Hydrophobicity measurements of microfiltration and ultrafiltration membranes

Keurentjes, J.T.F.; Harbrecht, J.G.; Brinkman, Dine; Hanemaaijer, J.H.; Stuart, M.A. Cohen; Riet, K. van ’t

doi:10.1016/s0376-7388(00)83084-7

Cited by 96 publications

(34 citation statements)

References 18 publications

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“…One possible reason for the presence of additional mass transfer resistance was that some pores were filled with water as claimed by Malek et al [14]. In this study, it was unlikely as the pressure difference between the shell side and the lumen side was less than 20 kPa, while the required pressure for water to penetrate into the pores should be 4246 kPa according to the Young-Laplace equation [27,28].…”

Section: Water Transportmentioning

confidence: 61%

A study of mass transfer in the membrane air-stripping process using microporous polyproplylene hollow fibers

Mahmud

Kumar

Narbaitz

et al. 2000

Journal of Membrane Science

109

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The mass transfer of water and chloroform in membrane air-stripping (MAS) was studied using a microporous polypropylene hollow fiber membrane module, with air flow on the lumen side and liquid cross-flow on the shell side. Water transport experiments showed that its mass transport decreased significantly when the membrane had been in contact with water for prolonged periods. It was hypothesized that the increased mass transfer resistance was due to water condensation in a fraction of the membrane pores. MAS of chloroform from aqueous solutions confirmed the additional mass transfer resistance with prior exposure to water. It was concluded that membrane pores were either completely air-filled or partially wetted with water during the MAS process. Existing models are able to predict the performance only for either completely air-filled or liquid-filled pores. A modified model was proposed to take into account the diffusion through partially wetted pores. The model described the data well. This hypothesis also provided a plausible explanation to the conflicting literature values of the membrane mass transfer resistance. It was found that the membrane mass transfer resistance of the partially wetted pores is two orders of magnitude higher than that of air-filled pores. The overall mass transfer coefficient was constant for initial feed chloroform concentrations ranging from 50 to 1000 ppm. Crown

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Section: Water Transportmentioning

confidence: 61%

A study of mass transfer in the membrane air-stripping process using microporous polyproplylene hollow fibers

Mahmud

Kumar

Narbaitz

et al. 2000

Journal of Membrane Science

109

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“…As discussed in section 3.1.1, chemical cleaning even at an elevated temperature did not result in any permanent changes in the charge of the membrane active layer. Therefore, the observed increase in the membrane contact angle during chemical cleaning at elevated temperatures is likely due to significant changes in the membrane porosity and/or roughness, which alter the capillary forces of the membrane surface, and thus the contact angle measurement [37]. On the other hand, EDTA cleaning at 20 and 35 °C increased the permeability of the NF270, whereas, the opposite effect was observed at a cleaning temperature of 50 °C (Figure 4).…”

Section: Surface Roughnessmentioning

confidence: 98%

Impact of chemical cleaning on the nanofiltration of pharmaceutically active compounds (PhACs): The role of cleaning temperature

Simon

Price

Nghiem

2013

Journal of the Taiwan Institute of Chemical Engineers

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This study investigated the impact of chemical cleaning on the physicochemical properties of a nanofiltration membrane and its subsequent separation efficiency of inorganic salts and two pharmaceutically active compounds (PhACs), sulfamethoxazole and carbamazepine. Chemical cleaning was simulated by immersing virgin membrane samples in aqueous citric acid, sodium hydroxide (NaOH), ethylenediaminetetraacetic-acid (EDTA) and sodium dodecyl sulphate (SDS) at various temperatures for 18 h. The cleaning temperature did not exert any discernible impact on the surface charge of the NF270 membrane selected in this study. However, high cleaning temperatures were shown to either amplify or reduce the impact of chemical cleaning on several other membrane properties (including hydrophobicity, surface roughness and permeability) as well as the rejection of both inorganic salts and PhACs. The influence of chemical cleaning on the membrane surface roughness was enhanced at elevated cleaning temperatures. Similarly, at a high cleaning temperature, caustic and acidic cleaning caused a more significant increase in the membrane surface hydrophobicity than that at an ambient temperature. An increase in the cleaning temperature could also slightly amplify the decrease in the membrane permeability due to acidic cleaning. When a caustic cleaning solution (pH 11.5) was used, the membrane permeability only varied slightly with the temperature. Results obtained from Fourier transform infrared spectroscopy (FTIR) analysis suggest that chemical cleaning even at a high temperature did not permanently alter the chemical composition of the membrane active or support layer. Indeed, the effects of chemical cleaning at a high temperature on the physicochemical properties of the membrane could be attributed to the conformational changes of the membrane polymeric matrix. Chemical cleaning using citric acid, SDS or EDTA at a high temperature resulted in a considerable increase in the rejection of salts and PhACs in their neutral form. On the other hand, caustic cleaning at an elevated temperature had no discernible impact on the rejection of inorganic salts and neutral PhACs. This is because caustic cleaning and an elevated cleaning temperature cause opposing effects on the rejection of these solutes. Chemical cleaning at all temperatures investigated in this study did not affect the removal of negatively charged sulfamethoxazole.

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“…A good approximation of ~c is the surface tension ~h at which air bubble detachment takes place [24 ]. Since surfaces of low ~d are hydrophobic, whereas a high value of ~d indicates a hydrophilic surface, we can use ~d as a quantitative measure of hydrophobicity.…”

Section: Hydrophobicitymentioning

confidence: 99%

“…Measurements of ~d were carried out using the sticking-bubble technique [24]. A piece of membrane material or polymer film (about 1 cm 2) is placed horizontally at the bottom of a beaker containing a liquid with surface tension YL.…”

Section: Hydrophobicitymentioning

confidence: 99%

Surfactant-induced wetting transitions: Role of surface hydrophobicity and effect on oil permeability of ultrafiltration membranes

Keurentjes

Stuart

Brinkman

et al. 1990

Colloids and Surfaces

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Hydrophobicity measurements of microfiltration and ultrafiltration membranes

Cited by 96 publications

References 18 publications

A study of mass transfer in the membrane air-stripping process using microporous polyproplylene hollow fibers

A study of mass transfer in the membrane air-stripping process using microporous polyproplylene hollow fibers

Impact of chemical cleaning on the nanofiltration of pharmaceutically active compounds (PhACs): The role of cleaning temperature

Surfactant-induced wetting transitions: Role of surface hydrophobicity and effect on oil permeability of ultrafiltration membranes

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