A comprehensive review of the application of modified carbon nanotubes (CNTs) for the removal of metals from wastewater

Abstract

Carbon nanotubes (CNTs), a type of carbonaceous material, have extremely distinctive qualities in terms of tensile strength, heat stability, electrical conductivity, catalysis, and adsorption. These properties rely on structure, length, and thickness. Carbon nanotube and metal oxide combination have been successfully used over the past few decades to create carbon nanomaterials with extraordinary features. The current study offers an outline of the developments in the theory, procedures, and chemical modification of CNT with metals or polymers. This review presents different synthesis methods of functionalized CNTs along with their properties and factors affecting their adsorption capacity. In addition, it explains the role of different functionalized CNTs in removing different metals like Pb ^2+ , Cd ^2+ , Cr ^3+ , Cr ^6+ , Ni ^2+ , Tl ^+3 , and Hg ^2+ from wastewater. The adsorption capacity of these modified CNTs is in the range of 130–180 mg g ^−1 . This review offers an essential understanding of the methods for creating multifunctional nano-hybrids for various applications and prospects of using nanomaterials for environmental remediation.

Keywords

• carbon nanotubes
• nanocomposites
• heavy metal removal
• adsorption
• electrostatic interactions
• physical adsorption