Simple and Green Fabrication of a Superhydrophobic Surface by One-Step Immersion for Continuous Oil/Water Separation

Abstract

In this paper, stainless steel meshes with superhydrophobic and superoleophilic surfaces were fabricated by rapid and simple one-step immersion in a solution containing hydrochloric acid and stearic acid. The apparent contact angles were tested by a video contact angle measurement system (CA). Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the surface topographies and chemical compositions. The SEM results showed that mesh surfaces were covered by ferric stearate (Fe[CH3(CH2)16COO]2) with low surface energy. The CA test results showed that the mesh had a maximum apparent contact angle of 160 ± 1.0° and a sliding angle of less than 5.0° for the water droplet, whereas the apparent contact angle for the oil droplet was zero. Ultrasound oscillation and exposure tests at atmospheric conditions and immersion tests in 3.5 wt % NaCl aqueous solution were conducted to confirm the mesh with excellent superhydrophobic and superoleophilic properties. On the basis of the superhydrophobic mesh, a miniature separation device pump was designed to collect pure oil from the oil/water mixture. It showed that the device was easier and convenient. The techniques and materials presented in this work are promising for application to wastewater and oil spill treatment.

Stearic Acid/Layered Double Hydroxides Composite Thin Films Deposited by Combined Laser Techniques

“…Both -CH 3 and -CH 2 - are hydrophobic groups and have low surface energy decreasing the surface energy of the surface they cover or of the materials they are grafted to [ 35 , 36 ]. The free -COOH band of solid stearic acid is still present in the spectrum of the as-deposited StMAPLE(266 nm) film while it vanishes in the spectrum of the film after 36 months of storage, which shows that the stearic acid had reacted with the Si surface, although there are no changes in contact angle value [ 37 , 38 ]. It has been observed that an “ordered” film of alkanoic acids is characterized by alkyl chains in all-trans configurations arranged in such a way that they are tilted from the normal surface at the same angle.…”

“…It has been observed that an “ordered” film of alkanoic acids is characterized by alkyl chains in all-trans configurations arranged in such a way that they are tilted from the normal surface at the same angle. This results in νCH 2 -asymmetric ≤ 2916 cm −1 [ 37 , 38 ]. Table 3 includes a column with the position of this peak.…”

Magnetic and Hydrophobic Composite Polyurethane Sponge for Oil–Water Separation

“…Changing the wetting properties of the material surface changes the selective adsorption of water-oil. A variety of oil-adsorbing and hydrophobic materials for oil-water separation have been prepared and encouraging results were obtained [10][11][12]. In addition, there are many 3D porous materials with hydrophobic and oil adsorption capacity that have been successfully applied to oil-water separation, but their practical applications are still limited by complex preparation methods and high raw material costs [13][14][15][16][17].…”

A robust duplex Cu/PDMS-coated mesh with superhydrophobic surface for applications in cleaning of spilled oil

“…Both low surface energy and rough surface structures are the main inuencing factors of superhydrophobicity. 12,13 Various ltration materials with superhydrophobicity and superoleophilicity, such as textiles, 14 meshes, 15 cellulose sponges, 16 and membranes, 17 have been fabricated to selectively lter water or oil from oil/water mixtures. Among articial superhydrophobic materials, [18][19][20][21][22] as-prepared mesh surfaces with superhydrophobic character have been some of the most promising examples owing to their strong water repellence, which endowed hierarchical surfaces with robust superhydrophobicity and uses in practical applications.…”

“…Previous studies demonstrated that the preparation process via one-step immersion is convenient and simple. 15 In this article, a superhydrophobic and superoleophilic mesh with hierarchical micro/nanostructures was fabricated via a green, rapid, and highly effective electrodeposition process and chemical modication with PDMS. The porous coated mesh retained excellent superhydrophobicity aer immersion in solutions of different pH values and abrasion cycling tests.…”