Investigation of grafting silane coupling agents on superhydrophobicity of carbonyl iron/SiO(2) particles for efficient oil/water mixture and emulsion separation

Unravelling the role of filler surface wettability in long-term mechanical and dielectric properties of epoxy resin composites under hygrothermal aging

Epoxy resin (EP) incorporating inorganic fillers has garnered significant attention in the electrical and electronic industries due to its enhanced dielectric and mechanical properties, but its long-term performance under harsh conditions remains a critical concern. This study investigates the effects of filler surface wettability on the durability of EP-SiO2 composites. Micro-sized SiO2 with hydrophilic (HP) and hydrophobic (HB) surfaces are prepared via surface treatment, before they are incorporated into epoxy resin and subjected to hygrothermal aging at 95 °C and 95 % relative humidity for up to 1200 h. Comprehensive characterizations of wettability, microstructure, mechanical properties, and dielectric performance are conducted. Results show that the composite with hydrophilic fillers, HP-SiO2-EP, exhibits superior dispersion and interfacial adhesion compared to its hydrophobic counterpart, HB-SiO2-EP. Consequently, HP-SiO2-EP demonstrates higher initial tensile strength, Young's modulus, and dielectric breakdown strength. Finite element simulations reveal the breakdown mechanism, highlighting that the hydrophobic SiO2 filler with interfacial defects results in earlier mechanical and dielectric failure. Furthermore, HP-SiO2-EP shows better resistance to hygrothermal aging compared to HB-SiO2-EP, with smaller increases in dielectric constant (+13 % vs. +28 %) and dielectric loss (+234 % vs. +311 %), as well as lower decrease in volume resistivity (-89 % vs. -93 %). This study provides valuable insights into the relationship between filler surface wettability and long-term composite performance, contributing to the design of more reliable materials for advanced dielectric applications.

Magnetic superhydrophobic melamine sponges for crude oil removal from water

This paper proposes the preparation of a new sorbent material based on melamine sponges (MS) with superhydrophobic, superoleophilic, and magnetic properties. This study involved impregnating the surface of commercially available MS with eco-friendly deep eutectic solvents (DES) and Fe3O4 nanoparticles. The DES selection was based on the screening of 105 eutectic mixtures using COSMO-RS modeling. Other parameters affecting the efficiency and selectivity of oil removal from water were optimized using the Box-Bhenken model. Menthol:Thymol (1:1)@Fe3O4-MS exhibited the highest sorption capacity for real crude oils (101.7-127.3 g/g). This new sponge demonstrated paramagnetic behavior (31.06 emu/g), superhydrophobicity (151°), superoleophobicity (0°), low density (15.6 mg/cm3), high porosity (99 %), and excellent mechanical stability. Furthermore, it allows multiple regeneration processes without losing its sorption capacity. Based on these benefits, Menthol:Thymol (1:1)@Fe3O4-MS shows promise as an efficient, cost-effective, and eco-friendly substitute for the existing sorbents.

Durable superhydrophobic/superoleophilic melamine foam based on biomass-derived porous carbon and multi-walled carbon nanotube for oil/water separation

In the present study, fabrications of two eco-friendly superhydrophobic/superoleophilic recyclable foamy-based adsorbents for oil/water mixture separation were developed. Hierarchically biomass (celery)-derived porous carbon (PC) and multi-walled carbon nanotube (MWCNT) were firstly synthesized and loaded on pristine melamine foam (MF) by the simple dip-coating approach by combining silicone adhesive to create superhydrophobic/superoleophilic, recyclable, and reusable three-dimensional porous structure. The prepared samples have a large specific surface area of 240 m²/g (MWCNT), 1126 m²/g (PC), and good micro-mesoporous frameworks. The water contact angle (WCA) values of the as-prepared foams, PC/MF and MWCNT/MF, not only were 159.34° ± 1.9° and 156.42° ± 1.6°, respectively but also had oil contact angle (OCA) of equal to 0° for a wide range of oils and organic solvents. Therefore, PC/MF and MWCNT/MF exhibited superhydrophobicity and superoleophilicity properties, which can be considered effective adsorbents in oil/water mixture separations. In this context, superhydrophobic/superoleophilic prepared foams for kind of different oils and organic solvents were shown to have superior separation performance ranges of 54-143 g/g and 46-137 g/g for PC/MF and MWCNT/MF, respectively, suggesting a new effective porous material for separating oil spills. Also, outstanding recyclability and reusability of these structures in the ten adsorption-squeezing cycles indicated that the WCA and sorption capacity has not appreciably changed after soaking into acidic (pH = 2) and alkaline (pH = 12) as well as saline (3.5% NaCl) solutions. More importantly, the reusability and chemical durability of the superhydrophobic samples made them good opportunities for use in different harsh conditions for oil-spill cleanup.