Concentrative isolation of uranium traces in aqueous solutions via resurfaced-magnetic carbon nanotube suspension. (1st October 2020)

• Record Type: Journal Article
• Authors: Aljarrah, Mohannad T.; Al-harahsheh, Mohammad S.; Alrebaki, Muna A.; Mayyas, Mohannad
• Is Part Of: Journal of environmental management. Volume 271(2020)
• Publication Date: 2020-10-01
• Subjects: Multi-wall carbon nanotubes -- PEI -- Magnetic nanocomposite -- Grafting -- Adsorption -- Uranium; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2020.110970
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The concentrative isolation of metal traces from aqueous solutions is of vital importance for environmental and industrial processes. Developing reliable systems of nanoscale that can be fine-tuned to effectively isolate these metals remains an intriguing aim which can potentially beget economic benefits and mitigate major environmental concerns. Here we demonstrate a conceptual metal extraction system where magnetic multi-wall carbon nanotubes (M-MWCNTs) are surface-equipped with a molecular network of polyethylenimine (PEI) to serve as a reusable nano-ionic exchanger, referred to as "M-MWCNTs-PEI". The designed nano-ionic exchanger forms readily stable suspensions with the metal-bearing aqueous solutions eliminating the need for vigorous agitation. Besides, it can be magnetically manipulated and separated in/from the solution. To exemplify its potential for the isolation of metal traces, the M-MWCNTs-PEI was tested with the uranium trace ions in aqueous media. The M-MWCNTs-PEI featured distinct sorption capacity of ~488 mg/g at pH 6, with moderate, but stable, binding affinity toward uranium ions. As such, excellent isolation performance is demonstrated while bound uranium ions are effectively concentrated and recovered from the interfacial PEI molecular network. This was efficiently achieved by exposing the loaded M-MWCNTs-PEI to solutions of small volumes and specific chemistry. Such combined qualities of large capacity and reusability have not been observed with the previously reported ion exchange systems. Altogether, our observations here demonstrate how functional systems of nanoscale can be adapted for industrial applications while this concept can be extended to address other important resources such as rare-earth and lanthanide elements. Graphical abstract: Image 1 Highlights: Successful preparation of magnetic MWCNTs grafted by polyethylenimine (M-MWCNT-PEI) was achieved. M-MWCNTs-PEI nano-composite was able to uptake 488 mg/g at pH = 6. Magnetic properties of M-MWCNTs-PEI provided simple separation from aqueous solution using magnets. The prepared nanocomposite demonstrated good reusability and stability for U separation from aqueous solutions.