INVESTIGATION OF SOME RARE EARTH ELEMENTS SORPTION BY USING MULTIWALLED CARBON NANOTUBES
Project no. 218 · Status: Kapanmış · 2016
Summary
Nowadays, rare earth elements enter into the structure of many industrial products requiring high technology and their usage areas are increasing day by day. The most important rare earth element ore in our country is Kızılcaören Eskişehir Bastneazit-Fluorite-Barite deposit. Turkey has ranked second in the world as rare earths reserves. Therefore, the separation of rare earth elements is the subject of many studies. Adsorption, which is one of the separation techniques, is important for separating trace amounts of elements from large volume solutions. In adsorption applications, many materials including activated carbon, biosorbents, various resins, composite materials, clay and zeolite are used. Among these, the carbon nanotubes, which discovered by lijima in 1991, are relatively new materials with graphite structure having a large surface area, porous and layered structure and exhibiting superior properties. The use of carbon nanotubes as sorbent material gives promising results in the management of liquid wastes and separation processes. The aim of this study is to investigate the separation of some rare earth elements by using multi-walled carbon nanotubes. For this purpose, removal of europium and samarium from aqueous solutions with different types of modified multi-walled carbon nanotubes has been researched. Surface modification of multi-walled carbon nanotubes were performed with HNO3 and KMnO4 and the parameters that affecting the adsorption (pH, initial metal concentration, temperature and contact time) were investigated. In this study, instead of individually observing each variable, “experimental design” technique was used. Adsorption isotherms (Langmuir and Freundlich) were investigated and the highest R2 values was obtained at the Langmuir isotherm for europium adsorption, Freundlich isotherm for samarium adsorption. It has been determined that the pseudo second-order rate equation is suitable for adsorption of europium and samarium adsorption on multi-walled carbon nanotubes.