Facile fabrication of three-dimensional and recyclable graphene oxide-melamine composites with high removal efficiency

Self-assembly of three-dimensional graphene oxide-melamine (GO-ME x:y ) composites with various GO-to-ME mass ratios (x:y) of 5:1 to 25:1 was carried out by a facile hydrothermal method. GO-ME was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The adsorption properties of GO-ME toward rare earth elements (REEs), phenols and dyes in aqueous solutions were investigated. It was found that REEs could be better adsorbed onto GO-ME 20:1 with maximum adsorption capacities of 25.04, 14.08, 20.88, 19.96, 26.68 and 25.28 mg g – 1 toward La 3 + , Y 3 + , Yb 3 + , Er 3 + , Eu 3 + and Nd 3 + , respectively. And GO-ME 15:1 showed relatively higher adsorption capacities of 65.77, 70.11 and 23.49 mg g – 1 for 3-nitrophenol, p-nitrophenol and hydroquinone, respectively. Organic dyes could be preferably adsorbed by GO-ME 10:1 , and its maximum adsorption capacities toward neutral red (NR) and alizarin yellow R (AYR) were 80.49 and 189.33 mg g – 1 , respectively. In brief, GO-ME x:y nanocomposites were expected to be used as efficient sorbents for the adsorption removal of REEs, phenols and organic dyes.