Carbon nanotubes (CNTs) were initially discovered at Japan in 1991 by Somui Ejeema, from that date CNTs were synthesized using different methods. In addition their physical and chemical properties were studied extensively [1, 2]. However, researchers were directed their attention towards synthesis and purification of these materials as they can play important roles in wide range of applications in both industrial and environmental fields [3, 4]. The main source of CNTs is the graphite which normally exists as sheets with hexagonal structure for carbon atoms. These sheets can be rolled up into cylindrical shape due to the presence of Van der Waals forces to produce tubular structure with nano scale radius with length of some micrometer scale. Due to this structure CNTs can be considered as an elongated hallow fullerene [5]. Generally, as a result of this structure of CNTs, it shows robust mechanical, electrical, thermal, and optical properties as well as large surface area with high adsorption ability which makes these materials to be a good candidate to remove many types of pollutants from air, water and soil. Generally CNTs consist of layers of graphite sheet with a thickness of one carbon atom with sp2 hybridization [6]. According to number of these layers CNTs can be classified into single-walled CNTs (SWNTs), Double-walled carbon nano tubes (DWCNs), and Multiwalled CNT (MWNTs).
م.م أمير عذاب عبد الكاظم | Ameer Athab Abulkahim AlAmeri | 2868