A fatty acid solvent of switchable miscibility

Qianqian Chen; Lei Wang; Gaihuan Ren; Qian Liu; Zhenghe Xu; Dejun Sun

doi:10.1016/j.jcis.2017.06.011

A fatty acid solvent of switchable miscibility

J Colloid Interface Sci. 2017 Oct 15:504:645-651. doi: 10.1016/j.jcis.2017.06.011. Epub 2017 Jun 7.

Authors

Qianqian Chen¹, Lei Wang¹, Gaihuan Ren¹, Qian Liu², Zhenghe Xu³, Dejun Sun⁴

Affiliations

¹ Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, Shandong 250100, PR China.
² School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, PR China.
³ Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 1000084, PR China.
⁴ Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, Shandong 250100, PR China. Electronic address: djsun@sdu.edu.cn.

PMID: 28618384
DOI: 10.1016/j.jcis.2017.06.011

Abstract

Ion pair interactions were explored to design a fatty acid solvent of switchable miscibility with water. Fatty acids of medium length chains are immiscible with water but become miscible with water when ion pairs are formed with amines. The ion pairs become phase separated after bubbling CO₂ into the solution due to the dissociation of the fatty acid-amine complexes. Ion pairs of caprylic acid (C8) and low toxic poly(oxypropylene) diamine (Jeffamine D-230) were characterized by FT-IR and ¹H NMR. Log K_ow values and surface activity were used to understand the switchable solvent mechanism in removing and recovering oily contaminants. More importantly, the ion pairs show a negligible adsorption on solid surfaces. Furthermore, both C8 and D-230 were recycled during the washing process. Thus the fatty acid as switchable solvent could be applied for oily contaminant removal from oily solid wastes.

Keywords: CO(2) switchable; Fatty acid-amine complex; Ion pair interaction; Oil contaminants removal; Oily solid wastes.