General synthesis of ultrafine metal oxide/reduced graphene oxide nanocomposites for ultrahigh-flux nanofiltration membrane

Abstract

Graphene-based membranes have great potential to revolutionize nanofiltration technology, but achieving high solute rejections at high water flux remains extremely challenging. Herein, a family of ultrafine metal oxide/reduced graphene oxide (rGO) nanocomposites are synthesized through a heterogenous nucleation and diffusion-controlled growth process for dye nanofiltration. The synthesis is based on the utilization of oxygen functional groups on GO surface as preferential active sites for heterogeneous nucleation, leading to the formation of sub-3 nm size, monodispersing as well as high-density loading of metal oxide nanoparticles. The anchored ultrafine nanoparticles could inhibit the wrinkling of the rGO nanosheet, forming highly stable colloidal solutions for the solution processing fabrication of nanofiltration membranes. By functioning as pillars, the nanoparticles remarkably increase both vertical interlayer spacing and lateral tortuous paths of the rGO membranes, offering a water permeability of 225 L m−2 h−1 bar−1 and selectivity up to 98% in the size-exclusion separation of methyl blue.

In Situ Reduced Graphene Oxide and Polyvinyl Alcohol Nanocomposites With Enhanced Multiple Properties

“…The incorporation of GO increased the FWHM of nanocomposites, indicating more oxygen containing groups inside. However, the FWHM decreased with the increase of GO wt% and also high DS of the carbazate groups for PVA-N-GO, attributed to more rGO existed inside the corresponding nanocomposites ( Rahoui et al, 2018 ; Zhang et al, 2022 ).…”

Nanocomposite Polymeric Membranes for Organic Micropollutant Removal: A Critical Review

“…Pristine GO- or rGO-coated membranes have low flux due to short d -spacings of GO and rGO laminates (0.8 and 0.35 nm, respectively) . This dense membrane structure would greatly hinder water transport leading to extremely low water permeation due to strong capillary forces in the compact nanochannels . While dense graphene membranes are effective at rejecting OMPs, the extremely low water fluxes through these membranes limit their use for most applications requiring OMP removal.…”

A Review of Advancing Two-Dimensional Material Membranes for Ultrafast and Highly Selective Liquid Separation

“…Widening the interlayer spacing has been used to modulate permeation in rGO films, and can comprise cationic crosslinking [103], carbon nanotube intercalation [104], polymer additives [105], etc. Zhang et al [106] demonstrated a versatile and facile method to synthesize ultrafine metal oxide/rGO nanocomposites through a heterogeneous nucleation and growth process for nanofiltration applications (Figure 7a). The uniform adhesion of these ultrafine metal oxide nanoparticles effectively suppressed the wrinkling and stacking of the resulting rGO sheets.…”