Sequestration of a cationic dye using graphene oxide as adsorbent

Herein, we reported graphene oxide, as a suitable adsorbent for wastewater treatment to remove crystal violet dye from an aqueous solution. Crystal violet is used for various purposes including colouring, textile, pharmaceuticals etc. It has many harmful effects as it is non-biodegradable, toxic and carcinogenic in nature. So, it is very important to eradicate it from the water. Graphene oxide has been prepared by the modified Hummer’s method and characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy and X-ray diffraction. Graphene oxide’s removal efficiency depends on various factors including temperature, pH, and substrate concentration. The experimental data from batch studies is well substantiated with pseudo-second-order kinetics with an R2 value of 0.98 and Temkin adsorption isotherm (R2 : 0.94) with a Temkin constant (bT) value of 328 kJ/mol. It also closely fits the intraparticle diffusion model (R2 : 0.99). The Langmuir adsorption capacity of graphene oxide was calculated to be 15.87 mg/g. The thermodynamic parameter study suggested that the adsorption process is exothermic and spontaneous in nature. Furthermore, a fixed bed column study was also conducted with a constant flow rate of 2.5 mL/min and bed height of 1 cm with a high concentration of crystal violet in a continuous mode of operation to evaluate its practical applicability and the area under the curve is found to be 4,701 cm2.