RESUMEN
The adhesion of high-viscosity oil contamination poses limitations on three-dimensional (3D) materials' practical use in treating oilfield-produced water (OPW). In this study, we developed a hybrid pDA/TiO2/SiO2 coating (PTS) on the surface of hydrophilic activated carbon (ACF1) through a combination of dopamine (DA) polymerization, ethyl orthosilicate (TEOS) hydrolysis, and the condensation of TiO2 nanoparticles (NPs) with SiO2 NPs. This coating was designed for gravity-based oil-water separation. The inherent porosity and generous pore size of ACF1-PTS conferred it an ultra-high permeation flux (pure water flux of 3.72 × 105 Lâm-2âh-1), allowing it to effectively separate simulated oil-water mixtures and oil-water emulsions while maintaining exceptional permeation flux and oil rejection efficiency. When compared to cleaning methods involving ethanol aqueous solutions and NaClO, ultraviolet (UV) illumination cleaning proved superior, enabling oil-contaminated ACF1-PTS to exhibit remarkable flux recovery efficiency and oil-removal capabilities during cyclic separation of actual OPW. Furthermore, the ACF1-PTS material demonstrated impressive stability and durability when exposed to acidic environments (acid, alkali, and salt), robust hydraulic washout conditions, and 25-cycle tests. This study offers valuable insights and research avenues for the development of highly efficient and environmentally friendly 3D oil-water separation materials for the actual treatment of OPW.
RESUMEN
Effective integrated methods for oil-water separation and water remediation have signifi-cance in both energy and environment fields. Materials with both superlyophobic and superlyophilic properties toward water and oil have aroused great attention due to their energy-saving and high-efficient advantages in oil-water separation. However, in order to fulfill the superlyophobicity, low surface tension fluorinated components are always being introduced. These constituents are environmentally harmful, which may lead to additional contamination during the separating process. Moreover, the heavy metal ions, which are water-soluble and highly toxic, are always contained in the oil-water mixtures created during industrial production. Therefore, material that is integrated by both capacities of oil-water separation and removal of heavy metal contamination would be of significance in both industrial applications and environmental sustainability. Herein, inspired by the composition and wettability of the shrimp shell, an eco-friendly chitosan-coated (CTS) cotton was developed. The treated cotton exhibits the superhydrophilic/underwater superoleophobic property and is capable of separating both immiscible oil-water mixtures and stabilized oil-in-water emulsions. More significantly, various harmful water-soluble heavy metal ions can also be effectively removed during the separation of emulsions. The developed CTS coated cotton demonstrates an attractive perspective toward oil-water separation and wastewater treatment in various applications.
RESUMEN
Intelligent surfaces with controlled wettability have caught much attention in industrial oily wastewater treatment. In this study, a hygro-responsive superhydrophilic/underwater superoleophobic coating was fabricated by the liquid-phase deposition of SiO2 grafted with perfluorooctanoic acid. The wettability of the surface could realize the transformation from superhydrophilicity/underwater superoleophobicity (SHI/USOB) to superhydrophobicity/superoleophilicity (SHB/SOI), both of which exhibited excellent separation performance towards different types of oil-water mixtures with the separation efficiency higher than 99%. Furthermore, the long-chain perfluoroakyl substances on the surface could be decomposed by mixing SiO2 with TiO2 nanoparticles under UV irradiation, which could reduce the pollution to human beings and environment. It is anticipated that the prepared coating with controlled wettability could provide a feasible solution for oil-water separation.
RESUMEN
Oil-water separation using super-wetting and the selective permeability of membranes for oil or water has great ecological and economic significance. We report on the transition of wettability response, from superhydrophilic underwater-superoleophobic to superhydrophobic-superoleophilic state, by nanostructuring stainless steel and copper meshes using ultrashort femtosecond laser pulses. Our approach is environment-friendly, chemical free, and efficient as it exploits the benefit of aging the processed samples in a high vacuum environment. We optimized the laser scanning parameters, mesh pore size, and aging conditions to produce membranes exhibiting an extraordinary separation efficiency of 98% for the oil-water mixture. A variation in the water and oil contact angles for different meshes is presented as a function of the laser scanning speed. Stainless steel meshes with 150 µm pore size and copper meshes with 100 µm pore size have demonstrated an excellent wettability response for oil and water phases. Vacuum aging causes rapid chemisorption of hydrocarbons on laser-structured surfaces in the absence of water molecules, rapidly transforming the wetting state from superhydrophilic to superhydrophobic.
RESUMEN
Developing an effective and sustainable solution for cleaning up or separating oily water is highly desired. In this work, we report a completely inorganic mesh membrane made up of cupric phosphate (Cu3(PO4)2) in a special intersected nanosheets-constructed structure. Combing the hierarchical structure with strong hydration ability of Cu3(PO4)2, the nanosheets-wrapped membrane exhibits a superior superhydrophilic and underwater anti-oil-fouling and antibio-fouling property for efficient oil/water separation to various viscous oils such as heavy diesel oil, light crude oil, and even heavy crude oil with underwater oil contact angles (CAs) all above 158° and nearly zero underwater oil adhesive force even when a large preload force of up to 400 µN was applied on the oil droplet. Simultaneously, the membrane exhibits a high chemical and thermal stability and outstanding salt tolerance. Continuous separation operated on a cross-flow filtration apparatus demonstrates a large separation capacity and long-term stability of the membrane during treating a 2000 L crude oil/water mixture with constantly stable permeating flux of â¼4000 L/m2 h and oil content in the filtrate below 2 ppm. The excellent anti-oil-fouling property, high separation capacity, and easily scaled-up preparation process of the membrane show great potential for practical application in treating oily wastewater.