Field-Flow fractionation (FFF)
| Technology | |
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| 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 class of analytical methods suitable for the separation and characterization of nanomaterials, 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 including tha Asymmetric flow FFF, centrifugal FFF, electrical FFF, split flow thin-cell fractionation (SPLITT), and thermal FFF. Depending on the applied technology particles can be separated in dependence of different physicochemical properties.
Asymmetric flow FFF (AF4)
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
This technology combines the FFF with an electrical field as additional separation force. Besides the separation based on particle size this method adds the capability to separate particles/molecules in dependence of their charge.
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
Possibly not relevant
Products
Post-treatment
Technology providers
| Company name | Country | City | Technology category | Technology name | TRL | 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
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| 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 |
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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}}}.