Cellulose Nanospheres Coated Polylactic Acid Nonwoven Membranes for Recyclable Use in Oil/Water Separation

Author(s):  
Jiexiu Wen ◽  
Qihao Yu ◽  
Chaofan Cui ◽  
Juanjuan Su ◽  
Jian Han

Abstract Oily wastewater has always been an environmental issue that we are concerned about and committed to managing. Although the superwetting membranes have been extensively studied and widely used in oil/water separation, the abundant discarded membranes are still headaches due to their non-degradable nature. In this work, all-around green, as well as superhydrophilic polylactic acid (PLA) nonwoven membrane, is designed by coating cellulose nanospheres (CNCs) with the aid of polydopamine (PDA). Abundant hydroxyl groups and hierarchical rough structure synergistically contribute to the superhydrophilicity and excellent oil/water separation performance of the resultant CNCs/PDA/PLA nonwoven membrane. Interestingly, the oil/water separation efficiency can be maintained above 98% after 100 times of repeated use. With outstanding durability, and easy controllability, the CNCs/PDA/PLA nonwoven membrane may provide effective solutions to simultaneously manage the oily wastewater and secondary pollution of the used membrane itself.

NANO ◽  
2021 ◽  
pp. 2150061
Author(s):  
Yuntian Wan ◽  
Xue Lin ◽  
Zhongshuai Chang ◽  
Xiaohui Dai ◽  
Jiangdong Dai

Currently, with the increasingly serious pollution problem of oily wastewater, it is urgent to develop advanced materials and methods. In this work, a Fe(III)-CMC@Ni(OH)2@Ni composite foam with superhydrophilic and underwater superoleophobicity was fabricated by an in situ growth of flower-like Ni(OH)2 nanoparticles and chelated assembly of Fe(III)-CMC nanohydrogel via a layer-by-layer self assembly using Fe[Formula: see text] ion and carboxymethyl cellulose (CMC). The composite foam could separate various oil/water mixtures and exhibited excellent efficiency over 99%. This foam possessed ultrahigh water flux (220000[Formula: see text]L m[Formula: see text] h[Formula: see text] and better resistant to penetration pressure (1.3[Formula: see text]kPa). After 30 cycles, the oil–water separation performance reduced only 0.5%, but the foam structure was still stable that guarantees a better lifetime. Besides, this composite foam showed anti-fouling, unique durability and excellent corrosion resistance performance. Taking into account all good properties, Fe(III)-CMC@Ni(OH)2@Ni composite foam was expected to be a potential candidate for responding to all kinds of complex oily wastewater conditions.


2021 ◽  
pp. 004051752110569
Author(s):  
Long Feng ◽  
Yimiao Hou ◽  
Qingqing Hao ◽  
Mingxing Chen ◽  
Shuo Wang ◽  
...  

The deterioration of water ecology caused by the discharge of oil spill wastewater, industrial sewage, and municipal sewage has attracted wide attention worldwide. Thus, it is significant to design a simple, environmentally friendly approach to separate oil–water mixtures. In this work, three different fabrics with pH-induced wettability transition were prepared by a dip-coating process for oil and water separation. The dip-coating fabrics had the advantages of oil–water separation, photocatalytic degradation, and recycling. Polyethylene terephthalate/polyamide nonwoven fabric was used as the substrate materials of the fabric. The carboxylic acid-modified TiO2 endowed the fabric with hydrophilicity–hydrophobicity and photocatalytic properties. The Fe3O4 nanoparticles obtained by the coprecipitation method provided magnetism for the fabric, facilitating the recycling of the fabric and improving the hydrophobicity of the fabric. The fabrics coated with dipping solutions were superhydrophobic in a neutral environment and hydrophilic in an alkaline environment. Among the three coated fabrics, the fabric coated with stearic acid/TiO2-Fe3O4 (FST) had the most satisfying oil–water separation performance and durability. Under the neutral condition, the contact angle of the FST was 151° and the separation efficiency was 98%. Under the alkaline condition, the underwater oil contact angle of the FST was 150° and the separation efficiency was 95%. After 15 cycles, the oil–water separation rate of the FST was still higher than 90%. Due to the presence of TiO2, the coated fabric had an exceptional performance in the photodegradation of organic pollutants (69.9%). In addition, the fabrics can be quickly recovered due to magnetism.


2021 ◽  
Author(s):  
Jun Lu ◽  
Chaofan Cui ◽  
Qihao Yu ◽  
Juanjuan Su ◽  
Jian Han

Abstract Oily wastewater is an urgent issue threatening the ecosystem and human health. Superhydrophobic porous materials are widely concerned as promising candidates for effective oil/water separation and oil adsorption. However, superhydrophobic porous materials are still confronted with frustrations such as complex preparation processes and secondary pollution to the environment. Superhydrophobic porous materials with biodegradability and a relatively simple preparation process are more attractive to practical application and environmental protection. In this work, biodegradable and industrially applied polylactic acid (PLA)nonwoven materials were used as porous membranes, then PLA nanoparticles were loaded on the membrane surface to construct the hierarchical rough structure. The modified PLA nonwoven membrane (Nano-PLA) shows superhydrophobicity and efficient oil/water separation performance. Moreover, strong mechanical strength and acceptable toughness are obtained. This work offers an easily controlled and industrially used pathway for the design of robust, highly selective, and biodegradable oil/water separation materials.


Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 66
Author(s):  
Zhongjie Zhu ◽  
Lei Jiang ◽  
Jia Liu ◽  
Sirui He ◽  
Wei Shao

A superhydrophobic fluorinated silica functionalized chitosan (F-CS) aerogel is constructed and fabricated by a simple and sustainable method in this study in order to achieve highly efficient gravity-driven oil/water separation performance. The fluorinated silica functionalization invests the pristine hydrophilic chitosan (CS) aerogel with promising superhydrophobicity with a water contact angle of 151.9°. This novel F-CS aerogel possesses three-dimensional structure with high porosity as well as good chemical stability and mechanical compression property. Moreover, it also shows striking self-cleaning performance and great oil adsorption capacity. Most importantly, the as-prepared aerogels exhibits fast and efficient separation of oil/water mixture by the gravity driven process with high separation efficiency. These great performances render the prepared F-CS aerogel a good candidate for oil/water separation in practical industrial application.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuanli Chen ◽  
Hui Fan ◽  
Xinlin Zha ◽  
Wenwen Wang ◽  
Yi Wu ◽  
...  

AbstractHigh efficiency and anti-pollution oil/water separation membrane has been widely explored and researched. There are a large number of hydroxyl groups on the surface of silica, which has good wettability and can be used for oil-water separation membranes. Hydrophilic silica nanostructures with different morphologies were synthesized by changing templates and contents of trimethylbenzene (TMB). Here, silica nanospheres with radical pores, hollow silica nanospheres and worm-like silica nanotubes were separately sprayed on the PVA-co-PE nanofiber membrane (PM). The abundance of hydroxyl groups and porous structures on PM surfaces enabled the absorption of silica nanospheres through hydrogen bonds. Compared with different silica nanostructures, it was found that the silica/PM exhibited excellent super-hydrophilicity in air and underwater “oil-hating” properties. The PM was mass-produced in our lab through melt-extrusion-phase-separation technique. Therefore, the obtained membranes not only have excellent underwater superoleophobicity but also have a low-cost production. The prepared silica/PM composites were used to separate n-hexane/water, silicone oil/water and peanut oil water mixtures via filtration. As a result, they all exhibited efficient separation of oil/water mixture through gravity-driven filtration.


2021 ◽  
Vol 18 (4) ◽  
pp. 887-899
Author(s):  
Yanling Tian ◽  
Jiekai Feng ◽  
Zexin Cai ◽  
Jiaqi Chao ◽  
Dawei Zhang ◽  
...  

AbstractReckless discharge of industrial wastewater and domestic sewage as well as frequent leakage of crude oil have caused serious environmental problems and posed severe threat to human survival. Various nature inspired superhy-drophobic surfaces have been successfully applied in oily water remediation. However, further improvements are still urgently needed for practical application in terms of facile synthesis process and long-term durability towards harsh environment. Herein, we propose a simple one-step dodecyl mercaptan functionalization method to fabricate Super-hydrophobic-Superoleophilic Copper Mesh (SSCM). The prepared SSCM possesses excellent water repellence and oil affinity, enabling it to successfully separate various oil-water mixtures with high separation efficiency (e.g., > 99% for hexadecane-water mixture). The SSCM retains high separating ability when hot water and strong corrosive aqueous solutions are used to simulate oil-water mixtures, indicating remarkable chemical durability of the dodecyl mercaptan functionalized copper mesh. Additionally, the efficiency can be well maintained during 50 cycles of separation, and the water repellence is even stable after storage in air for 120 days, demonstrating the reusability and long-term stability of the SSCM. Furthermore, the functionalized mesh also shows good mechanical robustness towards abrasion by sandpaper, and oil-water separation efficiency of > 96% can be obtained after 10 cycles of abrasion. The reported one-step dodecyl mercaptan functionalization could be a simple method for increasing the water repellence of copper mesh, and thereby be a great candidate for treating large-scale oily wastewater in harsh environments.


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