Development of graphene oxide-based polypyrrole nanocomposite for effective removal of anionic and cationic dyes from water

Abstract

The majority of toxins, including metal ions, organic wastes, particularly dyes, and other inorganic wastes, are released into the environment today as a main problem of increased industry. These pollutants primarily disrupt the balance of the environment and harm people's health. In this work, attempts were taken to develop a graphene oxide-based nanocomposite with polypyrrole (GO/PP) as a versatile adsorbent. Initially, GO/PP nanocomposites were prepared with different GO/PP ratios, and initial adsorption studies were conducted towards organic dyes, lead ions, cadmium ions, and fluoride ions to identify the best ratio. GO/PP with a 20:80 ratio was identified as the most efficient adsorbent out of all the prepared materials. This material was characterized to identify its crystallinity, morphology, functional groups, and thermal properties using the X-ray diffractometer (XRD) technique, Scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), UV–visible spectrometer, and Raman spectroscopy. In this work, we report the adsorption properties of cationic rhodamine B (RhB) and anionic methyl orange (MeO) towards GO/PP 20:80 nanocomposites. The best-fitted kinetic model for both dyes was the pseudo-second-order model. The calculated dye removal efficiency for MeO and RhB was 98.40% and 99.90% within a contact time of 30 min and 10 min respectively at optimum pH of 7. The best-fitted isotherm model for RhB was the Freundlich model with 10.52 mg g−1 and the best-fitted isotherm model for MeO was the Langmuir model with 9.61 mg g−1 maximum adsorption capacities. The studies indicated that GO/PP can be used in gravity filtration and can effectively be regenerated.

Keywords

• Graphene oxide
• Graphene oxide/polypyrrole
• Polypyrrole
• Dye adsorption
• Rhodamine B
• Methyl orange