r] (the hydraulic resistance due to reversible phenomena, such as concentration polarization
and/or reversible deposition).
ConFluReM will establish Strategic Tools and New Instruments to:(1) comprehend and quantify the prevalent mass transport resistances in representative membrane separation processes,(2) synthesize and fabricate new nano-, micro- and mesoscale material and device systems as instruments to control and overcome the limitations of concentration polarization
and fouling,Strategic Tools are experimental and simulation methods to quantify and engineer the mass transport and hydrodynamical properties of the new membrane systems.
Tseng, "Ion concentration polarization
in polyelectrolyte-modified nanopores," Journal of Physical Chemistry C, vol.
19) developed a mathematical model according to heat and mass transfer correlations that was able to describe the behavior of PV processes with strong control of concentration polarization
under common non-isothermal and non-stationary conditions using plates-and frames membrane modules.
Membrane separation is now widely applied for such purposes as biotechnology, clarifying fruit juices, and waste water treatment, but is limited by the presence of concentration polarization
and membrane fouling.
The new approach, called ion concentration polarization
, is described in a research paper by Postdoctoral Associate Sung Jae Kim and Associate Professor Jongyoon Han, both in MIT's Department of Electrical Engineering and Computer Science, and colleagues in Korea.
The three types of polarization encountered in electroplating are gas polarization, concentration polarization
and chemical polarization.
The electrodes must be face polarized to give a force across the face of the electrode in order to sweep away concentration polarization
with a rising or descending rapidly rotating helix.
This is difficult to explain using a concentration polarization
or resistance-in-series model.
in RO and NF processes may lead to the precipitation of inorganic materials on membrane surfaces, causing fouling.
The fluidization of the catalyst makes also possible to (i) overcome problems with temperature control (formation of hotspots or too low temperature), (ii) to operate with smaller particles while still maintaining very low pressure drops and (iii) to overcome any concentration polarization
issue associated with more conventional fixed bed membrane reactors.