Difference between revisions of "Field-Flow fractionation (FFF)"

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Revision as of 15:19, 31 January 2022

Technology

Technology details
Name:	Field-Flow fractionation
Category:	Separation technologies
Feedstock:	Food waste, Garden and park waste
Product:	Biomass in different physicochemical fractions

Field-Flow Fractionation (FFF) is a family of high resolution separation techniques especially applicable to macromolecules colloids and particles, and shares the most common likeness with liquid chromatography (LC). The mechanism for separation, however, does not involve interactions with a stationary phase used in LC methods. Instead, a field is applied normal to a laminar flow through a narrow channel, which reslts in a parabolic flow profile, separating different analytes into distinct regions of the velocity profile. The analytes can be fractionated according to their physicochemical properties such as charge, chemical composition, density, molar mass, and size. Beside analytical purposes the FFF can also be utilised for preparative purposes.

Feedstock

Origin and composition

Suitable feedstocks are heterogeneous mixtures of different substances in form of dilute suspensions (solids in liquid). Depending on the applied process and technology solids can be usually separated between the nm-µm range. The FFF is usually applied to separate cells, different kind of nanoparticles, polymers, and proteins for analytical and preparative purposes.

Pre-treatment

Mechanical separations
Ultrasonication

Process and technologies

Different variants of the FFF are available, which includes Asymmetric flow FFF (AF4), centrifugal FFF, electrical FFF (EFFF), split flow thin-cell fractionation (SPLITT), and thermal FFF (TF3). Depending on the applied technology particles can be separated in dependence of different physicochemical properties.

Asymmetric flow FFF (AF4)

Illustration of a separation channel for asymmetric flow field-flow-fractionation.

Animation of the AF4 separation driven by particle diffusion in a parabolic flow profile. Particles colored in red are the smaller and particles colored in blue are the larger ones. The force applied on the top is the crossflow (indicated by the arrows on the bottom). The elution flow in longitudinal direction is shown with the flow arrows indicating the velocity profile.

The asymmetric flow FFF (AF4) is realised in a separation channel where a separation force is generated in the form of an asymmetric crossflow through a semipermeable membrane and frit. The introduction of the crossflow through the semipermeable membrane holds the macromolecules back, and consequently, they get pushed against the membrane. The macromolecules move back into the channel from the accumulation membrane due to Brownian motion or normal diffusion. Diffusion is a size-dependent phenomenon. Hence, small molecules get access to high flow velocity solvent streams situated closer to the center of the parabolic flow profile. Consequently, macromolecules elute in order of increasing size.^[1] AF4 can be coupled with downstream detectors to obtain complementary data, which includes UV-vis spectra from diode array detectors, refractive index measurements, multiangel light scattering, or inductively coupled plasma mass spectroscopy (ICP-MS).^[2]

Centrifugal FFF

In centrifugal FFF the separation force is realised via an centrifugal field. Through the induced gravitational field larger particles accumulate at the channel bottom while smaller particles accumulate more at the upper part. The injected particles can be eluted through a parabolic flow-profile in combination with the reduction of the centrifugal field. Due to the large range of applicable centrifugal force the method has its advantage to separate a wide range of different sized particles (usually µm-nm range).

Electrical FFF (EFFF)

This technology combines the FFF with an electrical field as additional separation force. An electrical voltage is imposed between the top and bottom walls. Charged particles migrate toward either wall according to their electrophoretic mobility, which is determined by their sizes and charge densities, and undergo different flow velocity.^[3] Besides the separation based on particle size this method adds the capability to separate particles/molecules in dependence of their charge. EFFF is well suited to the fractionation of proteins and measuring protein adsorption on to surfaces.^[4]

Split flow thin-cell fractionation (SPLITT)

In Split flow thin-cell fractionation (SPLITT) earth's gravitational force is used to separate different sized particles (usually in µm-range). Usually the suspensions are introduced into the top of a separation channel while a carrier liquid is pumped into the channel from the bottom. The separation of different sized solids occurs along the channel induced by earth's gravity. Two outlets (one at the channel bottom, one at the channel top) at the end of the channel separates the particles into a larger and smaller fraction while the cut-off can be controllel via the channel flows.

Thermal FFF (TF3)

In Thermal FFF the separation force is established by applying a temperature gradient. the top wall of a Thermal FFF channel is heated up, while the bottom wall of the channel is cooled down. The higher the temperature difference between both plates of the separation channel, the higher is the separation force. In order to achieve optimum separation, the temperature difference across the elution time can be adjusted. TF3 is well suited to the separation of polymers and organic solvents.

Products

No products have been identified.

Post-treatment

Currently no post-treatment has been identified.

Technology providers

**Technology comparison**
Company name	Country	City	Capacity [kg/h]	Concentration (max.) [mg/mL]	Processable volume [L]	Separation range [µm]	Feedstock: Food waste	Feedstock: Garden & park waste	Separation according size	Separation according charge

Company 1	Germany	Cologne	9	0.00138	100	1-2	●	●	●	●
Company 2			9	0.003	0.5	0.5-100	●	●	●	●

Company 1

Field-Flow fractionation (FFF) provider
General information
Company:
Country:
Contact:
Webpage:
Technology and process details
Technology name:		Technology category:	Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL:		Capacity:	kg·h^-1
Carrier solution:		Concentration (max.):	mg/mL
Processable volume:	L	Separation range:	µm
Temperature:	°C	Other:
Feedstock and product details
Feedstock:		Product:

Description of company 1

Postnova Analysics GmbH

Wyatt Technology

Open access pilot and demo facility providers

Currently no providers have been identified.

Patents

Currently no patents have been identified.

References

↑ Robert I. MacCuspie, 2018: Characterization of Nanomaterials for NanoEHS Studies. Nanotechnology Environmental Health and Safety. {{{editor}}} (Ed.). William Andrew, {{{place}}}.
↑ P. Senthil Kumar, K. Grace Pavithra, Mu. Naushad, 2019: Characterization techniques for nanomaterials. Nanomaterials for Solar Cell Applications. {{{editor}}} (Ed.). Elsevier, {{{place}}}.
↑ T. Okada, 2007: Field Flow Fractionation: Electric Fields. Encyclopedia of Separation Science. {{{editor}}} (Ed.). Academic Press, {{{place}}}.
↑ R. Hecker, H. Colfen, 2000: PROTEINS/Field Flow Fractionation. Encyclopedia of Separation Science. {{{editor}}} (Ed.). Academic Press, {{{place}}}.

[1] Robert I. MacCuspie, 2018: Characterization of Nanomaterials for NanoEHS Studies. Nanotechnology Environmental Health and Safety. {{{editor}}} (Ed.). William Andrew, {{{place}}}.

[2] P. Senthil Kumar, K. Grace Pavithra, Mu. Naushad, 2019: Characterization techniques for nanomaterials. Nanomaterials for Solar Cell Applications. {{{editor}}} (Ed.). Elsevier, {{{place}}}.

[3] T. Okada, 2007: Field Flow Fractionation: Electric Fields. Encyclopedia of Separation Science. {{{editor}}} (Ed.). Academic Press, {{{place}}}.

[4] R. Hecker, H. Colfen, 2000: PROTEINS/Field Flow Fractionation. Encyclopedia of Separation Science. {{{editor}}} (Ed.). Academic Press, {{{place}}}.

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@@ Line 19: / Line 19: @@
 ==Process and technologies==
-Different variants of the FFF are available, which includes Asymmetric flow FFF (AF4), centrifugal FFF, electrical FFF (EFFF), split flow thin-cell fractionation (SPLITT), and thermal FFF. Depending on the applied technology particles can be separated in dependence of different physicochemical properties.
+Different variants of the FFF are available, which includes Asymmetric flow FFF (AF4), centrifugal FFF, electrical FFF (EFFF), split flow thin-cell fractionation (SPLITT), and thermal FFF (TF3). Depending on the applied technology particles can be separated in dependence of different physicochemical properties.
 ===Asymmetric flow FFF (AF4)===
@@ Line 36: / Line 36: @@
 === Thermal FFF (TF3) ===
-In Thermal FFF the separation force is established by applying a temperature gradient. the top wall of a Thermal FFF channel is heated up, while the bottom wall of the channel is cooled down. The higher the temperature difference between both plates of the separation channel, the higher is the separation force. In order to achieve optimum separation, the temperature difference across the elution time can be adjusted. TF3 is well suited to the fractionation of polymers.
+In Thermal FFF the separation force is established by applying a temperature gradient. the top wall of a Thermal FFF channel is heated up, while the bottom wall of the channel is cooled down. The higher the temperature difference between both plates of the separation channel, the higher is the separation force. In order to achieve optimum separation, the temperature difference across the elution time can be adjusted. TF3 is well suited to the separation of polymers and organic solvents.
 ==Products==