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.

• Microcapsule
• preparation method
• extraction
• octanol
• caprolactam

Acknowledgements

The authors would like to acknowledge the support of the National Natural Science Foundation of China (No. 20525622, 20676066) and National Basic Research Program of China (2007CB714302) on this work.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.