Chemically stable superhydrophobic polyurethane sponge coated with ZnO/epoxy resin coating for effective oil/water separation

Preparation of Superhydrophobic and Multifunctional Sponges for Oil/Water Separation and Oil Absorption

For settling the recycling problem of waste polyurethane sponges (PU) and environment pollution of oil spills simultaneously, this work exploited the multifunctional superhydrophobic PU materials via the dip-coating method, which were prepared by anchoring modified Fe3O4 and expandable graphite (EG) on PU sponges under the adhesion effect of polydimethylsiloxane (PDMS). The water contact angle and sliding angle of as-prepared PU sponges reached 154.1 ± 1.6 and 8°, respectively. Most importantly, the superhydrophobic PU sponges were endowed with the multipath oil treatment ability, which consisted of magnetically driven, gravity-driven, peristaltic pump-driven, and photothermally driven modes. Besides, the light oil absorption capacity, separation flux, and efficiency for superhydrophobic PU sponges reached 23.9 g/g, 27779 L m-2 h-1, and 99.5%, respectively. Owing to the photothermal conversion ability of Fe3O4 and EG, the temperature of superhydrophobic PU sponges was raised to 71.5 °C within 233 s under 1.2 solar irradiation (1200 W/m2), demonstrating its absorption potential for high-viscosity crude oils. In addition, the prepared sponges exhibited good chemical/mechanical stability, self-cleaning, and flame retardancy. In a nutshell, this article has evolved an environmentally benign and practical method for fabricating the multifunctional materials in oil spill treatment, which will efficiently accomplish the targets of low carbon and environmental management.

Bioinspired superwetting oil-water separation strategy: toward the era of openness

Bioinspired superwetting oil-water separation strategies have received significant attention for their potential in addressing global water scarcity and aquatic pollution challenges. Over the past two decades, the field has rapidly developed, reaching a pivotal phase of innovation in the oil-water separation process. However, many groundbreaking studies have not received extensive scientific recognition. In this review, we systematically examine the application of bioinspired superwetting materials for complex multiscale oil-water separation. We discuss the development of 2D membrane filtration and 3D sponge adsorption materials in confined spaces, summarizing the core separation mechanisms, key research findings, and the evolutionary logic of these materials. Additionally, we highlight emerging open-space separation strategies, emphasizing several novel dynamic separation devices of significant importance. We evaluate and compare the design concepts, separation principles, materials used, comprehensive performance, and existing challenges of these diverse strategies. Finally, we summarize these advantages, critical bottlenecks, and prospects of this field and propose potential solutions for real oil-water separation processes from a general perspective.

Electrochemically fast preparation of superhydrophobic copper mesh for high-efficiency oil spill adsorption and oil-water separation

Oily wastewater and marine oil spills are a massive environmental and human threat. Conventional oil spill treatment methods include adsorption by absorbent materials, dispersants or adsorbents, and in situ burning. Superhydrophobic materials, as a material that can achieve oil-water separation, have great potential for application in oil spill treatment. Research on superhydrophobic oil spill treatment mainly focuses on materials such as sponges and fabrics. Although these materials can effectively perform oil-water separation or oil spill adsorption, they also have the disadvantages of complicated preparation methods and high costs. Here, we present a miniature device for oil-water separation and oil spill collection and recovery. The superhydrophobic copper mesh box can be used on its own as an oil-water separation device or in combination with a commercial polyurethane sponge as a miniature oil-absorbing device. The robust copper mesh is prepared in two steps: anodizing and impregnation. The superhydrophobic copper mesh had a high oil separation flux (32,330 L m-2 h-1) and efficiency (97%), which remained high (28,560 L m-2 h-1) and efficient (95%) after 20 cycles of separation. The combined micro oil adsorption device can adsorb different oils and fats on the water surface, and it has good reusability with oil adsorption capacity and efficiency up to 15.28 g/g and 98% and still has good oil adsorption capacity (11.54 g/g) and efficiency (94.6%) after 20 cycles of adsorption. Therefore, the prepared micro oil-absorbing device has promising application prospects in oil-water separation, oil spill cleanup, etc. ENVIRONMENTAL IMPLICATION: This study demonstrates a facile electrochemical approach to prepare a miniature device for high-efficiency oil-water separation and oil spill collection and recovery. The modified copper mesh's separation flux could reach 32,330 L m-2 h-1, showing great promise in oil-water separation and oil spill cleanup.

Novel highly efficient ternary ZnO wrapped PPy-NTs/g-C3N4 nanocomposite as an epoxy coating for corrosion protection

The main goal of this study is to develop an epoxy coating coupled with an organic-inorganic hybrid nanocomposite that can be used as a corrosion-inhibiting pigment on carbon steel. Herein, polypyrrole nanotubes (PPy-NTs), polypyrrole nanotubes/g-C3N4 (PPy-NTs/g-C3N4) and novel nano-composite polypyrrole nanotubes/g-C3N4/ZnO (PGZ) were prepared by facile wet impregnation approach. The developed pigments were investigated using XRD, FTIR, FE-SEM equipped EDS. Electrochemical impedance spectroscopy (EIS) and polarization measurements were used to assess the behavior of the prepared pigments on the anticorrosion performance of epoxy resin coatings. EIS experiments revealed that introducing nano-pigments to neat coatings enhanced the epoxy resin and charge transfer resistance. The anticorrosion performance of the three nano-pigments was assessed as follows: PGZ ˃ PPy-NTs/g-C3N4˃ PPy-NTs.

Fabrication of Durable Superhydrophobic Surface for Versatile Oil/Water Separation Based on HDTMS Modified PPy/ZnO

Superhydrophobic materials have been widely applied in rapid removal and collection of oils from oil/water mixtures for increasing damage to environment and human beings caused by oil-contaminated wastewater and oil spills. Herein, superhydrophobic materials were fabricated by a novel polypyrrole (PPy)/ZnO coating followed by hexadecyltrimethoxysilane (HDTMS) modification for versatile oil/water separation with high environmental and excellent reusability. The prepared superhydrophobic surfaces exhibited water contact angle (WCA) greater than 150° and SA less than 5°. The superhydrophobic fabric could be applied for separation of heavy oil or light oil/water mixtures and emulsions with the separation efficiencies above 98%. The coated fabric also realized highly efficient separation with harsh environmental solutions, such as acid, alkali, salt, and hot water. The superhydrophobic fabric still remained, even after 80 cycles of separation and 12 months of storage in air, proving excellent durability. These novel superhydrophobic materials have indicated great development potentials for oil/water separation in practical applications.

Synthesis and Characterization of Biopolyol-Based Waterborne Polyurethane Modified through Complexation with Chitosan

In this study, a series of castor oil-based anionic waterborne polyurethane (CWPU) systems, which it has been suggested may be suitable for use as green elastomers with diverse applications in films and coatings, was prepared by modified with O-carboxymethyl chitosan (CS) as not only a reinforcing filler, but a chain-extender of polyurethane prepolymer to enhance the properties of polyurethanes. Moreover, not only was the system obtained with castor oil-based polyol in the absence of a catalyst, but it was maintained with low viscosity by using acetone instead of toxic methyl ethyl ketone (MEK) during the synthesis process. The sizes, zeta potential, chemical formation, and morphology of the CWPU-CS composites had been investigated by dynamic light scattering (DLS), infrared spectroscopy (IR), and scanning electron microscopy (SEM). Moreover, the results show that the modification allows to enhance storage/loss modulus, tensile properties, thermal stability at high temperature, and biocompatibility of CWPU and CWPU/CS nanocomposites according to various contents of CS.