Advanced Polymeric Nanocomposite Membranes for Water and Wastewater Treatment: A Comprehensive Review

Abstract

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, selectivity), but also the intrinsic properties (hydrophilicity, porosity, antifouling properties, antimicrobial properties, mechanical, thermal, and chemical stability) of these membranes. This review focuses on applications of different types of nanomaterials: zero-dimensional (metal/metal oxide nanoparticles), one-dimensional (carbon nanotubes), two-dimensional (graphene and associated structures), and three-dimensional (zeolites and associated frameworks) nanomaterials combined with polymers towards novel polymeric nanocomposites for water and wastewater treatment applications. This review will show that combinations of nanomaterials and polymers impart enhanced features into the pristine membrane; however, the underlying issues associated with the modification processes and environmental impact of these membranes are less obvious. This review also highlights the utility of computational methods toward understanding the structural and functional properties of the membranes. Here, we highlight the fabrication methods, advantages, challenges, environmental impact, and future scope of these advanced polymeric nanocomposite membrane based systems for water and wastewater treatment applications.

Keywords: biopolymers; computational studies; desalination; inorganic nanoparticles; polymer nanocomposites; water treatment.

Figure 6

Fabrication of blend containing polyvinylidene difluoride and TiO₂ nanoparticles into a membrane for oil–water separation. Adapted with permission from Du et al. [205]. Copyright (2021) Elsevier.

Figure 8

Cross sectional SEM illustration of (a) pristine PSf, (b) 1000 ppm GO loaded PSf, (c) 2000 ppm GO loaded PSf. Adapted with permission from Ganesh et al. [232]. Copyright (2013) Elsevier.

Figure 11

Migration behavior of Cu²⁺ on the ZIF–8 framework (a–c). Adapted with permission from Li et al. [286]. Copyright (2022) Elsevier.

Figure 1

Various methods of integrating nanoparticles with polymer to form polymer nanocomposite membranes: (a) Schematic representation of one of the phase inversion methods (non-solvent-induced phase separation) for fabrication of polysulfone (PSf) layer. (b) Integration of nanoparticles either in the polyamide (PA) layer or as a thin layer at the bottom of the PA layer on top of PSf layer in nanocomposite membrane using interfacial polymerization method (MPD—m-phenylenediamine, TMC—trimesoyl chloride). (c) Short polymer strands grafted on a nanoparticle surface or nanoparticles grafted from the polymer membrane. (d) Pressure driven filtration of dispersion/solution of polymer and nanoparticles (polymer grafted nanoparticles example in this case). (e) Dip coating of polymeric membrane in a dispersion/solution containing nanoparticles. (f) Electrospinning of nanoparticles added in sol–gel (g). Layer-by-layer assembly of polymer and nanoparticles (NPs—nanoparticles, NWs—nanowires), [83], © American Chemical Society, 2008. For easy interpretation, spherical shapes are used for nanoparticles in most of the figures.

Figure 2

Classification of nanomaterials of carbon allotropes based on their dimensionality. Adapted with permission from Gaur et al. [85]. Copyright (2021) MPDI.

Figure 3

Research impact of thin-film polymeric nanocomposites analyzed using web of science database for the past decade.

Figure 4

Fabrication of SiO₂−coated polyamide-based membrane for high-capacity rejection and antifouling activity. Adapted with permission from Istirokhatun et al. [123]. Copyright (2021). Elsevier.

Figure 5

Scanning electron microscopy (SEM) revealed that pore size is directly proportional to diatom loading. SEM surface porosity images of (a) Polysulfone (PSf) with 0.0% of diatom, (b) PSf with 0.1 wt.% of diatom, (c) PSf with 0.2 wt.% of diatom, (d) PSf with 0.5 wt.% diatom (×50,000, 100 nm scale bar in all micrographs). Adapted from Paidi et al. [172]. Copyright (2022) MDPI.

Figure 7

Schematic of the fabrication of anthracene-ending hyperbranched poly(ether amine)-coated carbon nanotube thin films formed by vacuum filtration. Adapted with permission from Zhang et al. [221]. Copyright (2016) American Chemical Society.

Figure 9

A 21 wt.% ZIF–8 loaded 2,2,6,6-tetramethylpiperidine 1-oxyl radical oxidized cellulose nanofibers membrane. Adapted with permission from Song et al. [279]. Copyright (2019) Elsevier.

Figure 10

Integration of new membrane properties due to ZIF–8 addition: (a) Enhanced hydrophilicity in ZIF–8 modified membrane [280], © Elsevier, 2022; (b) Possible mechanism for ZIF–8 mediated photocatalytic degradation of methylene blue [69], © ACS Omega, 2018.

Figure 12

Mechanisms of free–standing bacterial cellulose and graphene oxide membrane for selective ion permeation. Adapted with permission from Fang et al. [70]. Copyright (2016) Scientific Reports.

Figure 13

Various approaches of fabricating polymers and nanomaterials into membranes for water treatment applications: (a) cysteine-grafted cellulose nanofibers impregnated in electrospun polyacrylonitrile scaffold (microfiltration) [384], © Elsevier, 2014; (b) Graphene oxide (GO)-coated chitosan nanoparticles incorporated into (TFN-M) or at the bottom (TFN-U) of polyamide (PA) layer during interfacial polymerization process (ultrafiltration) [64], © Elsevier, 2021; (c) carboxylated carbon nanofibers embedded into polysulfone layer via phase inversion process with PA layer on top (forward osmosis) [385], © Elsevier, 2020; (d) GO coated on PA layer via layer-by-layer technique [386], © Elsevier, 2022; (e) Vacuum filtration of bacterial cellulose and GO dispersion [70], © Scientific Reports, 2016; (f) Membrane based on electrospun fibers of homogenous slurry of polyvinylidene difluoride and GO mixed with metal organic framework [67], © Elsevier 2022.