Multi-Strategy optimized UiO-66 composite for simultaneous efficient adsorption and visible-light degradation of tetracycline in wastewater

Abstract

Tetracycline hydrochloride (TC) is a widespread contaminant in aquatic environments, leading to the emergence of antibiotic-resistant bacteria and posing serious environmental and health threats. To address this issue, a highly efficient adsorbent-photocatalyst composite (BP@UiO-66–0.9Ni) was developed to achieve TC removal from wastewater. The results indicated that the total removal rate of TC in actual river water samples can reach 98 % after treatment with this composite, and was largely unaffected by pH and coexisting anions. Specifically, the adsorption capacity increased from 7.2 mg g⁻¹ of the original UiO-66 to 148.3 mg g⁻¹, which represented an enhancement of 20.6 times, while the visible-light degradation removal efficiency increased from 1.2 % to 90.2 %, representing an enhancement of 75.2 times. Moreover, under optimal pH conditions, the material exhibited a high adsorption capacity of 358 mg g⁻¹. The enhanced adsorption was due to the combined effects of π-π interactions, electrostatic forces, metal–organic complexation, and pore-filling mechanisms. Reactive species such as ·O₂⁻ and ¹O₂ were generated under visible light excitation, catalyzing oxidation, demethylation, and hydroxylation in TC molecules. These processes ultimately led to the degradation and removal of TC. The improved performance of BP@UiO-66–0.9Ni also resulted from efficient charge transfer and better separation of photogenerated electron-hole pairs, which collectively contributed to its superior adsorption and photocatalytic activity. In conclusion, this study demonstrated an effective strategy for the removal of TC from wastewater, providing valuable insights for designing high-performance materials for the treatment of antibiotic-contaminated water.