Highly efficient preparation of hexagonal boron nitride by direct microwave heating for dye removal

Within 40 min, hexagonal boron nitride (h-BN) was rapidly synthesized via microwave heating without using catalyst and protective gas. Melamine and boric acid were used as raw materials, and carbon fiber was utilized as microwave absorber, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) were used to characterize the structures and morphologies of the samples. Results indicated that the whisker-like h-BN with diameters of 200–500 nm and lengths of 15–25 μm were successfully obtained. The specific surface area of the product was 510.941 m2 g−1. The maximum adsorption capacity for methylene blue solution of the as-obtained h-BN was high up to ~ 230 mg g−1 at room temperature. The excellent adsorption performance of the samples may be attributed to the oxygen-containing functional groups and defects formed during the high-energy microwave irradiation.