Enhanced oil/water separation using superhydrophobic nano SiO2-modified porous melamine sponges

Recent advancements in functional sponge materials have garnered significant interest due to their efficacy and cost-effectiveness in oil spill remediation. This study introduces both silane coupling agent (methyltrichlorosilane and 3-aminopropyltriethoxysilane) and nano-SiO₂ particles into the melamine sponge framework via impregnation. Additionally, polydimethylsiloxane (PDMS) serves a crucial role in curing to fuse the substrate with the coating through robust covalent bonds. The modified sponges (SiMAPs) facilitate the formation of rough surfaces comprising hierarchical structures by the deposition of nano-SiO₂ particles, while the silane coupling agents and PDMS contribute to a reduced surface energy. These SiMAP sponges maintain high stability with a water contact angle of 162.6° and demonstrate an adsorption capacity ranging from 40 to 90 times their weight in oil or organic solvents. Furthermore, they achieve a separation efficiency exceeding 98% and an oil flux of 14.38 L/m2∙s in immiscible oil-water mixtures. Additionally, the sorption of trichloromethane reaches 88.1 g/g, and the separation efficiency for surfactant-stabilized emulsions containing diesel is 62.8%. Remarkably, the oil-water separation efficiency surpasses 99.8% in dynamic continuous oil-water separation cycles, as evidenced by 20 experimental trials. These results underscore the substantial potential of SiMAP-modified sponges for addressing oil pollution by enhancing oil-water separation.

Development Status of Solar-Driven Interfacial Steam Generation Support Layer Based on Polymers and Biomaterials: A Review

With the increasing shortage of water resources and the aggravation of water pollution, solar-driven interfacial steam generation (SISG) technology has garnered considerable attention because of its low energy consumption, simple operation, and environmental friendliness. The popular multi-layer SISG evaporator is composed of two basic structures: a photothermal layer and a support layer. Herein, the support layer underlies the photothermal layer and carries out thermal management, supports the photothermal layer, and transports water to the evaporation interface to improve the stability of the evaporator. While most research focuses on the photothermal layer, the support layer is typically viewed as a supporting object for the photothermal layer. This review focuses on the support layer, which is relatively neglected in evaporator development. It summarizes existing progress in the field of multi-layer interface evaporators, based on various polymers and biomaterials, along with their advantages and disadvantages. Specifically, mainly polymer-based support layers are reviewed, including polymer foams, gels, and their corresponding functional materials, while biomaterial support layers, including natural plants, carbonized biomaterials, and other innovation biomaterials are not. Additionally, the corresponding structure design strategies for the support layer were also involved. It was found that the selection and optimal design of the substrate also played an important role in the efficient operation of the whole steam generation system. Their evolution and refinement are vital for advancing the sustainability and effectiveness of interfacial evaporation technology. The corresponding potential future research direction and application prospects of support layer materials are carefully presented to enable effective responses to global water challenges.

Superhydrophobic foam prepared from high internal phase emulsion templates stabilised by oyster shell powder for oil-water separation

In this paper, poly(styrene-divinylbenzene) foams were synthesized using a high internal phase emulsion (HIPE) technique with Span 80 and with 900 °C calcined oyster shell powder as a co-emulsifier, 2,2'-azobisisobutyronitrile (AIBN) as an initiator and deionized water as the dispersing phase. SEM images revealed that the materials possess a hierarchical porous structure of nano/micro size, which resulted in saturated oil adsorption in only half a minute. The dispersing phase amount was investigated for its effect on adsorption. The optimized foams have 24.8-58.3 g g-1 adsorbencies for several organic solvents, and they demonstrated superhydrophobicity and excellent oleophilicity with the water contact angle (WCA) even close to 149° and oil contact angle approaching 0°. Moreover, the foams displayed high oil retention under pressure. The adsorption-centrifugation cycling results indicated high repeatability of the recovered foams. All of these features predicted the potential applications of superhydrophobic foams in oil-water separation.