Adsorption of aqueous cadmium (II) onto modified multi-walled carbon nanotubes following microwave/chemical treatment

• Published in: Desalination Vol. 249; no. 2; pp. 792 - 796
• Main Authors: Kuo, Chao-Yin, Lin, Han-Yu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2009; Elsevier
• Subjects: Adsorption; Applied sciences; Cadmium; Cadmium ion (II); Carbon monoxide; Carbon nanotubes; Chemical engineering; Exact sciences and technology; Microwave; Microwaves; Multi wall carbon nanotubes; Pollution; Spectra; Surface area; Surface chemistry; Microwave; Carbon nanotubes; Cadmium ion (II); Adsorption; Second order; Adsorption capacity; Microwave heating; Modeling; Chemical treatment; Hydroxyl group; pH; Kinetics; Surface area
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2008.11.023

This study evaluates the aqueous cadmium (II) adsorption efficiency of as-grown carbon nanotubes (CNTs) and of those modified by microwave (MW)/H 2SO 4 and MW/H 2SO 4/KMnO 4 processes. The surface area, pH iep, and FTIR spectra of CNTs were, before and after modification, compared. Aromatic groups, carbonyl groups and hydroxyl groups were herein detected on the surfaces of MW/H 2SO 4 and MW/H 2SO 4/KMnO 4-modified CNTs. At a particular pH, the adsorption capacity of Cd 2+ of the MW/H 2SO 4/KMnO 4-modified CNTs exceeded that of MW/H 2SO 4-modified CNTs and as-grown CNTs. The kinetic analyses of adsorption were performed and a pseudo second-order model accurately captured the adsorption kinetics. This study suggests that MW/H 2SO 4 and MW/H 2SO 4/KMnO 4 modification not only increased the area of active adsorption sites of CNTs but also reduced the modification period by microwave heating.