scholarly journals Fabricated of Superhydrophobic Silanized Melamine Sponge with Photochromic Properties for Efficiency Oil/Water Separation

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.

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3344
Author(s):  
De Liu ◽  
Shiying Wang ◽  
Tao Wu ◽  
Yujiang Li

The influence of different coupling agents and coupling times on the wettability of a polyurethane (PU) sponge surface were optimized. Octadecyltrichlorosilane (OTS) was selected as the optimal coupling agent to prepare the superhydrophobic sponge. The superhydrophobic sponge was prepared in one step, which has the advantages of simple operation and enhanced durability. The superhydrophobic sponge was characterized by scanning electron microscopy, Teclis Tracker tensiometry, and Fourier transform infrared (FT-IR) spectrophotometry. The water contact angle increased from 64.1° to 151.3°, exhibiting ideal superhydrophobicity. Oils and organic solvents with different viscosities and densities can be rapidly and selectively absorbed by superhydrophobic sponges, with an absorption capacity of 14.99 to 86.53 times the weight of the sponge itself, without absorbing any water. Since temperature affects the viscosity and ionic strength of oil, and influences the surface wettability of the sponges, the effect of temperature and ionic strength on the oil absorption capacity of the superhydrophobic sponges was measured, and its mechanism was elucidated. The results showed that the absorptive capacity retained more than 90% of the initial absorptive capacity after repeated use for 10 times. Low-cost, durable superhydrophobic sponges show great potential for large-scale oil-water separation.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2431
Author(s):  
Wen Zhang ◽  
Juanjuan Wang ◽  
Xue Han ◽  
Lele Li ◽  
Enping Liu ◽  
...  

In this paper, effective separation of oil from both immiscible oil–water mixtures and oil-in-water (O/W) emulsions are achieved by using poly(dimethylsiloxane)-based (PDMS-based) composite sponges. A modified hard template method using citric acid monohydrate as the hard template and dissolving it in ethanol is proposed to prepare PDMS sponge composited with carbon nanotubes (CNTs) both in the matrix and the surface. The introduction of CNTs endows the composite sponge with enhanced comprehensive properties including hydrophobicity, absorption capacity, and mechanical strength than the pure PDMS. We demonstrate the successful application of CNT-PDMS composite in efficient removal of oil from immiscible oil–water mixtures within not only a bath absorption, but also continuous separation for both static and turbulent flow conditions. This notable characteristic of the CNT-PDMS sponge enables it as a potential candidate for large-scale industrial oil–water separation. Furthermore, a polydopamine (PDA) modified CNT-PDMS is developed here, which firstly realizes the separation of O/W emulsion without continuous squeezing of the sponge. The combined superhydrophilic and superoleophilic property of PDA/CNT-PDMS is assumed to be critical in the spontaneously demulsification process.


Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 442 ◽  
Author(s):  
Mingguang Yu ◽  
Qing Wang ◽  
Wenxin Yang ◽  
Yonghang Xu ◽  
Min Zhang ◽  
...  

In this paper, we present a facile and efficient strategy for the fabrication of magnetic, durable, and superhydrophobic cotton for oil/water separation. The superhydrophobic cotton functionalized with Fe3O4 magnetic nanoparticles was prepared via the in situ coprecipitation of Fe2+/Fe3+ ions under ammonia solution on cotton fabrics using polyvinylpyrrolidone (PVP) as a coupling agent and hydrophobic treatment with tridecafluorooctyl triethoxysilane (FAS) in sequence. The as-prepared cotton demonstrated excellent superhydrophobicity with a water contact angle of 155.6° ± 1.2° and good magnetic responsiveness. Under the control of the external magnetic field, the cotton fabrics could be easily controlled to absorb the oil from water as oil absorbents, showing high oil/water separation efficiency, even in hot water. Moreover, the cotton demonstrated remarkable mechanical durable properties, being strongly friction-resistant against sandpaper and finger wipe, while maintaining its water repellency. This study developed a novel and efficient strategy for the construction of magnetic, durable, and superhydrophobic biomass-based adsorbent for oil/water separation, which can be easily scaled up for practical oil absorption.


Author(s):  
Niken Aprilia Eka Putri ◽  
Arif Tjahjono ◽  
Perdamean Sebayang

In this research, a modification of polyurethane (PU) sponge material has been made to obtain superhydrophobic-superoleophilic properties. The PU sponge was coated with several nanomaterials such as ZnO, Fe3O4+TEOS, and stearic acid by dip-coating and drop-coating methods. The tests include selective separation of oil and water with a magnetic response. Several types of oil and organic solvents were tested for absorption capacity. The results showed that the PU@ZnO@Fe3O4@SA sponge has a good absorption capacity, from 4.37 mL to 7.37 mL. The fabricated PU sponge could selectively separate oil from water with a separation efficiency above 99%. The fabricated PU sponge also could be magnetically driven by external magnetic fields. From the characterization using 3D OM, the water contact angle was 153.38°, which indicates that the PU@ZnO@Fe3O4@SA sponge is superhydrophobic. And from surface morphology obtained an average pore size diameter of 167.475 μm.


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.


RSC Advances ◽  
2016 ◽  
Vol 6 (105) ◽  
pp. 103632-103640 ◽  
Author(s):  
Arun K. Singh ◽  
Jayant K. Singh

Fluorine free superhydrophobic coating on cotton fabric by inexpensive dip coating method. The coated fabric exhibited high oil–water separation efficiency.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lizheng Sha ◽  
Chao Ma ◽  
Huifang Zhao ◽  
Supeng Qiu ◽  
Zhongyu Yan ◽  
...  

Abstract Superhydrophobic surfaces have high potential in self-cleaning and oil-water separation applications. We developed a three-step method for the preparation of superhydrophobic filter paper. It involved citric acid (CA) pretreatment to activate cellulose fibers, coating with cellulose nanofibrils/functionalized silica (CNFs/m-SiO2) slurry to increase surface roughness, and grafting of hexadecyltrimethoxysilane (HDTMS) to enhance water resistance. The water contact angle (WCA) and siding angle (SA) of the prepared filter paper reached 151.5° and 7.5°, respectively. The results showed that, compared to the coated filter paper without the added CNFs, the coated paper with CNFs had higher retention of m-SiO2, thus roughness required for superhydrophobic surface was achieved. Further test under frequent abrasion and acid or alkali conditions showed that CA pretreatment improved the durability of superhydrophobic filter paper due to chemical crosslinking between the modified substrate and m-SiO2. Besides, the prepared superhydrophobic filter paper had outstanding self-cleaning property and high oil-water separation efficiency for various oil-water mixtures. Therefore, it is expected to be used for the treatment of oily wastewater.


2021 ◽  
Author(s):  
Baiyi Chen ◽  
Rongrong Zhang ◽  
Hexuan Fu ◽  
Jiadai Xu ◽  
Yuan Jing ◽  
...  

Abstract There has been a growing interest in oil-water separation due to the massive economic and energy loss caused by world-wide oil spill. In the past decades, a new type of superhydrophobic surface has been developed for the efficient oil-water separation, but its large-scale use is significantly limited by its expensive, sophisticated, and fragile roughness structure. Meanwhile, to handle complex operating conditions, the transparency of the superhydrophobic surface has been more attractive due to its potential visual oil-water separation and optical applications. Herein, we showed a simple and versatile strategy to fabricate superhydrophobic coating with robustness and high transparency. Subsequently, this multifunctional superhydrophobic coating was utilized for oil-water separation and indicated excellent separation efficiency. In this strategy, candle soot composed of carbon nanoparticles was deposited onto the substrate and used as a rough surface template. Then, a filmy and hard silica shell was modified onto this template via chemical vapor deposition to reinforce the roughness structure. Following, this soot-silica coated substrate was calcined in air to remove the candle soot template. Finally, based on a rational surface design, this robust silica coating achieved excellent superhydrophobicity thereby showing inherently oil-water separation benefits. This reinforced superhydrophobic coating presented robust superhydrophobicity even after 410 s sand impacting with the height of 40 cm. Also, it retained excellent oil-water separation efficiency even after reuses.


Author(s):  
M. E. Mohamed ◽  
B. A. Abd-El-Nabey

Abstract In the present work, dopamine is self-polymerized on cotton fabric by a simple deep-coating method and followed by modification with an ethanolic solution of palmitic acid: a superhydrophobic/oleophilic cotton fabric was obtained. The as-prepared cotton fabric exhibits a superhydrophobic character with a water contact angle of 157o. The absorption capacity of as-prepared superhydrophobic/oleophilic cotton fabric in n-hexane, petroleum ether, and silicone oil was determined. The results show that silicone oil has the highest absorption capacity while n-hexane has the lowest value. The absorption capacity is nearly constant even after ten cycles, indicating the efficient recyclability of the as-prepared superhydrophobic/oleophilic cotton fabric for oil separation. The as-prepared superhydrophobic/oleophilic cotton fabric shows excellent separation efficiency, high flux rate, and excellent chemical and mechanical stability.


Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3434
Author(s):  
Haodong Zhao ◽  
Yali He ◽  
Zhihua Wang ◽  
Yanbao Zhao ◽  
Lei Sun

Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high permeability. Herein, a novel, simple and low-cost method has been proposed for the separation of emulsion containing surfactants. Polyacrylonitrile (PAN) nanofibers were prepared via electrospinning and then coated by polydopamine (PDA) by using self-polymerization reactions in aqueous solutions. The morphology, structure and oil-in-water emulsion separation properties of the as-prepared PDA@PAN nanofibrous membrane were tested. The results show that PDA@PAN nanofibrous membrane has superhydrophilicity and almost no adhesion to crude oil in water, which exhibits excellent oil–water separation ability. The permeability and separation efficiency of n-hexane/water emulsion are up to 1570 Lm−2 h−1 bar−1 and 96.1%, respectively. Furthermore, after 10 cycles of separation, the permeability and separation efficiency values do not decrease significantly, indicating its good recycling performance. This research develops a new method for preparing oil–water separation membrane, which can be used for efficient oil-in-water emulsion separation.


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