Water Emulsion Research Articles

Robust and durable hydrophobic sustainable and eco-friendly bio-based polybenzoxazine coated cotton fabric/paper for effective oil–water emulsion separation and self-cleaning applications

Robust and durable hydrophobic sustainable and eco-friendly bio-based polybenzoxazine coated cotton fabric/paper for effective oil–water emulsion separation and self-cleaning applications

Simultaneous use of disulphide oil for chemical‐enhanced oil recovery by emulsion formation and stability with asphaltene deposition control

AbstractDisulphide oil (DSO) is a by‐product of oil and gas refining processes that is generated during the removal of mercaptans and the sweetening of light hydrocarbons. Asphalt deposition, especially asphaltene deposition during enhanced oil recovery methods, reduces oil recovery from the reservoir, so the use of a substance such as DSO, which has the ability to control and reduce asphaltene deposition, can be effective in increasing oil recovery from the reservoir. In this research, a micromodel with a fracture design and a matrix that represents fracture reservoirs was utilized. These tests were conducted in two groups. The first group of tests is related to adding DSO to crude oil and using 70 to 30 vol.% oil–water emulsion containing salt, surfactant, and nanoparticles. The second group involved adding DSO to both crude oil and emulsion. The first group aimed at stimulation and the second group aimed at chemical enhanced oil recovery (C‐EOR). The formation and stability of water‐in‐oil emulsion was done by analyzing the average droplet size. As a result, in the first group of tests with the presence of DSO in the oil, by measuring the average diameter before and after injection of AOS surfactant, it was observed that the average droplet size decreased from 6.89 to 4.01 μm, which indicates an increase in the emulsion stability. In the second group, where DSO was present in both oil and water emulsion in injected oil, it can be seen that the average diameter of the droplets in the surfactant decreased from 5.12 to 3.21 μm.

Coalescence Frequency in O/W Emulsions: Comparisons of Experiments with Models.

We have studied the coalescence of oil in water emulsions under the influence of gravity. The emulsions were made with alkane oils and surfactants with varying physical chemistry. We chose cationic alkyl trimethylammonium bromides of different chain lengths and nonionic surfactants of ethylene oxide and sugar head groups, including polymeric surfactants. We observed phase separation in two steps. Creaming of the oil drops is followed by their rapid coalescence, increasing the average drop size and resulting in complete surfactant surface coverage of the interfaces. Full phase separation occurs after much longer times Tc when the emulsion drops coalesce dramatically. We have used a model by Dinh et al. to relate Tc to the coalescence frequency and hence to the activation energy for the rupture of the films between two neighboring drops. Our results support the view that the coalescence of stable emulsions (stable at least for a few hours) is a thermally activated process and is controlled by the surface compression elastic modulus. This modulus was determined using surface tension measurements and calculations using the Gibbs adsorption equation. The observed differences between ionic and nonionic systems are attributed to a two-step film rupture process in the case of ionic surfactants, which is not found in nonionic systems.

Polydopamine-incorporated MOF membrane with hydrophilicity for effective oil/water separation and fouling-resistant model analysis and prediction

A large number of oil spills and oily wastewater are discharged, in the modern industrial production process, resulting in serious water pollution. Oily wastewater can be extremely harmful to ecosystems and human health. Oil-water separation has become a major challenge at present, and membrane separation has aroused more and more concern in recent years due to its high economic efficiency. This paper fabricated PES filtration membranes using the novel nanoparticlesbased on both metal–organic frameworks-5 (MOF-5) and polydopamine (PDA) layers as dopants, and then adequately explored the porosity, morphology, separation, hydrophilicity, and fouling-resistant performance of the resultant membranes. In addition, the prepared membranes were used for oil–water separation, including soybean-in-water, petroleum ether-in-water, and gasoline-in-water emulsions. MOF@PDA membranes exhibit high separation efficiency of up to 99.8%. Subsequently, membrane fouling mechanisms were investigated using the Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and the molecular mode of interaction with the three oil–water emulsions with the membrane was compared. Newly prepared MOF@PDA membranes have better stability, fouling-resistant, and self-cleaning properties. Finally, an optimal machine learning model for oil–water separation efficiency was developed with a high prediction accuracy of 98%. The obtained results indicate that mixed matrix membranes exhibit excellent oil–water separation performance, demonstrating great application prospects in the remediation of oily wastewater.

Photopolymerization enabled in-air highly oleophobic and hydrophilic SiC membranes with improved antifouling performance in oil-in-water emulsion separation

Ceramic membranes with tailored surface wettability have gained increasing attention for improving their separation efficiency and antifouling ability, while most of the previous work focused on the underwater oleophobic behavior. In this work, in-air highly oleophobic and hydrophilic SiC membranes were achieved through the UV irradiation triggered polymerization and controlled crosslinking between oleophobic perfluorodecyl acrylate (TFOA) and hydrophilic methacrylic acid (MAA). These key processing parameters including MAA content, soaking time and irradiation duration were systematically studied through examining the changes in porous microstructure, surface wettability and separation performance in oil-in-water emulsion. Results showed that the flux attenuation rate of SiC membranes can be effectively reduced by regulating the content of hydrophilic components. Due to the alternation of the surface wettability to highly oleophobic in air, the oil droplets can hardly attach on the surface of modified SiC membranes at the beginning of filtration process, and the membrane fouling was significantly slow down yet dominated by the intermediate blocking. Correspondingly, a combined cleaning procedure was proposed to regenerate the fouled SiC membranes. Further, the antifouling ability of modified and original SiC membranes was comparatively studied under the conditions of a fixed permeate volume (15 ml) and various oil concentrations (200 ∼ 1000 ppm) in the separation of oil-in-water emulsion. The advantages of modified SiC membranes become more notable when used for highly concentrated oil–water emulsion as reflected by the slower flux decline and higher stable flux. This work provides a feasible pathway to realize the in-air highly oleophobic and hydrophilic surface on ceramic membranes, and primarily demonstrates the advantages of antifouling ability in oil-in-water emulsion separation.

Fabricating Antibacterial Powders from Olive Oil-In Water Emulsions Stabilized by Sour Cherry-Derived Hemicellulose and Pectin Crystalline Structures

Fabricating Antibacterial Powders from Olive Oil-In Water Emulsions Stabilized by Sour Cherry-Derived Hemicellulose and Pectin Crystalline Structures

Rifampicin-Loaded PLGA/Alginate-Grafted pNVCL-Based Nanoparticles for Wound Healing

The topical therapy with rifampicin (RF)-based formulations is beneficial for treating postoperative wound infections and to accelerate healing. Despite recent research highlighting the antibiotic’s significant anti-inflammatory properties, limited topical wound healing products are currently available. The present study aimed to prove that the newly synthesized nanoparticles based on grafted alginate and poly(N-vinylcaprolactam) (pNVCL) and poly-lactic-co-glycolic acid (PLGA) contribute to the healing process of a wound. The methods used were at first the synthesis of the copolymer of alginate and pNVCL via grafting from technique and radical polymerization followed by water-in-oil-in water (W/O/W) emulsification; as oil phase PLGA dissolved in dichloromethane (DCM) was used. The formed nanoparticles were than characterized. The loaded RF was determined to be 160 µg/mL for a 20 mg formulation and within a four-hour time frame approximately 10% of the total loaded amount was released. The inhibitory concentrations (IC50) were 192.1 µg/mL for the nanoparticle, 208.8 µg/mL for pure rifampicin, and 718.1 µg/mL for the rifampicin-loaded nanoparticles. Considering the double role rifampicin was used for, the result was considered satisfactory in the way that these formulations could be used predominantly for postoperative wound irrigation in order to avoid infections and to improve healing.

Hollow Silica Particles from Silica Sol

The possibility to obtain hollow particles using silica sol as a precursor of a silica shell at different pH values of a D4 emulsion in water is studied. It is shown that the yield of particles, their structure and sizes strongly depend on the pH value.

Hydrophilic PVDF emulsion separation membranes prepared using TA/APTES as a non-solvent: Effect of lithium chloride hydrate additive content

Currently, surfactant-containing oil–water emulsions are the more difficult part of oily wastewater to treat because of their small droplet size and stable oil–water interface. Membrane separation technology is commonly used for emulsion separation due to its surface wettability and adjustable pore size. Here, tannic acid (TA) and 3-aminopropyltriethoxysilane prepolymerization solutions are used as the exchange solvents, allowing growth on the surface and inside of polyvinylidene difluoride (PVDF). Among them, the content of lithium chloride (LCM) hydrate modulates the range and amount of growth. In the pressure range of 0.1–0.7 bar, the modified hydrophilic PVDF-TA/LCM-2 membranes exhibit high pure water permeation fluxes and emulsion separation efficiencies that can be adapted to different separation conditions. At 0.2 bar, the PVDF-TA/LCM-2 achieves pure water permeate flux and emulsion separation fluxes of 1860 and 648 L m-2 h−1 bar−1, and an emulsion separation efficiency of 99.5 %. In addition, for different kinds of oil-in-water emulsions, the high separation fluxes and high separation efficiencies indicate that PVDF-TA/LCM-2has good emulsion separation performance.

Laboratory performances during proficiency tests for the analysis of active substances in pesticide formulations during 2021–2023

During the period 2021–2023, the Italian National Institute of Health (ISS) organised, in collaboration with the Italian Health Ministry, proficiency testing (PTs) for about 22 Italian and other EU laboratories involved in the monitoring programmes for Plant Protection Products (PPPs). The aim of the PTs was to determine the amount of active ingredient in various formulations of PPPs. Overall, the type of formulations to be analysed were soluble concentrate (SL), suspension concentrate (SC), capsule suspension (CS), emulsion water oil (EW), soluble water granule (SG), dustable powder (DP), water dispersible granule (WDG) and emulsion concentrate (EC). In 2021, the ISS organised PTs for the determination of Imazamox, Fenhexamid and Trinexapac-ethyl in three different PPPs as soluble concentrate (SL), suspension concentrate (SC), and capsule suspension (CS), respectively. In 2022, PTs for the determination of Bentazone, Spinosad and Tau-Fluvalinate were organised. For this PTs, commercial PPPs were obtained from the Italian market as SC, emulsion oil water (EW) and soluble water granule (SG). In 2023, the PT was organised to determine the active ingredient Trifloxystrobin, Deltamethrin and Cyprodinil in the commercial product as water dispersible granule (WDG), dustable powder (DP) and emulsion concentrate (EC), respectively. Homogeneity and stability, performed for all PT samples, fulfilled the acceptability criteria. The Jarque–Bera test was used to verify the hypothesis of normality of the data distributions before to calculate the z-score values. Laboratory performances, expressed in terms of z-scores, were satisfactory for almost all participants for all substances.

Retraction Note: Break oily water emulsion during petroleum enhancing production processes using green approach for the synthesis of SnCuO@FeO nanocomposite from microorganisms.

Retraction Note: Break oily water emulsion during petroleum enhancing production processes using green approach for the synthesis of SnCuO@FeO nanocomposite from microorganisms.

Comprehensive review of stabilising factors, demulsification methods, and chemical demulsifiers of oil-water emulsions

With most crude oil extracted in the form of an emulsion, a substantial quantity of interfacially active substances such as asphaltenes and resins adsorbed at the oil–water interface can form a stable interfacial film through intermolecular interactions (hydrogen bonds or π-π stacking), which hinder the coalescence of water droplets. This process improves interface stability, making oil–water separation difficult, thus considerably increasing the petroleum industry’s cost. Hence, comprehending the stability mechanism of oil–water emulsions and destroying the stable oil–water interfacial structure is vital for effective demulsification. The paper systematically reviews types, stability factors, demulsification technologies and principles of oil–water emulsions, summarises common types of demulsifiers, explains the action mechanism of demulsifiers from structure-activity relationships, and proposes future development prospects in this field, thus providing support for formulating demulsification theoretical strategies.

High-strength, super-hydrophilic alginate electrospun nanofibrous membranes for rapid oil-water emulsion separation

Ultrafiltration membrane separation technology is considered an effective method for separating oil-water emulsions. However, oil droplets can easily deposit on the surface of the membranes, leading to severe fouling and a decrease in flux. In this study, poly (ethylene oxide)/acrylamide/sodium alginate (PEO/AM/NaAlg) hydrogel nanofibers were deposited on a poly (hydroxybutyric acid) (PHB) electrospun nanofibrous membrane. Subsequently, superhydrophilic (ethylene oxide)-poly(acrylamide)/calcium alginate hydrogel nanofiber composite filtration membranes (PEO/PAM/CaAlg-PHB) were prepared by polymerization and Ca2+ cross-linking using a PHB electrospun nanofibrous membrane as the matrix. The morphology, tensile strength, water contact angle, and oil–water emulsion separation properties of the PEO/PAM/CaAlg-PHB hydrogel filtration membrane were investigated. The results showed that the PEO/PAM/CaAlg-PHB membrane had good anti-fouling performance, with a tensile strength of 1.95 MPa. After 3 h of the filtration operation, the stable flux and oil–water emulsion rejection of the membrane reached 2925.2 L m−2 h−1 bar−1 and 98.66 %, respectively. The preparation method was simple, cost effective, and environmentally friendly, without introducing any organic pollutants. The PEO/PAM/CaAlg-PHB hydrogel filtration membrane shows promise for separating oil–water emulsions.

Advancing green technology: demulsifier preparation and evaluation for crude oil emulsion treatment using corn oil

Globally, oil production has steadily increased which causes a rise in the coproduction of oil and water emulsions. These emulsions pose significant challenges in transportation and the oil refinery industry, causing high-pressure drops and corrosion problems due to chlorides in the water. Despite advancements in renewable energy, crude oil remains a primary energy source. The crude oil industry faces numerous challenges, including cost emulsion issues. This study developed a corn oil bio-demulsifier (MFK). A unique demulsifier was tested using FTIR, GC-MS, and TGA. Using the bottle test method, the produced demulsifier MFK was tested with Basrah oil and East Baghdad S1 oil. The emulsion-breaking processes have been studied under several factors, such as settling time, dosage, temperature, pH, water content, and mixing time after demulsifier addition. At 2000 ppm Basrah oil, water separation efficiency reached 75%. For East Baghdad S1 oil, the highest separation result was 43.3% at 4000ppm, after 5 h of settling time at 70°C, with a 30/70 water-to-oil ratio. When studying the pH, the best water separation rate was 86.5% at a pH of 10. The best water content was 92% when the water-to-oil ratio was 50/50, and the best demulsifier mixing time with the emulsion was 2 min with a separation rate of 74.5%. When mixing was increased, undesirable results occurred. This study demonstrated that biodemulsifiers may replace conventional biodemulsifiers in early units while reducing environmental and economic impacts with further study and development.

Robust antifouling Poly(ionic liquid)s membrane with cyclodextrin skeleton for separation of oil/water emulsions

Membrane fouling remains a persistent and arduous challenge in the industrial treatment of different surfactants-stabilized oily wastewater. Constructing a robust antifouling and sustainable hydration coating on the membrane surface to efficiently repel oils or surfactants is a critical requirement. Herein, cyclodextrin-based poly(ionic liquid)s (PILs) coatings are cross-linked via the co-deposition on poly(vinylidene fluoride) (PVDF) of quaternized heptkis(6-deoxy-6-vinylimidazolium)-β-cyclodextrin (CD-Vi) derivatives as skeleton and acrylic acid (AA) monomers, and following one-step free radical photopolymerization. Combining with the strong hydration of the CD-based PILs coating, the resultant membrane exhibits fabulous superhydrophilicity and underwater superoleophobicity, oil repulsion, and self-cleaning capability. It demonstrates robust mechanical durability and chemical stability in harsh environments without losing its superhydrophilicity. Besides, the PIL-CD/AA coating can separate various surfactant-free and different surfactants (cationic CTAB, anionic SDS, and nonionic TWEEN 80) stabilized oil / water emulsions. During the long-term cycle operations, it also realizes stable recyclability with a series of permeation fluxes as high as removal efficiencies (>99.6 %) after 20 cycles for surfactant-free cyclohexane-in-water emulsion and 10 cycles for CTAB-stabilized isooctane-in-water emulsion.

Modified PVDF ultrafiltration membrane with host–guest supramolecular trapping for efficient separation of multiple organic contaminants

In our modern lifestyle, the cocktail of organic pollutants from everyday items, such as hair dyes, cloth dyes, food colours, hair oils, cooking oils, and agricultural proteins, enters water streams through household pipelines. This unnoticed contamination, growing alarmingly, poses a serious challenge beyond the scope of conventional separation techniques, calling for a comprehensive solution. While membrane technology offers a promising solution, it grapples with persistent surface fouling issues. This study introduces a novel approach through the development of extraordinary Polyvinylidene fluoride-Montmorillonite-Cucurbit[6]uril (PVDF-M-CB[6]) mixed matrix membranes, presenting a potential breakthrough in overcoming surface fouling challenges and offering a versatile solution for the separation of an array of organic contaminants. Powered by the synergistic host–guest supramolecular complexation of CB[6] onto montmorillonite (M) clay support, these membranes demonstrate swift and selective encapsulation, leading to superior cationic dye rejection. Adding to the allure, CB[6]’s structure encourages favorable carbonyl interactions with bovine serum albumin (BSA), effectively repelling the protein away from the membrane, while also promoting seamless oil–water emulsion separation with an underwater oil contact angle of 150 ± 3°, displaying its superoleophobic nature and enhancing remarkable antifouling properties. The PV-M-CB[6] membranes showcased 2x removal of cationic dyes, 1.3x removal of anionic dyes, 1.4x oil–water emulsion separation, and 2x BSA separation compared to the pristine polyvinylidene fluoride (PVDF) membrane. These membranes displayed 98.3 % efficiency in oil–water emulsion separation and sustained a flux recovery ratio of over >75% after seven cycles. Overall, PV-M-CB[6] membranes represent an innovative solution with heightened hydrophilicity, remarkable antifouling performance, and exceptional proficiency in delivering one-stop organic foulant separation.

Construction and characterization of pickering emulsion stabilized by amphoteric microgel and its application in cotton fabric

Studies with regard to how to obtain superhydrophobic properties by directly coating emulsified silicone oil onto the surface of cotton fabric have always been a hot topic in the field of textiles. In this paper, an amphoteric microgel with thermo- and pH-responsive ability was synthesized. Subsequently, a series of Poly(methylhydrosiloxane) (PMHS) /water emulsions were prepared by using these amphoteric microgels as a Pickering emulsifier. When the PMHS/water system's mass ratio was 5/5 and the microgel content was kept at 2.0 wt%, this emulsion showed good stability allowing the PMHS parts to be dispersed uniformly in aqueous solution. The optical microscopy showed the emulsion's particle size was in a range from 5 to 20 μm and the stability test confirmed that no stratification occurred when this emulsion was subjected to 3000 rpm for 30 min. By using this emulsion as a post-treatment reagent, cotton fabrics with different yarn counts can obtain a water contact angle as high as 150o, which is about 25 % higher than commercial emulsifiers. Furthermore, this cotton fabric can hold superhydrophobicity after 50 rubbing cycles and 10 peel-off cycles. The development of this work provides a new direction for the study of the application of microgels.

Ultrasound and high-speed shear pretreatments of walnut meal protein: Structural and functional characterization and mechanistic investigation

The study aims to investigate the effect of the addition of ultrasound (US) with high-speed shear (HSS) at the extraction stage on the yield, physicochemical, structural, and functional properties of walnut meal protein (WMP). Compared with the conventional alkaline soluble acid precipitation method, the WMP yields after US and HSS pretreatments were increased by 1.11 and 1.21 times, respectively. Protein samples treated with the US showed increased surface hydrophobicity, a more uniform distribution of particle sizes, and greater contact angles. SDS-PAGE results showed that the protein had broken peptide bonds at higher molecular weights. The proteins' free sulfhydryl groups and fluorescence intensity have both increased as a result of the two pretreatment approaches, indicating a substantial alteration in the proteins' tertiary structure. Dynamic light scattering and SEM findings revealed that the US and HSS treatments improved the protein water solubility and emulsion stability by reducing the aggregate particle size and homogenizing the protein dispersion system. These results indicate that US and HSS pretreatment can effectively solubilize WMP polymers and enhance the structural function of the protein. This provides a theoretical basis for the application of WMP in food processing and offers a suitable technology for improving protein utilization.

Multifunctional electrospun membranes incorporated with metal oxide nanoparticles, cellulose acetate, and polyvinylpyrrolidone for wastewater treatment: Oil/water separation, dye adsorption, and dye degradation

Multifunctional membranes have gained considerable attention as useful materials for the treatment of complex wastewater that contains dye and oil substances. Electrospun nanofiber membranes (ENM) have substantial advantages and potential for complex wastewater remediation, owing to their unique properties. In this study, an environmentally compatible ENM is fabricated by incorporating photocatalytic metal oxide nanoparticles of zinc oxide (ZnO) or silver-zinc Oxide (Ag-ZnO) into cellulose acetate (CA)/polyvinylpyrrolidone (PVP) nanofibers using electrospinning. Composite membranes ZnO/CA/PVP, Ag-ZnO/CA/PVP, ZnO/DCA/PVP (DCA: deacetylated cellulose acetate), and Ag-ZnO/DCA/PVP (deacetylated) were employed for oil–water emulsion separation, owing to their superhydrophilic and underwater superoleophobic nature, photocatalytic dye degradation due to the presence of ZnO or Ag-ZnO, and dye adsorption resulting from their high surface area. The composite membranes showed more than 95% efficiency for oil/water separation, malachite green adsorption, and photocatalytic methylene blue degradation. These membranes displayed simultaneous oil–water and dye separation efficiency, as well as antibacterial properties. The membrane we present here provides a simple and effective platform for wastewater remediation with a low energy consumption.

Thin film nanocomposite membrane ornamented with Z-scheme heterojunction carbon dot/NiFe–LDH for removal of organic contaminants from industrial wastewater

Removal of organics from wastewater is a tedious process and industries are looking for a facile, energy efficient strategy of wastewater treatment for producing clean water and recycling. Membrane technology is one of the efficient processes for wastewater treatment due to its energy efficient nature, simple operation and excellent performance. But, proneness of membrane fouling often limits its path to triumph. In this work, we have designed a ‘carbon dot/NiFe-layered double hydroxide (CD/NiFe–LDH)’ nanocomposite via in situ approach, which is coated on a poly(ethylene terephthalate) (PET) and cellulose based superhydrophillic membrane. The membrane is found to have excellent separation efficiency. The photocatalytic activity of CD/NiFe–LDH shows high oxidative degradation of the accumulated organics contaminants on the membrane surface providing self-cleaning ability and hence enhances the membrane’s lifetime. The membrane exhibits stable performance for 30 days continuous operation under UV-A light. The membrane flux is found to be ∼42 Lm−2 h−1 and 48 Lm−2 h−1 for crude oil–water emulsion and phenol respectively while rejection around ≥99 % is obtained for the both. The flux recovery ratio (FRR) of the post photo irradiated membrane is found to be 88.07 %. The membrane also shows organic solvent resistance property and prevents bacterial pathogens in wastewater.