Development of novel polymer supported nanocomposite GO/TiO2 films, based on poly(L-lactic acid) for photocatalytic applications

Abstract

In the present study the development of novel polymer-supported nanocomposite graphene oxide (GO)-TiO2 films, based on poly(L-lactic acid), one of the most exploited bioplastics worldwide, was explored for photocatalytic applications. The nanocomposites were synthesized and evaluated as photocatalysts for the removal of a mixture of nine antibiotics, consisting of two sulphonamides (sulfamethoxazole, sulfadiazine), three fluoroquinolones (levofloxacin, norfloxacin, moxifloxacin), one anti-TB agent (isoniazid), one nitroimidazole (metronidazole), one lincosamide (lincomycin) and one diaminopyrimidine (trimethoprim), which are commonly found in wastewaters. The films were synthesized using 1 wt% GO and different TiO2 content (10, 25, and 50 wt%) and characterized using Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Findings confirmed the successful immobilization of GO/TiO2 in all cases. The PLLA-GO-TiO2 50 wt% composite film demonstrated higher photocatalytic efficiency and, thus, was further investigated demonstrating excellent photostability and reusability even after four cycles. Overall, PLLA-GO-TiO2 50 wt% nanocomposite demonstrated high efficiency in the photocatalytic degradation of the antibiotics in various matrices including pure water and wastewater.