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Processes 2019, 7(4), 201;

Size Separation of Silica Particles using a Magnetite-Containing Gel-Packed Column

Department of Chemistry and Applied Chemistry, Saga University, Saga 840-8502, Japan
Nitchitsu Co., Ltd., Nagasaki 859-6203, Japan
Author to whom correspondence should be addressed.
Received: 23 February 2019 / Revised: 1 April 2019 / Accepted: 4 April 2019 / Published: 8 April 2019
(This article belongs to the Special Issue Membrane Materials, Performance and Processes)
PDF [505 KB, uploaded 8 April 2019]


A magnetite-containing gel was prepared by water-in-oil radical polymerization of N,N-dimethylacrylamide and N,N’-methylenebisacrylamide in the presence of magnetite. The size of the prepared gel particles was 86 µm. The obtained magnetite-containing gel was packed in a column and first permeated with water, which revealed that the gel displayed a nonlinear response to pressure drop with increasing flow rate. Thus, the gel particles at the bottom of the column felt more pressure from the fluid than those at the top, causing greater deformation of the gel particles at the bottom of the column than at the top. The gaps between the packed gel particles functioned as pores to filter particles of appropriate size and morphology. An industrial silica particle suspension with particle sizes of 300 nm, 800 nm, and 10 µm was permeated through the gel layer. The smallest (300 nm) silica particles passed through the column. The filtered silica particles were recovered from the gel layer by using a magnet to separate the magnetite-containing gel from the filtered silica particles. This magnetite-containing gel has wide application prospects for the separation of not only ceramics but also other colloids.
Keywords: magnetite-containing gel; separation; deformation; recovery; silica particle magnetite-containing gel; separation; deformation; recovery; silica particle
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Miyoshi, M.; Takayanagi, K.; Morisada, S.; Ohto, K.; Kawakita, H.; Morita, S. Size Separation of Silica Particles using a Magnetite-Containing Gel-Packed Column. Processes 2019, 7, 201.

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