Selective photodegradation of paracetamol by molecularly imprinted ZnO nanonuts

Photocatalysis-based technologies are currently striving to find a methodology able to selectively catch, and degrade specific organic contaminants. To solve this problem, we propose molecularly imprinted ZnO nanonuts as new nanomaterial. In this work, ZnO have been imprinted, through a chemical method, with one of the most diffused analgesic-antipyretic drugs: acetaminophen (commonly called "paracetamol"), today considered as an emergent environmental pollutant. The molecularly imprinted nanonuts have been characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) adsorption-desorption of N-2, X-ray diffraction analyses (XRD), high-resolution transmission scanning electron microscopy (HR-S/TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Thanks to the accurate performed characterization, the interaction between ZnO and paracetamol has been elucidated. The photodegradation of paracetamol in aqueous solution has been demonstrated under UV light irradiation. The selectivity of the photodegradation process has been additionally investigated thanks to the comparison with the degradation of methyl orange (MO) and phenol, another two common water pollutants. Imprinted ZnO nanonuts have shown a great affinity and selectivity for the paracetamol, being able to degrade all the paracetamol present in the solution in 3 h. This work offers a new, economic, and easy way to prepare molecularly imprinted ZnO nanonuts with high specificity, relevant in the contexts of environmental protection.