Enabling phase transition of infused lubricant in porous structure for exceptional oil/water separation

Feng Wang; Sihai Luo; Senbo Xiao; Wenjing Zhang; Yizhi Zhuo; Jianying He; Zhiliang Zhang

doi:10.1016/j.jhazmat.2020.122176

Enabling phase transition of infused lubricant in porous structure for exceptional oil/water separation

J Hazard Mater. 2020 May 15:390:122176. doi: 10.1016/j.jhazmat.2020.122176. Epub 2020 Jan 22.

Authors

Feng Wang¹, Sihai Luo², Senbo Xiao¹, Wenjing Zhang³, Yizhi Zhuo¹, Jianying He⁴, Zhiliang Zhang⁵

Affiliations

¹ NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
² Department of Chemistry, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
³ Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
⁴ NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway. Electronic address: jianying.he@ntnu.no.
⁵ NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway. Electronic address: zhiliang.zhang@ntnu.no.

PMID: 32006849
DOI: 10.1016/j.jhazmat.2020.122176

Abstract

The fundamental mechanism behind oil/water separation materials is their surface wettability that allows either oil or water to pass through. The conventional materials for oil/water separation generally have extreme wettability, namely superhydrophilic for water separation and superhydrophobic for oil separation. Using easily accessible materials that are medium hydrophobic or even relatively hydrophilic for preparing highly efficient oil/water separators have rarely been reported. In this work, a new strategy by triggering phase transition of infused lubricant from liquid to solid state in porous structure is realized in fabricating slippery lubricant infused porous structure for oil/water separations. By infusing polyester fabric with coconut oil, after phase transition, excellent water repellency and oil permeability by an absorbing-permeating mechanism are achieved, despite the low water contact angle on the new material. Although the new phase transformable slippery lubricant infused porous structure, features much milder hydrophobicity than conventional oil/water separators, it can remove diverse types of oil from water with high efficiencies. The phase transformable slippery lubricant infused porous structure is able to maintain their water repellency after immersing in high concentration salt (10 wt% NaCl), acid (25 % HCl), alkaline (25 % NH₃·H₂O) solutions for 120 h, showing remarkably functional durability in harsh environment. The lubricant phase transition mechanism proposed in this study is universally applicable to porous substrates with various chemical compositions and pore structures, such as porous sponges or even daily life breads, for creating efficient oil/water separators, which can serve as a novel accessible design principle of phase transformable slippery lubricant infused porous structure for eco-friendly oil/water separators.

Keywords: Absorbing-permeating; Eco-friendly; Oil/water separation; PTSLIPS; Phase transition.