Synthesis of High Surface Area Boron Nitride Nanosheets for the Removal of Methylene Blue and Rhodamine B Dyes from Contaminated Water

In this study, we report the synthesis and characterization of boron nitride nanosheets (BNNSs), and their application as an adsorbent to remove the cationic dyes methylene blue (MB) and rhodamine B (RhB) from contaminated water. The synthesized adsorbent was characterized by high-resolution transmission electron microscopy (HR-TEM), field emission electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and nitrogen adsorption-desorption isotherm. Detailed experiments and analysis were performed on various molar ratios of boron and nitrogen precursors (1:5 to 1:48) to achieve maximize specific surface area of BNNSs. Among all, the samples synthesized with boric acid and urea (1:30) dissolved in water and methanol produced maximum specific surface area (1801.9 m(2) g(-1)). Further, the adsorption study was performed in batches by investigating various adsorption parameters such as effect of pH, contact time, adsorbent dose and adsorption isotherm. The pH study revealed that optimum value was found to be at pH 8. It was found through the kinetic study that pseudo-second-order (PSO) kinetic model was followed by the adsorbent during the adsorption of both the dyes. Further, the adsorption isotherm data well fitted with Langmuir isotherm model. The maximum adsorption capacities of MB and RhB were found to be 333.33 and 312.5 mg g(-1), respectively. This demonstrates the potential of BNNSs as novel adsorbent for treatment of dye-contaminated water.