Photocatalytic degradation of ciprofloxacin and sulfamethoxazole on a carbon nanodot doped tungsten trioxide: degradation product study

Abstract

This work is focused on the photocatalytic degradation of antibiotics ciprofloxacin and sulfamethoxazole in wastewater using a nanocomposite of tungsten trioxide (WO3) and carbon nanodots (CNDs). This material was prepared by doping tungsten trioxide (WO3) with carbon nanodots (CNDs) by hydrothermal technique. The structural, optical, morphological and photocatalytic properties of the CNDs-doped WO3 nanocomposite as well as an undoped WO3 nanorod were successfully characterized by TEM, XRD, Raman, FTIR, BET and UV–Vis DRS. The photocatalytic degradation performance, degradation kinetics and degradation patterns were followed by UV–Visible spectroscopy and ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). The percentage removal of ciprofloxacin and sulfamethoxazole were higher with the WO3-CNDs than the pristine WO3 photocatalyst denoting the positive effect of doping. The percentage removal of the antibiotics when monitored by UPLC-MS was found to be higher than that of UV–Visible spectroscopy. The intermediate products and pathway were different with the doped and the undoped WO3 photocatalysts.