Preparation and characterization of PVDF flat-sheet membranes for direct contact membrane distillation

Hou, Deyin; Fan, Hongsong; Jiang, Qinliang; Wang, Jun; Zhang, Xiaohui

doi:10.1016/j.seppur.2014.08.023

Cited by 114 publications

(51 citation statements)

References 37 publications

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“…Membrane O5 had the lowest salt rejection and the conductivity increased quickly during MD operation, while other membranes presented a rejection higher than 99.9%. The membrane O3 had the highest flux of 24.86 kg/m 2 ·hr with a rejection of 99.83%, which was higher than in previous reports (Alkhudhiri et al, 2012;Hou et al, 2014). …”

Section: Effect Of Organic Micromolecule Additivescontrasting

confidence: 57%

Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

Zheng

Zhang

et al. 2016

Journal of Environmental Sciences

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Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H 2 O were used to prepare poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation (DCMD) of 3.5 g/L NaCl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol (PEG), organic acids, LiCl, MgCl 2 , and LiCl/H 2 O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate (DBP) showed a nonporous surface and symmetrical cross-section. When H 2 O and LiCl/H 2 O mixtures were also used as additives, they were beneficial for solid-liquid demixing, especially when LiCl/H 2 O mixed additives were used. The membrane prepared with 5% LiCl + 2% H 2 O achieved a flux of 24.53 kg/(m 2 ·hr) with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes.

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Section: Effect Of Organic Micromolecule Additivescontrasting

confidence: 57%

Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

Zheng

Zhang

et al. 2016

Journal of Environmental Sciences

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“…It has been confirmed that the membrane pore structure, roughness and the crystallites in membrane surface have tremendous impacts on membrane hydrophobicity [31,46,47]. In this study, the contact angles with water, glycerol, and diiodomethane were measured to indicate the membrane hydrophobicity, and the results were presented in Table 4.…”

Section: Membrane Surface Analysismentioning

confidence: 58%

“…However, the salt rejection was higher than 99.9% under each operation temperature. Based on the performance under different temperature, a comparison with the flat-sheet membranes reported in the recent four years was carried out and listed in Table 6 [31,[48][49][50][51][52][53][54][55][56][57][58][59][60][61]. It can be found that the PVDF-CTFE membrane prepared in this work presented higher permeate flux in MD desalination application except PES and PSf membranes modified by CF4 plasma.…”

Section: Comparison With Other Flat-sheet MD Membranesmentioning

confidence: 99%

“…Meanwhile, mixed additives have been a recent trend for polymer membrane preparation due to the synergistic effect among different additives. Polyethylene glycol (PEG) is a commonly used pore-former for membrane preparation, and the PVDF membrane prepared with PEG normally possesses a macrovoid structure with high porosity owing to the instantaneous phase inversion process induced by PEG [29][30][31][32][33]. LiCl is another frequently-used additive, which tends to enhance the viscosity of the casting solution.…”

Section: Introductionmentioning

confidence: 99%

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Preparation of PVDF-CTFE hydrophobic membranes for MD application: Effect of LiCl-based mixed additives

Zheng

Wei

et al. 2016

Journal of Membrane Science

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a b s t r a c tHydrophobic flat-sheet membranes were prepared by poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) via the non-solvent induced phase separation (NIPS) process for membrane distillation (MD) application. Different types of LiCl-based mixed additives were applied to investigate their effects on membrane properties and MD performance. The membranes were evaluated in terms of membrane morphology, pore size and distribution, porosity, surface roughness, hydrophobicity, as well as the direct contact membrane distillation (DCMD) performance. Clear evidences were obtained that the mixed additives altered the phase inversion process, which resulted in the variation in membrane morphology, structure, properties and performance. The mass ratio of PEG/LiCl ranging from 5:0 to 0:5 was comprehensively investigated to study the synergistic effects of two additives on PVDF-CTFE membranes. The membrane M5 (PEG:LiCl ¼1:1, total content 8 wt% ) showed optimal properties and MD performance for combining the structure of higher hydrophobicity and pore interconnectivity, small pore size and narrow pore size distribution. The addition of LiCl to PEG-containing solutions benefited the solid-liquid demixing process, which increased the hydrophobicity, porosity, pore interconnectivity, and MD performance of the resultant membranes. While added PEG to LiCl-containing solutions showed slightly influences. Furthermore, it was also found that PVP/LiCl and glycerol/LiCl were not suitable for hydrophobic membrane preparation as they strikingly reduced membrane hydrophobicity. While H 3 PO 4 and H 2 O were confirmed suitable to mix with LiCl for hydrophobic PVDF-CTFE membrane preparation.

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“…The thickness of the graphene/PVDF membranes ( Table 2) also increased with increasing graphene loading (from 82.8 µm for neat PVDF to 98.4 µm for 2 wt% graphene/PVDF). This observed thickness increase is primarily attributed to the increase in solution viscosity and the addition of more graphene [30].…”

Section: Evaluation Of Membrane Performance By Agmdmentioning

confidence: 97%

Graphene/PVDF flat-sheet membrane for the treatment of RO brine from coal seam gas produced water by air gap membrane distillation

Woo

Kim

Shim

et al. 2016

Journal of Membrane Science

123

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. (2016). Graphene/PVDF flat-sheet membrane for the treatment of RO brine from coal seam gas produced water by air gap membrane distillation. Journal of Membrane Science, 513 74-84.Graphene/PVDF flat-sheet membrane for the treatment of RO brine from coal seam gas produced water by air gap membrane distillation Keywords brine, ro, distillation, treatment, gap, membrane, sheet, flat, pvdf, graphene, air, water, produced, gas, seam AbstractBrine management of coal seam gas (CSG) produced water is a significant concern for the sustainable production of CSG in Australia. Membrane distillation (MD) has shown the potential to further reduce the volume of CSG reverse osmosis (RO) brine. However, despite its potential, the lack 2 of appropriate MD membranes limits its industrial use. Therefore, this study was aimed on the

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Preparation and characterization of PVDF flat-sheet membranes for direct contact membrane distillation

Cited by 114 publications

References 37 publications

Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

Preparation of PVDF-CTFE hydrophobic membranes for MD application: Effect of LiCl-based mixed additives

Graphene/PVDF flat-sheet membrane for the treatment of RO brine from coal seam gas produced water by air gap membrane distillation

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