Patterned superhydrophobic polyvinylidene fluoride (PVDF) membranes for membrane distillation: Enhanced flux with improved fouling and wetting resistance

Kharraz, Jehad A.; An, Alicia Kyoungjin

doi:10.1016/j.memsci.2019.117596

Cited by 100 publications

(37 citation statements)

References 38 publications

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“…Before reaching the constant value, the negative slope on the plot reflects the transition between pore blocking and cake filtration where a large reduction occurs in the flux decline rate [ 41 ]. The results of the flux decline measurements and data analysis are consistent with numerous other studies that have shown how patterning with micron-scale features can reduce fouling [ 17 , 42 , 43 ]. Some of the reasons for the decreased fouling propensity include increased shear stress on the apex regions of patterned membranes, vortex formation in regions of the pattern valleys, and selective particle accumulation in the valleys during the initial stage of fouling [ 15 , 35 , 43 , 44 ].…”

Section: Resultssupporting

confidence: 88%

Evaluating Protein Fouling on Membranes Patterned by Woven Mesh Fabrics

Malakian

Husson

2021

Membranes

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Membrane surface patterning is one approach used to mitigate fouling. This study used a combination of flux decline measurements and visualization experiments to evaluate the effectiveness of a microscale herringbone pattern for reducing protein fouling on polyvinylidene fluoride (PVDF) ultrafiltration membranes. Thermal embossing with woven mesh stamps was used for the first time to pattern membranes. Embossing process parameters were studied to identify conditions replicating the mesh patterns with high fidelity and to determine their effect on membrane permeability. Permeability increased or remained constant when patterning at low pressure (≤4.4 MPa) as a result of increased effective surface area; whereas permeability decreased at higher pressures due to surface pore-sealing of the membrane active layer upon compression. Flux decline measurements with dilute protein solutions showed monotonic decreases over time, with lower rates for patterned membranes than as-received membranes. These data were analyzed by the Hermia model to follow the transient nature of fouling. Confocal laser scanning microscopy (CLSM) provided complementary, quantitative, spatiotemporal information about protein deposition on as-received and patterned membrane surfaces. CLSM provided a greater level of detail for the early (pre-monolayer) stage of fouling than could be deduced from flux decline measurements. Images show that the protein immediately started to accumulate rapidly on the membranes, likely due to favorable hydrophobic interactions between the PVDF and protein, followed by decreasing rates of fouling with time as protein accumulated on the membrane surface. The knowledge generated in this study can be used to design membranes that inhibit fouling or otherwise direct foulants to deposit selectively in regions that minimize loss of flux.

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Section: Resultssupporting

confidence: 88%

Evaluating Protein Fouling on Membranes Patterned by Woven Mesh Fabrics

Malakian

Husson

2021

Membranes

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“…One can also chemically modify the surface to increase the contact angle of a nanofiber surface [95], or nanoparticles coated surfaces [69] [16]. Electrospun [96] or electrospray [46] have been utilized to improve the surface roughness and the fluorination achieved by CF4 [97,98] or heptadecafluorotetrahydrodecyl trichlorosilane (denoted as 17-FAS) [99,100]. All superhydrophobic membranes demonstrate improved fouling and/or scaling resistance (Referring to the description in Table 2).…”

Section: Engineered Superhydrophobic and Omniphobic Membranes With Improved Fouling Resistancementioning

confidence: 99%

Understanding the fouling/scaling resistance of superhydrophobic/omniphobic membranes in membrane distillation

et al. 2021

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“…Generally, during the desalination process, a diminution of all fluxes was observed because of a reduction in driving forces associated with the presence of non-volatile NaCl in the feed. It is coherent with the physiochemistry of the desalination process governed by Raoult's law [61]. In MD, the salt rejection coefficient is a crucial parameter describing the effectiveness of separation.…”

Section: Desalinationmentioning

confidence: 69%

Surfaces with Adjustable Features—Effective and Durable Materials for Water Desalination

Al‐Gharabli

El-Rub

Hamad

et al. 2021

IJMS

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Materials based on PVDF with desirable and controllable features were successfully developed. The chemistry and roughness were adjusted to produce membranes with improved transport and separation properties. Membranes were activated using the novel piranha approach to generate OH-rich surfaces, and finally furnished with epoxy and long-alkyl moieties via stable covalent attachment. The comprehensive materials characterization provided a broad spectrum of data, including morphology, textural, thermal properties, and wettability features. The defined materials were tested in the air-gap membrane distillation process for desalination, and improvement compared with pristine PVDF was observed. An outstanding behavior was found for the PVDF sample equipped with long-alkyl chains. The generated membrane showed an enhancement in the transport of 58–62% compared to pristine. A relatively high contact angle of 148° was achieved with a 560 nm roughness, producing a highly hydrophobic material. On the other hand, it was possible to tone the hydrophobicity and significantly reduce adhesion work. All materials were highly stable during the long-lasting separation process and were characterized by excellent effectiveness in water desalination.

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Patterned superhydrophobic polyvinylidene fluoride (PVDF) membranes for membrane distillation: Enhanced flux with improved fouling and wetting resistance

Cited by 100 publications

References 38 publications

Evaluating Protein Fouling on Membranes Patterned by Woven Mesh Fabrics

Evaluating Protein Fouling on Membranes Patterned by Woven Mesh Fabrics

Understanding the fouling/scaling resistance of superhydrophobic/omniphobic membranes in membrane distillation

Surfaces with Adjustable Features—Effective and Durable Materials for Water Desalination

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