Novel PVDF hollow fiber membranes for vacuum and direct contact membrane distillation applications

Drioli, Enrico; Ali, Aamer; Simone, Silvia De; Macedonio, Francesca; Aljlil, Saad A.; Shabonah, F.S. Al; AlRomaih, Hamad; Alharbi, Omar; Figoli, Alberto; Criscuoli, A.

doi:10.1016/j.seppur.2013.04.040

Cited by 111 publications

(64 citation statements)

References 43 publications

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“…Regarding the bore fluid effect, it is well known in literature that the co-presence of solvents and alcohols slows down the de-mixing rate leading to a reduction of the finger-like structure [24,26]. However, due to the particular dope solution and spinning temperature employed, the kinetic enhancement of de-mixing prevailed on the inner coagulant effect.…”

Section: Membrane Characterizationmentioning

confidence: 99%

“…This aspect can be justified considering that the coagulation of the inner layer of the fibers starts immediately after the extrusion due to the contact with the bore fluid, while the outer layer passes through an air gap of 25.5 cm before immersion in the coagulation bath. The delayed coagulation of the outer layer, therefore, can lead to the fading of the macrovoids in favor of a spongelike structure [26].…”

Section: Membrane Characterizationmentioning

confidence: 99%

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Functional Properties of Punica granatum L. Juice Clarified by Hollow Fiber Membranes

et al. 2016

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Abstract:There is currently much interest in pomegranate juice because of the high content of phenolic compounds. Moreover, the interest in the separation of bioactive compounds from natural sources has remarkably grown. In this work, for the first time, the Punica granatum L. (pomegranate) juice-clarified by using polyvinylidene fluoride (PVDF) and polysulfone (PSU) hollow fiber (HF) membranes prepared in the laboratory-was screened for its antioxidant properties by using different in vitro assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric Reducing Antioxidant Power (FRAP), and β-carotene bleaching tests, and for its potential inhibitory activity of the carbohydrate-hydrolysing enzymes, α-amylase and α-glucosidase. The effects of clarification on quality characteristics of the juice were also investigated in terms of total phenols, flavonoids, anthocyanins, and ascorbic acid. Experimental results indicated that PVDF membranes presented a lower retention towards healthy phytochemicals in comparison to PSU membranes. Accordingly, the juice clarified with PVDF membranes showed the best antioxidant activity. Moreover, the treatment with PVDF membranes produced a clarified juice with 2.9-times fold higher α-amylase inhibitory activity in comparison to PSU (IC 50 value of 75.86 vs. 221.31 µg/mL, respectively). The same trend was observed using an α-glucosidase inhibition test. These results highlight the great potential of the clarified juice as a source of functional constituents.

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Section: Membrane Characterizationmentioning

confidence: 99%

Section: Membrane Characterizationmentioning

confidence: 99%

Functional Properties of Punica granatum L. Juice Clarified by Hollow Fiber Membranes

et al. 2016

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“…Membrane distillation (MD) is an emerging non-isothermal membrane separation process, being one of the promising techniques for the desalination of highly saline waters [1][2][3][4][5][6][7]. Contrary to pressure-driven techniques, the driving force in the membrane distillation process is related to the difference in chemical potential (generated by difference of temperatures) between the two sides of the hydrophobic membrane [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…In all configurations, the liquid-vapor equilibrium is the determining factor yielding to the selectivity of the MD processes. The mass transfer in MD follows three subsequent steps: liquid-vapor phase transition at the membrane pores entrance on feed side; transfer of vapors through the pores of the membrane; and condensation of vapors on the permeate side of the membrane [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Ceramic Membranes for Water Desalination

et al. 2017

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Hydrophilic ceramic membranes (tubular and planar) made of TiO 2 and Al 2 O 3 were efficiently modified with non-fluorinated hydrophobic grafting molecules. As a result of condensation reaction between hydroxyl groups on the membrane and reactive groups of modifiers, the hydrophobic surfaces were obtained. Ceramic materials were chemically modified using three various non-fluorinated grafting agents. In the present work, the influence of grafting time and type of grafting molecule on the modification efficiency was evaluated. The changes of physicochemical properties of obtained hydrophobic surfaces were determined by measuring the contact angle (CA), roughness (RMS), and surface free energy (SFE). The modified surfaces were characterized by contact angle in the range of 111-132 • . Moreover, hydrophobic tubular membranes were utilized in air-gap membrane distillation to desalination of sodium chloride aqueous solutions. The observed permeate fluxes were in the range of 0.7-4.8 kg·m −2 ·h −1 for tests with pure water. The values of permeate fluxes for membranes in contact with NaCl solutions were smaller, within the range of 0.4-2.8 kg·m −2 ·h −1 . The retention of NaCl in AGMD process using hydrophobized ceramic membranes was close to unity for all investigated membranes.

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“…1 There are a variety of MD processes, and the most popular ones are direct-contact membrane distillation (DCMD), vacuum membrane distillation (VMD), sweeping gas MD, and air-gap membrane distillation (AGMD). 2 Table I summarizes recent studies related to MD from 2010 to 2016. Generally, VMD has a higher permeation flux and less conductive heat loss compared to other MD forms.…”

Section: Introductionmentioning

confidence: 99%

Effect of the exposure time on the structure and performance of hydrophobic polydimethylsiloxane–poly(vinylidene fluoride) membranes via a non‐solvent‐induced phase separation process in a clean room

Zhang

Sun

et al. 2016

J of Applied Polymer Sci

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The objective of this study was to investigate the effects of the exposure time on the properties and permeability of polydimethylsiloxane (PDMS)-poly(vinylidene fluoride) (PVDF) blend hydrophobic microporous membranes, which were fabricated via a non-solvent-induced phase separation process at 25 8C and 60% relative humidity in a clean-room circumstance. For the prepared PDMS-PVDF membranes, the membrane morphologies were observed by scanning electron microscopy. Crystalline structures were observed by X-ray diffraction. Pore structures were analyzed by membrane porosity and mean pore size. Hydrophobicity was measured by contact angle measurement, and the mechanical properties were characterized by tensile strength testing. Our study results show that with increasing exposure time from 10 to 110 s, all of the membranes showed a similar pore structure: a spongelike substrate layer with a thin realm of fingerlike structures under the top surface. Phase separation between PDMS and PVDF occurred. The membrane porosity and mean pore radius decreased, and the membrane thickness increased. The membrane hydrophobicity decreased, and the mechanical properties first increased and then decreased. In addition, vacuum membrane distillation experiments were conducted. With the increase in the exposure time from 10 to 110 s, the membrane permeate flux decreased from 16.54 to 6.65 kg m 22 Áh 21, and the salt rejection was higher than 99.9%.

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Novel PVDF hollow fiber membranes for vacuum and direct contact membrane distillation applications

Cited by 111 publications

References 43 publications

Functional Properties of Punica granatum L. Juice Clarified by Hollow Fiber Membranes

Functional Properties of Punica granatum L. Juice Clarified by Hollow Fiber Membranes

Hydrophobic Ceramic Membranes for Water Desalination

Effect of the exposure time on the structure and performance of hydrophobic polydimethylsiloxane–poly(vinylidene fluoride) membranes via a non‐solvent‐induced phase separation process in a clean room

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