Degradation of Rhodamine B in the photocatalytic reactor containing TiO2 nanotube arrays coupled with nanobubbles

Although photocatalytic technology is applied in water treatment, the challenge still exists due to its low photocatalytic performance. Herein, a photocatalytic reactor coupled with nanobubbles (NBs) is developed to degrade organic pollutants in wastewater. The reactor contains Ti mesh coated with TiO₂ nanotube arrays as a photocatalyst. The introduction of NBs in the reactor increases the dissolved oxygen content to enhance photocatalytic performance. The photocatalytic reactor exhibits outstanding photocatalytic performance, and the degradation ability of Rhodamine B is 95.39% after 2 h of irradiation treatment. The reactor also shows excellent photodegradation performance for other organic pollutants, such as methylene blue (74.23%), tetracycline (68.68%), and oxytetracycline hydrochloride (64.10%). Radical trapping experiments further prove that ·O₂⁻, h⁺ and ·OH are the active species for the degradation of RhB in the photocatalytic system. Therefore, this work provides a feasible strategy to design a photocatalytic reactor coupling with nanobubbles technology for the photodegradation of organic pollutants in wastewater.