Superhydrophobic and superlipophilic LDH flower balls/cellulose membranes for efficient oil–water separation

Abstract

In this work, superhydrophobic and superlipophilic Ni–Al LDH/cellulose membranes with flower-like microscopic surface morphology were successfully prepared at low cost. The rough surface morphology was obtained by in situ growth of Ni–Al LDH (layered double hydroxide) on cellulose membranes, which were then modified with hexadecyltrimethoxysilane (HDTMS) for surface hydrophobicity. In addition, the effects of different amounts of HDTMS were investigated and optimised. The results showed that the water contact angle of the membrane produced was as high as 157° and the oil contact angle was 0°. The membrane has a high oil–water separation efficiency (99.6%) and flux (up to a maximum of 1412 L m⁻² h⁻¹). The separation efficiency, permeate flux and oil and water contact angles could be maintained at a high level under adverse conditions, and the water contact angle was above 150° after repeated recycling, which has good recyclability and is promising for oil–water separation.