ULTRAFILTRATION

A MEMBRANE SEPARATION TECHNIQUE

NAGARAJU M

Ph.D. Scholar

Dept. of PHP&FE

CAE, Jabalpur (M.P.)

1

.

OUTLINE

Membrane separation techniques

Filtration spectrum

Modes of filtration

Ultrafiltration

Membrane configurations

Applications of ultrafiltration

Case study

Membrane fouling

Conclusion

References

2

MEMBRANE SEPARATION TECHNIQUES

Membrane separation is a technology which

selectively separates (fractionates) materials via pores

and/or minute gaps in the molecular arrangement of a

continuous structure

Separation process is purely physical

3

MEMBRANE SEPARATIONS

Pressure driven

• RO, NF, UF, MF, Gas separation, Pervaporation

Thermal driven

• Membrane distillation

Concentration driven

• Dialysis

Voltage/Charge driven

• Electro dialysis 4

5

CHARACTERISTICS OF PRESSURE DRIVEN

MEMBRANE PROCESSES

6

Process

technology

Typical operating

pressure (bar)

Feed recovery (%) Rejected species

MF 0.5-2 90-99.99 Bacteria, cysts, spores

UF 1-5 80-98 Proteins, viruses, endotoxins

NF 3-15 50-95 Sugars, pesticides

RO 10-60 30-90 Salts, sugars

ADVANTAGES OF MEMBRANE PROCESSES

Energy efficient by virtue of ambient temperature

operation

No phase change

Physical separation of compounds

Low capital & operating costs

Simplicity of operation and therefore minimum training

requirement to operators

Availability of different configurations

Modular in nature-over a wide range of capacities can

easily be fabricated

Short start-up and shut down times

Minimum of moving parts

7

APPLICATIONS OF MEMBRANE TECHNIQUES IN

FOOD SECTOR Food sector Membrane separation

technique

Purpose

Reference

Fruit and

Vegetable

Juices

MF or UF

MF and RO

Clarification

Fruit juice concentrates

Todisco et al.,

1998

Sugar Juices MF or UF Clarification Herve, 1994

Cane Sugar

Refinery

NF Separate colourings and salts Kwok, 1996

Vegetable

Proteins

UF and diafiltration High protein yield Be´rot et al., 1998

Brewing

Sector

MF mash separation, clarification of

rough beer

Fillaudeau, 1999

Wine Making MF

Electrodialysis

Microbiological stability

Tartaric stability

Daufin et al., 2001

Milk and Dairy

Industry

RO

MF

NF

Whey concentration

Globular milk fat fractionation,

protein extraction process

Whey protein valorization

Le et al., 2014 8

FILTRATION MODES

Full feed supply passes directly

through the filter. These filters

require periodic cleaning (or

back washing) of membranes

Requires less energy

Membrane fouling predominant

Employs a high velocity of feed

flowing in parallel over the

membrane surface

Higher filtration rates by

reducing membrane fouling

Direct Flow Mode Cross Flow Mode

9

ULTRAFILTRATION

Pressure driven membrane filtration technique for

concentration, fractionation and purification of

macromolecules in solutions without phase change or

addition of chemicals or solvents

Principle of sieving on a molecular level

Low applied pressures are sufficient to achieve high

flux rates

10

ULTRAFILTRATION

The pore size and molecular weight cut-off (MWCO) are

used to characterize a membrane

The MWCO of ultrafiltration membranes ranges between

1-1000 kDa

Transport of solutes through ultrafiltration membranes

depends on:

1) pore size of the membrane

2) interactions between UF feed components and membrane

matrix

11

12

PRINCIPLE

Pressure induced separation of solutes from a solvent through a semi permeable membrane

The relationship between the applied pressure on the solution to be separated and the flux through the membrane is described by the Darcy equation:

J: flux (flow rate per membrane area)

TMP: Trans membrane pressure (pressure difference between feed and permeate stream)

μ: solvent viscosity

Rt: total resistance (sum of membrane and fouling resistance)

13

FACTORS AFFECTING THE PERFORMANCE OF

ULTRAFILTRATION

Flow velocity

Critical for liquids containing emulsions or suspensions

Higher flow velocity reduces the fouling

Operating pressure

Permeate rate is directly proportional to the applied pressure

Operating temperature

Permeate rates increase with increasing temperature

Flow type

Dead end configurations: batch processes with low suspended solids

Cross flow configurations: continuous operations 14

15

UF membrane materials

Polymers

Polyvinylidiene fluoride (PVDF)

Polyether sulfone (PES)

Polysulfone (PS)

Polyacrylonitrile (PAN)

Polyethylene (PE)

Polypropylene (PP)

Polyvinyl chloride (PVC)

Ceramic membranes

UF membrane expected properties

Mechanical strength

Hydrophilicity

Durability

Chemical stability

Low polymer cost

Current standards (> 85% solutions)

PVDF

Chemical stability

Mechanical strength

Durability

PES

Hydrophilicity

Low polymer cost

History (early ‘90s)

UF MEMBRANE CONFIGURATIONS

Hollow fibre

Tubular

Spiral wound

plate and frame

16

17

UF applications

Water treatment

Waste water treatment and reclamation

Food processing

industry

Biotech and Pharmaceutical

Industries

Purification and concentration of products

Automobile industry

Egg-white concentration

Textile industry

Paper and pulp industry

18

UF IN FOOD INDUSTRY

Recovery of whey protein and concentration of skim

milk in dairy industry

Clarification and bacteria removal of wine

Recover valuable products from soya whey and other

dilute waste streams

Purification of fermentation solution, and clarification

and concentration of fruit juice

Concentration of gelatin

Recovery of sugar from sugary water

Fractionation and concentration of egg albumin,

proteins, extracts such as vanilla, lemon, peel extract,

etc., and animal, fish and vegetable oils 19

CASE STUDY

Concentration of lycopene in the pulp of

papaya(Carica papaya L.) by ultrafiltration on a pilot

scale

Juliana et al., 2015

Objective: To evaluate the performance of two

polymeric membranes (polysulfone 100 kDa and

polyethersulfone 50 kDa) in the concentration of

lycopene of papaya pulp (Carica papaya L.) by

ultrafiltration on a pilot scale

Food and bioproducts processing, 9 (6):296–305

20

MATERIALS AND METHODS

Raw material

Whole papaya pulp (soluble solids11.5 Brix), pasteurized and frozen

Equipment

Membranes

PES50, made of polyethersulfone with a molecular weight cutoff of 50 kDa

PS 100, made of polysulfone, with a molecular weight cutoff 100 kDa 21

FT: feed tank

V: valve

LP: lobe pump

MFM: magnetic flow meter

MN: manometer

MB: membrane

TE: thermometer

MV: micrometric valve

BP: Becker to permeate

B: Balance

Effect of enzymatic treatment on the raw material in the papaya pulp

ultrafiltration

Pectinase (Pectinex Ultra SP-L)

Pectinase 0.1% of initial volume of papaya pulp

constant manual stirring at 35°C for 60 min.

Pulp heated to 50°C

UF: 1 bar pressure and velocity 3 m s−1.

pH, total solids and lycopene of the permeate and retentate, carotenoids

retention rate in the retentate, final permeate flux, and total ultrafiltration time

were statistically analyzed using ANOVA and Tukey test(p = 0.05)

Effect of operational conditions in the concentration of lycopene by

ultrafiltration using the membrane PS 100 and PES 50

Operational pressure1 or 2 bar and tangential velocity 3 or 6 m s−1 for PS 100

Operating pressure 0.8, 1.5 or 3 bar for PES 50 22

Physicochemical analysis

Papaya pulp, retentate and permeate, were analyzed on:

total carotenoids, total solids and pH

Permeate flux (J), concentration factor (CF) and

retention index (R%)

mp: mass of the permeate in time t

AP: permeation area of the membrane

ma: mass of the feed

mr: mass of the retentate

Cp and CR: concentrations of the component of interest in

the permeate and the retentate

23

RESULTS AND DISCUSSION

Effect of enzymatic treatment on the raw material in the ultrafiltration of the

papaya pulp

24

Table 1 – Average values of the results obtained in the ultrafiltration of papaya pulp (Carica papaya L.) at the

different conditions. (A) CF = 1.65,using polymeric membrane PS100, with or without enzymatic treatment of the

raw material, v = 3m s−1, p = 1 bar. (B) CF = 1.50, using polymeric membrane PES50, v = 6 m s−1 and p = 3.0,

1.5 or 0.8 bar.

25

Total solids (a) and lycopene (b) contents of the retentate and the permeate obtained in the UF of papaya pulp (Carica papaya

L.) at 50°C using polymeric membrane PS 100 as a function of pressure and operating velocity

26

Lycopene retention index (a), final permeate flux (b) and total time of ultrafiltration (c) obtained in the UF of papaya pulp

(Carica papaya L.) at 50°C using polymeric membrane PS 100 as a function of pressure and operating velocity

CONCLUSION

UF processes resulted in retention of more than 98% of

the lycopene

Enzymatic treatment of the raw material, in the

conditions studied, had no significant effect on the

permeate flux

The best UF performance was obtained with the

polysulfone membrane with a molecular weight cutoff of

100 kDa, pressure 1 bar and tangential velocity 6 m s−1

27

Study Findings Reference

Fruit juices UF membrane is able to retain large particles such

as microorganism, lipids, protein and colloids; and

the small particles, for example vitamins, salts,

and sugars, are well reserved in juice

Cassano, et al.,

2007

Korla pear

juice

TSS, total sugar, pH and TA of UF pre-treated

korla pear juice were no significant change

compared to raw juice (P > 0.05)

After UF, total phenols and ascorbic acid were

decreased. Decrease of total phenols was due

to UF retention of compounds with large

molecular weight, such as self-conjugated

phenols and the bounded phenols with other

compounds. Loss of ascorbic acid was due to the

exposure to light and oxygen during the feed liquid

circulation of UF treatment

main aroma compounds in UF pre-treated juice

showed no significant change compared to raw

korla pear juice (P > 0.05)

Zhao et al, 2016

28

Reviews regarding applications of UF in food sector

Study Findings Reference

Membrane

fouling

The physical strategies for fouling reduction include the

use of turbulence generating devices, sonication,

centrifuge and use of electric and magnetic fields

Vardanega

et al., 2013

Date palm

sap syrups

UF process affects significantly the sap syrup

composition. Retention of sucrose through tubular

membranes caused a decrease in its content in sap

permeate and also in the corresponding syrups, and a

richness in reducing sugars. This contributes to a

reduction of the syrup crystallization phenomenon

Ines et al.,

2016

Protein

separation

Two proteins with a close molecular weight such as

the hemoglobin (64677 Da) and bovine serum albumin

(66430 Da) can also effectively separated by stacking

flat ultrafiltration with same membranes

Feins &

Sirkar, 2005

Separation

of alpha-

chain

subunits

from tilapia

skin gelatin

α1-subunit was effectively separated by a two-step

ultrafiltration process combined a single 100 kDa

MWCO RC membrane and a sandwich configuration of

same membranes. The α2-subunit was also separated

by the same ultrafiltration process with 150 kDa MWCO

PES membranes

Shulin et al,

2015

29

Study Findings Reference

Cheese

making

Membrane technology is practical for handling a

considerably large amount of production (1–2 kg of cheese

yields 8–9 kg of whey), and it is able to separate protein,

lactose, salt and water from cheese whey. In industry,

ultrafiltration is widely used to concentrate whey protein

because it can exclude impurities to some extent

Baldasso et

al., 2011

Soy

protein

isolate

The combination of the Jet Cooking and the enzyme-

assisted UF treatments are able to effectively reduce the

anti-nutritional factors found in the soy products. This

processing strategy offers a strong potential for application

in the production of soy protein products for use in infant

formulas

Yang et al.,

2014

Honey Ultra filtration improves the quality of honey and provides

honey as a safe ingredient in food processing

Itoh et al.,

1999

fish meal

effluents

UF is a promising separation process for the recovery and

concentration of proteins from fish meal effluents

Afonso et al.,

2004

30

MEMBRANE FOULING

Fouling refers to the irreversible alteration in

membrane properties, resulting from several

interactions of feed stream components and

membrane (Saxena et al., 2009)

In food application, membrane is usually fouled by

biofoulants such as protein and polysaccharide

(Tsagaraki & Lazarides, 2011)

Membrane fouling results in substantial flux decline

and increase of plant maintenance and operating costs

31

MECHANISMS OF MEMBRANE FOULING BY

PROTEIN SUSPENSIONS

The phenomenon of concentration polarization

followed by the formation of a gel layer (Porter,

1972)

Adsorption of solutes on the membrane surface and

inside the pore structure (Aimar et al., 1986)

Deposition and pore blocking of protein aggregates

due to denaturation (Martine et al., 1991)

32

MEMBRANE FOULING

Bio-fouling

Organic fouling

Inorganic fouling

Particulate fouling

Pretreatment

(pre-filtration, dispersants,

anti-scalants etc.)

Membrane/module

(membrane surface

modification,

spacer/channel design)

Operation

(cleaning, recovery)

Categories

Control

33

TECHNICAL & SCIENTIFIC CHALLENGES

Membrane

Fouling…

Membrane

Integrity…

Trace Organics

Rejection…

Module Design… 34

CONCLUSIONS

Membrane filtration processes are gaining more

attention and focus in food industry due to its

advantages (environmental friendliness, cost saving,

and product improvement) as compared with other

conventional methods

Ultrafiltration becomes an essential part in food

technology as a tool for separation and concentration

Fouling is the major problem in UF and various studies

are being conducted to improve ultrafiltration, focusing

on membrane fouling control and cleaning of fouled

membranes 35

REFERENCES Afonso, M. D., Ferrer, J. and Bo´ rquez, R., 2004. An economic

assessment of proteins recovery from fish meal effluents by ultrafiltration. Trends in Food Science & Technology. 15: 506–512.

Aimar, P., Baklouti, S. and Sanchez, V., 1986. Membrane–solute interactions: influence on pure solvent transfer during ultrafiltration. Journal of Membrane Science, 29(2): 207–224.

Baldasso, C., Barros, T. C. and Tessaro, I. C. 2011. Concentration and purification of whey proteins by ultrafiltration. Desalination, 278(1–3): 381–386.

Be´rot, S., Nau, F., Thapon, J.-L., Que´meneur, F., Jaouen, P. and Vandanjon, L., 1998, Vegetal and animal proteins, Membrane separations in the Processes of the Food Industry, G. DauŽ n, F. Rene´, P. Aimar (Eds.) (Lavoisier Tech and Doc, Paris France), pp. 373–417.

Daufin, G., Escudier, J.P., Carrère, H., Bérot, S., Fillaudeau, L. and Decloux, M., 2001. Recent and emerging applications of membrane processes in the food and dairy industry. Food and Bioproducts Processing. 79(2):89-102.

Feins, M. and Sirkar, K. K., 2005. Novel internally staged ultrafiltration for protein purification. Journal of Membrane Science, 248(1): 137–148.

Fillaudeau, L., 1999. Cross-•flow microŽ filtration in the brewing industry— An overview of uses and applications, Brewer’s Guardian, 128(7): 22–30.

36

Herve´, D., 1994, Production de sucre rafŽ ne´ en sucrerie de canne, Industries Alimentaires et Agricoles, 111(7/8): 429–431.

Ines. M., Samia, B., Abir, M., Sabine, D., Hamadi, A., Christophe, B., Souhail, B. and Manel M. 2016. Effect of ultrafiltration process on physico-chemical, rheological, microstructure and thermal properties of syrups from male and female date palm saps. Food Chemistry. 203: 175–182.

Itoh, S., Yoshioka, K., Terakawa, M., Sekiguchi, Y., Kokubo, K. and Watanabe, A., 1999. The use of ultrafiltration membrane treated honey in food processing. Journal of the Japanese Society for Food Science and Technology. 46(5): 293-301.

Juliana, P., Clarissa, R. C. and Luiz, A. V., 2015. Concentration of lycopene in the pulp of papaya (Carica papaya L.) by ultrafiltration on a pilot scale. food and bioproducts processing. 96: 296–305.

Kwok, R.J., 1996, Production of super VLC raw sugar in Hawai: Experience with the new NAP ultraŽ ltration/softening process, Int Sugar J, 98(1173): 490–496.

Le, T. T., Angeli, D., Cabaltica and Bui, V. M., 2014. Membrane separations in dairy processing. Journal of Food Research and Technology. 2(1): 01-14

Martine, M., Pierre, A. and Victor, S., 1991. Albumin denaturation during ultrafiltration: effects of operating conditions and consequences on membrane fouling. Biotechnology and Bioengineering, 38(5): 528–534.

Porter, M. C. (1972). Concentration polarization with membrane ultrafiltration. Product R&D, 11(3): 234–248.

37

Saxena, A., Tripathi, B. P., Kumar, M. and Shahi, V. K., 2009. Membrane-based techniques for the separation and purification of proteins: an overview. Advances in Colloid and Interface Science, 145(1–2): 1–22.

Shulin, C., Lanlan, T., Wenjin, S., Wuyin, W., Kazufumi, O. and Munehiko, T., 2015. Separation and characterization of alpha-chain subunits from tilapia (Tilapia zillii) skin gelatin using ultrafiltration. Food Chemistry.188: 350–356.

Todisco, S., Tallarico, P. and Drioli, E., 1998. Modelling and analysis of ultrafiltration effects on the quality of freshly squeezed orange juice. Italian Food & Beverage Technology, XII: 3–8.

Tsagaraki, E. V. and Lazarides, H. N., 2011. Fouling analysis and performance of tubular ultrafiltration on pretreated olive mill waste water. Food and Bioprocess Technology, in press.

Vardanega, R., Tres, M.V., Mazutti, M.A., Treichel, H., De Oliveira, D., Di Luccio, M. and Oliveira, J.V., 2013. Effect of magnetic field on the ultrafiltration of bovine serum albumin. Bioprocess Biosyst. Eng. 36 (8): 1087–1093.

Yang, j., Jian, G., Xiao-Quan, Y., Na-Na Wuc, Jin-Bo, Z., Jun-Jie, H., Yuan-Yuan, Z. and Wu-Kai, X. 2014. A novel soy protein isolate prepared from soy protein concentrate using jet-cooking combined with enzyme-assisted ultra-filtration. Journal of Food Engineering. 143: 25–32

Zhao, L., Yongtao, W., Xiaotong, H., Zhijian, S. and Xiaojun, L., 2016. Korla pear juice treated by ultrafiltration followed by high pressure processing or high temperature short time. LWT - Food Science and Technology. 65: 283-289

38

39