Superhydrophobic Stainless-Steel Mesh with Excellent Electrothermal Properties for Efficient Separation of Highly Viscous Water-in-Crude Oil Emulsions

Abstract

The separation of tiny water droplets from viscous crude oil is urgently needed and still remains a substantial challenge because of severe membrane fouling resulting from the high viscosity and adhesive property of crude oil. To solve this issue, the electrothermal effect, for the first time, was utilized to heat the water-in-crude oil emulsion using electrical current as an energy source to extremely reduce the viscosity of the water-in-crude oil emulsion and thus to realize efficient viscous emulsion separation. A silicone-modified stainless-steel mesh (SSM) was fabricated via coating silicone on the SSM and transient heating. The as-prepared silicone-modified SSM allows for an outstanding integration of superhydrophobic/superoleophilic properties from the partial thermal degradation of the silicone coating and superior electrothermal capability from SSM. Thanks to the excellent electrothermal capability, the silicone-modified SSM achieved a high electrothermal power density of 3.43 W cm–2 at a low input voltage of 5 V. The resulting Joule heating, superhydrophobicity, and micropore structure enabled the silicone-modified SSM to efficiently separate a viscous water-in-crude oil emulsion (2.6 × 104 mPa s at 20 °C) with high separation efficiency (98.9%) and separation flux (314 L m–2 h–1). Moreover, the silicone-modified SSM presented optimal reusability and stability after six cycles for the viscous water-in-crude oil emulsion. This electrothermal-assisted viscous emulsion separation strategy can provide some new perspectives for viscous oil/water emulsion separation.

Facile Construction and Fabrication of a Superhydrophobic and Super Oleophilic Stainless Steel Mesh for Separation of Water and Oil

“…As described in Figure S3 and Figure 4 , the elemental distribution of Si components on OTS@Fe 2 O 3 -NCs@SSM can verify that the hydrophobic components of OTS are successfully coated on the substrate. As shown in Figure 5 a, the surface XPS results of SSM verify the existence of C (284.6 eV), O (530.6 eV), and Fe (711.2 eV) elements [ 30 ]. In addition, the Si 2s and Si 2p signal peaks are detected on the surface of SSM, which is consistent with the EDS results ( Figure S1 ).…”

“…As shown in Figure 5 b, the crystal phases of SSM, Fe 2 O 3 -NCs@SSM, and OTS@Fe 2 O 3 -NCs@SSM were analyzed by XRD patterns. The XRD patterns of the samples have two characteristic peaks at 44.0 and 51.1°, which are assigned to the (111) and (200) lattice planes of SSM, respectively [ 30 ]. In addition, the diffraction patterns of Fe 2 O 3 -NCs@SSM exhibit four characteristic peaks, corresponding to the (104), (110), (024), and (214) lattice planes of Fe 2 O 3 nanoparticles at 33.2, 35.6, 49.5, and 62.4°, respectively [ 37 ].…”

“…Over the past few years, oil/water separation materials, based on metal meshes [ 20 , 21 , 22 ], especially stainless steel meshes (SSM) [ 23 , 24 , 25 , 26 ], have drawn much attention, with significant advantages in terms of their high mechanical strength, easy availability, and long durability. The preparation of superhydrophobic mesh is mainly based on surface modification by changing the chemical composition or the microscopic geometry of the surface [ 27 , 28 , 29 , 30 ]. For example, Jiang et al first prepared a superhydrophobic mesh with high oil–water separation efficiency via surface modification with polytetrafluoroethylene [ 31 ].…”

Straightforward fabrication of robust and healable superhydrophobic steel mesh based on polydimethylsiloxane

“…Various metallic mesh films with superhydrophobic and superoleophilic properties have been developed. [23][24][25] These materials include fluoropolymer/ SiO 2 nanoparticles coated stainless steel mesh (SSM), 26 supported pure-silica zeolite beta, 27 silicone modified stainless-steel mesh, 28 MgAlZn layered double hydroxidecoated stainless-steel mesh, 29 phosphorylated PVA (PPVA) hydrogel-coated stainless-steel mesh, 30 etc. Unfortunately, most materials easily lose their excellent superwettability after being severely damaged by contamination or abrasion.…”

Robust and Eco-Friendly Superhydrophobic Starch Nanohybrid Materials with Engineered Lotus Leaf Mimetic Multiscale Hierarchical Structures

“…Despite remarkable progress, current research still focuses its attention on using an intrinsically durable substrate, such as cotton fabric, 32 glass, 33 wood, 34 paper, 35 or metal meshes. 36 Achieving a robust superhydrophobic surface on fragile biopolymeric materials (e.g., starch or cellulose) through facile, cost-effective, and environmentally friendly approaches still remains a huge challenge. Most recent studies have only mimicked the superhydrophobic property of lotus leaf, and to the best of our knowledge, only limited success has been achieved to precisely mimic its excellent hierarchical surface structure.…”