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Highly Efficient and Recyclable Carbon‐Nanofiber‐Based Aerogels for Ionic Liquid–Water Separation and Ionic Liquid Dehydration in Flow‐Through Conditions
Author(s) -
Guan Li Zhi,
Gutiérrez María C.,
RoldánRuiz María J.,
Jiménez Ricardo,
Ferrer M. Luisa,
del Monte Francisco
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201903418
Subject(s) - ionic liquid , materials science , aqueous solution , chemical engineering , absorption (acoustics) , electrochemistry , carbon nanofiber , catalysis , carbon nanotube , nanotechnology , organic chemistry , composite material , electrode , chemistry , engineering
Ionic liquids (ILs) are being widely used in many diverse areas of social interest, including catalysis, electrochemistry, etc. However, issues related to hygroscopicity of many ILs and the toxic and/or nonbiodegradable features of some of them limit their practical use. Developing materials capable of IL recovery from aqueous media and dehydration, thus allowing their recycling and subsequent reutilization, in a single and efficient process still poses a major challenge. Herein, electrically conductive aerogels composed of carbon nanofibers (CNFs) with remarkable superhydrophobic features are prepared. CNF‐based 3D aerogels are prepared through a cryogenic process, so called ice‐segregation‐induced self‐assembly (ISISA) consisting of the unidirectional immersion of an aqueous chitosan (CHI) solution also containing CNFs in suspension into a liquid nitrogen bath, and subsequent freeze‐drying. The CNF‐based 3D aerogels prove effective for absorption of ILs from aqueous biphasic systems and recovery with quite low water contents just through a single process of filtration. Moreover, the electrical conductivity of CNF‐based 3D aerogels is particularly interesting to treat highly viscous ILs because the Joule effect allows not only shortening of the absorption process but also enhancement of the flux rate when operating in flow‐through conditions.