Understanding the Integrated Adsorption and Photocatalytic Processes of Tetracycline over TiO<sub>2</sub>@UiO-66-NH<sub>2</sub> Heterojunctions
Ying Yang, Long Chen, Miao Li, Xiaoqing Qiu
Abstract
Semiconductor photocatalysis holds great potential for removing organic contaminants in wastewater, where pollutant adsorption onto photocatalysts is crucial for effective degradation. Herein, tetracycline (TC) was selected as a model pollutant to explore the integrated adsorption and photocatalytic processes of TiO 2 @UiO-66-NH 2 (TUON). Structural characterizations confirm the successful formation of the TUON heterojunction, with uniform nanoparticles and a homogeneous elemental dispersion. BET analysis shows a surface area of 429.1 m 2 g –1, and the micromesoporous structure (pore size: 1–3 nm) facilitates TC adsorption (saturated adsorption capacity of 131.6 mg g –1 at 298.15 K). Adsorption follows the quasi-second-order model and the Langmuir isotherm. The absorption process is spontaneous, exothermic, and entropy-increasing. Under UV irradiation, TUON achieves almost complete TC removal within 60 min, with a rate constant of 0.04742 min –1, outperforming pure TiO 2 (0.02004 min –1 ) and UiO-66-NH 2 (0.00739 min –1 ). This study brings light to comprehend the pollutant adsorption and photodegradation mechanisms, promoting efficient photocatalysts for environmental applications.