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- Penha, Frederico Marques, et al.
(författare)
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Influence of different solvent and time of pre-treatment on commercial polymeric ultrafiltration membranes applied to non-aqueous solvent permeation
- 2015
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Ingår i: European Polymer Journal. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0014-3057 .- 1873-1945. ; 66, s. 492-501
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Tidskriftsartikel (refereegranskat)abstract
- Several pre-treatments and solvents were tested through permeation in commercial polymeric membranes (UH004, UP005, UP010 and UH050 - Microdyn-Nadir) with different molar mass cut-offs (4 kDa, 5 kDa, 10 kDa and 50 kDa, respectively), in order to evaluate their efficiency and stability through non-aqueous solvent permeation. After pre-treatments and permeations, membranes were characterised with contact angle, Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electronic Microscopy (FESEM) to evaluate structural integrity. The results of solvent permeation suggest that selectivity of the polymeric matrix depends not only on pore size, but also, in great extent, on the interaction between solvent and polymer. A strong relation can be noted between the conditioning length and permeability for ethanol pre-treatments. Permeability to n-hexane increased from 4 to 18 times after pre-treatment, depending on the time of exposure to ethanol and n-hexane. Characterisation analyses show no significant changes on the membranes surface. In some cases, discrepancies observed among permeate fluxes and contact angles might be an indicative of the occurrence of swelling and plasticisation. However, results suggest the feasibility in the use of these membranes for the recovery of solvents in the oil industry, if suitable process parameters are chosen.
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| 2. |
- Zanatta, Vanessa, et al.
(författare)
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Stability of oil-in-water emulsions produced by membrane emulsification with microporous ceramic membranes
- 2017
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Ingår i: Journal of Food Engineering. - : ELSEVIER SCI LTD. - 0260-8774 .- 1873-5770. ; 195, s. 73-84
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Tidskriftsartikel (refereegranskat)abstract
- Membrane emulsification has been drawing attention due to its many application possibilities. This study aimed to assess the preparation and stability of oil in water (O/W) emulsions by membrane emulsification technique. Microporous ceramic membranes with mean pore size 0.2 mu m and 0.8 mu m were used for producing sunflower oil in water emulsions, displaying mean droplet size ranging from 2.9 to 11.6 mu m and from 4.8 to 16.2 mu m, respectively. The effect of the oil concentration (10%-20%), surfactant concentration (1%-4%), tangential velocity (0.12 m s(-1) to 0.24 m s(-1)), and feed pressure (100 kPa-300 kPa) on the process performance was investigated using an experimental design. All the parameters significantly influenced the mean droplet size, the droplet size distribution, and the emulsion stability. Depending on the emulsification conditions, monodisperse and polydisperse emulsions were obtained. The use of a membrane with 0.2 mu m mean pore size led to better results than those obtained with a 0.8 mu m membrane, since they yielded emulsions displaying smaller droplet size and narrower size distribution. The emulsions prepared using this membrane were stable up to 100 days. (C) 2016 Elsevier Ltd. All rights reserved.
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