▎ 摘　　要

This work is focused on the synthesis of expanded graphene (EG), polypyrrole-magnetite (PPy/Fe3O4) and expanded graphene-polypyrrole-magnetite nanocomposite (EG-PPy/Fe3O4) electrodes and their application in the degradation of organic pollutants in water. The nanocomposites were synthesized through the co-precipitation method and characterized using ultraviolet-visible spectroscopy, Brunauer-Emmett-Teller surface area analyser, scanning electron microscope, energy dispersive X-ray, X-ray diffractometer and X-ray photoelectron spectroscope. The EG, PPy/Fe3O4 and EG-PPy/Fe3O4 electrodes were applied in a comparative photoelectrochemical degradation of 0.1 x 10(-4) M methylene blue (MB) dye and bisphenol A (BPA) in 0.1 M Na2SO4 under visible light irradiation. The degradation was also performed through photolysis, electrochemical and photoelectrochemical processes. The results showed that the pure PPy and EG-PPy/Fe3O4 were present in the Anatase phase of PPy. The EG-PPy/Fe3O4 composite absorbed a noticeable amount of light in the entire visible light region compared to pure PPy and PPy/Fe3O4. The surface area and pore volume of pure PPy was observed to decrease after modification with the EG as a result of the interpenetration of the porous matrix of EG by the PPy nanoparticles. The EG-PPy/Fe3O4 electrode was the most effective in the degradation of both dyes. The order of efficiency was EG < PPy/Fe3O4 < EG-PPy/Fe3O4. The photoelectrochemical degradation process resulted in improved degradation efficiency of 92% (MB) and 88% (BPA) within 240 min and was observed to be greater than that of photolysis and electrochemical oxidation methods. The EG-PPy/Fe3O4 photoanode is regarded as an effective material for the degradation of MB and BPA in wastewater. [GRAPHICS]