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ID 34827
file
creator
Sakohara, Shuji
Yagi, Seiichi
subject
Dewatering
Inorganic sludge
Thermosensitive polymer
Hydrophobic interaction
Dual ionic polymers
Polymer complex
NDC
Chemical technology
abstract
The dewatering of inorganic sludge by a novel method based on the hydrophilic/hydrophobic transition of ionic thermosensitive polymers was investigated. As an inorganic sludge, the drinking water treatment sludge was used. Cationic thermosensitive polymers, poly(NIPAM-co-DMAPAA), which were synthesized by copolymerizing N,N-dimethylaminopropylacrylamide (DMAPAA) as the cationic component with N-isopropylacrylamide (NIPAM) as the thermosensitive component, were effective in dewatering the sludge. When the dewatering was performed at room temperature, the optimum polymer dosage for the dewatering rate was observed similar to the conventional hydrophilic polymeric flocculants. On the other hand, when the dewatering was carried out above the lower critical solution temperature (LCST) of poly(NIPAM-co-DMAPAA), the dewatering rate increased remarkably as the polymer dosage increased. Such high dewatering rates can be attributed to the hydrophobic interaction among the thermosensitive polymer molecules adsorbed on the sludge. However, the LCST of poly(NIPAM-co-DMAPAA) increased considerably as the DMAPAA content increased. In order to solve this problem, the use of dual ionic thermosensitive polymers was investigated. By using the anionic thermosensitive polymer, poly (NIPAM-co-AAC), which was synthesized by copolymerizing acrylic acid (MC) with NIPAM, in combination with cationic poly(NIPAM-co-DMAPAA), the dewatering rate was remarkably increased at relatively low temperatures. This increase was attributed to the formation of a polymer complex that decreased the LCST of the polymer molecules adsorbed on the sludge.
journal title
Separation and Purification Technology
volume
Volume 80
issue
Issue 1
start page
148
end page
154
date of issued
2011
publisher
Elsevier Science BV
issn
1383-5866
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
(c) 2011 Elsevier B.V. All rights reserved.
relation url
department
Graduate School of Engineering