Synthesis and characterization of a porous and hydrophobic cellulose-based composite for efficient and fast oil–water separation

• Porous and hydrophobic cellulose composite was fabricated by sol–gel method.
• Silanized cellulose can selectively separate oil–water mixture at very fast speed.
• Silanized cellulose showed excellent separation efficiency and reusability.

Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, silanized cellulose was prepared by sol–gel reaction between microcrystalline cellulose (MCC) and hexadecyltrimethoxysilane (HDTMS) using for oil–water separation. The silanized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). A higher mass ratio of HDTMS to MCC made silanized cellulose become looser, and showed lower water absorbency. The silanized cellulose exhibited specific separation performance towards vegetable oil–water mixture (not for mineral oil–water mixture) with separation efficiency of 99.93%. Moreover, the separation was fast with a water flux of 4628.5 L m−2 h−1. The separation efficiency still remained at 99.77% even after recycling for 10 times.