Lightweight, Flexible and Hydrophobic Cotton Fiber/Silica Aerogel Composite by Freeze-Drying for Organic Solvent/Water Separation and Thermal Insulation

2021 ◽  
Vol 13 (9) ◽  
pp. 1820-1824
Author(s):  
Jian-Chun Huo ◽  
Hai-Xia Yang ◽  
Yuan Ma ◽  
Jie Bai

Natural cotton fiber used for reinforcement is low-cost, environmentally friendly, good flexibility and easy to obtain. In this study, a new cotton fiber/silica aerogel composite was developed by sol–gel method via freezedrying. The obtained composite has excellent flexibility and can be restored to its original state after bending for 180° without obvious cracks. After 20 cycles continuous compression, the total unrecoverable strain loss is only 20% under strain of 60%. The composite also shows very prominent hydrophobicity, and the contact angle with water reaches 145 degrees. It has strong adsorption capacity for organic reagents and oil, with adsorption ratios of 500% and 600%, respectively. In addition, the composite has a low thermal conductivity of 0.038 W/(m·K) at room temperature. The obtained composite exhibits considerable promise in oil-water separation and thermal insulation.

RSC Advances ◽  
2018 ◽  
Vol 8 (53) ◽  
pp. 30257-30264 ◽  
Author(s):  
Na Lv ◽  
Xiaoli Wang ◽  
Shitao Peng ◽  
Lei Luo ◽  
Ran Zhou

A superhydrophobic and superoleophilic oil sorbent was prepared by attaching SiO2 particles onto a cotton fiber surface by a sol–gel method and subsequent octadecyltrichlorosilane modification.


Soft Matter ◽  
2021 ◽  
Author(s):  
Caimei Zhao ◽  
Lei Chen ◽  
Chuanming Yu ◽  
Binghua Hu ◽  
Haoxuan Huang ◽  
...  

Super-hydrophobic porous absorbent is a convenient, low-cost, efficient and environment-friendly material in the treatment of oil spills. In this work, a simple Pickering emulsion template method was employed to fabricate...


2021 ◽  
Author(s):  
Cailin Liu ◽  
Li Yu ◽  
Yue Fan ◽  
Chang Li ◽  
Xianyan Ren ◽  
...  

Abstract In the oil-water separation, the difficulty to recover and low hydrophobicity are key limitation factors for practical applications. In this paper, we design Cobalt ferrite hybird Polystyrene divinylbenzene microspheres (CoFe2O4/SDB), which were conducted through in-situ suspension copolymerization. The CoFe2O4 is prepared by low heat solid phase sol-gel method. It had been found that the CoFe2O4/SDB have a spherical structure, good adsorption behavior, highly hydrophobicity and even superhydrophobicity. The adsorption capacity of CoFe2O4/SDB composites could absorb kerosene up to 6 times of its own weight. Interestingly, kerosene can be easily separated from the surface of CoFe2O4/SDB particles with ultrasonic operation. CoFe2O4/SDB particles can still maintain good hydrophobicity and adsorption capacity of kerosene after 11 cycles after drying. With in situ polymerization of St、DVB and CoFe2O4, CoFe2O4/SDB as a promising absorbent of kerosene which has great potential in application of oil-water separation.


Soft Matter ◽  
2021 ◽  
Author(s):  
Jixi Zhang ◽  
Ligui Zhang ◽  
Xiao Gong

In this work, we prepare a PDMS-SiO2-PDA@fabric with high water contact angle (WCA=155o). Combining dopamine self-polymerization and sol-gel method, SiO2 is in situ grown on a PDA-modified fabric surface to...


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 659 ◽  
Author(s):  
Sheng Lei ◽  
Xinzuo Fang ◽  
Fajun Wang ◽  
Mingshan Xue ◽  
Junfei Ou ◽  
...  

The mixture of insoluble organics and water seriously affects human health and environmental safety. Therefore, it is important to develop an efficient material to remove oil from water. In this work, we report a superhydrophobic Cu2O mesh that can effectively separate oil and water. The superhydrophobic Cu2O surface was fabricated by a facile chemical reaction between copper mesh and hydrogen peroxide solution without any low surface reagents treatment. With the advantages of simple operation, short reaction time, and low cost, the as-synthesized superhydrophobic Cu2O mesh has excellent oil–water selectivity for many insoluble organic solvents. In addition, it could be reused for oil–water separation with a high separation ability of above 95%, which demonstrated excellent durability and reusability. We expect that this fabrication technique will have great application prospects in the application of oil–water separation.


2020 ◽  
Vol 8 ◽  
Author(s):  
Usama Zulfiqar ◽  
Andrew G. Thomas ◽  
Allan Matthews ◽  
David J. Lewis

Oil/water mixtures are a potentially major source of environmental pollution if efficient separation technology is not employed during processing. A large volume of oil/water mixtures is produced via many manufacturing operations in food, petrochemical, mining, and metal industries and can be exposed to water sources on a regular basis. To date, several techniques are used in practice to deal with industrial oil/water mixtures and oil spills such as in situ burning of oil, bioremediation, and solidifiers, which change the physical shape of oil as a result of chemical interaction. Physical separation of oil/water mixtures is in industrial practice; however, the existing technologies to do so often require either dissipation of large amounts of energy (such as in cyclones and hydrocyclones) or large residence times or inventories of fluids (such as in decanters). Recently, materials with selective wettability have gained attention for application in separation of oil/water mixtures and surfactant stabilized emulsions. For example, a superhydrophobic material is selectively wettable toward oil while having a poor affinity for the aqueous phase; therefore, a superhydrophobic porous material can easily adsorb the oil while completely rejecting the water from an oil/water mixture, thus physically separating the two components. The ease of separation, low cost, and low-energy requirements are some of the other advantages offered by these materials over existing practices of oil/water separation. The present review aims to focus on the surface engineering aspects to achieve selectively wettability in materials and its their relationship with the separation of oil/water mixtures with particular focus on emulsions, on factors contributing to their stability, and on how wettability can be helpful in their separation. Finally, the challenges in application of superwettable materials will be highlighted, and potential solutions to improve the application of these materials will be put forward.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Peng Hong ◽  
Zhu Liu ◽  
Yang Gao ◽  
Yubin Chen ◽  
Mingxun Zhuang ◽  
...  

Superhydrophobic sponge as potential absorbing material for oil/water separation is attracting great attention recently. However, there are still some challenges to feasibly fabricate superhydrophobic sponge with large scale and low cost. Herein, a novel photochromic superhydrophobic melamine sponge (PDMS-SP sponge) is fabricated by facilely dip-coating and thermocuring of hydroxyl-terminated polydimethylsiloxanes mixed with photochromic spiropyran. FT-IR, EDS, and XPS results confirm the successful coating of PDMS-SP upon melamine sponge. The resultant sponge not only possesses excellent water repellency with a contact angle of 154.5° and oil-water separation efficiency with an oil absorption capacity of 48–116 folds of itself weight, but also shows photochromic phenomenon between colorless and purple when it is successively exposed to UV irradiation and visible light.


2016 ◽  
Vol 74 (8) ◽  
pp. 1936-1945 ◽  
Author(s):  
Zhengshan Cui ◽  
Wanxia He ◽  
Jun Liu ◽  
Wei Wei ◽  
Liang Jiang ◽  
...  

Through sol-gel and dip-coating processes, commercial polyurethane sponge modified by polysiloxane was fabricated under low temperature (60 °C) and atmosphere. The contact angle of the obtained polysiloxane/polyurethane sponge is 145 ± 5°. Hence, the polysiloxane/polyurethane sponge could float on water and selectively absorb organics from the surface of the water, indicating simultaneous properties of hydrophobicity and oleophilicity. The absorbent maximum value is 50–150 times of its own weight. The polysiloxane/polyurethane sponge exhibited excellent recyclability, which could be reused by squeezing the sponge due to its high mechanical stability and flexibility. Thermogravimetry-differential thermal analysis test indicated that the polysiloxane/polyurethane sponge exhibited good thermal stability and the stable contact angle of samples tested under increasing temperature indicated its good weather resistance. Due to the commercial property of polyurethane sponge and easy-handling of polysiloxane, the polysiloxane/polyurethane sponge can be easily scaled up to recover a large-area oil spill in water and further work based on the designed equipment has been under consideration.


2017 ◽  
Vol 224 ◽  
pp. 117-124 ◽  
Author(s):  
Chuqi Zhang ◽  
Yanmei Li ◽  
Ningning Bai ◽  
Cui Tan ◽  
Peng Cai ◽  
...  

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