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Natural gas hydrates can readily form in deep-water oil production processes and pose a great threat to the oil industry. Moreover, the coexistence of hydrate and asphaltene can result in more severe challenges to subsea flow assurance. In order to study the effects of asphaltene on hydrate growth at the oil–water interface, a series of micro-experiments were conducted in a self-made reactor, where hydrates nucleated and grew on the surface of a water droplet immersed in asphaltene-containing oil. Based on the micro-observations, the shape and growth rate of the hydrate shell formed at the oil–water interface were mainly investigated and the effects of asphaltene on hydrate growth were analyzed. According to the experimental results, the shape of the water droplet and the interfacial area changed significantly after the formation of the hydrate shell when the asphaltene concentration was higher than a certain value. A mechanism related to the reduction of the interfacial tension caused by the absorption of asphaltenes on the interface was proposed for illustration. Moreover, the growth rate of the hydrate shell decreased significantly with the increasing asphaltene concentration under experimental conditions. The conclusions of this paper could provide preliminary insight how asphaltene affect hydrate growth at the oil–water interface.

In this work, robust superhydrophobic cotton fabrics with UV shielding, self-cleaning, photocatalysis, and oil/water separation were successfully prepared based on micro/nano hierarchical ZnO/HNTs (halloysite nanotubes) hybrid particles and silicone elastomer polydimethylsiloxane (PDMS). ZnO/HNTs hybrid particles were prepared by in-situ growth of ZnO nanoparticles on the surface of halloysite nanotubes (HNTs). ZnO/HNTs hybrid particles and PDMS were used to successively coat cotton fabric by dip-coating approach. The coated cotton fabric displayed excellent superhydrophobicity with a water contact angle of 162.5 ± 1° and photocatalytic degradation of methylene blue solution under UV irradiation owing to the roughness and photocatalytic performance provided by micro/nano hierarchical ZnO/HNTs hybrid particles and low surface energy achieved by PDMS. The as-prepared fabric also displayed outstanding self-cleaning and antifouling properties. In addition, due to its both superhydrophobic and superoleophilic characteristics, the as-prepared cotton fabric can be used to separate several oil/water mixtures and showed good recoverability. The superhydrophobic cotton fabric also exhibited excellent UV shielding performance with a large UV protection factor of 1643.28 due to strong ultraviolet-absorption, light scattering and frequent light reflection of ZnO nanoparticles in ZnO/HNTs composites coated on cotton fabric. Importantly, the as-prepared fabric retained superhydrophobic performance after 2000 cycles rubbing, 90h UV illumination, and immersing in acidic and alkali solutions with different pH values ranging from 1 to 14 for 1 h. These characteristics make multifunctional cotton fabrics a satisfactory candidate in various promising fields.

In view of the classical Lucas-Washburn equation, which can only describe the spontaneous imbibition of single wetted capillary, a tilted composite capillary model with circular cross section, composed of different wettability capillary wall was established. The model can describe the spontaneous oil-water imbibition of water-wet capillary, oil-wet capillary and mixed wetting capillary. Through numerical solution of the model equation, it is found that the component content of the capillary walls, the capillary radius and the oil-water viscosity ratio have great effects on the spontaneous oil-water imbibition. Effects of capillary inclination angle and inertia force on spontaneous oil-water imbibition are related to the capillary scale. Effects of capillary inclination angle and inertia force can be ignored in small radius capillary, while effects of inclination angle and inertia force can not be ignored in large radius capillary.

Due to their low oil adhesion and selective oil–water separation, screens with superhydrophilicity and underwater superoleophobicity have attracted significant attention. However, oil–water separation materials with high efficiency and low cost are still urgently in demand. Here, inspired by natural marine mussels, we prepared a self-healing hydrogel-coated screen to achieve highly efficient oil–water separation. Polydopamine (PDA) was incorporated into polyacrylamide (PAM) and uniformly coated on a stainless steel screen to prepare a self-healing hydrogel-coated screen. The results showed that the PDA-PAM hydrogel coating firmly adhered to the stainless steel screen and exhibited superhydrophilicity and underwater superoleophobicity. Regarding the PDA-PAM hydrogel-modified screen with a coating time of 7 min, different types of oil–water mixtures could be driven by gravity to achieve a highly efficient oil–water separation rate of over 97%, and the water flux could reach 91,673 L m−2 h−1. After ten cycles, the separation efficiency did not decrease significantly, suggesting that the self-healing hydrogel-coated screen has excellent stability and recycling performance. This inexpensive novel filter screen with high efficiency has a wide range of potential application in the field of oil–water separation.

The deterioration of water ecology caused by the discharge of oil spill wastewater, industrial sewage, and municipal sewage has attracted wide attention worldwide. Thus, it is significant to design a simple, environmentally friendly approach to separate oil–water mixtures. In this work, three different fabrics with pH-induced wettability transition were prepared by a dip-coating process for oil and water separation. The dip-coating fabrics had the advantages of oil–water separation, photocatalytic degradation, and recycling. Polyethylene terephthalate/polyamide nonwoven fabric was used as the substrate materials of the fabric. The carboxylic acid-modified TiO2 endowed the fabric with hydrophilicity–hydrophobicity and photocatalytic properties. The Fe3O4 nanoparticles obtained by the coprecipitation method provided magnetism for the fabric, facilitating the recycling of the fabric and improving the hydrophobicity of the fabric. The fabrics coated with dipping solutions were superhydrophobic in a neutral environment and hydrophilic in an alkaline environment. Among the three coated fabrics, the fabric coated with stearic acid/TiO2-Fe3O4 (FST) had the most satisfying oil–water separation performance and durability. Under the neutral condition, the contact angle of the FST was 151° and the separation efficiency was 98%. Under the alkaline condition, the underwater oil contact angle of the FST was 150° and the separation efficiency was 95%. After 15 cycles, the oil–water separation rate of the FST was still higher than 90%. Due to the presence of TiO2, the coated fabric had an exceptional performance in the photodegradation of organic pollutants (69.9%). In addition, the fabrics can be quickly recovered due to magnetism.

Статья посвящена исследованию разделения водонефтяных эмульсий. Большинство существующих месторождений находятся на завершающей стадии разработки, что характеризуется ростом обводненности добываемой нефтяной фракции. При наличии высокоустойчивых «застарелых» ловушечных нефтей для повышения эффективности и надежности процессов их обезвоживания используют методы разделения с применением деэмульгаторов. Наибольшее распространение, в настоящее время получили деэмульгаторы неионогенной природы. В работе была оценена эффективность трех деэмульгаторов, соответствующих государственным санитарно-эпидемиологическим правилам и нормативам: Эмалсатрон R2601-A, Химтехно-527, СНПХ-4114. Исследуемые деэмульгаторы успешно прошли испытания и могут быть рекомендованы к промышленному применению, так как обладают рядом преимуществ. The article is devoted to the study of the separation of oil-water emulsions. Most of the existing fields are at the final stage of development, which is characterized by an increase in the water content of the extracted oil fraction. In the presence of highly stable "old" trap oils, separation methods with the use of demulsifiers are used to increase the efficiency and reliability of their dewatering processes. The most widespread, at present, are demulsifiers of a non-ionic nature. The work evaluated the effectiveness of three demulsifiers that comply with state sanitary and epidemiological rules and regulations: Emalsatron R2601-A, Chemtechno-527, SNPH-4114. The studied demulsifiers have been successfully tested and can be recommended for industrial use, as they have a number of advantages.

This study developed a facile and environmentally-friendly method to prepare SiO2/silk fibroin (SF) composite melamine sponges modified using SF and hydrophobic SiO2 nanoparticles (NPs). During the preparation procedure, the SiO2 NPs were bonded to skeletons of porous sponges with the SF binding agent using a dip-coating method. The SiO2 NPs and SF with hydrophobicity constructed a rough surface. The obtained sponges possess a high absorption capacity of 70.9–160.8 times of its weight for various oils and organic solvents and a high water-contact angle greater than 151°. More importantly, the modified sponges showed good recyclability, and could return to its original shape even after 100 cyclic compression. The as-prepared sponge also showed high buoyancy outstanding elasticity, and maintained high absorption capacity even after 10 cycles of repetitive absorption-desorption. The prepared sponges could efficiently separate oil or organic solvents from oil–water mixtures, indicating that the SiO2/SF/MS sponges are promising candidates for remediating oil spills and oily wastewater.

Optical trapping of inorganic nanocrystals at oil/water interfaces was investigated under a loose focus condition. The target nanocrystals were octahedral gold nanoparticles (OGPs, 70 nm in size), ...

A simple, efficient, and economical method was developed to fabricate superhydrophobic surfaces on various substrates, including wood, bamboo, cotton, filter paper, sponge, glass, textile, and copper. This method involves synthesizing a two-component modifier solution consisting of SiO2 nanoparticles combined with poly(methylhydrogen)siloxane (PMHS) modification. The superhydrophobicity of the coated surfaces was created by PMHS combined with SiO2 nanoparticles to construct a rough hierarchical structure on the surface of the substrate. All superhydrophobic surfaces were maintained at a relative humidity of 50% for 30 days in an indoor environment and subsequently, the superhydrophobic surfaces were kept minus 20 °C for 24 h. It was confirmed that these surfaces exhibited excellent self-cleaning, oil/water separation, and elimination of underwater oil properties. The method for fabricating superhydrophobic materials proposed in this study will have great potential to prepare large-scale superhydrophobic surfaces for use in ancient building protection.

CeO2 was synthesized by the co-precipitation method on the Cu mesh substrate and modified the surface of CeO2@Cu mesh by stearic acid (SA). The superhydrophobic behavior was ascribed to the combination of hierarchical micro-nanostructure of CeO2 and the hydrophobic alkyl groups from SA. The SA-CeO2@Cu mesh had antiacid and base stability and excellent durability as well as high separation efficiency. The separation efficiency can be up to 98.0% after separating 30 times.

Tremendous efforts have been exerted to develop effective and ecofriendly materials for separation of oil/water mixtures and emulsions. However, porous materials with superwettability for oil/water separation are usually fabricated from nonrenewable precursors, which contradicts with the concept of green development. Inspired by the cellular porosity and hierarchical organization of wood, biodegradable cut and sawed wood slices with different pore sizes were separately machined by a razor blade and a fine-toothed saw. The cut and sawed slices separately possessed rough single- and double-layer structures. After silylation with MTCS, both machined slices repelled water entirely but allowed the complete permeation of oils. The fragment-free cut slice with relatively large pore size was able to separate immiscible oil/water mixtures, while the fragment-covered sawed slice with relatively small pore size could separate water-in-oil emulsions. Compared with other wood slice by sawing, the section structure and superoleophilic property made the slices have a high oil flux for a series of mixtures and emulsions, which reached 72 kL m−2 h−1 and 464 L m−2 h−1, respectively. The flux was high even after 10 cycles, exhibiting favorable recyclable stability.

A novel cement-alumina coated stainless steel mesh (CA@SSM) was fabricated by a simple, economical and green blade coating route. The superhydrophilic-underwater superoleophobic CA@SSM exhibits hig...

Summary Liquid-liquid phase flow in pipes merits further investigation as a challenging issue that has very rich physics and is faced in everyday applications. It is the main problem challenging the fluid flow mechanism in the oil and gas industry. The pressure gradient of liquid flow and flow pattern are still the topics of numerous research projects. In this paper, the emphasis is on further investigation to research the flow pattern, water holdup (HW), and pressure decrease for vertical, horizontal, and inclined flow directions of oil and water flows. Test section lines of 4.19-in. (106.426 mm) inner diameter (ID) and 5-m horizontal, 5-m inclined, and 5-m vertical test sections were serially connected. The experiments were conducted at 40°C using 2-cp viscosity oil and tap water, and oil density of 850 kg/m3, at the standard conditions. Fifty experiments were executed at 250 kPa at the multiphase flow test facility, with horizontal, upward (0.6° and 4°), downward (−0.6° and −4°) hilly terrain and vertical pipes. The oil and water superficial velocities were changed between 0.03 and 2 m/s. This evidence was obtained using video recordings; the flow patterns were observed, and the selection of each flow pattern was depicted for each condition. For horizontal and inclined flow, new flow patterns were documented (e.g., oil transfer in a line forms at the top of the pipeline, typically at high water rate, and water transfer at the lower part of the pipe at a high oil rate). The data were taken at each flow condition, resulting in new holdup and pressure drop. The results show that the flow rate and the pipe inclination angle have major impacts on the holdup and pressure drop performances. In the vertical flow, a clear peak was demonstrated by experiments after the superficial oil velocity reached a certain value. This peak is known as phase inversion point, where after this peak, the pressure starts declining as the superficial oil velocity increases. Also, slippage has been observed after varying inlet oil flow rates between the two phases. The experiments showed that with minor alteration in the inclination angle, the slippage was significantly changed. This study presented new experimental results (measured mainly at horizontal, inclined, and vertical flow conditions) of HW, flow pattern, and pressure drop. These findings are key evidence of the evolving oil-water and flowline estimate models.

A hydrophobic/oleophilic cotton fabric was prepared based on thiol–ene click reaction. The preparation method was simple, which consists of only two steps. Firstly, self-assembly of 3-mercaptopropy...

The superoleophobic/superhydrophilic material has attracted considerable interest due to the incomparable property of it for the oil-water separation. However, it is a challenge to make the prepared surface superoleophobic and superhydrophilic at the same time since the oleophobic surface tends to repel water. Herein, a hygro-responsive superoleophobic/superhydrophilic coating was fabricated by liquid-phase deposition of TiO2 with perfluorooctanoic acid. The wettability of the coating could complete the transformation from superoleophobicity/superhydrophilicity to superhydrophobicity/superoleophilicity, both of which exhibit excellent selective superwettability under the air, underwater, salt, alkali, and acid conditions. The hygro-responsive coating can separate different types of oil-water mixtures, and the separation efficiency could be over 99% using different capillary forces acting on the oil and water phases before and after wettability transformation. Last but not least, long-chain perfluoroalkyl substances on the coating could be decomposed by UV irradiation, which could reduce the harm to the environment and human beings. It is anticipated that the developed superoleophobic/superhydrophilic coating provides a feasible solution for the application of oil-water separation.

Multiple oily wastewaters are necessary for scientific research and technological development. Experimental oily wastewater is prepared with an in-line high shear mixer at a constant flow rate. Rot...

Stimuli-responsive surfaces with wettability change between superhydrophilic and superhydrophobic are susceptible to oil contamination which often ruins the surface. Herein, a coating with pH-switchable wettability transition between superamphiphobic and superhydrophilic-superoleophobic is achieved by rationally designing oleophobic/pH-responsive polymer heterogeneous chemistry. Fabrics modified with this coating show repellency to both water and oils, while upon exposure to acidic water (pH = 1) the fabrics change to be superhydrophilic-superoleophobic within a short response time of5 s. More importantly, the superamphiphobicity of the fabric can be restored under mild alkaline condition (pH = 10), and the transition is reversible for many cycles. The effective in situ or ex situ wettability change under acidic/alkaline water treatment makes the coated fabric capable of separating oil-water mixture or even some mixtures of immiscible organic solvents. In addition, the coated fabric is also demonstrated to be promising as a new class of functional fabrics that provide protection against water and many oils in one condition, and can change to be hygroscopic, anti-static, oil-repellent and anti-oil-fouling in the other condition for improved wear comfort and self-cleaning.

An increase in the consumption of petroleum products in the transport and energy systems and intensive development of some branches of industry (especially petrochemical industry and oil refining) results in the accumulation of numerous waste in the form of waste oils, oil sludge and other oily liquids. The problem of waste disposal can be solved by using oily liquids as fuel for combustion at thermal power plants in order to produce thermal and electrical energy. To study the rheological characteristics of oil-water-coal emulsions based on anthracite with the solid phase concentration of 40%, an oil phase with the concentration of 49% (motor oils Motul 8100 X-cess 5W-40 and Comma Xtech 5W-30), water (10%) and nonionic surfactant (1%) as an emulsifier-stabilizer. It was found that the rheological characteristics of oil-water-coal emulsions depend not only on the granulometric composition of coal, but also on the viscosity of the dispersed medium (motor oils). Physicochemical and service properties of oil-water-coal systems under consideration allow using them as fuel. Given the availability and relative cheapness of feedstock, this type of fuel can successfully compete with traditional types of liquid fuels.

There has been a growing interest in developing effective strategies to inhibit lipid oxidation in emulsified food products by utilization of natural phenolic antioxidants owing to their growing popularity over the past decades. However, due to the complexity of emulsified systems, the inhibition mechanism of phenolic antioxidants against lipid oxidation is rather complicated and not yet fully understood. In order to highlight the importance of polarity of phenolic antioxidants in emulsified systems according to the polar paradox, this review covers the recent progress on chemical, enzymatic, and chemoenzymatic lipophilization techniques used to modify the polarity of antioxidants. The partitioning behavior of phenolic antioxidants at the oil-water interface, which can be influenced by the presence of synthetic surfactants and/or antioxidant emulsifiers (e.g., polysaccharides, proteins, and phospholipids), is discussed. In addition, the emerging phenolic antioxidants among phenolic acids, flavonoids, tocopherols, and stilbenes applied in food emulsions are elaborated. As well, the interactions of polar-nonpolar antioxidants are stressed as a promising strategy to induce synergistic interactions at oil-water interface for improved oxidative stability of emulsions.

In this research, a modification of polyurethane (PU) sponge material has been made to obtain superhydrophobic-superoleophilic properties. The PU sponge was coated with several nanomaterials such as ZnO, Fe3O4+TEOS, and stearic acid by dip-coating and drop-coating methods. The tests include selective separation of oil and water with a magnetic response. Several types of oil and organic solvents were tested for absorption capacity. The results showed that the PU@ZnO@Fe3O4@SA sponge has a good absorption capacity, from 4.37 mL to 7.37 mL. The fabricated PU sponge could selectively separate oil from water with a separation efficiency above 99%. The fabricated PU sponge also could be magnetically driven by external magnetic fields. From the characterization using 3D OM, the water contact angle was 153.38°, which indicates that the PU@ZnO@Fe3O4@SA sponge is superhydrophobic. And from surface morphology obtained an average pore size diameter of 167.475 μm.

We would like to thank the King Abdullah University of Science and Technology (KAUST) and Saudi Aramco for generous funding to support this project (RGC/3/3577-01-01).

A cotton fabric with special wettability was prepared in two simple steps. The surface of the fabric was grafted with silicon-oxygen group using 3-(methacryloyloxy) propyl trimethoxysilane (MSPMA) as the reagent, and then (3-mercaptopropyl)triethoxysilane (MPTES) was used to react with the grafted fabric under ultraviolet light according to the principle of thiolene reaction. Meanwhile, the modified cotton fabrics with various pore sizes were obtained via modifying the cotton fabric with different pore size under the same experimental conditions. The as-prepared fabric had a better hydrophobic and lipophilic effect, whose water contact angle could be up to 146.7° and the separation efficiency for different kinds of oil/water mixtures was better than 94%. In addition, the pore sizes of cotton fabrics had a great effect on the rate of oil/water separation, which increased with the increase of the pore size.

The process of production of a highly dispersed oil-in-water emulsion in a rotary-cavitation machine was studied. Influence of the key factors (rotor rpm speed and type of surfactant) on the dispersion characteristics of the emulsion was evaluated. Physical aspects of dispersion in a rotary machine were considered. The experimental procedure implemented in a colloidal-cavitation setup was described. Generation of cavitation in this setup, by contrast to rotary-pulsating apparatuses, is due to the presence of numerous grooves rather than of notches on the rotor and stator. Specific features and characteristics of the surfactants used in the experiments were discussed.

This essay considers the unworldly setting of Jean Rolin’s novel Ormuz (2013), composed around the attempt by a shadowy character named Wax to swim across the Strait of Hormuz. This twenty-one-nautical-mile-wide stretch of sea separating Iran from the Arabian Peninsula, through which is shipped 35 percent of the world’s petroleum, is a waterway of the utmost geopolitical importance, its harbors built not for dreamy swimmers but for giant oil tankers and the elaborate maritime-military infrastructure assuring their passage. Such a setting would seem to stand as a bleak other to the novel as genre. Yet if one thinks of the history of the novel as inseparable from that of carbon capitalism (as Amitav Ghosh has argued), such a claim is reversed—this site where powerful strategic interests drive the flow of oil, capital, and power is the place of the continual making and unmaking, by night and day, of the world order, and thereby of the modern novel. The essay reflects on what Wax’s weird wager—as an emblem for a remarkable narrative wager—may owe to such intertexts as Google, Descartes’s Meditations, and Jules Verne’s Tour du monde, and argues for reading Ormuz as an ecological novel for our times.

Present study reports the application potential of a natural down fiber in the fields of oil-water separation and interfacial dye adsorption. The dripping experiment shows that the blue water dropl...

Hypothesis A binary mixture was used during injection with one water-miscible component and the other water-immiscible, which can help particles to migrate toward and then self-assemble at the interface. Experiments The ethanol-tetrachloromethane binary mixture was used to verify the self-assembly method, with the diameter of droplets being about 1 mm. As the ethanol diffused into the colloidal solution, the colloidal particles efficiently moved towards and self-assembled on the oil/water interface, while a colloidal particle film with high-coverage was able to rapidly form on the droplet surface even in an ultra-low concentration colloidal solution. The effects of ethanol concentration and particle concentration on self-assembly were investigated. Findings The driving force for self-assembly originated from the tension gradient generated by ethanol's concentration gradient at the particle/liquid interfaces, where the concentrations of ethanol and the colloidal solution had significant effects on self-assembly. The simulation and calculations results aligned well with experiments, providing the theoretical basis for this self-assembly method. Further, as-prepared magnetic particle-coated droplets transformed into a non-wetting soft solid, which had long lifetimes and could be precisely moved, coalesced, and transferred in various two-dimensional and three-dimensional liquid environments. Thus, wider applications are facilitated, such as droplet transfer, microreactor and other potential fields.

Materials with different wettability features have attracted intensive attention due to their outstanding performances and the broad application prospects. In this work, we report an applicable and...

We evaluated the idea of adding nanoparticles in an aqueous phase to enhance its wetting affinity to siltstone core plugs by conducting dynamic contact-angle experiments and by calculating the tota...

Various types of Enhanced Oil Recovery (EOR) methods have generally been used to recover the residual oil left in the pores after secondary recovery processes. Surfactant flooding has been in use f...

This article provides a perspective review on the use of modified cotton fabrics for oil–water separation. The principles of surface hydrophobicity of cotton fabrics are first described, from which the basis for producing superhydrophobic surfaces is presented. Then the preparation methods to convert hydrophilic cotton fabrics to hydrophobic fabrics are reviewed and discussed. Based on literature results the way to design novel preparation methods, the need to summarize testing protocols, and the comprehensive technoeconomic and sustainability analyses, are proposed. A demonstrative cotton fabrics test is used to reveal the significant role of conjugated fluid flows and surface interactions under different application scenarios for determining the separation efficiency of the oil–water mix.