Mechanism of pore wetting in membrane distillation with alcohol vs. surfactant

Wang, Zhangxin; Chen, Yuanmiaoliang; Sun, X.; Duddu, Ravindra; Lin, Shihong

doi:10.1016/j.memsci.2018.04.045

Cited by 133 publications

(92 citation statements)

References 46 publications

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“…Surfactants are amphiphilic compounds that can lower the feed solution surface tension, thereby allowing the passage of liquid water with its dissolved salts within the membrane pores 30,31 . In such a case, the wetting kinetics is controlled by the rate at which the pore surface is saturated by the adsorbed surfactant molecules 24 . Once the membrane is wetted, the MD process is no longer governed by the trans-membrane vapor tension difference but is instead controlled by the hydraulic pressures.…”

Section: Resultsmentioning

confidence: 99%

“…Membrane wetting can be described as the progressive loss of hydrophobicity caused by compounds able to decrease the surface tension 23 , such as organics (especially those with amphiphilic nature) and salt crystals. While these phenomena have been observed in many studies, the literature comprises contradictory reports concerning the extent and the mechanism of wetting, as well as the onset and consequences of scaling 24,25 . Few MD experiments have been performed thus far with the complex mixture that characterizes produced water streams, and few as well had the aim of achieving high water recovery rates.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Desalination of Produced Water by Membrane Distillation: Effect of the Feed Components and of a Pre-treatment by Fenton Oxidation

Ricceri

Giagnorio

Farinelli

et al. 2019

Sci Rep

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The treatment of produced waters (by-products of oil and gas extraction) with the innovative process of membrane distillation is challenging, because these highly saline streams contain high concentrations of organic compounds and hydrocarbons that cause membrane wetting and impairment of performance. To design the most compact treatment scheme and with the aim of obtaining an easier management of produced water for reuse purposes, Fenton oxidation is here investigated as a feed pre-treatment that may produce an effluent easily handled by membrane distillation. In high-recovery membrane distillation tests, we systematically investigate the detrimental effects of individual contaminants in a synthetic produced water mimicking the composition of a real sample. The recovery rate depends strongly on the initial salinity, which eventually causes scaling and pore blocking. Surfactants are found to be mainly responsible for membrane wetting, but volatile and hydrophobic organics also spoil the quality of the product water. A Fenton oxidation pre-treatment is thus performed to degrade the target organics, with the aim of enhancing the effectiveness of the following membrane distillation and to improve the quality of the final product. The combined oxidation-membrane distillation scheme has both advantages and limitations, which need to be carefully evaluated and further investigated.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Desalination of Produced Water by Membrane Distillation: Effect of the Feed Components and of a Pre-treatment by Fenton Oxidation

Ricceri

Giagnorio

Farinelli

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Considering the fact that there was no wetting by CaSO 4 scaling without SDS, the results can be interpreted that SDS induced wetting. It seems that the reduction in the hydrophobicity by SDS led to the penetration of feed water into some pores (partial wetting) [25]. Fig.…”

Section: Effect Of Sds On Wetting and Fouling By Inorganic And/or Orgmentioning

confidence: 98%

“…Membrane wetting is generally observed during the long-term operation of the MD process [24]. Factors affecting membrane wetting include transmembrane pressure, capillary condensation, scale deposition (inorganic fouling), organic fouling, surfactants, and membrane degradation [8,19,23,25]. The membrane wetting reduces the quality of product water and changes the flux through the membrane [21,26].…”

Section: Introductionmentioning

confidence: 99%

Fouling-induced wetting of membranes in membrane distillation (MD) systems

Kim¹,

Cho²,

Choi³

et al. 2019

Desalination and Water Treatment

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One of the challenges of membrane distillation (MD) technology is the wetting of the membranes. However, relatively little information is available on membrane wetting induced by fouling in MD process. Accordingly, this study examines the MD membrane wetting caused by fouling under various conditions. Various feed solutions containing NaCl, CaSO 4 , humic acid, alginate, and SDS were compared using polyvinylidene fluoride and polytetrafluoroethylene membranes in a series of MD experiments. Scanning electron microscope (SEM), liquid entry pressure and dynamic contact angle were used to interpret the results from the MD wetting experiments. Results showed that wetting was induced by severe fouling in the cases of 200,000 mg L-1 NaCl solution and 200,000 mg L-1 NaCl and 2,000 mg L-1 CaSO 4 solution. The organic matters (50 mg L-1 humic acid and 50 mg L-1 alginate) did not cause neither fouling nor wetting by themselves. On the other hand, the addition of 50 mg L-1 SDS accelerated wetting. Based on these experimental results, the wetting potentials for various combinations of foulants are presented.

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“…20 However, the pore wetting in largepore-size membranes results in the penetration of saline water and the consequent failure of MD operation. [21][22][23] As a result, the pore size of most MD membranes reported in literatures was limited to 0.2 and 0.45 mm. 12,24,25 Membrane orientation was reported to signicantly impact the water ux and salt rejection of asymmetric MD membranes due to the wetting of relatively large pores.…”

Section: Introductionmentioning

confidence: 99%