Surface Design of Separators for Oil/Water Separation with High Separation Capacity and Mechanical Stability

Abstract

A convection heat treatment that can replace existing chemical oxidation methods was developed for the preparation of hierarchically oxidized Cu meshes with various surface morphologies, representing a very simple and green route that does not involve toxic chemicals. Three types of Cu meshes [bumpy-like (BL) and short and long needle-like (NL) structures] exhibited similar separation efficiencies of 95-99% over 20 separation cycles, as indicated by their similar water contact angles (WCAs; 147-150°). However, these Cu meshes exhibited different flux behaviors. Excessively rough and excessively smooth surfaces of the Cu mesh resulted in increased resistance to flow and to a decrease of the penetration of oil. A surface with intermediate smoothness, such as the BL-Cu mesh, was necessary for high flux over a broad range of oil viscosities. Furthermore, a less rough surface was more suitable for the separation of highly viscous oil. Computational fluid dynamics (CFD) simulations were carried out to support our experimental results. The BL-Cu meshes also showed outstanding mechanical stability because of their low resistance to the flow of fluids.

Performance Analysis of Gravity-Driven Oil–Water Separation Using Membranes with Special Wettability

“…18 A more complete model was recently proposed by considering all relevant contributionsinertia, hydrostatic pressure, viscous loss, and capillarity. 57,58 However, their model should be solved numerically while requiring several implicit geometrical parameters, which makes it difficult to apply to the present results.…”

“…56 Deng et al proposed the mass flux model when the mass flux through the membrane was driven by capillarity, but they did not consider the influence of hydrostatic pressure and inertia. 18 A more complete model was recently proposed by Coene et al 57 and Lim et al 58 However, both of the two relied on numerical simulation to obtain the solution, which made them impractical to apply in real applications. The main objective of the present study is to develop a simple, practical model to accurately predict the mass flux through the oil−water separation membrane driven by gravity or hydrostatic pressure, which can be utilized to evaluate the separation performance of oil−water mixtures together with the intrusion pressure and separation efficiency.…”

An Active Absorbent for Cleanup of High-Concentration Strong Acid and Base Solutions

“…Droplets of NaOH solution were dropped from a height of 3 cm onto each surface during the dropping tests. When a droplet of a strong base solution (50%) was dropped on a superhydrophilic Cu mesh [36] with a smooth surface, a hemispherical droplet with a water contact angle (WCA) of 91° formed, remained for 2 min, and then gradually disappeared after 10 min (Figure S6a). For the bare MFS and pad samples, the initial droplet shapes and sizes were maintained for over 2 min, and the droplets gradually disappeared after 2 min (Figure S6b,c).…”

Solar-Driven Unmanned Hazardous and Noxious Substance Trapping Devices Equipped with Reverse Piloti Structures and Cooling Systems

“…There are two types of typical approaches for oil/water separation: filtration and absorption. The filtration method is suitable for industrial oil/water separation settings because it allows a higher flux than the absorption method [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Since absorbents can be simply placed on oil spill sites and oil can be easily removed in situ by absorbents, the absorption method is more practical than the filtration method in cases of oil spill accidents [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”