Browsing by Author "Yavuz, Cafer Tayyar"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Accessible and green manufacturing of magnetite (ferrous ferric oxide) nanocrystals and their use in magnetic separations(2008) Yavuz, Cafer Tayyar; Colvin, Vicki L.This work describes the first size dependent magnetic separation in nanoscale. Magnetite (Fe3O4) nanocrystals of high quality and uniform size were synthesized with monodispersity below 10%. Magnetite nanocrystals of 4 nm to 33 nm (average diameter) were produced. Batch synthesis was shown to go up to 20 grams which is more than 10 times of a standard nanocrystal synthesis, without loosing the quality and monodispersity. Reactor design for mass (1 gram per hour) production of magnetite nanocrystals is reported for the first time. The cost of a kg of lab purity magnetite nanocrystals was shown to be $2600. A green synthesis that utilizes rust and edible oils was developed. The cost of a kg was brought down to $22. Size dependency of magnetism was shown in nanoscale for the first time. Reversible aggregation theory was developed to explain the low field magnetic separation and solution behavior of magnetite nanocrystals. Arsenic was removed from drinking water with magnetite nanocrystals 200 times better than commercial adsorbents. Silica coating was successfully applied to enable the known silica related biotechnologies. Magnetite--silica nanoshells were functionalized with amino groups. For the first time, silver was coated on the magnetite--silica nanoshells to produce triple multishells. Anti-microbial activity of multishells is anticipated.Item Magnetic purification of a sample(2011-05-10) Colvin, Vicki L.; Yavuz, Cafer Tayyar; Mayo, John Thomas; Yu, Weiyong; Rice University; United States Patent and Trademark OfficeMethods for separating magnetic nanoparticles are provided. In certain embodiments, a method is provided for separating magnetic nanoparticles comprising: providing a sample comprising a plurality of magnetic nanoparticles; passing the sample through a first magnetic field; at least partially isolating nanoparticles of the first nanoparticle size desired; altering the strength of the first magnetic field to produce a second magnetic field; and at least partially isolating nanoparticles of the second nanoparticle size desired.