Length dependency of flux and protein permeation in crossflow microfiltration of skimmed milk

Piry, Alexander; Kühnl, W.; Grein, T.; Tolkach, A. M.; Ripperger, Siegfried; Kulozik, Ulrich

doi:10.1016/j.memsci.2008.09.025

Cited by 63 publications

(53 citation statements)

References 20 publications

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“…In cross-flow mode, as a consequence of flow, the pressure on the feed/retentate side declines while passing along the module from its inlet value P f to the outlet pressure P r (Piry et al ., 2008).…”

Section: Transmembrane Pressure and Fluxmentioning

confidence: 99%

Principles of Membrane Filtration

Hausmann

Duke

Demmer³

2012

Membrane Processing

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Section: Transmembrane Pressure and Fluxmentioning

confidence: 99%

Principles of Membrane Filtration

Hausmann

Duke

Demmer³

2012

Membrane Processing

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“…There are numerous studies on fouling phenomena occurring with dairy components [8][9][10][11][12][13], however little can be found on the actual mechanisms behind the fouling. Most studies focus on membrane performance, not investigating kinetics behind fouling phenomena observed.…”

Section: Introductionmentioning

confidence: 99%

Fouling mechanisms of dairy streams during membrane distillation

Hausmann

Sartipy

Vasiljevic

et al. 2013

Journal of Membrane Science

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This study reports on fouling mechanisms of skim milk and whey during membrane distillation (MD) using polytetrafluoroethylene (PTFE) membranes. Structural and elemental changes along the fouling layer from the anchor point at the membrane to the top surface of the fouling layer have been investigated using synchrotron IR micro-spectroscopy and electron microscopy with associated energy dispersive X-ray spectroscopy (EDS). Initial adhesion of single components on a membrane representing a PTFE surface was observed in-situ utilizing reflectometry. Whey components were found to penetrate into the membrane matrix while skim milk fouling remained on top of the membrane. Whey proteins had weaker attractive interaction with the membrane and adhesion depended more on the presence of phosphorus near the membrane surface and throughout to establish the fouling layer. This work has given detailed insight into the fouling mechanisms of MD membranes in major dairy streams, essential for maintaining membrane distillation operational for acceptable times, therewith allowing further development of this emerging technology. 2 IntroductionMembrane distillation (MD) is a thermally driven membrane process and relies on a highly hydrophobic porous membrane to maintain a liquid-vapour interface. Common membrane materials for MD are polypropylene (PP), polyvinylidene fluoride (PVDF) and PTFE [1,2]. The highest performing membrane material for MD is PTFE due to its high hydrophobicity, chemical inertness and open porous structure [3]. Fouling in the MD process is different to that observed in pressure driven processes such as RO. The low operating pressure used in MD may potentially lead to a less compact, more easily removed, fouling layer. Also, since only volatile compounds pass through the membrane pores, the potential for in-pore fouling is minimized in MD applications. Studies of MD processes have, however, revealed that penetration of foulants into the membrane can occur in some instances [4]. There is a need for a better understanding how dairy components interact with MD membranes and accumulate at the membrane surface. This understanding may allow better control of performance of membrane distillation via better mitigation of fouling.The high hydrophobicity of MD membranes can result in the establishment of hydrophobic interactions between the membrane and any solutes that have hydrophobic components, such as proteins and fats. While hydrophilic coatings may be a possible avenue to reduce the fouling that results from these hydrophobic interactions [5][6][7], simple uncoated membranes have advantages in terms of lower cost and can be easier to manage over time as there is no requirement to maintain a specialised surface coating.There are numerous studies on fouling phenomena occurring with dairy components [8][9][10][11][12][13], however little can be found on the actual mechanisms behind the fouling. Most studies focus on membrane performance, not investigating kinetics behind fouling phenomena observed. In cases wh...

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“…The extent of the changes on colloidal calcium phosphate during UF depends mainly on processing conditions (such as temperature and pH of filtration), and micellar dissociation has been reported to occur during UF (Singh 2007). Changes in the chemical and physical properties of skim milk during membrane filtration have been extensively investigated (JimenezLopez et al 2008;Karlsson et al 2005); the casein micelles are recognized as key factors in the processing performance during filtration (David et al 2008;Piry et al 2008;Rabiller-Baudry et al 2005). However, the effects of UF on the structure function of the casein micelles have received very little attention.…”

Section: Introductionmentioning

confidence: 99%

Does ultrafiltration have a lasting effect on the physico-chemical properties of the casein micelles?

Ferrer

Alexander

Corredig

2011

Dairy Science & Technol.

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The objective of this work was to determine if concentration of milk using ultrafiltration (in the absence of diafiltration) affects the physico-chemical properties of the casein micelles. The milk, once concentrated, was brought back to its original concentration and the physico-chemical properties as well as its susceptibility to rennet induced gelation were assessed. Although much is understood on the renneting behavior of concentrated milk, no information is available on how (or if) ultrafiltration per se modifies the properties of the micelles. Two times (2×) or five times (5×) concentrated milk (based on volume reduction) was prepared by ultrafiltration. Casein micelles were redispersed in their corresponding permeates and dialyzed against untreated skim milk. The stability of the casein micelles, their scattering properties, and the renneting properties were observed under the same volume fraction and ionic conditions of the skim milk control. There was a higher susceptibility to aggregation and a lower gel stiffness for the reconstituted micelles from the 5× milk compared to the 2× milk. 5× Ultrafiltration induced losses of calcium from the micelle, while 2× milk showed similar value as the control. The results suggest that the process of ultrafiltration affected the internal structure of the

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Length dependency of flux and protein permeation in crossflow microfiltration of skimmed milk

Cited by 63 publications

References 20 publications

Principles of Membrane Filtration

Principles of Membrane Filtration

Fouling mechanisms of dairy streams during membrane distillation

Does ultrafiltration have a lasting effect on the physico-chemical properties of the casein micelles?

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