Adsorption of Molybdenum(VI) and Rhenium(VII) on Mechanoactivated Graphite

For the first time, the sorption properties of mechanically activated graphite in relation to molybdenum and rhenium were studied. Optimal conditions have been found under which the separation of metals is possible, that is, the adsorption of molybdenum up to 95% is achieved with a rhenium adsorption of 3%: nitric acid solution, pH 3 in the presence of 50 vol % ethanol, and stirring for 60 min. The maximum sorption capacity of the sorbent with respect to Mo(VI) according to the Langmuir model was 115 mg/g. The adsorption followed a pseudo-second-order kinetics model. The sample after molybdenum adsorption was characterized by XPS, X-ray phase analysis, and scanning electron microscopy. As a result of mechanical activation, there was a decrease in the average size of graphite crystallites, an increase in the distance between layers, and a change in the surface state of carbon.