2.1 Pressure-Driven Membrane Separation Processes
The membrane separation processes where pressure acts as the driving force are
known as pressure-driven membrane separation processes [1]. The common examples of pressure-driven membrane separation processes are microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Figure 1 shows a representative
pressure-driven membrane separation process. These membrane separation processes are commonly used in various bioprocess-associated industries, such as
biotechnology, chemical, pharmaceutical, food, and dairy. The membranes used in
these membrane separation processes are either polymeric, ceramic, or metallic.
Furthermore, these processes are classified based upon the pore size, charge, or
pressure range used. The overall membrane separation efficiency (MS e ) depends
upon various factors, such as feed and membrane type, feed particle size, and
Table 1 Membrane processes are classified based upon their mechanism of separation
Membrane process
Feed phasepermeate phase
Driving
force
Size of retained
compounds
Type of retained
compounds
Microfiltration (MF)
L-L
ΔP
0.1–100 μm
Fine solids, bacteria
Ultrafiltration (UF)
L-L
ΔP
5 nm to 100 μm Suspended solids,
viruses, natural organic
matter
Nanofiltration (NF)
L-L
ΔP
1 nm to 100 μm Surfactants, dyes,
sugars, inorganics
Reverse osmosis (RO) L-L
ΔP
0.1 nm to 100 μm Minerals, metal ions
salts
Pervaporation
L-G
ΔP
0.5 nm to 100 μm Liquids
Dialysis
L-L
ΔC
–
–
Electrodialysis
L-L
Δф
–
Ions
Membrane distillation L-L
ΔT
–
Liquids
L-L liquid-liquid, G-G gas-gas, L-G liquid-gas, ΔP pressure difference, ΔC concentration difference, Δф electric potential difference, ΔT temperature difference
Fig. 1 Schematic representation of pressure-driven membrane separation processes [1]
(Reproduced with permission from Taylor and Francis)
Membrane Technology in Bioprocess Engineering
5
The membrane separation processes where pressure acts as the driving force are
known as pressure-driven membrane separation processes [1]. The common examples of pressure-driven membrane separation processes are microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Figure 1 shows a representative
pressure-driven membrane separation process. These membrane separation processes are commonly used in various bioprocess-associated industries, such as
biotechnology, chemical, pharmaceutical, food, and dairy. The membranes used in
these membrane separation processes are either polymeric, ceramic, or metallic.
Furthermore, these processes are classified based upon the pore size, charge, or
pressure range used. The overall membrane separation efficiency (MS e ) depends
upon various factors, such as feed and membrane type, feed particle size, and
Table 1 Membrane processes are classified based upon their mechanism of separation
Membrane process
Feed phasepermeate phase
Driving
force
Size of retained
compounds
Type of retained
compounds
Microfiltration (MF)
L-L
ΔP
0.1–100 μm
Fine solids, bacteria
Ultrafiltration (UF)
L-L
ΔP
5 nm to 100 μm Suspended solids,
viruses, natural organic
matter
Nanofiltration (NF)
L-L
ΔP
1 nm to 100 μm Surfactants, dyes,
sugars, inorganics
Reverse osmosis (RO) L-L
ΔP
0.1 nm to 100 μm Minerals, metal ions
salts
Pervaporation
L-G
ΔP
0.5 nm to 100 μm Liquids
Dialysis
L-L
ΔC
–
–
Electrodialysis
L-L
Δф
–
Ions
Membrane distillation L-L
ΔT
–
Liquids
L-L liquid-liquid, G-G gas-gas, L-G liquid-gas, ΔP pressure difference, ΔC concentration difference, Δф electric potential difference, ΔT temperature difference
Fig. 1 Schematic representation of pressure-driven membrane separation processes [1]
(Reproduced with permission from Taylor and Francis)
Membrane Technology in Bioprocess Engineering
5