Facile preparation of porous polymeric composite monoliths with superior performances in oil–water separation – a low-molecular mass gelators-based gel emulsion approach

Abstract

A series of water in oil (W/O) gel emulsions was prepared by using a low-molecular mass gelator (LMMG), a ferrocene derivative of cholesterol, as a stabilizer and tertiary butylmethacrylate (t-BMA) as the continuous phase. Via polymerization of the emulsions as created, a series of porous polymeric monoliths with different internal structures was prepared. SEM observation reveals that the internal structures of the monoliths could be largely adjusted via simple variation of the compositions of the gel emulsions. Importantly, introduction of hydrolysable silanes into the continuous phase of the gel emulsion before polymerization significantly alters the mechanical strengths of the porous materials, and remarkably promotes the sorption of the porous materials to some water-immiscible and -miscible liquids, such as benzene, kerosene, already-used transformer oil, ethanol, tetrahydrofuran, etc., of which kerosene is a representative of oils of lower viscosities and the transformer oil a representative of oils of higher viscosities. Furthermore, the oil absorbed by the monoliths could be recovered by centrifugation or squeezing, and the monoliths could be reused by washing them with alcohol or some other suitable volatile organic liquids. The sorption and desorption process could be repeated at least 13 times. More importantly, the LMMGs-based gel emulsion approach established in the present study for preparing porous polymeric or composite monoliths is facile, versatile and environmentally benign, showing a bright future for real-life uses.