Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 3, 2020
Previous Article Next Article

Water-dispersible few-layer graphene flakes for selective and rapid ion mercury (Hg2+)-rejecting membranes

Author affiliations

Abstract

Mercury (Hg) is a global highly toxic pollutant released by both anthropogenic and natural sources. Hg decontamination is of the utmost importance for human and ecosystem protection. Here, we propose a novel graphene-based membrane capable of performing rapid and highly selective Hg2+-rejection from water. Functionalized graphene flakes are produced by a non-oxidative, room-temperature and post processing-free “green” method to simultaneously exfoliate graphite into single-/few-layer graphene (SLG/FLG) flakes in water and functionalize them with cationic rhodamine 6G (R6G) via a physisorption process (aromatic ring π–π stacking). The rhodamine 6G-functionalized graphene (R6G-FG) membrane shows a low-density (<0.5 g cm−3) packed laminar structure, where R6G molecules act as spacers between the SLG/FLG flakes. The presence of hydrophilic micro/nanodomains in this low-density structure results in a water permeation rate as high as 789.6 L m−2 h−1 bar−1 (for an 80 μm-thick membrane, R6G-FG mass loading of 3.58 g m−2). Meanwhile, the R6G-FG complexes perform as ion-selective nano-traps for Hg2+, showing almost complete rejection (>99%) for a filtered solution volume normalized to the R6G-FG mass superior to 3 L g−1. The selective rejection capability of the R6G-FG membrane is ruled by competitive adsorption of metal ions and positively charged R6G molecules with different affinity onto the negatively charged graphene surface. Lastly, a washing treatment in alkaline conditions is also proposed for membrane regeneration and reuse. The rationalization of the working mechanism of the R6G-FG membrane is promising for eliminating the “permeability–selectivity trade-offs” often tackled by laminar two-dimensional material membranes.

Graphical abstract: Water-dispersible few-layer graphene flakes for selective and rapid ion mercury (Hg2+)-rejecting membranes

Back to tab navigation

Supplementary files

Article information


Submitted
28 Feb 2020
Accepted
28 Apr 2020
First published
29 Apr 2020

This article is Open Access

Mater. Adv., 2020,1, 387-402
Article type
Paper

Water-dispersible few-layer graphene flakes for selective and rapid ion mercury (Hg2+)-rejecting membranes

L. Najafi, R. Oropesa-Nuñez, B. Martín-García, F. Drago, M. Prato, V. Pellegrini, F. Bonaccorso and S. Bellani, Mater. Adv., 2020, 1, 387
DOI: 10.1039/D0MA00060D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

Reproduced material should be attributed as follows:

  • For reproduction of material from NJC:
    [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
  • For reproduction of material from PCCP:
    [Original citation] - Published by the PCCP Owner Societies.
  • For reproduction of material from PPS:
    [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
  • For reproduction of material from all other RSC journals:
    [Original citation] - Published by The Royal Society of Chemistry.

Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.


Social activity

Search articles by author

Spotlight

Advertisements