One-pot fabrication of hydrophilic-oleophobic cellulose nanofiber-silane composite aerogels for selectively absorbing water from oil–water mixtures

Abstract

While cellulose nanofiber is advantageous for the preparation of porous materials with selective absorption, cellulose-based, hydrophilic-oleophobic aerogels are only prepared through complicated surface-modification. Herein, we report a facile one-pot fabrication of hydrophilic-oleophobic composite aerogels firstly through polycondensation of cellulose nanofiber and three silane coupling agents. The hydrophilic-oleophobic aerogels exhibited interconnected macroporous structures, robust compressive property (without failure at a high strain of 80%), excellent water resistance (without failure even at 100 °C, pH = 1 or pH = 12), the ability to selectively absorb water from oil–water mixtures, and excellent reusability (without significant decrease in hexadecane contact angle and absorption capacity after five absorption–regeneration cycles). The facile one-pot polycondensation and unique hydrophilicity-oleophobicity enabled the aerogels to be practical for removing water from oil–water mixtures.