A new method to determine the skin thickness of asymmetric UF-membranes using colloidal gold particles

Cuperus, F.P.; Bargeman, D.; Smolders, Kees

doi:10.1016/0021-9797(90)90019-k

Cited by 18 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…30 Tracer Filtration Tests. Tracer filtration tests (also known as penetration tests in some earlier studies 49 ) were performed for BW30 and NF90 in a customized filtration cell (effective filtration area of ∼19.6 cm 2 ) to assess the interconnectivity within the PA layer and to determine the location where separation takes place. HA was chosen as a tracer in this study due to its good solubility and low cost.…”

Section: T H Imentioning

confidence: 99%

“…HA was chosen as a tracer in this study due to its good solubility and low cost. Its small size (∼1.1–5.4 nm) and soft nature may allow better penetration into pores and defects compared to rigid silver or gold nanoparticles. ,,, For a typical test, a virgin membrane was operated in the “reverse orientation” with its substrate side exposed to the feed solution (a 5 mg/L HA solution) under a constant pressure of 0.69 MPa (i.e., 100 psi) for 96 h. Such a tracer test in the “reverse orientation” allows HA macromolecules to access the backside of the PA layer. Additional HA tracer tests were performed in the “normal orientation” to allow HA macromolecules to access the frontside of the PA layer (see more details in Supporting Information S8).…”

Section: Experimental Sectionmentioning

confidence: 99%

See 1 more Smart Citation

Intrinsic Nanoscale Structure of Thin Film Composite Polyamide Membranes: Connectivity, Defects, and Structure–Property Correlation

Song

Gan

et al. 2020

Environ. Sci. Technol.

167

150

View full text Add to dashboard Cite

Transport of water, solutes, and contaminants through a thin film composite (TFC) membrane is governed by the intrinsic structure of its polyamide separation layer. In this work, we systematically characterized the nanoscale polyamide structure of four commercial TFC membranes to reveal the underlying structure–property relationship. For all the membranes, their polyamide layers have an intrinsic thickness in the range of 10–20 nm, which is an order of magnitude smaller than the more frequently reported apparent thickness of the roughness protuberances due to the ubiquitous presence of nanovoids within the rejection layers. Tracer filtration tests confirmed that these nanovoids are well connected to the pores in the substrates via the honeycomb-like opening of the backside of the polyamide layers such that the actual separation takes place at the frontside of the polyamide layer. Compared to SW30HR and BW30, loose membranes XLE and NF90 have thinner intrinsic thickness and greater effective filtration area (e.g., by the creation of secondary roughness features) for their polyamide layers, which correlates well to their significantly higher water permeability and lower salt rejection. With the aid of scanning electron microscopy, transmission electron microscopy, and tracer tests, the current study reveals the presence of nanosized defects in a polyamide film, which is possibly promoted by excessive interfacial degassing. The presence of such defects not only impairs the salt rejection but also has major implications for the removal of pathogens and micropollutants.

show abstract

Section: T H Imentioning

confidence: 99%

Section: Experimental Sectionmentioning

confidence: 99%

Intrinsic Nanoscale Structure of Thin Film Composite Polyamide Membranes: Connectivity, Defects, and Structure–Property Correlation

Song

Gan

et al. 2020

Environ. Sci. Technol.

167

150

View full text Add to dashboard Cite

show abstract

“…A new approach to determine the skin thickness of anisotropic UF membranes is baaed on the penetration of colloidal particles of a well-known size and a very narrow size distribution into the macroporous sublayer of an anisotropic UF-membrane [50]. The particles entering from the macroporous sublayer side, penetrate into the porous support until small pores near or in the skin am reached.…”

Section: Top Layer Thicknessmentioning

confidence: 99%

Characterization of UF membranes

Cuperus

Smolders

1991

Advances in Colloid and Interface Science

101

View full text Add to dashboard Cite

The field of membrane filtration is currently enjoying a great deal of interest and its field of application is expanding rapidly. Since membrane separations are possible at moderate process conditions the application of membrane filtration in food industry and biotechnology is growing very fast [ 11. Furthermore, the possibility to perform separations at low energy costs makes membrane filtration competitive with classical separation techniques. Although the performances of the current membrane systems are sometimes quite satisfying, the fundamentals of membrane separation actions, irrespective whether it concerns gas separation or microfiltration membranes, are not very well understood yet. One of the reasons for this apparent contradiction is that the physical and chemical nature of the applied membranes is intricate, whereas the relation between the membrane structure and the actual performance, i.e., the transport mechanism, is very complex [l-3]. It is recognized nowadays that these problems can only be overcome when the relevant data, describing the membrane structure and transport properties, are known accurately. These parameters can only be found when different characterization techniques are combined. In this paper a number of techniques which are used for the characterization of porous membranes are reviewed. Although the present survey is not entirely complete, it certainly covers the techniques which are sufficiently developed to be exploited with some success [3].

show abstract

“…This effect has been described with resistance models by Henis and Tripodi [5] for skinned asymmetric membranes and Pinnau et al [ 61 for composite membranes. According to Cuperus, Bargeman and Smolders [7] PPO-membranes of the latter type can be considered as membranes consisting of two distinct layers: the sublayer and the compact toplayer, which is gas selective.…”

Section: Introductionmentioning

confidence: 99%

The resistance towards gas transport of the sublayer of asymmetric PPO hollow fiber membranes determined by plasma-etching

Bauer¹,

Smid²,

Olijslager³

et al. 1991

Journal of Membrane Science

View full text Add to dashboard Cite

Plasma-etching is a powerful tool in the determination of the resistance of the sublayer of skinned asymmetric hollow fiber membranes of poly (2,6-dimethyl-1,4-phenylene oxide). Using a resistance model and data provided by etched hollow PPO fiber membranes it is possible to predict the ultimate selectivity of the total membrane for helium over nitrogen and oxygen over nitrogen. From this model and from permeability measurements it is shown that the gas resistance of the sublayer of asymmetric membranes with a selective layer has a large effect on the ultimate overall selectivity of the membranes. In order to improve the membrane performance the resistance of the sublayer has to be minimized. Etching experiments were performed on follow fiber membranes spun from PPO-types with different intrinsic viscosities. The resistance of the sublayer decreased markedly with increasing intrinsic viscosity of the PPO. To a lesser extent the membrane preparation (the length of the air gap) influences the gas resistance of the sublayer.

show abstract

A new method to determine the skin thickness of asymmetric UF-membranes using colloidal gold particles

Cited by 18 publications

References 12 publications

Intrinsic Nanoscale Structure of Thin Film Composite Polyamide Membranes: Connectivity, Defects, and Structure–Property Correlation

Intrinsic Nanoscale Structure of Thin Film Composite Polyamide Membranes: Connectivity, Defects, and Structure–Property Correlation

Characterization of UF membranes

The resistance towards gas transport of the sublayer of asymmetric PPO hollow fiber membranes determined by plasma-etching

Contact Info

Product

Resources

About