A few-layer graphene for advanced composite PVDF membranes dedicated to water desalination: a comparative study

Frappa, Mirko; Castillo, Antonio Esaù Del Rio; Macedonio, Francesca; Politano, Antonio; Drioli, Enrico; Bonaccorso, Francesco; Pellegrini, Vittorio; Gugliuzza, Annarosa

doi:10.1039/d0na00403k

Cited by 23 publications

(25 citation statements)

References 74 publications

(132 reference statements)

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“…The choice of preparing membranes with filler concentrations equal to 0.5% and 7% derives from the results obtained in some previous works [ 7 , 15 , 19 ]. Five different PVDF composite membranes with graphene platelets (GP) as filler were prepared in [ 19 ].…”

Section: Resultsmentioning

confidence: 99%

“…The membranes were prepared by dry-wet phase inversion technique according to the same procedure detailed in previous works [ 15 , 18 ]. In particular, 12 wt.% of PVDF powder was added under mechanical stirring to the dispersions containing the 2D materials.…”

Section: Methodsmentioning

confidence: 99%

“…Wet-jet milling (WJM) is, in fact, a technique allowing to produce few-layer flakes with larger lateral size than compared to that from other techniques, e.g., exfoliation by ultrasonic waves (UW) [19,30]. For example, in the case of graphene, usually, the lateral size of the exfoliated flakes is lower (around 120 nm), while the thickness is similar to that obtained by WJM [15,31,32] All the prepared membranes showed good hydrophobic proprieties with contact angle values equal or higher than 128 • (Table 2). The thickest membrane was the one with high concentration of Bi 2 Te 3 (7%).…”

Section: Membrane Preparation and Characterizationsmentioning

confidence: 99%

“…Membrane modification or special coating might be done to enhance the mass transfer through the membrane thus improving the MD/MCr performance [ 7 , 8 , 9 , 10 , 11 ]. In this regard, graphene flakes, due to their attractive hydrophobic and anti-wetting nature, anti-fouling properties, and selective sorption of water vapours, were used for the preparation of composite PVDF membranes [ 12 , 13 , 14 ] and tested in MD and MCr processes [ 7 , 12 , 14 , 15 , 16 , 17 , 18 , 19 ]. Recently, other transition metal dichalcogenide monolayers (TMDCs) are being introduced in PVDF-based membranes to enhance the performance of MD and MCr, too [ 16 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

“…Usually, TMDCs are composed by layers combined with each other, layer by layer, with van der Waals force, and the weak interaction between layers influences the properties of the bulk TMDCs significantly [ 21 ]. Unlike the most commonly studied 2D material (i.e., graphene), TMDCs have an intrinsic direct bandgap, and are promising in applications such as electronic components, in desalination or water treatment devices, and others [ 7 , 15 , 17 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

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Performance of PVDF Based Membranes with 2D Materials for Membrane Assisted-Crystallization Process

et al. 2021

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Membrane crystallization (MCr) is a promising and innovative process for the recovery of freshwater from seawater and for the production of salt crystals from the brine streams of desalination plants. In the present work, composite polymeric membranes for membrane crystallization were fabricated using graphene and bismuth telluride inks prepared according to the wet-jet milling (WJM) technology. A comparison between PVDF-based membranes containing a few layers of graphene or bismuth telluride and PVDF-pristine membranes was carried out. Among the 2D composite membranes, PVDF with bismuth telluride at higher concentration (7%) exhibited the highest flux (about 3.9 L∙m−2h−1, in MCr experiments performed with 5 M NaCl solution as feed, and at a temperature of 34 ± 0.2 °C at the feed side and 11 ± 0.2 °C at the permeate side). The confinement of graphene and bismuth telluride in PVDF membranes produced more uniform NaCl crystals with respect to the pristine PVDF membrane, especially in the case of few-layer graphene. All the membranes showed rejection equal to or higher than 99.9% (up to 99.99% in the case of the membrane with graphene). The high rejection together with the good trans-membrane flux confirmed the interesting performance of the process, without any wetting phenomena, at least during the performed crystallization tests.

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