Realizing small-flake graphene oxide membranes for ultrafast size-dependent organic solvent nanofiltration.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32494655.
- Also identified by DOI 10.1126/sciadv.aaz9184 and PMC identifier 7182426.
- Licence recorded as CC BY-NC.
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Abstract
Membranes for organic solvent nanofiltration (OSN) or solvent-resistant nanofiltration (SRNF) offer unprecedented opportunities for highly efficient and cost-competitive solvent recovery in the pharmaceutical industry. Here, we describe small-flake graphene oxide (SFGO) membranes for high-performance OSN applications. Our strategy exploits lateral dimension control to engineer shorter and less tortuous transport pathways for solvent molecules. By using La<sup>3+</sup> as a cross-linker and spacer for intercalation, the SFGO membrane selective layer was stabilized, and size-dependent ultrafast selective molecular transport was achieved. The methanol permeance was up to 2.9-fold higher than its large-flake GO (LFGO) counterpart, with high selectivity toward three organic dyes. More importantly, the SFGO-La<sup>3+</sup> membrane demonstrated robust stability for at least 24 hours under hydrodynamic stresses that are representative of realistic OSN operating conditions. These desirable attributes stem from the La<sup>3+</sup> cross-linking, which forms uniquely strong coordination bonds with oxygen-containing functional groups of SFGO. Other cations were found to be ineffective.