The adsorption kinetics of cadmium by three different types of carbon nanotubes
Article
-
- Overview
-
- Research
-
- Identity
-
- Additional Document Info
-
- View All
-
Overview
abstract
-
Oxidized nitrogen-doped multiwall carbon nanotubes (ox-N-MWCNTs), oxidized multiwall carbon nanotubes (ox-MWCNTs), and oxidized single-wall carbon nanotubes (ox-SWCNTs) were evaluated via batch adsorption kinetic experiments to determine the effect of nanotube morphology on the adsorption rate of cadmium. The nanotubes were characterized by HRTEM, XRD and Raman spectroscopy. Cadmium adsorption isotherms were determined at pH 6. Analyses of the kinetic data with an external mass transport model and an intraparticle diffusion model considered two cases: (1) single nanotubes suspended in aqueous solution and (2) agglomerates of nanotubes suspended in aqueous solution. The intraparticle diffusion model produced the best fit to the experimental data. However, only the diffusivity coefficients for single nanotubes suspended in solution were similar to literature values: about 4×10-9, 1×10-9 and 2.4×10-11cm2/s for ox-N-MWCNTs, ox-MWCNTs and ox-SWCNTs, respectively. The morphology of the various carbon nanotubes might determine cadmium diffusivity. The high amount of sidewall pores observed in the single-walled carbon nanotubes could limit cadmium diffusion and account for the slow diffusion rate of 180min. Conversely, the short length, small surface area and bamboo-type morphology observed with nitrogen-doped multiwall carbon nanotubes may account for the relatively fast adsorption rate of 15min as this morphology prevents cadmium diffusion through the internal tubular space of these nanotubes. © 2011 Elsevier Inc.
publication date
funding provided via
published in
Research
keywords
-
Adsorption kinetics; Carbon nanotubes; Diffusion; Morphology; Toxic metals Adsorption kinetics; Adsorption rates; Batch adsorption; Best fit; Cadmium diffusion; Diffusivity coefficient; Experimental data; Intraparticle diffusion models; Kinetic data; Mass transport model; Nanotube morphology; Nitrogen-doped; Single nanotubes; Single-wall carbon nanotubes; Slow diffusion; Surface area; Toxic metals; XRD; Adsorption; Agglomeration; Cadmium; Diffusion; Doping (additives); Dyes; High energy physics; Kinetics; Morphology; Multiwalled carbon nanotubes (MWCN); Raman spectroscopy; Solutions; Single-walled carbon nanotubes (SWCN); cadmium; multi walled nanotube; nanocrystal; nitric acid; nitrogen; single walled nanotube; adsorption kinetics; aqueous solution; article; chemical analysis; chemical bond; chemical modification; isotherm; nonhuman; oxidation; particle size; pH; physical chemistry; priority journal; Raman spectrometry; X ray diffraction
Identity
Digital Object Identifier (DOI)
Additional Document Info
start page
end page
volume
issue