Selective solid phase extraction and determination of trace Pd(II) using multi-walled carbon nanotubes modified with 8-aminoquinoline

• Published in: Journal of molecular liquids Vol. 232; pp. 139 - 146
• Main Authors: Shaheen, Huda A., Marwani, Hadi M., Soliman, Ezzat M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2017
• Subjects: 8-aminoquinoline, Pd(II); Adsorption; Carbon nanotubes; ICP-OES; Carbon nanotubes; Adsorption; ICP-OES; 8-aminoquinoline, Pd(II)
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2017.02.069

In this article, a new solid phase, oxidized multi-walled carbon nanotubes (MWCNTs-COOH) functionalized with 8-aminoquinoline (8-AQ) was prepared, and then used for the extraction and determination of the divalent palladium ions, Pd(II), from water samples was developed using inductively coupled plasma optical emission spectrometry (ICP-OES). The effects of various parameters such as pH, adsorption capacity and contact time have been investigated. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 7.09mgg−1. The adsorption data of Pd(II) were modeled using both Langmuir and Freundlich classical adsorption isotherms, and based on the least square fit, a linear plot was obtained from Langmuir isotherm equation confirming the validity of Langmuir adsorption isotherm model for the adsorption process and the results showed that obeyed Langmuir model. Also, the kinetic study of Pd(II) was modeled using both pseudo first-order and pseudo second-order models, and the results demonstrated that the adsorption of Pd(II) onto modified carbon nanotubes with 8-aminoquinoline (MCNTs-8-AQ) obeyed a pseudo-second-order kinetic model. The utility of the MCNTs-8-AQ was tested in some environmental water samples and showed the percentage of extraction up to 85.0%, reflecting its accuracy and reproducibility.
The graph shows the SEM images for (a) MWCNTs-COOH and (b) MCNTs-8-AQ. [Display omitted]
•Modified multi-walled carbon nanotubes with 8-aminoquinoline (MCNTs-8-AQ) synthesized and characterized•MCNTs-8-AQ were used for selective adsorption of trace Palladium (Pd(II)).•The effect of different parameters that affected the adsorption process was explored.•The adsorption data of Pd(II) were modeled using both classical adsorption isotherms and kinetic studies.•The utility of the MCNTs-8-AQ was tested in some environmental water samples.