Adsorption properties of methylene blue and gentian violet of sodium vanadate nanowire arrays synthesized by hydrothermal method

In the present study, the facile hydrothermal method is used to prepare sodium vanadate (Na5V12O32) nanowire arrays to act as adsorbents for removing cationic dyes. The samples are characterized and compared using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrum, and X-ray diffraction. The adsorption quantity of methylene blue and gentian violet increases with the increase of adsorbent dose, adsorption time and initial dye concentration. Further, the adsorption kinetic and isotherm are well modeled by the Pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The rate control step is administered by means of intra-particle diffusion during the adsorption process. The maximum adsorption capacities of methylene blue and gentian violet are 1249.0 and 1079.7 mg g−1, respectively. Additionally, the maximum dye removal rates for MB and GV are 85.32 % and 84.46 % after five cycles, respectively. As such, Na5V12O32 nanowire arrays can be used as an efficient, low-cost and recyclable adsorbent for cationic dyes removed from wastewater. © 2022