Cu 2+ coordination-induced in situ photo-to-heat on catalytic sites to hydrolyze β-lactam antibiotics pollutants in waters

Abstract

For degradation of β-lactam antibiotics pollution in waters, the strained β-lactam ring is the most toxic and resistant moiety to biodegrade and redox-chemically treat among their functional groups. Hydrolytically opening β-lactam ring with Lewis acid catalysts has long been recognized as a shortcut, but at room temperature, such hydrolysis is too slow to be deployed. Here, we found when Cu 2+ was immobilized on imine-linked COF (covalent organic framework) (Cu 2+ /Py-Bpy-COF, Cu 2+ load is 1.43 wt%), as-prepared composite can utilize the light irradiation (wavelength range simulated sunlight) to in situ heat anchored Cu 2+ Lewis acid sites through an excellent photothermal conversion to open the β-lactam ring followed by a desired full-decarboxylation of hydrolysates. Under 1 W/cm 2 simulated sunlight, Cu 2+ /Py-Bpy-COF powders placed in a microfiltration membrane rapidly cause a temperature rising even to ~211.7 °C in 1 min. It can effectively hydrolyze common β-lactam antibiotics in waters and even antibiotics concentration is as high as 1 mM and it takes less than 10 min. Such photo-heating hydrolysis rate is ~24 times as high as under dark and ~2 times as high as Cu 2+ homogenous catalysis. Our strategy significantly decreases the interference from generally coexisting common organics in waters and potential toxicity concerns of residual carboxyl groups in hydrolysates and opens up an accessible way for the settlement of β-lactam antibiotics pollutants by the only energy source available, the sunlight.