Preparation of hexagonal boron nitride nanosheets in low eutectic solvent and its application for dye adsorption

The layered material hexagonal boron nitride nano-sheets (BNNSs) have similar exotic properties like graphite and have been extensively used in thermal coating, automotive industry and many other applications. However, it is still a challenge to find a green and environmentally friendly method for BNNSs preparation from hexagonal boron nitride (h-BN). This research reported a liquid phase stripping method to prepare BNNSs by using low eutectic solvent (DES) as dispersion, which consists of choline chloride as hydrogen bond acceptor and triethanolamine as hydrogen bond donor. h-BN was exfoliated by ultrasonic method to obtain few layers of BNNSs. The structure and morphology of BNNSs were characterized by Raman spectroscopy , X-ray diffraction, Fourier transform infrared spectroscopy , scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The results show that BNNSs are successfully peeled by liquid-phase ultrasonic method with DES as dispersion. The size of the peeled BNNSs was small, and the thickness was only 1.2 nm. The hydroxylation product of the BNNSs can reach adsorption capacities of 286.51 mg/g for Rhodamine B and 147.46 mg/g for Cango red, which were respectively 1.22 and 1.50 times of those for BNNSs. The preparation method for BNNSs was simple and without secondary pollution. The hydroxylation modification for BNNSs was successful to improve its adsorption capacity.