Preparation of polysulfone microcapsules containing 1-octanol for the recovery of caprolactam

Abstract: Polysulphone (PSF) microcapsules containing 1-octanol were prepared with solvent extraction method for the recovery of caprolactam. One-step and two-step processes were, respectively, applied to prepare microcapsules. In order to get high extractant loading, a loading method with the assistance of ultrasound has been developed. With the two-step preparation process the extractant loss can be avoided. A very high extractant loading ratio of 5.96 g g-1 and the maximum uptake to caprolactam of 65.6 mg g-1 were achieved. Under the action of ultrasound the extractant loading efficiency is greatly intensified. With the one-step process 1-octanol loading ratio is highly limited. Only 1.74 g g-1 loading ratio and 29.9 mg g-1 uptake to caprolactam were realized. Meanwhile the extractant loss in the one-step process is serious. Considering extraction capacity and extractant loss in the preparation process, it is suggested that PSF microcapsules containing 1-octanol should be prepared with the two-step process. To fasten mass transfer rate, microcapsules with relatively smaller size are desired.

Published in:  Journal of Microencapsulation, Volume 26, Issue March 2009 , pages 104 – 110

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