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Membrane technology has become a promising solution for a wide range of separation processes, including wastewater treatment, solvent recovery, and oil–water separation, due to its low energy consumption, cost-effectiveness, and minimal space needs. However, membrane damage caused by suspended pollutants or improper handling remains a challenge, often leading to decreased filtration capability and the need for replacement of membrane modules. Self-repairing membranes have emerged as a new solution, with various materials demonstrating autonomous healing properties through dynamic bonds such as hydrogen bonds or boronic ester bonds. However, many of these self-repairing membranes suffer from excessive swelling in water, compromising their mechanical stability. Herein, we report a self-repairing and low-swelling polymer network based on dopamine acrylamide (DA) and n-butyl acrylate (BA), crosslinked with p-phenylenediboronic acid (PDBA). The boronic ester bond formation between catechol and boronic acid groups confers self-healing properties to the polymer, while the hydrophobic nature of BA minimizes swelling in water. The polymer exhibits a low swelling ratio of 2.1% after 7 days of submersion in water. A cellulose-based filter paper coated with the polymer demonstrated that it can recover its water flux up to 91% after repairing damage. Lastly, an ultrafiltration polyethersulfone (PES)-based filter coated with the polymer demonstrated that it recovers its solute rejection capability after repairing damage. 

Understanding the wetting properties of shale reservoirs can benefit their development for energy-related purposes and their potential for long-term carbon dioxide injection and storage. Given its potential volumetric abundance and high surface area, the wetting behavior of kerogen in shale requires assessment. Despite their known limitations, wettability studies are commonly limited to static contact angle (θ) measurements. In this Article, the conflicting factors related to the analysis and interpretation of kerogen wetting via static contact angle measurements are discussed. Contact angle data for deionized water, brine (5% NaCl), and n-dodecane are presented for seven paleomarine type-II kerogens spanning a wide range of thermal maturities (vitrinite reflectance, Ro: 0.55 to 2.75%) and chemical composition (aromatic carbon content, H/C ratio, O/C ratio). Droplets of n-dodecane instantaneously absorbed (θ* ≈ 0°) upon contact with all kerogen pellet surfaces, showing the oleophilic nature of kerogen for all maturities tested. Apparent contact angles of water with kerogen surfaces were positively correlated with H/C ratios and inversely correlated with aromatic carbon content, while the bulk and surface oxygen concentrations did not strongly correlate with the measured data. Kerogen exhibited hydrophobic (θwater > 90°) behavior, except at the highest thermal maturities. For example, the least thermally mature and most thermally mature samples studied presented apparent contact angles for water of 123 ± 15 and 59 ± 10°, respectively. Profilometry analyses showed roughness average values ranging from 0.4 ± 0.1 to 3.9 ± 0.7 μm, with the indication that sample topology can affect measured contact angles, albeit in second order as compared to sample chemistry in this study. We recommend caution when associating contact angle data alone with wetting behavior, as data obtained through sessile droplet analysis are subject to known but not always considered, caveats. 

Abstract This study reports the superior performance of graphene nanosheet (GNS) materials over Vulcan XC incorporated as a cathode catalyst in Li–O2 battery. The GNSs employed were synthesized from a novel, eco-friendly, and cost-effective technique involving chamber detonation of oxygen (O2) and acetylene (C2H2) precursors. Two GNS catalysts i.e., GNS-1 and GNS-2 fabricated with 0.3 and 0.5 O2/C2H2 precursor molar ratios, respectively, were utilized in this study. Specific surface area (SSA) analysis revealed significantly higher SSA and total pore volume for GNS-1 (180 m2 g−1, 0.505 cm3 g−1) as compared with GNS-2 (19 m2 g−1, 0.041 cm3 g−1). GNS-1 exhibited the highest discharge capacity (4.37 Ah g-1) and superior cycling stability compared with GNS-2 and Vulcan XC. Moreover, GNS-1 demonstrated promising performance at higher current densities (0.2 and 0.3 mA cm−2) and with various organic electrolytes. The superior performance of GNS-1 can be ascribed to its higher mesopore volume, SSA, and optimum wettability compared to its counterparts. 

Separating oil-water mixtures is critical in a variety of practical applications, including the treatment of industrial wastewater, oil spill cleanups, as well as the purification of petroleum products. Among various methodologies that have been utilized, membranes are the most attractive technology for separating oil-water emulsions. In recent years, selective wettability membranes have attracted particular attention for oil-water separations. The membrane surfaces with hydrophilic and in-air oleophobic wettability have demonstrated enhanced effectiveness for oil-water separations in comparison with underwater oleophobic membranes. However, developing a hydrophilic and in-air oleophobic surface for a membrane is not a trivial task. The coating delamination process is a critical challenge when applying these membranes for separations. Inspired by the above, in this study we utilize poly(ethylene glycol)diacrylate (PEGDA) and 1H,1H,2H,2H-heptadecafluorodecyl acrylate (F-acrylate) to fabricate a hydrophilic and in-air oleophobic coating on a filter. We utilize methacryloxypropyl trimethoxysilane (MEMO) as an adhesion promoter to enhance the adhesion of the coating to the filter. The filter demonstrates robust oil repellency preventing oil adhesion and oil fouling. Utilizing the filter, gravity-driven and continuous separations of surfactant-stabilized oil-water emulsions are demonstrated. Finally, we demonstrate that the filter can be reused multiple times upon rinsing for further oil-water separations. 

Per- and polyfluoroalkyl substances (PFAS) have been extensively utilized in practical applications that include surfactants, lubricants, and firefighting foams due to their thermal stability and chemical inertness. Recent studies have revealed that PFAS were detected in groundwater and even drinking water systems which can cause severe environmental and health issues. While adsorbents with a large specific surface area have demonstrated effective removal of PFAS from water, their capability in desorbing the retained PFAS has been often neglected despite its critical role in regeneration for reuse. Further, they have demonstrated a relatively lower adsorption capacity for PFAS with a short fluoroalkyl chain length. To overcome these limitations, electric field-aided adsorption has been explored. In this work, reversible adsorption and desorption of PFAS dissolved in water upon alternating voltage is reported. An inexpensive graphite adsorbent is fabricated by using a simple press resulting in a mesoporous structure with a BET surface area of 132.9 ± 10.0 m 2 g −1 . Electric field-aided adsorption and desorption experiments are conducted by using a custom-made cell consisting of two graphite electrodes placed in parallel in a polydimethylsiloxane container. Unlike the conventional sorption process, a graphite electrode exhibits a higher adsorption capacity for PFAS with a short fluoroalkyl chain (perfluoropentanoic acid, PFPA) in comparison to that with a long fluoroalkyl chain (perfluorooctanoic acid, PFOA). Upon alternating the voltage to a negative value, the retained PFPA or PFOA is released into the surrounding water. Finally, we engineered a device module mounted on a gravity-assisted apparatus to demonstrate electrosorption of PFAS and collection of high purity water. 

Abstract Membrane-based separation technologies are attractive to remediating unconventional water sources, including brackish, industrial, and municipal wastewater, due to their versatility and relatively high energy efficiency. However, membrane fouling by dissolved or suspended organic substances remains a primary challenge which can result in an irreversible decline of the permeate flux. To overcome this, membranes have been incorporated with photocatalytic materials that can degrade these organic substances deposited on the surface upon light illumination. While such photocatalytic membranes have demonstrated that they can recover their inherent permeability, less information is known about the effect of photocatalysis on the kinetics of the permeate flux. In this work, a photocatalytic mesh that can selectively permeate water while repelling oil was fabricated by coating a mixture of nitrogen-doped TiO₂(N-TiO₂) and perfluorosilane-grafted SiO₂(F-SiO₂) nanoparticles on a stainless steel mesh. Utilizing the photocatalytic mesh, the time-dependent evolution of the water-rich permeate flux as a result of photocatalytic degradation of the oil was studied under the visible light illumination. A mathematical model was developed that can relate the photocatalytic degradation of the organic substances deposited on a mesh surface to the evolution of the permeate flux. This model was established by integrating the Langmuir–Hinshelwood kinetics for photocatalysis and the Cassie–Baxter wettability analysis on a chemically heterogeneous mesh surface into a permeate flux relation. Consequently, the time-dependent water-rich permeate flux values are compared with those predicted by using the model. It is found that the model can predict the evolution of the water-rich permeate flux with a goodness of fit of 0.92. 

Membrane-based separation technologies are the cornerstone of remediating unconventional water sources, including brackish and industrial or municipal wastewater, as they are relatively energy-efficient and versatile. However, membrane fouling by dissolved and suspended substances in the feed stream remains a primary challenge that currently prevents these membranes from being used in real practices. Thus, we directly address this challenge by applying a superhydrophilic and oleophobic coating to a commercial membrane surface which can be utilized to separate and desalinate an oil and saline water mixture, in addition to photocatalytically degrading the organic substances. We fabricated the photocatalytic membrane by coating a commercial membrane with an ultraviolet (UV) light-curable adhesive. Then, we sprayed it with a mixture of photocatalytic nitrogen-doped titania (N-TiO2) and perfluoro silane-grafted silica (F-SiO2) nanoparticles. The membrane was placed under a UV light, which resulted in a chemically heterogeneous surface with intercalating high and low surface energy regions (i.e., N-TiO2 and F-SiO2, respectively) that were securely bound to the commercial membrane surface. We demonstrated that the coated membrane could be utilized for continuous separation and desalination of an oil–saline water mixture and for simultaneous photocatalytic degradation of the organic substances adsorbed on the membrane surface upon visible light irradiation.