Abstract
This work describes the application of graphene nanosheets (GNS) as a solid adsorbent for the simultaneous removal of the toxic tungsten ions (W+6) and rhodamine B dye (RhB) from model and real water. Physical characterization of the GNS showed their presence as overlapped sheets of different length and width, and with an average thickness of 20.0 nm and a high specific surface area of 279 m(2) g(-1). The influence of different experimental conditions on removal efficiency such as pH of the solution, GNS mass, contact time, solution temperature, and ionic strength were investigated. The results from the experimental data showed GNS can remove most of W ions and RhB species from the aqueous solution in 30 min, at pH 1.0, with adsorption efficiency of 99.1% using 17.5 mg of GNS, and with adsorption capacity 93.5 mg of W g(-1) of GNS and 41.8 mg of RhB g(-1) of GNS. The removal process of W ions and RhB dye by GNS were studied kinetically using different kinetic models, and the results indicated the pseudo-second-order kinetic model suitability for the adsorption process description. The removal process was studied thermodynamically, and the results revealed that the removal was spontaneous, endothermic in nature, and associated with increase in random-ness. Finally, the efficiency of GNS for the adsorption of tungsten ions and rhodamine B dye from real samples were explored using three different real environmental water samples. The data confirms that GNS has great efficiency in removing tungsten ions and rhodamine B dye from aqueous solution.