Preparation of the graphene-based smart hydrophobic nanocomposite and its application in oil/water separation.

Designing and synthesizing materials with smart hydrophobicity against an external magnetic field for efficient oil/water separation is of great importance due to the increasing problems caused by oil pollution. Here, the nanocomposites were fabricated based on graphene and different iron oxides exhibit smart hydrophobicity against an external magnetic field and they are in powder form eliminating the requirement for a substrate employing a facile and echo friendly method. The results prove that autoclaving of graphene leads to its ferromagnetic property; then it is attached to iron oxides by magnetic attraction and a nanocomposite is produced. The magnetic property of the resulting nanocomposite is higher than the magnetic property of its individual components. In addition, following nanocomposite formation, its hydrophobicity and surface area also change. FESEM images were taken from the nanocomposites to study their surface morphology, and EDS-MAP analysis to observe the elemental distribution uniformity of the nanocomposites. Also, to measure the surface area and pore size, BET analysis has been performed on pure materials and graphene-black iron oxide nanocomposite (graphene@black iron oxide). The results show that the specific surface area of black iron oxide increases after being composited with graphene dispersed at 5000 rpm. Indeed, graphene forms a composite by binding to iron oxide, and therefore, its specific surface area increases compared to iron oxide and graphene alone. These results show an increase in oil sorption and better separation of oil from water by the prepared nanocomposite. Also, to measure the magnetic properties of pure materials, graphene@black iron oxide, and ferromagnetic graphene at 3000 and 5000 rpm, the Vibrating Sample Magnetometer analysis has been performed. The results have proven that the nanocomposite powder prepared by a simple method obtained from cost-effective and available materials is hydrophobic and becomes more hydrophobic by applying an external magnetic field. Due to the ease with which oil can be readily removed from the nanocomposite by eliminating the external magnetic field, this nanocomposite is an excellent choice for the separation of oil from water.

Scalable, Green, and Cost-Effective Carbonized Sand for Efficient Solar Desalination.

Nowadays, sweet and drinkable water shortage is a global issue which has attracted widespread attention. Desalination of seawater as the greatest source of water on our planet using solar energy as the most abundant and green energy source for producing fresh water can help us address this issue. Interfacial solar desalination is a state-of-the-art, sustainable, green, and energy-efficient method that has been studied lately. One of the key parameters for researching this method with reasonable efficiency is a photothermal material. Herein, carbon-coated sand was synthesized using abundant, green, and low-cost materials (sand and sugar), and its performance as a photothermal material is investigated and reported. In this work, a three-dimensional (3D) system is introduced to develop the performance and efficiency of the system under real sun irradiation and natural circumstances. The salt rejection ability of the system is another important thing we should notice due to the high salinity of seawater that we want to desalinate. The superhydrophilic carbonized sand demonstrated a good evaporation rate of 1.53 kg/m2h and 82% efficiency under 1 sun irradiation and upright salt rejection ability, which exhibited its capability to be used in green solar-driven water vaporization technology for sweet water production. The effects of important parameters, including light intensity, wind speed, and environment temperature, on the evaporation rate using carbonized sand as a solar collector in a solar desalination system were studied in both laboratory and real systems.

Fast Capture, Collection, and Targeted Transfer of Underwater Gas Bubbles Using Janus-Faced Carbon Cloth Prepared by a Novel and Simple Strategy.

Transportation of bubbles in liquids in a controlled fashion is a challenging task and an important subject in numerous industrial processes, including elimination of corrosive gas bubbles in fluid transportation pipes, water electrolysis, reactions between gases, heat transfer, etc. Using superaerophilic surfaces represents a promising solution for bubble movement in a programmed way. Here, a novel and low-cost method is introduced for the preparation of Janus-faced carbon cloth (Janus-CC) using poly(dimethylsiloxane) (PDMS) coating and then burning one side of the carbon cloth/PDMS on an alcoholic burner. The results show that the superhydrophobic face behaves as a superaerophilic surface, while the superhydrophilic side is aerophobic underwater. Subsequently, the Janus-CC is applied for pumpless transport of underwater gas bubbles even under harsh conditions. The movement of gas bubbles on the surface of the Janus-CC is interpreted based on the formed gaseous film on the aerophilic side of the Janus-CC. Various applications of the prepared Janus-CC for underwater bubble transportation, such as underwater gas distributor, gas collector membrane, gas transport for chemical reactions, unidirectional gas membrane, and elimination of gas bubbles in transport pipe, are presented.

Catalytic synthesis of new pyrazolo [3,4-b] pyridine via a cooperative vinylogous anomeric-based oxidation.

In this study, a novel nano-magnetic metal-organic frameworks based on Fe3O4 namely Fe3O4@MIL-101(Cr)-N(CH2PO3)2 was synthesized and fully characterized. The prepared sample was used as catalyst in the synthesis of pyrazolo [3,4-b] pyridines as convenient medicine by condensation reaction of aldehydes, 5-(1H-Indol-3-yl)- 2H-pyrazol-3-ylamine and 3-(cyanoacetyl)indole via a CVABO. The products were obtained with high yields at 100 °C and under solvent-free conditions.

Preparation of Polycarbonate-ZnO Nanocomposite Films: Surface Investigation after UV Irradiation.

Polycarbonate (PC)-ZnO films with different percentages of ZnO were prepared by a solution stirring technique and subjected to ultraviolet (UV; λ = 254 nm) irradiation. Structural parameters of the samples and the effects of UV irradiation on the surface properties of the PC and PC-ZnO nanocomposites were evaluated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle (WCA) measurements, and a Vickers microhardness (HV) tester. The XRD patterns of the nanocomposite films were found to show an increase in crystallinity with the increasing ZnO nanoparticles percentage. The WCA was found to be reduced from 90° to 17° after 15 h of UV irradiation, which could be ascribed to the oxidation of the surface of the samples during the irradiation and exposure of the ZnO nanoparticles, a result that is also supported by the obtained XPS data. The microhardness value of the PC-ZnO films including 30 wt.% ZnO enhanced considerably after UV radiation, which can also be attributed to the exposition of the ZnO nanoparticles after photodegradation of the PC superficial layer of the nanocomposite films.

Hybrid superhydrophobic/hydrophilic patterns deposited on glass by laser-induced forward transfer method for efficient water harvesting.

In recent years, the combination of factors such as growing population and global climate change has resulted in freshwater shortages. Therefore, water harvesting from the atmospheric fog in order to produce freshwater supply inspired by nature has received much attention. The water harvesting capability of the creatures is significantly based on the combination of both wettability states on their surfaces. In this study, a facile physicochemical hybrid method was used for the fabrication of glass surfaces with contrast wettability. First, fractal and regular repeated geometric patterns were deposited on a glass substrate using brass sheet as donor material by laser induced forward transfer (LIFT) method. Subsequently, stearic acid (SA) treatment was used to convert the wettability of the superhydrophilic (SHL) deposited patterns on glass to superhydrophobic. In order to investigate the effect of the shape of designed patterns on glass surfaces in the water harvesting efficiency, the amount of collected water for a period of time from untreated hydrophilic (HL) glass, superhydrophobic (SHB) glass and hybrid superhydrophobic/hydrophilic (SHB-HL) surfaces were measured. The obtained results indicate that the hybrid of superhydrophobic and hydrophilic regions and selecting the optimal pattern can improve the water harvesting performance by up to 300%.

A magnetic porous organic polymer: catalytic application in the synthesis of hybrid pyridines with indole, triazole and sulfonamide moieties.

Herein, the synthesis and characterization of a triazine-based magnetic ionic porous organic polymer are reported. The structure, morphology, and components of the prepared structure have been investigated with several spectroscopic and microscopic techniques such as FT-IR, EDX, elemental mapping, TGA/DTA, SEM, TEM, VSM, and BET analysis. Also, catalytic application of the prepared triazine-based magnetic ionic porous organic polymer was investigated for the synthesis of hybrid pyridine derivatives bearing indole, triazole and sulfonamide groups. Furthermore, the prepared hybrid pyridine systems were characterized by FT-IR, 1H NMR, 13C NMR and mass analysis. A cooperative vinylogous anomeric-based oxidation pathway was suggested for the synthesis of target molecules.

Synthesis of triarylpyridines with sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation.

Herein, novel magnetic nanoparticles with pyridinium bridges namely Fe3O4@SiO2@PCLH-TFA through a multi-step pathway were designed and synthesized. The desired catalyst and its corresponding precursors were characterized with different techniques such as Fourier transform infrared (FT-IR) spectroscopy, 1H NMR, 13C NMR, Mass spectroscopy, energy dispersive X-ray (EDX) analysis, thermogravimetric/derivative thermogravimetry (TG/DTG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). In addition, the catalytic application of the prepared catalyst in the synthesis of new series of triarylpyridines bearing sulfonate and sulfonamide moieties via a cooperative vinylogous anomeric-based oxidation was highlighted. The current trend revealed that the mentioned catalyst shows high recoverability in the reported synthesis.

Naturally Abundant Green Moss for Highly Efficient Solar Thermal Generation of Clean Water.

Water and energy scarcity are the challenges for humankind in the coming years. Sun is the largest source of energy available on the planet. Also, brackish seawater covers more than 70% of the surface of the planet. Therefore, combining these two valuable natural resources represents an appealing solution to overcome the problem of sweet water shortage. To achieve this goal, the missing link is to develop appropriate photothermal materials with efficient light-to-heat-to-vapor generation. In this work, green moss is introduced as a natural, eco-friendly, abundant, superhydrophilic, fast water transporter, salt rejector, and highly efficient solar collector material. Green moss, owing to its open-microgrooves, can supply adequate water to the evaporation surface, while its open capillary channels can reject the precipitated salt, allowing its reusability. The green moss solar steam generator demonstrated an outstanding solar evaporation rate of 2.61 kg m-2 h-1 under 1 sun illumination, which is much higher than other reported natural and chemically modified biomasses under otherwise similar conditions. Interestingly, upon chemical modification of the green moss surface, it is possible to increase its solar evaporation rate to >3 kg m-2 h-1. Using the moss to purify and desalinate brackish water, it was demonstrated that it has the ability to decrease salinity below the WHO standards for drinkable water.

Facile Approach to Conductive Polymer Microelectrodes for Flexible Electronics.

Conductive polymers have been intensively investigated as materials for electrodes in flexible electronics due to their favorable biocompatibility and reliable electrochemical stability. Nevertheless, patterning of conductive polymers for the fabrication of devices and in various electronics applications confronts multifarious limitations and challenges. Here, we present a simple but efficient strategy to obtain conductive polymer microelectrodes via utilization of surface-tension-confined liquid patterns. This method shows universality for various oxidizers and conductive polymers, high resolution, stability, and favorable compatibility with different surfaces and materials. The developed method has been demonstrated for creating conductive polymer microelectrodes with a customized reaction process, defined geometry, and flexible substrates. The obtained microelectrodes were assembled into flexible capacitive sensors. Thus, the method realizes a facile approach to conductive polymer microelectrodes for flexible electronics, biomedical applications, human activity monitors, and electronic skin.

Elemental Sulfur-Stabilized Liquid Marbles: Properties and Applications.

Sulfur-stabilized liquid marbles were readily prepared by rolling water droplets on a sulfur (S8) powder bed. Because of the construction of a gel layer on the surface of liquid marbles, the resulting liquid marbles have shape-designable characteristics. The effects of rolling time and volume of droplets on the deformability of sulfur-stabilized liquid marbles were investigated along with their mechanical stability and lifetime. The capability of sulfur-stabilized liquid marbles to be deformed at different pH values enables these liquid marbles to act as microreservoirs with desired shapes for aqueous solutions. Immersing the sulfur-stabilized liquid marbles into organic liquids leads to an increase in the liquid marbles' lifetime, and thereby they can survive at the interface of aqueous-organic two-phased systems for a long time. Finally, the applications of sulfur-stabilized liquid marbles as photocatalytic microreactors, electrochemical microcells, and monodisperse Pickering-like emulsions were demonstrated.

A Sharp Jump in Photocatalytic Activity of Elemental Sulfur for Dye Degradation in Alkaline Solution.

Elemental sulfur is a low-cost and abundant substance as one of the largest by-products of the oil industry which was widely used in many industrial activities. Cyclo-octasulfur (S8 ) is one of the sulfur allotropes that is a very stable substance in standard conditions. In this study, we report a low-cost and fast method for the degradation of methyl violet in water under visible light and also sunlight by using elemental sulfur (S8 ). The results show that sulfur is a good photocatalyst which operates under visible light and can be utilized for degradation of methyl violet. The photocatalytic degradation of methyl violet in acidic, neutral, and alkaline media was investigated, and it was found that the photocatalytic efficiency increases dramatically in alkaline solution. The effects of the initial concentration of the dye, photocatalyst dosage, solution pH, and photocatalyst reusability were investigated. The kinetics of the reaction were studied in detail, and the photocatalytic rate equation was presented.

Laser-assisted preparation of Pd nanoparticles on carbon cloth for the degradation of environmental pollutants in aqueous medium.

Laser ablation in liquid (LAL), one of the attractive methods for fabrication of nanoparticles, was used for the modification of carbon cloth (CC) by deposition of palladium nanoparticles (Pd NPs); a simple stirring method was deployed to deposit Pd NPs on the CC surface. Characterization techniques viz X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) were applied to study the surface of the ensuing samples which confirmed that LAL technique managed to fabricate and deposit the Pd NPs on the surface of CC. In addition, the catalytic prowess of the carbon cloth-Pd NPs (CC/Pd NPs) was investigated in the NaBH4- or HCOOH-assisted reduction of assorted environmental pollutants in aqueous medium namely hexavalent chromium [Cr(VI)], 4-nitrophenol (4-NP), congo red (CR) and methylene blue (MB). The CC/Pd NPs system has advantages such as high stability/sustainability, high catalytic performance and easy reusability.

Extractive desulfurization of liquid fuel using diamine-terminated polyethylene glycol as a very low vapour pressure and green molecular solvent.

Removal of sulfur compounds from liquid fuel is one of the important issues in the field of energy and environment. Among the available methods, extractive desulfurization (EDS) is of great interest due to its convenient operating conditions. In this study, EDS performance of 4,7,10-trioxatridecane-1,13-diamine (TTD), a very low vapour pressure diamine-terminated oligomeric polyethylene glycol (PEG), was studied. Effect of the influencing factors, as well as multiple extraction, mutual solubility, reusability and regeneration of TTD were investigated. Results showed that the TTD/fuel volume ratio of 0.5 could extract benzothiophene, dibenzothiophene and dimethyl dibenzothiophene with the efficiencies 67%, 74% and 53%, respectively, in less than 1 min at ambient temperature. The distribution coefficient (KN ) value for removal of dibenzothiophene by TTD was 3.66 higher than that of PEG, and it is similar to KN values (approx. 4) for polyethylene glycol dimethyl ether (as a modified PEG) and Lewis acid-containing ionic liquids. It was observed that spent TTD after five cycles could be regenerated using the back-extraction method. Also, deep EDS was achievable after three times extraction using fresh TTD. Finally, the extraction mechanism was studied using 1H-NMR. These observations, as well as very low vapour pressure and insignificant dependency of TTD on the initial S-concentration of fuel and temperature, make this extractant to be introduced as a valuable option for green and effective EDS.

Shape-Designable Liquid Marbles Stabilized by Gel Layer.

Shape-designable liquid marbles were simply prepared by rolling the water droplets over the stearic acid powder for several seconds to encapsulate them. The effects of droplet volume, pH, and rolling time on the deformability of liquid marbles from sphere were investigated. The stearic acid-stabilized liquid marbles can be deformed to any desirable and stable shapes including ellipsoids and letters, thanks to the gel layer formed at liquid marble surfaces during the preparation. The gel layer works as a flexible and plastic membrane, which makes the liquid marbles irreversibly deformable. Finally, the applications of the liquid marbles as a microreactor were demonstrated.

Alginate-Based Hydrogel Beads as a Biocompatible and Efficient Adsorbent for Dye Removal from Aqueous Solutions.

In this study, sodium alginate was employed as a starting material for preparing two kinds of biocompatible adsorbents, including calcium alginate hydrogel beads and magnetic hydrogel beads. Fourier transform infrared spectroscopy, X-ray diffraction pattern, and scanning electron microscopy/energy-dispersive X-ray techniques were used to characterize the prepared adsorbents. The performance of the prepared adsorbents for the removal of methyl violet from aqueous solution was studied in detail. Both kinetics and equilibrium aspects of methyl violet adsorption were investigated, and the obtained equilibrium and kinetics data were described with various adsorption models. The effects of initial dye concentration, adsorbent dosage, and temperature on adsorption performance were investigated. Thermodynamic parameters of adsorption were obtained as well.

Nanoporous Carbon Derived from MOF-5: A Superadsorbent for Copper Ions.

In this work, nanoporous carbon (NPC) was synthesized by direct carbonization of MOF-5 (a famous metal-organic framework). The structure and morphology of the prepared MOF-derived nanoporous carbon (MOF-NPC) were investigated by X-ray diffraction, N2 adsorption/desorption isotherm, Raman spectroscopy, thermogravimetric analysis, and scanning electron microscopy methods. The MOF-NPC was then used to adsorb copper ions from aqueous solutions. To evaluate the performance of the prepared MOF-NPC to remove copper ions, both adsorption kinetics and adsorption equilibrium experiments were carried out and then the obtained data were modeled with various models. Also, the efficacy of temperature and the pH of the solution on the removal efficiency were checked. The results show that the prepared MOF-NPC is a superadsorbent for the removal of copper ions from aqueous solutions. Finally, the removal percentage of copper ions by the prepared MOF-NPC was compared with other activated carbon adsorbents to show its incredible efficiency.

Fabrication of an Oil Spill Collector Package by Using Polyurethane Foam Wrapped with Superhydrophobic ZnO Microrods/Carbon Cloth.

A new package, including polyurethane foam wrapped with superhydrophobic ZnO microrods/carbon cloth with long-life elasticity, was fabricated and was utilized for oil spill clean-up. First, the carbon cloth (CC) was coated with ZnO microrods, which were modified with stearic acid (SA) to obtain superhydrophobic and superoleophilic properties. The coating process was conducted in mild conditions, involving the hydrothermal growth of ZnO microrods on the surface of the carbon cloth. The obtained hydrophobic sample was modified to a superhydrophobic one by adsorption of stearic acid (SA) on its surface. The prepared sample (CC/ZnO/SA) was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), and contact angle measurements. The prepared sample shows a water contact angle (WCA) of 160°. A piece of polyurethane foam was wrapped with the prepared superhydrophobic CC/ZnO/SA making an oil collecting package, which can float on the water surface and absorb various oils from the water surface in both static and turbulent conditions very quickly. The prepared package exhibits excellent mechanical robustness and can be used several times for oil/water separation without capacity decrease. The kinetics of oil spill absorption by the prepared package were studied, too.

Effect of spacer length on the interfacial behavior of N,N'-bis(dimethylalkyl)-α,ω-alkanediammonium dibromide gemini surfactants in the absence and presence of ZnO nanoparticles.

In this paper the interfacial behavior of aqueous solutions of cationic gemini surfactants of the, N,N'-bis(dimethylalkyl)-α,ω-alkanediammoniumdibromide type (known as the 12-s-12 series), in the absence and presence of ZnO nanoparticles was studied. Equilibrium and dynamic interfacial tension between n-decane and aqueous surfactant solutions were investigated. It was concluded that the synergistic effect between surfactants and nanoparticles increases the surfactant efficiency with respect to reducing the interfacial tension. Moreover, the magnitude of the effect of ZnO nanoparticles on the interfacial tension decreases with increasing length of the spacer group in the gemini surfactant structure. Dynamic studies illustrate that the migration mechanism of gemini surfactants (regardless of the presence of ZnO) from the bulk to the interface was controlled by both diffusion and adsorption. The effect of spacer length on the contact angle and emulsion stability both with and without nanoparticles was also studied.

Synthesis of a Novel Highly Oleophilic and Highly Hydrophobic Sponge for Rapid Oil Spill Cleanup.

A highly hydrophobic and highly oleophilic sponge was synthesized by simple vapor-phase deposition followed by polymerization of polypyrrole followed by modification with palmitic acid. The prepared sponge shows high absorption capacity in the field of separation and removal of different oil spills from water surface and was able to emulsify oil/water mixtures. The sponge can be compressed repeatedly without collapsing. Therefore, absorbed oils can be readily collected by simple mechanical squeezing of the sponge. The prepared hydrophobic sponge can collect oil from water in both static and turbulent conditions. The proposed method is simple and low cost for the manufacture of highly oleophilic and highly hydrophobic sponges, which can be successfully used for effective oil-spill cleanup and water filtration.