Equilibrium thermodynamics of the ternary membrane-forming system nylon, formic acid and water

Bulte, A.M.W.; Naafs, E.M.; Eeten, F. van; Mulder, M.H.V.; Smolders, C.A.; Strathmann, H.

doi:10.1016/0032-3861(96)83714-1

Cited by 44 publications

(36 citation statements)

References 13 publications

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“…The exchange rate is induced by the difference between solubility parameters, the diffusion force of nonsolvent and physical factors of the phase inversion process [28]. Furthermore, the properties of the polymer casting solution are presumed to affect the structure of the resulting membrane [29,30].…”

Section: Phase Inversion Membranesmentioning

confidence: 99%

Phase Diagram and Membrane Desalination

El–Gendi¹

2015

Desalination Updates

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Desalination technologies have made a significant impact in seawater and brackish water desalination. Recently, the evolution of membrane development has improved performance to lower operating costs and membranes have become the preferred technology for water desalination. Fortunately, different raw materials can be used for preparing membrane sheets which include either organic or inorganic materials, such as cellulose acetate, polyamide, polyimide, ceramic, natural, or artificial polymers. On the one hand, as a result of the variety of the raw materials which already exist in the entire world, different membrane separation processes might be applied dependent on the nature of the membrane sheet and the requirements of treatment process. On the other hand, there are different types of membranes can be used for membrane desalination by using different technologies such as reverse osmosis (RO), membrane distillation (MD), and forward osmosis (FO). The ternary phase diagram for membrane casting solution has an important role to get the required membranes.

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Section: Phase Inversion Membranesmentioning

confidence: 99%

Phase Diagram and Membrane Desalination

El–Gendi¹

2015

Desalination Updates

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“…In the first part of this series the system: nylon 4,6, formic acid and water was studied [13] making use of the earlier developed knowledge of the thermodynamics of the system [10]. This paper will emphasize whether intermediate stages in membrane formation can be experimentally studied and related to final membrane morphology.…”

Section: Distance From the Interface Diffu$ion Front Initial Polymer mentioning

confidence: 99%

“…The theory is used in order to describe the liquid-liquid phase separation border [4][5][6][7][8] as well as solid-liquid phase separation [9,10].…”

Section: Introductionmentioning

confidence: 99%

Diffusion induced phase separation with crystallizable nylons. II. Relation to final membrane morphology

Bulte

1996

Journal of Membrane Science

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Intermediate stages during membrane formation by means of immersion precipitation were studied by cryo-substitution for the system nylon 4,6, formic acid and water. The presence, nature and size of solid particles was determined as a function of time and of the distance from the interface. The spherulitic nature of these particles was confirmed by staining the samples. It was shown that at a relatively low nucleation density the concentration profile in the film was hardly influenced by a starting phase separation process, while in a situation with a relatively high number of nuclei per volume concentration patterns must be considerable altered.

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“…1. Isothermal (phase) diagram at 30°C for the ternary system water (1), formic acid (2) and nylon 4,6 (3), with the experimentally determined crystallization line and the calculated liquidliquid demixing gap depicted [3]. The virtual binodal does not represent existing equilibria in this thermodynamic phase diagram.…”

Section: Introductionmentioning

confidence: 99%

“…At lower polymer concentrations the typical cellular morphology, which is a result of liquid-liquid demixing, has been observed. The equilibrium thermodynamics of this system has been described previously [3]. Thermodynamically, crys- Fig.…”

Section: Introductionmentioning

confidence: 99%

Diffusion induced phase separation with crystallizable nylons. I. Mass transfer processes for nylon 4,6

Bulte

Mulder

Smolders

et al. 1996

Journal of Membrane Science

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Mass transfer during membrane formation by means of phase inversion for a polymeric system with both a solid-liquid and a liquid-liquid equilibrium was studied on the basis of the theory developed by Reuvers and Smolders. During the first moments of immersion in the coagulation bath, the concentrations at the interface between bath and film are governed by the virtual liquid-liquid equilibrium. This equilibrium no longer exists at a larger time scale. The interfacial concentrations as a result of the local liquid-liquid equilibrium during mass transfer are located deeply in the crystallization region or solid-liquid demixing area and after an induction time the solid-liquid phase separation (crystallization) takes place when membranes are formed with an initial polymer concentration of 20% or larger. The calculated initial concentration profiles show a shallow pattern in polymer content for the films with initial concentration of 20 and 25%. From the calculated initial concentration profiles an isotropic morphology in the final membrane can be expected. A steep increase of the polymer concentration at the interface was observed for the more concentrated films correlated with a skinned morphology in the final membrane.

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Equilibrium thermodynamics of the ternary membrane-forming system nylon, formic acid and water

Cited by 44 publications

References 13 publications

Phase Diagram and Membrane Desalination

Phase Diagram and Membrane Desalination

Diffusion induced phase separation with crystallizable nylons. II. Relation to final membrane morphology

Diffusion induced phase separation with crystallizable nylons. I. Mass transfer processes for nylon 4,6

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