State-of-the-Art of Polymer/Fullerene C60 Nanocomposite Membranes for Water Treatment: Conceptions, Structural Diversity and Topographies

Abstract

To secure existing water resources is one of the imposing challenges to attain sustainability and ecofriendly world. Subsequently, several advanced technologies have been developed for water treatment. The most successful methodology considered so far is the development of water filtration membranes for desalination, ion permeation, and microbes handling. Various types of membranes have been industrialized including nanofiltration, microfiltration, reverse osmosis, and ultrafiltration membranes. Among polymeric nanocomposites, nanocarbon (fullerene, graphene, and carbon nanotubes)-reinforced nanomaterials have gained research attention owing to notable properties/applications. Here, fullerene has gained important stance amid carbonaceous nanofillers due to zero dimensionality, high surface areas, and exceptional physical properties such as optical, electrical, thermal, mechanical, and other characteristics. Accordingly, a very important application of polymer/fullerene C₆₀ nanocomposites has been observed in the membrane sector. This review is basically focused on talented applications of polymer/fullerene nanocomposite membranes in water treatment. The polymer/fullerene nanostructures bring about numerous revolutions in the field of high-performance membranes because of better permeation, water flux, selectivity, and separation performance. The purpose of this pioneering review is to highlight and summarize current advances in the field of water purification/treatment using polymer and fullerene-based nanocomposite membranes. Particular emphasis is placed on the development of fullerene embedded into a variety of polymer membranes (Nafion, polysulfone, polyamide, polystyrene, etc.) and effects on the enhanced properties and performance of the resulting water treatment membranes. Polymer/fullerene nanocomposite membranes have been developed using solution casting, phase inversion, electrospinning, solid phase synthesis, and other facile methods. The structural diversity of polymer/fullerene nanocomposites facilitates membrane separation processes, especially for valuable or toxic metal ions, salts, and microorganisms. Current challenges and opportunities for future research have also been discussed. Future research on these innovative membrane materials may overwhelm design and performance-related challenging factors.

Keywords: fullerene C60; membrane; nanocomposite; nanofiltration; permeability; polymer; salt rejection; selectivity; water treatment.

Figure 1

Fullerene nanostructures.

Figure 2

Fabrication of conventional nanocomposite membranes [130]. Reproduced with permission from Elsevier.

Figure 3

Snapshots of cis-1,4-polyisoprene and C₆₀-based nanocomposite membranes with varying nanofiller contents from 0 (melt) to 32 phr [153]. Reproduced with permission Creative Commons Attribution License.

Figure 4

Fabrication process and water desalination setup using C₆₀-grafted graphene oxide membranes. (a) Graphene oxide membrane without C₆₀; (b) C₆₀-grafted graphene oxide membrane; (c) optical micrograph of a cross-sectional area with a scale bar of 100 µm. The micrograph shows 148 µm thick graphene oxide laminates embedded in 81 µm thick epoxy; (d) graphene oxide-C₆₀ membrane encapsulated with epoxy in a plastic disk of 47 mm; (e) graphene oxide-C₆₀ membrane inside a water desalination setup; (f,g) schematic setup of a flat membrane made of graphene oxide and a C₆₀ hybrid for water desalination [162]. Reproduced with permission from American Chemical Society.

Figure 5

Optical micrographs of Nafion/C₆₀ fullerene nanocomposites (a) and Nafion/polyhydroxy fullerene nanocomposites (b) by doping and Nafion/C₆₀ fullerene nanocomposites (c) and Nafion/polyhydroxy fullerene nanocomposites (d) by solution casting [176]. Reproduced with permission from Elsevier.

Figure 6

(a) Initial structure of C₆₀ and Nafion oligomers; (b) snapshots of Nafion oligomers; (c) C₆₀ and Nafion oligomers; and (d) polyhydroxy and Nafion oligomers (taken after 1 ns molecular dynamic simulations) [176]. Reproduced with permission from Elsevier.

Figure 7

Graphical development of novel polyphenylene isophthalamide pervaporation (PV) membranes modified with various types of fullerene C₆₀ derivatives [166]. Reproduced with permission from Elsevier.

Figure 8

Dependence of the permeation flux on the methanol content in feed for membranes based on neat PA and nanocomposites with fullerene and fullerene derivatives during pervaporation of methanol-toluene mixtures with 10–72 wt % methanol (22 °C) [166]. PA, polyphenylene isophthalamide; PA/F, polyphenylene isophthalamide/fullerene; PA/CF, polyphenylene isophthalamide/carboxyfullerene; PA/AF, polyphenylene isophthalamide/fullerene derivative with L-arginine; PA/HF, polyphenylene isophthalamide/polyhydroxylated fullerene. Reproduced with permission from Elsevier.

Figure 9

Distribution of the pore volume measured from scanning electron microscopy of nanofibers [188]. PS, polystyrene; C₆₀-PS, fullerene-polystyrene; MWCNT-PS, multi-walled carbon nanotube-polystyrene; GO-PS, graphene oxide-polystyrene. Reproduced with permission from Elsevier.

Figure 10

Transmission electron microscopic images of the neat PS and the nanocomposite nanofiber [188]. PS, polystyrene; C₆₀-PS, fullerene-polystyrene; MWCNT-PS, multi-walled carbon nanotube-polystyrene; GO-PS, graphene oxide-polystyrene. Reproduced with permission from Elsevier.