کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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152707 | 456504 | 2010 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Removal of cadmium from aqueous solutions by oxidized and ethylenediamine-functionalized multi-walled carbon nanotubes Removal of cadmium from aqueous solutions by oxidized and ethylenediamine-functionalized multi-walled carbon nanotubes](/preview/png/152707.png)
Surface functionalization of multi-walled carbon nanotubes (MWCNTs) by ethylenediamine, via chemical modification of carboxyl groups, using O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate, was performed. The resulting materials were characterized by different techniques, such as FTIR, TGA and elemental analysis. Biocompatibility studies showed that the functionalized MWCNTs, at concentrations between 1 and 50 μg mL−1, were not cytotoxic for the fibroblast L929 cell line. In batch tests, the influences of solution pH, contact time, initial metal ion concentration and temperature on the sorption of Cd2+ ions onto raw-MWCNTs (raw-MWCNT), oxidized MWCNTs (o-MWCNT) and ethylenediamine-functionalized MWCNTs (e-MWCNT) were studied. The adsorption of Cd2+ ions by o-MWCNT and e-MWCNT was strongly pH dependent. The time dependent Cd2+ sorption onto raw-MWCNT, o-MWCNT and e-MWCNT can be described by a pseudo-second-order kinetic model. The Langmuir isotherm model agrees well with the equilibrium experimental data. The maximum capacity was obtained for e-MWCNT, 25.7 mg g−1, at 45 °C. The thermodynamic parameters were also deduced for the adsorption of Cd2+ ions on raw-MWCNT, o-MWCNT and e-MWCNT and the results showed that the adsorption was spontaneous and endothermic.
Journal: Chemical Engineering Journal - Volume 157, Issue 1, 15 February 2010, Pages 238–248