Synthesis of zeolite-doped polyaniline composite for photocatalytic degradation of methylene blue from aqueous solution

Abstract

The generation of wastewater has increased rapidly with the expansion of industries, hence, posing a risk to human health and the environment. The development of novel materials and technologies for textile wastewater treatment is constantly evolving. In this work, the photocatalytic degradation of methylene blue employing ZSM-5 zeolite-doped polyaniline composites is presented. To fabricate ZSM-5-based polyaniline (PANI) composites, the simple approach of in situ oxidative polymerization has been adopted. Different weight ratios of ZSM-5 have been used for the synthesis, and samples have been labelled as PAZe-1, PAZe-5, and PAZe-10. Different characterization techniques were used to characterize the prepared composites, including field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermo-gravimetry analysis (TGA). The photocatalytic performance of polyaniline, ZSM-5, and their composites was assessed by monitoring the degradation of methylene blue in the presence of visible light. Degradation results of the polyaniline-doped composites were found to be better than that of the polyaniline alone. When the photocatalytic efficiencies of different composites were compared, the PAZe-1 showed the best performance, with 99.9% degradation efficiency after 210 min of irradiation, while PANI, PAZe-5, PAZe-10, and ZSM-5 show 38%, 82%, 71%, and 99% removal efficiency. Apart from methylene blue, the composite PAZe-1 was further explored for the degradation of other organic pollutants such as methyl orange, chlorpyrifos, 2,4-dichlorophenoxy acetic acid, and p-nitroaniline. To determine the reactive species involved in the photocatalysis mechanism, scavenger studies were performed.

Keywords: Composite; Methylene blue; Photocatalysis; Polyaniline; Zeolite.