Fabrication of N, P-codoped reduced graphene oxide and its application for organic dye removal

N, P-codoped reduced graphene oxide (PA-RGO) was synthesized from graphene oxide (GO) and phytic acid (PA) mixture with the reductant of hydrazine hydrate (N₂H₄) via one-pot solution method. PA can modify the surface of RGO to enhance the hydrophilicity of RGO, and supply anionic functional groups, which can complex with cationic dye via anion-cation interaction. PA-RGO with different amount doped PA were used to remove multiple organic dyes from aqueous solution. The adsorption properties of the PA-RGO-2.0 towards Rhodamine B (RhB) were investigated under various parameters such as different pH of initial solution, different dosage of the PA-RGO-2.0, shaking speed and temperature. To study structural and chemical characterization of PA-RGO-2.0, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscope (AFM), X-ray photoelectron and spectroscopy (XPS) were used, and UV-vis spectrum was used to monitor the absorbance of adsorbate. The batch adsorption experiments of RhB on PA-RGO-2.0 showed that the RhB equilibrium capacity was about 149 mg/g. In addition, the adsorption process was well-matched with the pseudo-second-order rate model. The as-prepared composites were found to be highly selective for cationic organic dyes. The good reusability of PA-RGO indicated that the adsorbent possessed potential practical application.