A review on membrane fabrication: Structure, properties and performance relationship

In this chapter, organic/montmorillonite nanocomposite membrane and membrane fabrication techniques are discussed. The fabrication technique, properties of the fabricated membranes, and performance are explained in detail and compared. With the addition of clay addition, important parameters which affect the membrane performance, such as crystallinity, porous structure, hydrophobicity/hydrophilicity, membrane charge, and surface roughness were analyzed. Despite the fact that extensive knowledge exist on membrane pore structure after clay incorporation including its surface properties and cross-section morphology by selection of appropriate fabrication methods, there is still a challenge to produce reliable membranes with antifouling properties, thermal resistance, chemical resistance, high-mechanical strength with high flux and selectivity. To ensure progress in polymer–clay membrane performance, further improvements are needed for common membrane fabrication techniques, such as solution casting, phase inversion, and interfacial polymerization. At the same time, the potential of novel fabrication techniques such as electro spinning and track-etching are also assessed. A comprehensive understanding between structure-surface properties and performance is a key for further development and progress in organic/montmorillonite membrane technology.

A review of superhydrophobic and omniphobic membranes as innovative solutions for enhancing water desalination performance through membrane distillation

Experimental and theoretical investigation of thin ZIF-8/chitosan coated layer on air gap membrane distillation performance of PVDF membrane

Graphene-coated membranes for membrane distillation have been fabricated by using a wet-filtration approach. Graphene nanoplatelets have been deposited onto PVDF membrane surfaces. Morphology and physicochemical properties have been explored to evaluate the changes in the surface topography and related effects on the membrane performance in water desalination. The membranes have been tested in membrane distillation plants by using mixtures of sodium chloride and humic acid. The multi-scale rough structure of the surface has been envisaged to amplify the wetting and fouling resistance of the graphene-coated membranes so that a better flux and full salt rejection have been achieved in comparison with pristine PVDF. Total salt rejection and an increase of 77% in flux have been observed for coated membrane with optimized graphene content when worked with NaCl 0.6 M (DCMD, ΔT ≈ 24 °C) over a test period of 6 h. The experimental findings suggest these novel graphene-coated membranes as promising materials to develop functional membranes for high-performing water desalination.

Chapter 4 - Fabrication of sustainable membranes with functionalized nanomaterials (FNMs)

A new procedure to produce poly(vinylidene fluoride)/boron nitride hybrid membrane is presented for application in membrane distillation (MD) process. The influence of hexagonal boron nitride (h-BN) incorporation on the performance of the polymeric membranes is studied through the present investigation. For this aim, h-BN nanopowders were successfully synthesized using the simple chemical vapor deposition (CVD) route and subsequent solvent treatments. The resulting h-BN nanosheets were blended with poly(vinylidene fluoride) (PVDF) solution. Then, the prepared composite solution was subjected to phase inversion process to obtain PVDF/h-BN hybrid membranes. Various examinations such as scanning electron microscopy (SEM), wettability, permeation flux, mechanical strength and liquid entry pressure (LEP) measurements are performed to evaluate the prepared membrane. Moreover, Air gap membrane distillation (AGMD) experiments were carried out to investigate the salt rejection performance and the durability of membranes. The results show that our hybrid PVDF/h-BN membrane presents higher water permeation flux (~18 kg/m2 h) compared to pristine PVDF membrane. In addition, the experimental data confirms that the prepared nanocomposite membrane is hydrophobic (water contact angle: ~103 degree),has a porous skin layer (>85%), as well competitive fouling resistance and operational durability. Furthermore, the total salt rejection efficiency was obtained for PVDF/h-BN membrane. The results prove that the novel PVDF/h-BN membrane can be easily synthesized and applied in MD process for salt rejection purposes.

The study of performance of polyethylene chlorinetrifluoroethylene membranes used for brine desalination by membrane distillation

Robust omniphobic ceramic hollow fibre membrane with leaf-like copper oxide hierarchical structure by membrane distillation

Hydrophobic porous alumina hollow fiber for water desalination via membrane distillation process

Polyvinylidene fluoride (PVDF) membrane for oil rejection from oily wastewater: A performance review

Role of covalent crosslinking and 2D nanomaterials in the fabrication of advanced organic solvent nanofiltration membranes: A review of fabrication strategies, recent advances, and challenges

Recent developments in polymeric nano-based separation membranes

Improved PVDF membrane performance by doping extracellular polymeric substances of activated sludge

Molecular dynamics study on water desalination performance and related mechanism of hydrophobic α-Al2O3 ceramic membrane

Polymeric membrane is widely adopted for water treatment due to its stability in thermal and chemical resistance, smaller footprints and relatively low cost. However, polymer membrane always suffers the poor performance due to its hydrophobic nature. In the recent years, nanomaterials were introduced into membrane matrices to increase the hydrophilicity. In this study, three different types of nanomaterial, iron oxide (Fe3O4), graphene oxide (GO), and iron oxide-decorated graphene oxide (Fe3O4/GO) were embedded in the polysulfone (PSf) mixed-matrix membranes (MMM). This study investigated the effect of three different nanomaterials on the membrane characteristics, performance, and antifouling properties. Membrane characterization, performance, and antifouling was carried out by pore size, porosity, contact angle analysis, zeta potential analysis, flux measurements and flux recovery ratio respectively. First, GO, Fe3O4 and Fe3O4/GO nanomaterials were synthesized using Hummers method, co-precipitation method, and co-precipitation method in the presence of GO. After that, membranes were fabricated using phase inversion method. In this study, Fe3O4/GO-PSf MMM (76.35%) and GO-PSf MMM (64.39%) showed enhanced porosity as compared to the pure PSf membrane (56.89%) due to the presence of abundance hydrophilic group in GO nanoplates. However, the Fe3O4-PSf MMM show slightly lower porosity (53.82%). Contact angle analysis also revealed that Fe3O4-PSf MMM (71.47°), GO-PSf MMM (69.17°), Fe3O4/GO-PSf MMM (69.97°) showed improved hydrophilicity as compared to the pure PSf membrane (78.80°). Experiment also demonstrated that all the MMMs exhibit higher negatively surface zeta potential as compared to pure PSf membrane. The membrane performances were investigated using pure water flux and congo red (CR) dye removal. Study showed that Fe3O4/GO-PSf MMM give the best membrane performance with the flux of 112.47 L/m2. h and CR dye removal of 97%±2. Fouling analysis reveal that all MMMs exhibit high flux recovery ratio (>80%) as compare to pure PSf membrane.