Temperature and concentration polarization in membrane distillation of aqueous salt solutions

Martı́nez-Dı́ez, L.; Vázquez‐González, Margarita

doi:10.1016/s0376-7388(98)00349-4

Cited by 400 publications

(182 citation statements)

References 10 publications

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“…On the other hand, the calculation of the permeances as shown in Figures 33 and 34 diverges from the flux trends. The divergence could be related to inaccuracy in the true pressure difference due to possible temperature polarization [285] across the membrane. In addition, heat loss due to water evaporation leads, as it is commonly known in MD [222], to a drop of the temperature of the feed between the inlet and outlet.…”

Section: Performance Of Organic and Hybrid Membranesmentioning

confidence: 99%

Advances in Membrane Distillation for Water Desalination and Purification Applications

Camacho

Dumée

Zhang

et al. 2013

Water

629

342

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Membrane distillation is a process that utilizes differences in vapor pressure to permeate water through a macro-porous membrane and reject other non-volatile constituents present in the influent water. This review considers the fundamental heat and mass transfer processes in membrane distillation, recent advances in membrane technology, module configurations, and the applications and economics of membrane distillation, and identifies areas that may lead to technological improvements in membrane distillation as well as the application characteristics required for commercial deployment. Keywordsa function of temperature, vapor pressure, and of the gas molecular mass K 0 membrane characteristic defined by Equation (9) Kn Knudsen number K(T) a function of temperature and molecular weight of the gas l mean free path of the molecules l m distance between parallel spacer fibres (m) LEP Limit Entry Pressure (kPa) M molecular mass (g/mol) M w molecular weights of water (g/mol) M a molecular weights of air (g/mol) n number of CNTs per unit cross section in bucky-paper P pressure in the air gap (kPa) half time to reach the maximum intensity-laser flash technique (s) t proportion of conductive heat (balance due to evaporative heat) loss through the membrane T mean temperature in the pores (K)

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Section: Performance Of Organic and Hybrid Membranesmentioning

confidence: 99%

Advances in Membrane Distillation for Water Desalination and Purification Applications

Camacho

Dumée

Zhang

et al. 2013

Water

629

342

View full text Add to dashboard Cite

show abstract

“…We therefore speculate that the reduction of vapor flux was mostly attributable to the enhanced temperature polarization in the coating layer. The hydrated nanocomposite coating is a hydraulically stagnant layer insusceptible to the cross-flow induced mixing in the feed channel [2,67,68]. Similar to the internal concentration polarization in forward osmosis which has a detrimental impact on mass transfer [69], the temperature polarization across the hydrated nanocomposite layer was also "internal" in the sense that it occurred within the membrane structure.…”

Section: Membrane Performance In MD Experimentsmentioning

confidence: 99%

Tailoring surface charge and wetting property for robust oil-fouling mitigation in membrane distillation

Wang

Jin

Hou

et al. 2016

Journal of Membrane Science

127

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a b s t r a c tThe efforts of developing anti-oil-fouling membranes have so far been focusing on tailoring membrane surface wetting properties, whereas the impacts of surface charge are often eclipsed. In this study, we investigated the impacts of surface charge and wetting property on oil fouling kinetics in membrane distillation (MD). Two composite membranes with in-air hydrophilic and underwater oleophobic surfaces, one of positive charge and the other of negative charge, were fabricated by modifying a hydrophobic polyvinylidene fluoride (PVDF) membrane with hydrophilic polyelectrolytes with different charges. The modified composite membranes were compared with the reference PVDF membrane for their contact angles, adhesion force curves, and fouling kinetics in MD processes. It was found that the negatively charged composite membrane performed the best in mitigating fouling by the negatively charged oil emulsion, followed by the positively charged composite membrane, with the pristine PVDF membrane being the most susceptible to oil fouling in MD experiments. The results from underwater oil CA measurements and oil probe force spectroscopy corroborated the results in the fouling experiments. The impact of surface charges on oil-membrane interaction and associated mechanism were also discussed.

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“…Several MD models with varying degrees of complexity have been developed to understand the effect of system parameters on flux [25,26]. Fewer, however, have analyzed energy efficiency [6,27,28].…”

Section: Reviewmentioning

confidence: 99%

Energy efficiency of permeate gap and novel conductive gap membrane distillation

Swaminathan

Chung

Warsinger

et al. 2016

Journal of Membrane Science

134

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This work presents numerical modeling results and flux experiments for a novel membrane distillation configuration called conductive gap membrane distillation (CGMD), as well as permeate gap membrane distillation (PGMD). CGMD has a conductive spacer in the gap between the membrane and condensing surface rather than more commonly used insulating materials. Flux measurements with two experimental systems are used to validate the numerical models for PGMD and CGMD. PGMD has 20% higher GOR (energy efficiency) than an air gap membrane distillation (AGMD) system of the same size, whereas CGMD can have two times higher GOR than even PGMD. Increasing gap effective thermal conductivity in CGMD has negligible benefits beyond k gap ≈ 10 W/m·K under the conditions of this study. The direction of pure water flow in the gap has a significant influence on overall system energy efficiency, especially in the case of CGMD. Using a countercurrent configuration for the pure water flow in the gap relative to the cold stream leads to 40% higher GOR than flow cocurrent with the cold water stream.

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Temperature and concentration polarization in membrane distillation of aqueous salt solutions

Cited by 400 publications

References 10 publications

Advances in Membrane Distillation for Water Desalination and Purification Applications

Advances in Membrane Distillation for Water Desalination and Purification Applications

Tailoring surface charge and wetting property for robust oil-fouling mitigation in membrane distillation

Energy efficiency of permeate gap and novel conductive gap membrane distillation

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