The Evaluation and Comparison of Single- and Multi-Walled Carbon Nanotubes in the Removal of Heavy Metals from Water

Abstract

The water scarcity crisis and water pollution are among the key issues both in the current century and in the future. Several different techniques have been introduced for the decontamination of water pollution, among which using the nanotubes is one of the most influential. In this project, the single-walled and multi-walled carbon nanotubes were employed to test the possibility of removing heavy metal ions, such as Fe²⁺, Cd²⁺, Pb²⁺ and Ni²⁺. The effects of three factors including carbon nanotubes, ions’ initial concentration, and contact time were tested. According to the difference rate of nanotubes’ adsorption diagrams, the maximum differences in the performance of single- and multi-walled are obtained as 30 percent for the initial solution concentration and  around 5 percent for Nano adsorbent concentration. The results showed that in the different initial concentrations of metal ions, multi-walled nanotube had a better performance, while in case of changing the amount of adsorbent; the single-walled nanotube had a higher adsorption. And if the time changes, multi-walled carbon nanotube can have a higher adsorption.