The document discusses membrane separation processes, including microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, which are widely used in chemical and food industries for various separation tasks. Key principles, types of membranes, processing modes, advantages, and applications in food processing are outlined, highlighting their efficiency and environmental benefits. The document concludes that membrane technology is a green alternative to traditional methods, driving the innovation of new food products.

1. Membrane
Separation Processes
PRESENTED BY: Nadiminti Chandana Sri Sai
SUBMITTED TO: Dr. Anil Kumar Chauhan
MF, NF, UF & RO: - Mechanisms and Food
Industry Applications MF, NF, UF & RO
COURSE TITLE: FST 504
FOOD PROCESSING
DSFT - IAS, BHU

2. OVERVIEW
➢ Introduction
➢ Principle
➢ Types of Membranes
➢ Modes of Membrane
Processing
➢ Classification
➢ Types of Membrane
Processing
➢ Advantages & Disadvantages
➢ Applications
➢ Conclusion
1. Micro Filtration
2. Ultra Filtration
3. Nano Filtration
4. Reverse Osmosis

3. Introduction
➔ The membrane processes are an accepted unit operations for a variety of separations in
chemical and food industries.
➔ The processes are driven by pressure, concentration, or electric force across the membrane
and can be differentiated according to the type of driving force, molecular size, or type of
operations.
➔ Basic Unit of Membrane Separation processes - MEMBRANE
➔ Membranes are semi-permeable barriers, used to separate two phases (permeate and
retentate) on the basis of particle size, electric charge etc,.
➔ It performs separation by a combination of filtration, purification, sieving and diffusion
mechanisms.
➔ The separation efficiency is usually affected by different processing factors like feed
composition, pH, temperature, pressure, feed flow and interactions between feed component
& membrane surface

4. Principle
The separation is accomplished with the
application of driving force on the solution or the
feed to pass through a specific membrane.
In membrane separation process the feed stream
is separated into two fractions:
● Permeate: - The fraction of feed that
permeates through membrane is called
permeate
● Retentate: - The fraction of feed stream that
is retained over (doesn’t permeate) through
membrane is called retentate.

5. Types of
Membranes
Classified based on
material composition
Membranes are most commonly
made up of: -
1. Organic polymers like cellulose
and its derivative, polyamides,
polyolefines, polycarbonate,
polysulfones, chlorine and
fluorine substituted
hydrocarbons
2. Inorganic membranes based on
oxides of silicium, zirconium,
titanium, and aluminum.
The principal requirements of membrane
are:
● High permeate flux
● Chemical stability and inertness
● Good mechanical strength
● Thermal stability
● Good retention capability
● Smooth, fouling resistant surface
● Resistance against microbial action
● Affordable cost
● Long service life

6. DEAD END
Feed flow is perpendicular to the
membrane surface
This causes a large reduction in flux
CROSS FLOW
Flow of solution is parallel to the
membrane surface.
Flow causes turbulence and produces
shear.
Modes of membrane
Filtration

7. Factors controlling
membrane
processing
Factors Membrane Properties Feed Properties Hydrostatic Effect
Pore Size Thickness Porosity Tortuosity
Compacti
on
Concent
ration
Viscosity
Temperat
ure
Trans
membra
ne
pressure
Cross
flow
Velocity
Change Increase Increase Increase Increase Increase Increase Increase Increase Increase Increase
Effect
on Flux
Increase
Decrease
Increase
Decrease Decrease
Decrease
Decrease
Increase Increase Increase

8. Classification Based on Driving Force
Membrane Separation Processes
(Driving Force)
Pressure driven
membrane
Concentration driven
membrane
Dialysis
Electro-osmosis
Electrodialysis
Micro Filtration
Potential driven
membrane
Ultrafiltration
Nano Filtration
Reverse Osmosis

9. Classification Based on Size of the Material

10. Categories of
pressure driven
membrane processes
Micro Filtration
(MF)
Ultra Filtration
(UF)
Nano Filtration
(NF)
Reverse Osmosis
(RO)
Pore Size
(µ)
102 - 104 1 -102 1 - 10 10-1 - 1
Operating
Pressure
(bar)
<1 1 -10 20 - 40 30 - 60
Basis of
rejection
Absolute Size of
Particles (0.02-
10µm)
Molecular weight
cut-off (103 – 105
Da)
Molecular weight
cut-off (200 – 1000
Da)
Molecular weight
cut-off
Solutes to
be
separated
Clay, Paint, Oil
droplets,
Suspended
matters, micro-
organisms
Pectins, Proteins,
High molecular
weight,
polyphenols,
enzymes
Sugars, Low
molecular weight,
polyphenols, dyes
Salts, Electrolytes
Purpose Clarification or turbidity removal
Decolourization
and purity
increase
Concentration
and desalination

11. Micro Filtration
● Microfiltration is a low-pressure cross-
flow membrane process
● Microfiltration (MF) designates a
membrane separation process with
larger membrane pore size i.e.
macromolecules.
● Separates the colloidal and suspended
particles in the range of 0.05-10 microns
● It is used for bacteria removal,
fermentation broth clarification and
biomass clarification and recovery.
● Microfiltration is used as pre-treatment
before ultra filtration or reverse
osmosis.
MICRO
FILTRATION

12. Micro Filtration
Applications in Food Industry:
● Clarification of beer and wine i.e. for
removal of yeasts, microorganisms.
● Removal of oil droplets and fat globules
● Removal of suspended solids and fat
present in the brine used in fish
processing.
● Pre filtration of wastewater streams
generated in food processing.
Application in Dairy Industry:
● For making low-heat sterile milk
● Removal of bacteria from milk
● Pre-treatment of cheese whey.

13. Ultrafiltration
● Ultrafiltration is a selective fractionation
process.
● They operate under low pressures i.e up to 10
bars.
● ultrafiltration (UF) lies between microfiltration
and nanofiltration in terms of pore size, which
can range from 1-100 nm i.e 0.1 to 0.01 microns
● UF allows for the concentration of high
molecular weight proteins, macromolecules,
and other small, suspended solids.
● Polymers like polysulfones, polyamides, PVC,
polystyrene, polycarbonates and polyethers
are normally used.
ULTRA
FILTRATION

14. Ultrafiltration
● Inorganic salts, lactose and water are
removed as permeate where as fat
globules and proteins are retained over the
membrane. This concentrated milk
(retantate) is used in the manufacture of
many types of cheeses from milk.
● whey protein concentrate is retained over
the membrane. This retentate is used to
produce protein concentrates from whey.
● Ultrafiltration can be used for isolated
soybean protein production.

15. Nanofiltration
● Size and charge play a role in
nanofiltration (NF) separation processes, it
is also known as loose reverse osmosis
● Pressure range: 10-50 bar (lower pressure
than RO)
● Pore size between 0.1-10 nm i.e. 0.001 μm
to 0.01 μm
● The mass transfer mechanism in Nanofiltration is diffusion
● NF membrane permeates: certain ionic solutes (such as sodium
and chloride), monovalent ions, as well as water.
NANO
FILTRATION
● NF membrane retains: Larger ionic species, including divalent and multivalent ions and
more complex molecules.

16. Nanofiltration
● Nanofiltration is used to remove
mainly the monovalent ions. A partly
demineralization and water removal
is obtained.
● Nanofiltration can perform separation
applications such as color removal, and
desalination.
● Applications for NF membranes range from the removal of natural
organic matter in wastewater treatment, hardness reduction in
water purification, and whey demineralization in dairy processing.

17. Reverse Osmosis
● Definition:
It is a membrane separation process, driven by a
pressure gradient, in which the membrane
separates the solvent (generally water) from other
components of a solution. The solvent flow is
opposite to the normal osmotic flow.
The process is used to produce relatively pure water or a concentrated solution of microsolutes
from a given salt solution. The membrane configuration is usually cross-flow.
● Mechanism:
By exerting a hydraulic pressure greater than the sum of the osmotic
pressure difference and the pressure loss of diffusion through the
membrane, that can cause water to diffuse in the opposite direction,
into the less concentrated solution. This is reverse osmosis.
The greater the pressure applied, the more rapid the diffusion. Using reverse
osmosis we are able to concentrate various solutes, either dissolved or dispersed, in
a solution.

18. Reverse Osmosis
● Operational pressure: 30-60 bar
● Pore size: 101- 10 pm (lower than the pore size of MF,
UF and NF) i.e. 0.0001 μm to 0.001 μm
● In a reverse-osmosis system, water is the permeating
material referred to as “ permeate, ”and the remaining
solution concentrated with the solutes is called “
retentate. ”
● Reverse osmosis is a high-efficient technique for
dewatering process streams,
concentrating/separating low-molecular-weight
substances in solution, or cleaning wastewater. It has
the ability to concentrate all dissolved and suspended
solids. The permeate contains a very low
concentration of dissolved solids. Reverse Osmosis is
typically used for the desalination of seawater.

19. Reverse Osmosis
● Reverse osmosis is used for the must correction,
rejuvenation and dealcoholization of wine, Must
composition is balanced with the help of RO,
which increase sugar content in wine through
concentration and at the same time enhances
tannins and organoleptic components by 5-20%.
● Concentrate and purify fruit juices, enzymes, fermentation liquors
and vegetable oils; pre-concentrate juices and dairy products
before evaporation.
● Concentrate wheat starch, citric acid, egg white, milk, coffee, syrup,
natural extracts and flavors.
● To determine and purify water from boreholes or rivers or
desalination of sea water.
● Water and waste water purification.
● Concentration of whey during cheese manufacture.

20. Advantages
The main advantages of membrane separation technology are:
● Separation of streams or components at a lower temperature
● Minimized thermal damage to the product
● Separating the component in its native form
● Less energy use
● Easy to operate
● Environmentally safe
● It doesn’t denature the proteins.
● No requirement for chemicals.
● Can remove 90–100% pathogens from the water sample.
● It allows the filtration of any volumes of non-turbid water through the disk.

21. Disadvantages
The main disadvantages of membrane separation technology are:
• The turbid water can not be used.
• There may be a risk of bacterial abundance, as the water carries numerous microorganisms.
• Glass filters are breakable and can break quickly.
• The membrane filters can crack easily.
• Only liquids are sterilized by this method.
• Filters are costly to repair, mainly nano-filters.
• Constitutional restrictions of supplies used in filters alter the effectiveness of this process
such as damage of glass filters, fracture of the membrane filter, and consumption of the
filtrate.
• Require a high differential pressure.
• Clogging can occur

22. Applications
1. In industries and laboratories, it is used to sterilize the heat-labile fluid materials.
2. Most effective and acceptable method for filtration of drinking water.
3. In the pharmaceutical, cosmetics, electronics, and food and beverage industries
is used to monitor the bacterial cells.
4. Used in wastewater treatment.
5. Used in cold sterilization of beverages and pharmaceuticals.
6. Used for separation of milk fraction.
7. Used to concentrating the proteins.
8. Used for defeating skimmed milk and whey.
9. Used for the partial demineralization of whey

23. Conclusion
Membrane separation technology serves as alternative for
various conventional methods like evaporation,
centrifugation and filtration etc. widely usage of membrane
processing over conventional methods is mainly due to
following reasons: minimized thermal damage to product,
energy saving and better product quality etc.
As demand for novel food products or ingredients is
increasing, membrane processing can create novel products
and ingredients with desired characteristics.
Membrane technology is considered as green technology
due to their efficient energy utilization without using
chemicals and additives.

24. References
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