Magnetophoretic cell clarification

(cont.) the feed fluid was achieved after one pass through the counter current system. In the second case, four permanent magnets were arranged in a quadrupole around a central column to create areas of high magnetic field at the column walls and areas of low magnetic field at the centerline, inducing non-magnetic particles to concentrate at the centerline, where they were removed through a coaxial central outlet tube at the top of the column. Depending on the flow rate, up to 99% of polystyrene beads of different sizes could be removed from the feed after one pass through the quadrupole system. The recovery efficiency decreased with increasing flow rate, i.e. with decreasing residence time in the device. E. coli cells were able to be removed with separation efficiencies as high as 95% at much higher flow rates due to the formation of [approximately]12 micron aggregates in the presence of the magnetic nanoparticles; these large aggregates experienced enhanced magnetic forces over individually-dispersed cells and could be recovered more effectively. The governing equations for magnetophoretic clarification were applied to the quadrupole configuration to predict particle trajectories through the column and to predict the separation efficiency under different flow conditions, which showed a good match to the experimental results. It was also shown that axial magnetic field gradients near the entrance region acted effectively as a barrier to entry of particles in the slow moving regions near the walls; this retardation of their axial movement provided a longer residence time for the particles that allowed them to be moved more efficiently to the centerline ...

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Sharpe, Sonja Ann, 1974-

Advisor dc:contributor.advisor

• T. Alan Hatton.

• Chemical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/28663

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/28663