Sono-photocatalytic degradation of Tetracycline and Ciprofloxacin antibiotics using microwave-reflux of NiO-MoS2/rGO ternary nanocomposite.

• NiO/MoS 2 /rGO ternary nanocomposites were synthesized via microwave-assisted reflux method. • NiMG-50 is studied towards sonocatalytic, photocatalytic and sono-photocatalytic degradation. • NiMG-50 composite exhibited superior sono-photocatalaytic degradation of TTC and CIP. • ̇ OH and ̇ O 2 – radicals are the primary active agents participating in the degradation of the antibiotics. • The NiMG-50 has a Z-scheme charge transfer and migration mechanism. In this study, NiO-MoS 2 /rGO nanocomposites were synthesized successfully by a simple microwave assisted refluxing method by varying the mass ratios of rGO. The NiMG-50 ternary nanocomposite has been applied by sonocatalytic, photocatalytic and sono-photocatalytic degradation for the removal of tetracycline (TTC) and ciprofloxacin (CIP) antibiotics. Physicochemical properties of the synthesized samples were characterized by Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray Spectroscopy (EDAX) and X-ray Photoelectron Spectroscopy (XPS) corroborated the phase purity of NiMG-50 nanocomposite. The High Resolution Scanning Electron Microscopy (HR-SEM) image reveals the zigzag arrangements of NiO nanoflakes over MoS 2 and rGO sheets. The tight contact of platelet shaped-NiO NP's and curled layer-MoS 2 on the sheets of rGO results in the separation of photo-induced e--h+ pairs as demonstrated by the High Resolution Transmission Electron Microscopy (HR-TEM) analysis. Optical properties reveal a reduced band gap and enhanced separation efficiency with fast charge transfer rate, improving the organic pollutant degradation efficiency. NiMG-50 demonstrated a good catalytic activity against TTC and CIP in sono-photocatalytic process with an efficiency of 94.10 % and 83.96 % at 35 and 90 min, respectively. Simultaneously, the experimental results showed that the NiMG-50 composite follows the pseudo-first order reaction kinetics with a rate constant (K SP) value of 0.077 min−1 and 0.015 min−1 for TTC and CIP. The radical trapping test and degradation mechanism indicated that the continuous contribution of ̇ OH and ̇ O 2 – reactive radicals are the major ones responsible for the active involvement in the degradation reaction. This research work gives a fresh prospects to the as prepared NiMG catalyst as an efficient composite with a good applicability for the sono-photocatalytic degradation of pharmaceutical products. [ABSTRACT FROM AUTHOR]