Sorption, diffusion, and pervaporation of organics in polymer membranes

Lee, Young M.; Bourgeois, Daniel; Belfort, Georges

doi:10.1016/s0376-7388(00)83350-5

Cited by 124 publications

(48 citation statements)

References 10 publications

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“…In PV process, mass transport of binary liquid mixtures through a nonporous polymer membrane is generally described by the solution2diffusion mechanism, which occurs in three steps: sorption, diffusion and evaporation [45]. Thus, permeation rate and selectivity are governed by the solubility and diffusivity of each component of the feed mixture to be separated.…”

Section: Diffusion Coefficientmentioning

confidence: 99%

Preparation and pervaporation performance of chitosan-poly(methacrylic acid) polyelectrolyte complex membranes for dehydration of 1,4-dioxane

Choudhari

Premakshi

2016

Polym Eng Sci

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Polyelectrolyte complex (PEC) membranes composed of chitosan (CS) and poly(methacrylic acid) (PMAA) were prepared by mixing the polymer solutions in different ratios. The chemical interaction and crystallinity of the resulting PEC membranes were respectively analyzed by Fourier transform infrared spectroscopy (FTIR) and wide-angle Xray diffraction (WAXD). Differential scanning calorimetry (DSC) was used to characterize the thermal properties of the membranes. The membranes thus obtained were subjected to pervaporation (PV) separation of water-dioxane mixtures. Among the PEC membranes, membrane containing 30 wt% ratio of PMAA (M-3) exhibited the highest separation selectivity of 840 with a flux of 12.07 3 10 22 kg/m 2 h at 308C at 15 wt% of water in the feed. By the incorporation of NaY zeolite into PEC up to 5 wt%, we have been able to overcome the trade-off phenomenon existing between flux and selectivity in PV process. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The resulting activation energy values obtained for water permeation (E pw ) are much lower than those of dioxane permeation (E po ), suggesting that the developed membranes have higher separation efficiency for waterdioxane system. Based on the heat of sorption (DH s ) values, the mode of sorption was discussed. POLYM. ENG. SCI.,

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Section: Diffusion Coefficientmentioning

confidence: 99%

Preparation and pervaporation performance of chitosan-poly(methacrylic acid) polyelectrolyte complex membranes for dehydration of 1,4-dioxane

Choudhari

Premakshi

2016

Polym Eng Sci

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“…11,12 However, comparing Figures 6 and 7, one can observe that, in certain ranges of composition, the flux and selectivity increase simultaneously.…”

Section: Resultsmentioning

confidence: 95%

“…Their total permeation rates were between 7 and 160 g/(m 2 Áh), with selectivity between 2.4 and 6.7 (30-37 C, 10 wt % ethanol in water), and an increase in selectivity was often associated with a decrease in the flux. 11,12 Such performances are not satisfactory in applications.…”

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confidence: 99%

Pervaporation of Ethanol/Water Mixtures Using Novel Hydrophobic Membranes Based on Concentrated Emulsion Polymerization

Shi

Zhang

et al. 2005

Polym J

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ABSTRACT:A pervaporation membrane was prepared via the concentrated emulsion polymerization method. The concentrated emulsion formed was pre-polymerized, after which a mixture of another hydrophobic monomer, a crosslinker and an initiator were added with stirring to the system. The gel formed was located between two glass plates and subjected to polymerization. The membrane copied the structure of its precursor concentrated emulsion and composed of closely packed latexes that squeezed each other. The micro-channel among the latexes provided additional pathways for the permeates. The morphologies of the concentrated emulsion and membrane were examined via optical and electron microscopies. The pervaporation performance of the membrane in the extraction of ethanol from ethanol/water mixtures was investigated. In certain ranges of composition, the flux and selectivity simultaneously increased. [DOI 10.1295/polymj.37.925] KEY WORDS Pervaporation Membrane / Ethanol / Concentrated Emulsion /The emphasis in this paper is on a new method to prepare pervaporation membranes. The prepared membranes will be used to pervaporate ethanol from ethanol/water mixtures. While the pervaporation of water from ethanol/water mixtures was investigated in a large numbers of papers, 1-6 the pervaporation of ethanol from such mixtures was examined in much fewer papers and is more difficult to achieve.Between ethanol and water, ethanol is more hydrophobic; for this reason, hydrophobic materials were naturally selected to pervaporate ethanol from ethanol/water mixtures.7-10 Most of the membranes were based on homopolymers or copolymers of siloxanes. However, polydimethylsiloxane membranes prepared using conventional methods, such as solvent casting and hot pressing, were dense membranes. Their total permeation rates were between 7 and 160 g/(m 2 Áh), with selectivity between 2.4 and 6.7 (30-37 C, 10 wt % ethanol in water), and an increase in selectivity was often associated with a decrease in the flux. 11,12Such performances are not satisfactory in applications.It was noticed that the polymeric membrane prepared via traditional methods are all dense ones, [13][14][15][16] in which the gap among the chains provides the pathway of the permeates. However, the average interchain distance among the amorphous flexible chains is 0.4-0.5 nm 17 and the van der Waals radius of ethanol molecules is 0.52 nm. For this reason, the interchain gap is not big enough for ethanol molecules to diffuse. In other words, the separation selectivity is not only controlled by the polarity, but also by the size of the molecule. For the purpose of preferably separation of ethanol from water, additional larger pathway for permeates should be provided. Among various preparation methods developed, concentrated emulsion polymerization constitutes the first choice.A series of hydrophilic/hydrophobic composite membranes was prepared via the concentrated emulsion polymerization method. 18,19 In a concentrated emulsion, the volume fraction of the dispersed phase is larger t...

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“…Pervaporation performance of organic aqueous solu tions has been reported by many researchers (1)(2)(3)(4)(5)(6)(7)(8) (14), and compared to other polymer, CMC, has many unique features as a hydrophilic polymer: (1) Readily soluble in cold and hot water to give viscous solutions, (2) The degree of polymerization of PVA was 1,600-1,700 and the saponification degree was 98.5%. Poly (acrylic acid) (PAA; Mw=150,000 25% aqueous solution) was purchased from Wako Pure Chemical (Japan).…”

Section: Introductionmentioning

confidence: 99%

Pervaporation Dehydration of Organic Liquids Using Composite Membranes Based on Carboxymethylcellulose.

1996

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Sorption, diffusion, and pervaporation of organics in polymer membranes

Cited by 124 publications

References 10 publications

Preparation and pervaporation performance of chitosan-poly(methacrylic acid) polyelectrolyte complex membranes for dehydration of 1,4-dioxane

Preparation and pervaporation performance of chitosan-poly(methacrylic acid) polyelectrolyte complex membranes for dehydration of 1,4-dioxane

Pervaporation of Ethanol/Water Mixtures Using Novel Hydrophobic Membranes Based on Concentrated Emulsion Polymerization

Pervaporation Dehydration of Organic Liquids Using Composite Membranes Based on Carboxymethylcellulose.

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