Search

Due to ever‐increasing environmental problems caused by oily wastewater, it is necessary to develop methods for separating oil/water mixtures. However, oil‐in‐water and water‐in‐oil emulsions are highly stable due to the action of surfactants, making them enormously difficult to separate. In this study, we report a 3D superhydrophobic/superoleophilic porous material with a microporous structure and strong negative charge via high internal phase emulsion polymerization to overcome these difficulties. The introduction of 10 wt% α‐zirconium phosphate significantly improved the hydrophobicity of the material (water contact angle = 153°) and also endowed the material with a strong negative charge. The material could separate immiscible oil/water mixtures under turbulent condition and high‐ or low‐temperature environments. Driven by gravity, the as‐prepared monolith separated various oil/water mixtures with the separation efficiency exceeding 99.16%. Benefiting from the diametrically‐opposing wettability and interconnected micropore structure, the foam could separate a Span 80‐stabilized water‐in‐oil emulsion. Furthermore, a cationic surfactant‐stabilized oil‐in‐water emulsion was also separated due to strong electrostatic interactions, which destabilized the oil/water interfacial film. Based on these properties, the as‐prepared porous material shows huge potential for complex oily wastewater treatment. [ABSTRACT FROM AUTHOR]

Three-dimensional superhydrophobic/superlipophilic porous materials have attracted widespread attention for use in the separation of oil/water mixtures. However, a simple strategy to prepare superhydrophobic porous materials capable of efficient and continuous separation of immiscible and emulsified oil/water mixtures has not yet been realized. Herein, a superhydrophobic graphene/polystyrene composite material with a micro-nanopore structure was prepared by a single-step reaction through high internal phase emulsion polymerization. Graphene was introduced into the polystyrene-based porous materials to not only enhance the flexibility of the matrix, but also increase the overall hydrophobicity of the composite materials. The resulting as-prepared monoliths had excellent mechanical properties, were superhydrophobic/superoleophilic (water/oil contact angles were 151° and 0°, respectively), and could be used to continuously separate immiscible oil/water mixtures with a separation efficiency that exceeded 99.6%. Due to the size-dependent filtration and the tortuous and lengthy micro-nano permeation paths, our foams were also able to separate surfactant-stabilized water-in-oil microemulsions. This work demonstrates a facile strategy for preparing superhydrophobic foams for the efficient and continuous separation of immiscible and emulsified oil/water mixtures, and the resulting materials have highly promising application potentials in large-scale oily wastewater treatment. [ABSTRACT FROM AUTHOR]

Superhydrophobic polymeric foams, with good thermal stability and high‐recycling capacity to remove oil from oily wastewater, are highly desirable for current oily wastewater purification. Herein, poly (styrene‐acrylic acid 2,2,3,4,4,4‐hexafluoro‐butyl ester‐divinylbenzene) foam with porosity as high as 99.27% has been prepared through high‐internal phase emulsions. Therein, poly (cyclotriphosphazene‐co‐4,4′‐sulfonyldiphenol) microspheres, and Span80 act as co‐emulsifier to stabilize the emulsion system. The as‐prepared foams exhibited super hydrophobicity with a water contact angle of 150.3° and thermal stability. Additionally, the oil adsorption capacity of the porous material could reach up to 25.6–53.4 times its mass with accessible and high‐recycling capacity. These aforementioned outstanding properties make our superhydrophobic foam hold potential applications in oil/water separation. [ABSTRACT FROM AUTHOR]

Superhydrophobic materials for efficient oil/water separation have significant industrial application value, but their preparation through low-cost and simple strategy is still a great challenge. Herein, melamine foam (MF) was superhydrophobically modified by polydimethylsiloxane (PDMS) through one-pot emulsion polymerization. The nanospheres generated via emulsion polymerization in-situ formed micro-nanostructures on the MF skeleton. During emulsion polymerization, the crosslinking between PDMS was simultaneously carried out to form a hydrophobic layer on the surface of the skeleton. The modified MF was superhydrophobic (the water contact angle and rolling angle were 156.8° and 3°, respectively), had high saturated absorption capacities (61.49–122.73 g/g), and separation efficiency > 99.5% for various oils/organic solvents. Moreover, the foam featured excellent chemical/physical stability, and the surface wettability did not change significantly for acidic (pH = 1), basic (pH = 13), or saturated NaCl solutions or when sonicated. Meanwhile, the foam can continuously separate oil/water mixtures with the assistance of vacuum pump. Furthermore, our foam can also effectively separate the surfactant-stabilized emulsion via simply mechanical compression strategy. These results open an alternative and simple route for treating oily wastewater in practice. [Display omitted] • Foam was superhydrophobically modified by PDMS through one-pot emulsion polymerization. • The foam held excellent stability in corrosive conditions. • The MF@P(St-DVB)/PDMS showed excellent separation performance. • Emulsion separation can be achieved by a simple mechanical compression strategy. [ABSTRACT FROM AUTHOR]

The superhydrophobic P(St-DVB)-PDMS 8 foam with hierarchical porous structure prepared by one-pot method can continuously and efficiently handle immiscible oil/water mixtures and surfactant-stabilized microemulsions in harsh environments, making it a great potential for current complex polluted aquatic system. [Display omitted] • Superhydrophobic foam with hierarchical porous was fabricated via one-pot method. • The foam holds excellent stability in corrosive or high/low temperature conditions. • Various oil/water mixtures can be efficiently separated under harsh conditions. • Surfactant-stabilized emulsion can be efficiently and continuously separated. Three-dimensional (3D) superhydrophobic/superoleophilic polymeric materials, with highly efficient and continuous separation ability of immiscible oil/water mixtures and water-in-oil emulsions, combined with robust physical/chemical stability, are highly desirable for remediating complex oily wastewaters, but still remain a challenge to be realized. Herein, polystyrene-divinylbenzene-polydimethylsiloxane based superhydrophobic/superoleophilic foam with hierarchical porous structure was designed and prepared by high internal phase emulsion polymerization to overcome the aforementioned challenge. With hierarchical porous structure and superhydrophobic/superoleophilic properties (water/oil contact angles were 152° and 0°, respectively), the as-prepared foam could continuously separate different immiscible oil/water mixtures and water-in-oil emulsions with high separation efficiencies (>99.57 % and 99.1 %, respectively). Interestingly, our foam also displayed other properties such as stability, strong wear-resistance (the surface wettability was intact even after 100 abrasion cycles), robust anti-corrosive performance (the surface wettability and structure did not change after immersing the foam in acidic/basic/saline solutions or strongly polar organic solvents (DMF, DMSO) for a week), and broad range of temperature tolerance from −18 ℃ to 150 ℃. Due to these outstanding functions, our foam has great potential for remediation of complex oily wastewaters. [ABSTRACT FROM AUTHOR]

Herein, a scalable and facile strategy is presented to fabricate ultra-small nickel phosphide nanoparticles loaded reduced graphene oxide on nickel foam (Ni 2 P/RGO@NF) through an interfacial redox reaction between GO and NF in water, followed by a simple phosphorization process. This self-supported Ni 2 P/RGO@NF catalyst with favorable 3D hierarchical nanostructure, enhanced electrical conductivity and high density of ultra-small Ni 2 P (24,000 particles per square micron) shows outstanding bifunctional catalytic performance toward overall water splitting under alkaline and neutral conditions. Notably, the Ni 2 P/RGO@NF electrode delivers low cell voltage of just 1.58 V and 1.68 V at a current density of 10 mA cm−2 in alkaline and neutral electrolytes with prominent stability for more than 20 h, respectively. Moreover, ultra-small cobalt phosphide loaded RGO on cobalt foam samples have also been prepared by the same method. Thus, this strategy provides a general way for fabricating self-supported electrocatalysts with ultra-small metal-based nanoparticles, which is scalable and applicable in energy storage and conversion devices. Image, graphical abstract [ABSTRACT FROM AUTHOR]