Gluconacetobacter xylinus synthesized biocellulose nanofiber membranes with superhydrophilic and superoleophobic underwater properties for the high-efficiency separation of oil/water emulsions

• Published in: Journal of membrane science 2020-06, Vol.605, p.118091, Article 118091
• Main Authors: Zhuang, Guo-Liang, Wu, Shu-Yii, Lo, Ying-Chen, Chen, Ying-Cheng, Tung, Kuo-Lun, Tseng, Hui-Hsin
• Format: Article
• Language: English
• Subjects: Alkali treatment; Biocellulose nanofiber membrane; Oil/water separation; Ultralow oil adhesion
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2020.118091

Compared with plant-derived cellulose, developing biocellulose nanofibers (bio-CNFs) as a functional membrane material is of great interest in membrane filtration for the effective separation of emulsified oily wastewater due to its low cost, renewability, high water-holding capacity and anti-oil-fouling properties. In this work, a bio-CNF membrane was produced by cultured Gluconacetobacter xylinus through a simple biosynthetic process followed by a purification step involving alkali treatment. Herein, the bio-CNF membrane treated with 0.75 M NaOH solution formed a unique, porous nanonetwork structure with good hydrophilicity and ultralow-oil-adhesion properties, and this was successfully applied for the separation of surfactant-stabilized oil/water emulsions. The superhydrophilic and superoleophobic bio-CNF membranes exhibited superior performance for separating surfactant-stabilized oil/water emulsions, showing a separation efficiency of ~99% and a high permeate flux recovery ratio (above 94%) for long-term separation processes. The bio-CNF membrane, which showed good hydrophilicity and a nanonetwork structure, exhibited not only an excellent oil rejection rate but also a high permeate flux recovery ratio. [Display omitted] •Biocellulose nanofibers (bio-CNFs) as a membrane material for oil-in-water separation.•The bio-CNF membranes possess a nanonetwork structure and are superhydrophilic.•The bio-CNF membranes are well suited for treating the nanoemulsions.•The 0.75 M-treated bio-CNF membrane maintains a uniform structure and properties.•The bio-CNF membranes exhibit good stability for multiple filtration cycles.