Copper-Based Photocatalysts with Natural Organic Ligands for Efficient Removal of Tetracycline Under Visible Light

Abstract

The excessive use of broad-spectrum antibiotics, such as tetracycline, has posed significant challenges to human survival and development. The oxygen-rich vacancy (OVs) metal-organic frameworks (MOFs) materials have been synthesized by using natural organic acids (L-malic acid, L-aspartate, L-asparagine) with similar structures and different charge density differences, and copper as metal linkers. The presence of oxygen vacancies (OVs) in the catalyst offers a plethora of active sites for facilitating photocatalytic reactions The organic ligands with different charge density differences make the photocatalysts have different endogenous electric fields and show different catalytic activities in the process of photocatalysis. DFT calculations confirmed that L-asparagine possessed the largest electron density difference among the three natural organic ligands, and Cu-MOF with L-asparagine (Cu-ASU) as raw material has the highest photocatalytic activity under visible light excitation. Notably, this catalyst showed high photocatalytic activity for tetracycline antibiotics under the same conditions (93.5% of tetracycline, 81.4% of oxytetracycline, and 95.6% of chlortetracycline hydrochloride were removed), which provides a new concept and method for the design of photocatalytic degradation of antibiotics. a new concept and method.

Keywords: Visible light photocatalysis, Tetracycline degradation, oxygen vacancies (OVs), natural organic ligand, charge density difference