CF4 plasma-modified superhydrophobic PVDF membranes for direct contact membrane distillation

Yang, Chi; Li, Xuemei; Gilron, Jack; Kong, Dingfeng; Yin, Yong; Oren, Yoram; Linder, Charles; He, Tianhu

doi:10.1016/j.memsci.2014.01.013

Cited by 202 publications

(114 citation statements)

References 25 publications

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“…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%

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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Section: Comparison With Other Flat-sheet MD Membranesmentioning

confidence: 99%

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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“…The detailed process was reported in our previous work [23]. Each membrane was measured at least three times with a typical variation b10%.…”

Section: Immersing In Water Bathmentioning

confidence: 99%

“…The membrane surface morphology was controlled using a solvent/ water mixture as the first coagulation bath, followed by a water bath [20][21][22]. The membranes were converted hydrophobic via a CF 4 plasma treatment process [23,24]. The influence of the composition of the first coagulation bath was studied.…”

Section: Introductionmentioning

confidence: 99%

CF4 plasma modified highly interconnective porous polysulfone membranes for direct contact membrane distillation (DCMD)

et al. 2015

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“…Thus, water flux in MD is negligibly affected by the feed water salinity. In other words, MD can be used for desalinating hypersaline feed streams or to achieve high water recovery desalination [11][12][13][14][15][16]. Given the discontinuity of the liquid phase across the membrane and a small hydraulic pressure on the membrane surface, MD is less susceptible to membrane fouling compared to RO, and hence does not require extensive pre-treatment [7].…”

Section: Introductionmentioning

confidence: 99%

Optimising thermal efficiency of direct contact membrane distillation by brine recycling for small-scale seawater desalination

Duong

Cooper

Nelemans³

et al. 2015

Desalination

113

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A technique to optimise thermal efficiency using brine recycling during direct contact membrane distillation (DCMD) of seawater was investigated. By returning the hot brine to the feed tank, the system water recovery could be increased and the sensible heat of the hot brine was recovered to improve thermal efficiency. The results show that in the optimal water recovery range of 20 to 60% facilitated by brine recycling, the specific thermal energy consumption of the process could be reduced by more than half. It is also noteworthy that within this optimal water recovery range, the risk of membrane scaling is negligible -DCMD of seawater at a constant water recovery of 70% was achieved for over 24. h without any scale formation on the membrane surface. In contrast, severe membrane scaling was observed when water recovery reached 80%. In addition to water recovery, other operating conditions such as feed temperature and water circulation rates could influence the process thermal efficiency. Increasing the feed temperature and reducing the circulation flow rates increased thermal efficiency. Increasing the feed temperature could also mitigate the negative effect of elevated feed concentration on the distillate flux, particularly at a high water recovery. Abstract:A technique to optimise thermal efficiency using brine recycling during direct contact membrane distillation (DCMD) of seawater was investigated. By returning the hot brine to the feed tank, the system water recovery could be increased and the sensible heat of the hot brine was recovered to improve thermal efficiency. The results show that in the optimal water recovery range of 20 to 60% facilitated by brine recycling, the specific thermal energy consumption of the process could be reduced by more than half. It is also noteworthy that within this optimal water recovery range, the risk of membrane scaling is negligible  DCMD of seawater at a constant water recovery of 70% was achieved for over 24 hours without any scale formation on the membrane surface. In contrast, severe membrane scaling was observed when water recovery reached 80%. In addition to water recovery, other operating conditions such as feed temperature and water circulation rates could influence the process thermal efficiency. Increasing the feed temperature and reducing the circulation flow rates increased thermal efficiency. Increasing the feed temperature could also mitigate the negative effect of elevated feed concentration on the distillate flux, particularly at a high water recovery.

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CF4 plasma-modified superhydrophobic PVDF membranes for direct contact membrane distillation

Cited by 202 publications

References 25 publications

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

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

CF4 plasma modified highly interconnective porous polysulfone membranes for direct contact membrane distillation (DCMD)

Optimising thermal efficiency of direct contact membrane distillation by brine recycling for small-scale seawater desalination

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