 3 , NiO, ZnO, and ZrO 2 with energy bandgaps of 8.30 eV, 1.34 eV, 2.43 eV, 3.08 eV, 1.85 eV, 5.77 eV, 2.99 eV, 3.66 eV, 3.31 eV, and 5.04 eV respectively, the energy bandgap of TiO 2 is 3.2 eV [4][5][6].…”