Light or heavy oil and water mixtures can by separated selectively with high efficiency using potato residue coated meshes.

Oil-polluted water has become a worldwide problem due to increasing industrial oily wastewater as well as frequent oil-spill pollution. Compared with underwater superoleophobic (water-removing) filtration membranes, superhydrophobic/superoleophilic (oil-removing) materials have advantages as they can be used for the filtration of heavy oil or the absorption of floating oil from water/oil mixtures. However, most of the superhydrophobic materials used for oil/water separation lose their superhydrophobicity when exposed to hot (e.g. >50 °C) water and strong corrosive liquids. Herein, we demonstrate superhydrophobic overlapped candle soot (CS) and silica coated meshes that can repel hot water (about 92 °C) and strong corrosive liquids, and were used for the gravity driven separation of oil-water mixtures in hot water and strong acidic, alkaline, and salty environments. To the best of our knowledge, we are unaware of any previously reported studies on the use of superhydrophobic materials for the separation of oil from hot water and corrosive aqueous media. In addition, the as-prepared robust superhydrophobic CS and silica coated meshes can separate a series of oils and organic solvents like kerosene, toluene, petroleum ether, heptane and chloroform from water with a separation efficiency larger than 99.0%. Moreover, the as-prepared coated mesh still maintained a separation efficiency above 98.5% and stable recyclability after 55 cycles of separation. The robust superhydrophobic meshes developed in this work can therefore be practically used as a highly efficient filtration membrane for the separation of oil from harsh water conditions, benefiting the environment and human health.

Oil/water separation has recently become a global challenging task due to the frequent oil spill accidents and increasing industrial oily waste water. Here, we first demonstrate underwater superoleophobic palygorskite coated meshes, which were fabricated by spraying palygorskite and polyurethane mixtures on copper mesh substrates. The underwater superoleophobic meshes were then used to study gravity driven oil/water separation for a series of oil/water mixtures, where only the water from the oil/water mixture is allowed to permeate through the mesh. Separation efficiency up to 99.6 % could be achieved through the coated mesh for the kerosene-water mixture. In addition, the palygorskite coated mesh still maintained high separation efficiency over 99.0 % and stable recyclability after 50 separation cycles with the surface morphology of the palygorskite coated mesh nearly unchanged. Furthermore, the palygorskite coated meshes exhibit excellent environmental stability under a series of harsh conditions, which are used for the separation of the mixtures of oil and various corrosive and active aqueous solutions, including strong acidic, 2 alkaline, or salt aqueous solutions, even hot water. The fabrication approach presented here can be applied for coating large surface areas and to develop a large-scale oil/water separation facility for oil and various corrosive and active aqueous mixtures. Figure 2. FE-SEM images of (a) the original copper mesh and (b-c) the as-prepared palygorskite coated mesh surface at low and high magnifications, respectively. The inset (a) is the magnified image of the original mesh.

The superhydrophobic PU sponges separated oils from immiscible oil/water mixture and oil-in-water emulsion with the separation efficiency over 99.8%.

In this paper, tunable adhesive superhydrophobic ZnO surfaces have been fabricated successfully by spraying ZnO nanoparticle (NP) suspensions onto desired substrates. We regulate the spray-coating process by changing the mass percentage of hydrophobic ZnO NPs (which were achieved by modifying hydrophilic ZnO NPs with stearic acid) in the hydrophobic/hydrophilic ZnO NP mixtures to control heterogeneous chemical composition of the ZnO surfaces. Thus, the water adhesion on the same superhydrophobic ZnO surface could be effectively tuned by controlling the surface chemical composition without altering the surface morphology. Compared with the conventional tunable adhesive superhydrophobic surfaces, on which there were only three different water sliding angle values: lower than 10°, 90° (the water droplet is firmly pinned on the surface at any tilted angles), and the value between the two ones, the water adhesion on the superhydrophobic ZnO surfaces has been tuned effectively, on which the sliding angle is controlled from 2 ± 1° to 9 ± 1°, 21 ± 2°, 39 ± 3°, and 90°. Accordingly, the adhesive force can be adjusted from extremely low (∼2.5 μN) to very high (∼111.6 μN). On the basis of the different adhesive forces of the tunable adhesive superhydrophobic surfaces, the selective transportation of microdroplets with different volumes was achieved, which has never been reported before. In addition, we demonstrated a proof of selective transportation of microdroplets with different volumes for application in the droplet-based microreactors via our tunable adhesive superhydrophobic surfaces for the quantitative detection of AgNO3 and NaOH. The results reported herein realize the selective transportation of microdroplets with different volumes and we believe that this method would potentially be used in many important applications, such as selective water droplet transportation, biomolecular quantitative detection and droplet-based biodetection.

crude oil that greatly harmed the coastline and near-shore water, killing huge populations of marine animals and plants.Various methods have been applied in oil spill cleanup such as mechanical collection, controllable burn, and chemical decomposition. [3][4][5] However, those techniques are time-consuming, environment unfriendly, and expensive. Recently, researchers prefer to design and fabricate functional membrane materials and adsorbents with special wettability for oil/ water separation, protecting environment from secondary pollution and reducing the loss. [6][7][8][9] Jiang and co-workers, for the fi rst time, fabricated a mesh fi lm possessing both superhydrophobic and superoleophilic properties to separate oil from water, exhibiting high oil/water separation effi ciency and selectivity. [ 10 ] Subsequently, abundant materials with both superhydrophobic and superoleophilic properties are generally applied to removal of oil from water, [11][12][13][14][15][16][17][18][19][20] such as metallic mesh-based materials, [21][22][23] sponges and foam-based materials, [24][25][26] ceramic microfi ltration membranes, [ 27 ] carbon-based materials, [ 28,29 ] oil-absorptive rubber, [ 30 ] fabrics, [31][32][33] etc. In general, these materials were obtained by roughening of their surfaces and posthydrophobization. Various approaches have been used to construct hierarchical rough structures needed for superhydrophobicity, such as a sol-gel method, [ 34 ] chemical vapor deposition, [ 35 ] hydrothermal method, [ 36 ] electrochemical method, [ 37 ] spray method, [ 38,39 ] and so forth. Nevertheless, most of the methods involved in fabricating superhydrophobic surfaces have limitations for large-scale fabrication, due to complicated processes, sophisticated equipment, and low commercial availability of raw materials. In addition, the traditional fi lterable materials cannot easily be applied in oil spills, because they need to gather polluted water fi rst and then fi lter it. Therefore, it is imperative to fi nd high-performance absorbent materials for the removal of large amounts of oil pollutant from the water surface.Recently, superhydrophobic/superoleophilic 3D sponges have received considerable attention due to their rapid absorption Removal of oil from water has become an increasingly important fi eld due to the frequent oil spill accidents as well as industrial oily wastewater. In this study, a bag is made from superhydrophobic fabric and stuffed with pristine polyurethane (PU) sponge just utilizing the synergetic effect of the superhydrophobic and superoleophilic selective absorption of oil from water of the fabric and the excellent large volume-based oil storage capacity of the PU sponge. The superhydrophobic fi lling bag can quickly absorb and collect a large amount of oil from a polluted water surface with the separation effi ciency always above 98.2% % for a series of oil/water mixtures. In addition, the fi lled orignial sponges exhibit large volume-based absorption capacity up to 20-36 times its own weight, ke...

A simple method was used to generate colorful hydrophobic stearate particles via chemical reactions between inorganic salts and sodium stearate. Colored self-cleaning superhydrophobic coatings were prepared through a facile one-step spray-coating process by spraying the stearate particle suspensions onto stainless steel substrates. Furthermore, the colorful superhydrophobic coating maintains excellent chemical stability under both harsh acidic and alkaline circumstances. After being immersed in a 3.5 wt % NaCl aqueous solution for 1 month, the as-prepared coatings remained superhydrophobic; however, they lost their self-cleaning property with a sliding angle of about 46 ± 3°. The corrosion behavior of the superhydrophobic coatings on the Al substrate was characterized by the polarization curve and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance, which could supply efficient and long-term preservation for the bare Al substrate.

In this work, a facile and inexpensive one-step sonochemistry irradiation method was developed for the fabrication of SiO2 nanoparticles functionalized with octadecyltrimethoxysilane and their in situ incorporation into cotton fabrics. The double sides of as-prepared fabrics show both superhydrophobic and superoleophilic properties simultaneously with a high water contact angle of 159 ± 1° and an oil contact angle of 0°. Thus, it can be used to separate and capture a series of oils from water, like kerosene, toluene and chloroform, etc. In addition, the as-prepared fabrics still have superhydrophobicity with a water contact angle of above 150° after 40 separation cycles with the separation efficiency for the kerosene-water mixture always above 94.6%. More importantly, the as-prepared fabrics showed robust and stable superhydrophobic properties towards hot water, many corrosive solutions (acidic, basic, salt liquids) and mechanical abrasion. Therefore, this reported fabric has the advantages of scalable fabrication, high separation efficiency, stable recyclability, and excellent durability, exhibiting the strong potential for industrial production.