Magnetic superhydrophobic melamine sponges for crude oil removal from water

Deep eutectic solvent-induced coacervation in micellar solution of alkyl polyglucoside surfactant: Supramolecular solvent formation and application in food analysis

The number of deep eutectic solvents were investigated to induce coacervation and cause phase separation in the micellar solution of the alkyl polyglucoside C8-C10. Three fatty acids were selected as hydrogen bond donors namely hexanoic acid, heptanoic acid, and octanoic acid, while quaternary ammonium salts and a monoterpenoid thymol were used as hydrogen bond acceptors to obtain deep eutectic solvents. The precursors of the deep eutectic solvents could be incorporated into the micelle structure of alkyl polyglucoside C8-C10 and modulate its properties, improving the interaction with the target compounds and promoting phase separation due to the increasing size of the micellar aggregates. The synergy of green surfactant and deep eutectic solvent has been demonstrated in the determination of capsaicinoids as secondary metabolites retaining the pungency of chili peppers and, thus, of spicy foods. Extraction recoveries were above 75 % for target analytes. The limits of detection were found to be 1.7 μg g -1 for capsaicin and dihydrocapsaicin. The relative recoveries were in the range of 76 -130 %. The research presented is the first example of synergy between alkyl polyglucoside and deep eutectic solvent. The proposed extraction system has the potential to be used in many other analytical tasks, especially in the analysis of solid and heterogeneous samples. Not only fatty acid-based deep eutectic solvents but other based on alcohols, monoterpenoids, etc. can also be used for coacervation. Thus, wide range of already studied deep eutectic solvents could be investigated for this purpose.

Superhydrophobic magnetic melamine sponge modified by flowerlike ZnO and stearic acid using dip coating method for oil and water separation

The increasing occurrence of oil spills and industrial effluents containing oil have heightened the need for effective oil-water separation. This study developed a magnetic superhydrophobic melamine sponge using a dip-coating method with ZnO, stearic acid, and Fe3O4 nanoparticles. Characterization via XRD, FESEM, EDX, FT-IR, AFM, VSM, and water contact angle measurements (160.96˚ ± 0.65˚) revealed its excellent properties. The sponge demonstrated a sorption capacity of 36.12 ± 1.9 to 83.71 ± 2.8 g·g-1 and separation efficiency ranging from 97.82 ± 1.3 to 99.83 ± 1.7%. Its performance in removing oil from real industrial effluent was also evaluated. Additionally, the sponge exhibited reusability and high efficiency in separating emulsified oil droplets. These results highlight the potential of the modified sponge as an effective sorbent for oily wastewater treatment.

Hierarchical 0D CuO Wrapped by Petal-like 2D ZnO: A Strategic Approach of Superhydrophobic Melamine Sponge toward Wastewater Treatment

In addressing the pressing environmental challenges posed by frequent oil spills, this work presents a novel approach of synthesizing a superhydrophobic three-dimensional (3D) porous melamine sponge (MS). CuO and ZnO nanoparticles were grown on the MS via a hydrothermal method to create MS/CuO/ZnO with multiscale hierarchical nanostructures. The resulting material exhibited a stable water contact angle of 155° through various tests. MS/CuO/ZnO demonstrated exceptional oil absorption capacities (40-145 g/g and 0.83-0.99 mL.cm-3), surpassing 98% efficiency in oil separation, and retained reusability for 10 cycles. Impressively, the sponge achieved successful separation of oil/water emulsions with a permeation flux of 14870 L m-2 h-1. The composite sponge, distinguished by its high photodegradation ability, can degrade both water- and oil-targeted pollutants under visible light irradiation from light-emitting diode (LED). With its remarkable attributes including superior oil absorption, excellent oil/water separation, mechanical resistance, and excellent photocatalytic ability, it exhibits considerable potential for applications in both wastewater treatment and large-scale marine oil spill response. The easily prepared MS/CuO/ZnO emerges as a versatile solution capable of addressing pressing challenges and marking a significant leap toward sustainable and impactful environmental remediation.

Superhydrophobic Co-MOF-based sponge for efficient oil-water separation utilizing photothermal effect

Effectively addressing crude oil spills remains a global challenge due to its high viscosity and limited flow characteristics. In this study, we successfully prepared a modified sponge (PCP@MS) by embedding the photothermal material of Co-HHTP and coating the melamine sponge (MS) with low-surface-energy polydimethylsiloxane (PDMS). The PCP@MS exhibited outstanding hydrophobicity with WCA of 160.2° and high oil absorption capacity of 59-107 g/g. The PCP@MS showed high separation efficiency of 99.2% for various oil-water mixtures, along with notable self-cleaning properties and mechanical stability. The internal micro-nano hierarchical structure on the sponge surface significantly enhanced light absorption, synergizing with the photo-thermal conversion properties of Co-HHTP, enabled PCP@MS to achieve a surface temperature of 109.2 °C under 1.0 solar light within 300 s. With the aid of solar radiation, PCP@MS is able to heat up quickly and successfully lowering the viscosity of the surrounding crude oil, resulting in an oil recovery rate of 8.76 g/min. Density functional theory (DFT) calculation results revealed that Co-HHTP featured a zero-gap band structure, rendering advantageous electronic properties for full-wavelength light absorption. This in situ solar-heated absorbent design is poised to advance the practical application of viscous oil spill cleanup and recovery.