Prof. MA Wanhong and his colleagues from the Institute of Chemistry, Chinese Academy of Sciences (ICCAS) and their collaborator posed a practical approach for the effective removal of antibiotic products through the in-situ heating catalytic hydrolysis sites by light illumination. This innovation paves the way for addressing challenging-to-degrade pollutants in water.
The work was published in Proceedings of the National Academy of Sciences of the United States of America and highlighted by Chemical & Engineering News from American Chemical Society (ACS).
The residual β-lactam antibiotics in various water sources and the subsequent dissemination of drug-resistance genes have raised widespread concern, but the economic and efficient methods for eliminating these antibiotics remain a significant challenge. The Lewis acid-catalyzed hydrolysis pathway emerges as a promising strategy to achieve this objective through breaking open the key four-membered β-lactam ring they share. However, the catalytic hydrolysis at room temperature is too slow to be adapted in practical application.
To address this problem, the researchers utilized a bipyridine linker on covalent organic framework (COF) materials to anchor Cu²⁺, creating a novel Lewis acid hydrolysis catalyst. This method can preserve the Lewis acid catalytic properties of Cu²⁺. Besides, Cu²⁺/COF can accumulate heat on limited catalytic sites during the photothermal conversion under visible light. The Cu²⁺ sites on the support could be locally heated to over 211 °C within 1 minute (gas/solid medium) by using a 300W Xe lamp. In an aqueous solution, the local temperature of catalytic sites could also be elevated to ~60 °C from room temperature, significantly enhancing the catalytic hydrolysis of the β-lactam bond. β-lactam antibiotics can be effectively hydrolyzed in waters for less than 10 minutes. Such photo-heating hydrolysis rate is about 24 times as high as under dark catalysis.This work opens an avenue for utilizing cleaner solar energy to degrade antibiotics.

Schematic representation of Cu2+/COF photothermal hydrolysis/decarboxylation of β-lactam antibiotics (Imaged by Li Jiazhen)

Contact:
Prof. MA Wanhong
Institute of Chemistry, Chinese Academy of Sciences
Email: whma@iccas.ac.cn