Kinetics of the adsorption of scandium and cerium ions in sulfuric acid solutions on a nanomodified activated carbon

The adsorption of rare-earth elements (cerium and scandium) on pristine and nanomodified activated carbons in sulfuric acid solutions simulating the composition of multi-metallic ore leaching solutions was studied. New applications of scandium and cerium in industry, which constitute the main segment of wastewater pollution, were described. Various materials used to extract target metals were considered. A hybrid material based on carbon nanotubes-modified coconut shell activated carbon was proposed, and its structural and physico-chemical characteristics were described. The kinetic parameters of the adsorption of the rare earth elements studied, as well as adsorption rate constants, were determined. The optimum adsorption time was found to be 60 min. It was established that the process of adsorbing the cerium and scandium ions is driven by mixed diffusion, and the adsorption kinetics can also be satisfactorily described using the pseudo-first order model for all the ions. Thus, both physical adsorption and chemical interactions among the metal ions and the adsorbent functional groups can be assumed to take place during the extraction of the cesium and scandium ions.