Bioinspired cellulose-based membranes in oily wastewater treatment

Abstract

It is challenging to purify oily wastewater, which affects water-energy-food production. One promising method is membrane-based separation. This paper reviews the current research trend of applying cellulose as a membrane material that mimics one of three typical biostructures: superhydrophobic, underwater superoleophobic, and Janus surfaces. Nature has provided efficient and effective structures through the evolutionary process. This has inspired many researchers to create technologies that mimic nature’s structures or the fabrication process. Lotus leaves, fish scales, and Namib beetles are three representative structures with distinct functional and surface properties: superhydrophobic, underwater superoleophobic, and Janus surfaces. The characteristics of these structures have been widely studied and applied to membrane materials to improve their performance. One attractive membrane material is cellulose, whichhas been studied from the perspective of its biodegradability and sustainability. In this review, the principles, mechanisms, fabrication processes, and membrane performances are summarized and compared. The theory of wettability is also described to build a comprehensive understanding of the concept. Finally, future outlook is discussed to challenge the gap between laboratory and industrial applications.

Superhydrophobic TiN-Coated Cotton Fabrics with Nanoscale Roughness and Photothermal Self-Healing Properties for Effective Oil–Water Separation

“…Due to the excellent water repellency of the SPS cotton fabric, the droplets form a stable spherical structure on the cotton fabric. When placed in water, the fabric produces a significant silver mirror effect due to the micro–nanorough structure of the SPS cotton fabric surface and the thin layer of air between the liquid . The above phenomena prove that this SPS cotton fabric was capable of being hydrophobic in everyday life.…”

Performance of modified hollow fiber membrane silver nanoparticles-zeolites Na–Y/PVDF composite used in membrane bioreactor for industrial wastewater treatment

“…The hydroxyl group can strongly interact with water so that the zeolites can easily absorb water, as shown in Fig. 4 [ [42] , [43] , [44] ]. The highest water flux of membranes was obtained at 204.54 L/m 2 h by the addition of 0.2 g AgNPs/Zeolite Na–Y into the PVDF matrix polymer membrane bioreactor.…”

“…A high water content indicates a higher hydrophilicity of the membrane. Previous reports have mentioned that the high hydrophilicity of the surface increases the water flux due to its positive capillary force [ 44 , 49 , 50 ]. As a result, AgNPs surface contains hydroxyl groups that attach water to form a water moiety.…”

Fluorinated Poly(ionic liquid)s Coated Superhydrophobic Functional Materials with Efficient Oil/Water Separation Performance

“…Therefore, the development of effective methods to remove oil from water before it is discharged into the environment has become an emerging and urgently necessary critical issue. Different techniques and related materials have been reported to remove oil from water, including gravity separation, skimming flotation, filtration, adsorption, de-emulsification and others [6][7][8][9][10][11][12][13]. These techniques and related materials have their own advantages and disadvantages.…”