NaOH-Induced Fabrication of a Superhydrophilic and Underwater Superoleophobic Styrene-Acrylate Copolymer Filtration Membrane for Effective Separation of Emulsified Light Oil-Polluted Water Mixtures.

Oil-polluted water mixtures are difficult to separate, and thus, they are considered as a global challenge. A superior superhydrophilic and low-adhesive underwater superoleophobic styrene-acrylate copolymer filtration membrane is constructed using a salt (NaOH)-induced phase-inversion approach. The as-fabricated filtration membrane provides a hierarchical-structured surface morphology and three-dimensional high density open-rough porous geometry with a special chemical composition including highly accessible hydrophilic -COO- agents, which all are of great importance for long-term usage of immiscible/emulsified (light) oil-polluted wastewater separation. The separation is performed with a high efficiency and a high flux under either a gravity-driven force or a small applied pressure of 0.1 bar. The filtration membrane indicates an excellent anti-fouling property and is easily recycled during multiple cycles. The outstanding performance of the filtration membrane in separating oil-polluted water mixtures and the cost-effective synthetic approach as well as commercially scaled-up initial materials all highlight its potential for practical applications.

Durable Light-Driven Three-Dimensional Smart Switchable Superwetting Nanotextile as a Green Scaled-Up Oil-Water Separation Technology.

Stimuli-responsive polymer architectures are attracting a lot of interest, but it still remains a great challenge to develop effective industrial-scale strategies. A single-stage and cost-effective approach was applied to fabricate a three-dimensional (3D) smart responsive surface with fast and reversibly switchable wetting between superhydrophobicity and superhydrophilicity/underwater superoleophobicity properties induced by photo and heat stimuli. Commercially available PVDF and P25TiO2 as starting materials fabricated with a scaled-up electrospinning approach were applied to prepare 3D smart switchable PVDF-P25TiO2 nanotextile superwetted by both UV and solar light that is simply recovered by heat at a reasonable time. The superhydrophilic/underwater superoleophobic photo-induced nanotextile will act in "water-removing" mode in which water quickly passes through and the oil is blocked on the surface. An acceptable recycling, reusing, and superior antifouling and self-cleaning performance arising from a TiO2 photocatalytic effect makes it highly desired in a green scaled-up industry oily wastewater treatment technology. With these advantages, a large-scale industrial production process can be simply simulated by applying a conducting mesh-like collector substrate.

Wool-Like Fibrous Nonwoven Mesh with Ethanol-Triggered Transition between Antiwater and Antioil Superwetting States for Immiscible and Emulsified Light Oil-Water Separation.

Superwetting antiwater and antioil textiles are not only very attractive for efficient and cost-effective oil-water separation but also very challenging to be prepared. A well-designed polystyrene wool-like fibrous mesh was fabricated by a controlled electrospinning setup to provide simple and quick reversible ethanol-triggered switching between antiwater and antioil superwetting states in various media such as air, water, and oil. Additionally, it exhibits a long-term stability against acid, alkaline, and salt at high concentrations. Such characteristics will prove unusual capabilities for controllable gravity-driven separation of both immiscible and emulsified oil-water mixtures with a separation efficiency more than 99.0%, as well as a prolonged antifouling property and an excellent recyclability; all will be advantageous for technical applications including oil removing and water removing. Furthermore, light oil-polluted water and water-soluble pollutants can be simultaneously cleaned well by the antioil mesh acting in the water-removing mode.

Structure-Property Relationships of Nanosheeted 3D Hierarchical Roughness MgAl-Layered Double Hydroxide Branched to an Electrospun Porous Nanomembrane: A Superior Oil-Removing Nanofabric.

A straightforward approach was successfully developed to fabricate a well-designed three-dimensional rough sheetlike MgAl-layered double hydroxide (LDH) array to stand vertically on poly(acrylonitrile) porous nanofibrous membranes based on an electrospun-nanofiber-templated in situ hydrothermal strategy, and then the surface was modified with cyclohexanecarboxylic acid. The as-spun highly dense ordered sheetlike LDH porous nanofabric exhibited a superior durability in superhydrophobicity and superoleophilicity, which has achieved high oil-removing capability including both oil harvesting and oil separation to harvest/separate a wide range of organic solvents and oils from an oil-water mixture and, especially, exhibited a very good recycling and reusing performance. Interestingly, a steady water repellency was obtained against both drinkable hot (about 95 °C) and cool water. Outstanding oil harvesting, oil separation, and highly durable water repellant can be attributed to an effective synergistic effect between the high-density roughness of LDH nanosheets modified with acid and the very high porosity in the electrospun nanofibers, as well as the interspace between LDH nanosheets that acted as both a textile for selective oil separation and a container for penetrated oil storage, leading to special wettability, making the as-spun nanofabric a promising textile for large-scale removal and recollection of hydrophobic spillage on the water surface.