A Co 3 O 4 nano-needle mesh for highly efficient, high-flux emulsion separation

often stable and have complex structures because of the presence of surfactants. [12] This is particularly the case for micrometer-scale emulsions with droplet sizes smaller than 20 µm. Therefore, a low-cost, high-efficiency separation technology was urgently needed to mitigate or even solve these pollution problems.Membrane filtration techniques such as ultrafiltration [13,14] are mainly based on a "size-sieving" effect and have been used to separate various emulsified oil/ water mixtures during large-scale processing because they give simple separation and have low energy consumption. Wettability [15][16][17] is a key feature of membranes for oil/water separation. A superhydrophobic/superoleophilic membrane can filter oil from water, whereas a superhydrophilic/underwater superoleophobic membrane can be used to filter water from oil. [18] However, a single wetting film can separate surfactant-free oil/water mixtures but not emulsified oil/water mixtures. A membrane with an appropriate pore size, i.e., less than the diameter of the emulsion droplets, and appropriate wettability can effectively separate emulsified oil/water mixtures. [19,20] In view of this membrane separation technology, we used a low-cost, corrosion-resistant stainless steel mesh for hydrothermal treatment and compounding with sodium titanate nanowires to perform oil-water separation, which solves the drawbacks of low-cost, high-efficiency separation that conventional separation technologies cannot achieve.In previous studies, researchers have designed various types of separation membranes based on the two strategies described above; these membranes have mainly consisted of organic and inorganic films. [21][22][23] Organic membranes such as the poly(vinylidene fluoride) membrane [24] fabricated by Jiang and co-workers and the hierarchical membranes [25] fabricated by Yang and co-workers give excellent emulsion separation for a variety of water phases and relatively inert oils such as diesel or gasoline. Inorganic films have been receiving increasing attention because of their superior mechanical properties, stability, and facile and inexpensive preparation methods; they give high flux, and sustained and efficient separation. For example, a TiO 2 nanocluster-based mesh [26] fabricated by Feng and co-workers, free-standing CaCO 3 film [27] prepared by Wang and co-workers, Ultrawetting membranes have enabled great progress in oil/water separation and have helped to address global industrial wastewater pollution and marine oil spills. However, there are few reports of 3D multilayer network membranes that can be easily prepared, and give efficient separation in micro-and nanoscale oil-in-water emulsions. A membrane is designed for emulsion separation; it consists of ultralong (over 10 µm) sodium titanate nanofibers as the selective layer and a jungle-like Co 3 O 4 nanoneedles mesh as the support layer. This mesh shows superhydrophilicity in air and lowadhesive superoleophobicity under water. This membrane gives 99.9% separation efficiency and good pe...

Section: Resultsmentioning

confidence: 99%

“…Then, the pink mesh was calcined at 400 °C for 4 h in the muffle furnace. The mesh transformed from pink to black …”

Section: Methodsmentioning

confidence: 99%

Multilayer Network Membranes Based on Evenly Dispersed Nanofibers/Co₃O₄ Nanoneedles for High‐Efficiency Separation of Micrometer‐Scale Oil/Water Emulsions

Qian

Chen

et al. 2018

“…Finally, although the abovementioned testing strategies are based on measuring contact angles (Figure a,b) or measuring the change in oil–water (non‐corrosive) separation performance after corrosion (Figure c), which reflect chemical resistance, the practical separation of a variety of complex oil–water mixtures composed of corrosive solutions or organic solvents to imitate real harsh conditions also makes sense (Figure d). Several separation systems especially for corrosive water–oil mixtures, water–organic solvents mixtures, and corrosive water–organic solvents mixtures have been established.…”

Section: Robust Superwettable Membranes For Oil–water Separationmentioning

confidence: 99%

Recent Advances in Robust Superwettable Membranes for Oil–Water Separation

Lin

Hong

2019

118

Over the past decade, much progress has been made in the application of multifunctional membranes with special wettability for the separation of oil–water mixtures. This progress has been driven by frequent oil spill accidents and oily wastewater, which are enormous threats to the vulnerable aquatic environment. The design of permeable superwettable membranes for oil–water separation has been inspired by the development of highly wetting/nonwetting interfaces, but these membranes are susceptible to factors such as mechanical forces, chemical corrosion, biological fouling, and other environmental influences. Considering the complex and harsh environments that superwettable membranes must endure during the separation process, membrane durability against the loss of superwettability is critical in prolonging the life of an oil–water filtration system. Although significant advances in superwettable membranes have been made, the robustness issue remains challenging and has become a focus of many investigations. Covering nearly all publications concerning “robust, durable, usable, resistant, tolerant, or antifouling oil–water separation” published in the last five years, this work is intended as an introduction for new researchers wishing to create durable superwettable membranes for oil–water separation, as well as providing perspectives and guidance for future research in several logical directions.

“…Therefore, the detection of pollutants and the purification of contaminated water have drawn much attention in recent years . Many excellent researchers have devoted into developing various oil/water separating materials to clean organic compounds from water sources, such as nanofibers, metal foams, polymer sponges, metal meshes, membrane, and aerogels . Among above materials, copper meshes have been paid much attention due to their big voids, good mechanical stability, high separation efficiency, and stable durability .…”

Section: Introductionmentioning

confidence: 99%

Trifunctional Copper Mesh for Integrated Oil/Water Separation, SERS Detection, and Pollutant Degradation

Cheng

et al. 2019

In real environment, wastewaters containing various oily organic solvents or soluble dyes bring serious damage to the environment and threaten the health of human. Although substantial efforts are devoted to removing oily pollutants from water, it cannot solve the problem of water pollution thoroughly since some soluble dyes still exist in separated water phase. Meanwhile, it is still a challenge to directly detect pollutants with low concentration in oil/water mixtures by surface‐enhanced Raman spectroscopy (SERS) technique owing to the mutual interference of Raman signals by mixed organic solvents and soluble dyes. Therefore, developing an effective solution for separating oil/water mixture, detecting, and degrading pollutants simultaneously is highly desired. In this work, a trifunctional superhydrophobic copper mesh which integrates the separation, detection, and further degradation of the dyes in one material is reported. The trifunctional copper mesh is fabricated by in situ growing Au/AgCl nanoparticles on the surface of copper mesh. Au/AgCl nanoparticles improve the roughness and hydrophobic performance of copper mesh. Au provides abundant plasmonic hotspots which are beneficial to the improved SERS activity, and AgCl exhibits highly efficient photocatalytic ability for degrading organic dyes. The idea of integrating three functions in one substrate will open a novel horizon for realistic wastewater purification.