▎ 摘　　要

Methyl orange (MO) dye, with frequent usage in several industries, is a threat to the environment owing to its toxic nature. Wastewater from several industries must be treated before release to the environment. Here, we have synthesized Gd2O3/Bi2O3@GO nanocomposite through the one-pot hydrothermal method as an adsorbent for removal of methyl orange dye and then the result was compared with Bi2O3@GO and Gd2O3@GO nano-composites. From X-Ray diffraction (XRD) study hexagonal Bi2O3 nanoparticle and cubic Gd2O3 nanoparticles were found on the GO sheets and the functional groups in the nanocomposite were also confirmed from the Fourier transform infrared (FT-IR) spectroscopy technique. Morphologically, flakes type Bi2O3 nanoparticle and granular Gd2O3 nanoparticle were observed on GO sheets, which were further analyzed through transmission electron microscopy (TEM) technique. At an optimized contact time (45 min), amount (5.0 mg), pH (6) and temperature (35 degrees C), the adsorption study was performed. The adsorption capacity of the Bi2O3@GO, Gd2O3@GO and Gd2O3/Bi2O3@GO nanocomposite were measured to be 308 mg g(-1) and 392 mg g(-1) and 544 mg g(-1), respectively. The removal efficiency of Bi2O3@GO, Gd2O3@GO and Gd2O3/Bi2O3@GO nanocomposite were recorded to be 72%, 82.3%, and 95%, respectively. The adsorption experiment with Gd2O3/ Bi2O3@GO nanocomposite follows the Langmuir adsorption isotherms and pseudo-second-order kinetic model.