Oil-water Separation Performance Research Articles

Highly adhesive bioinspired membrane for efficient oil/water separation by optimization of synergistic effects of hierarchical structure and superhydrophobic modification

Superwetting membranes have good prospective for treatment of oil-containing wastewaters. However, development of highly adhesive superhydrophobic membranes with efficient oil-water separation performance remains a great challenge that needs to be addressed urgently. Herein, highly adhesive membrane surface with hierarchical structure were fabricated by in-situ TEOS hydrolysis and fluorinated modification. The interface bonding force between polyvinylidene fluoride (PVDF) and silica nanoparticles (SiO2 NPs) was increased through the dopamine self-polymerization and adhesion. The hierarchical structure was obtained by simultaneously adjusting TEOS and ammonia contents. The three-dimensional hierarchical membrane structure which is similar to that of a rose petal was shown by SEM analysis. The obtained membrane showed a water contact angle of 158 ± 2°, while the oil contact angle approaches 0°. In-situ grown multi-scale SiO2 NPs, perfluorooctyltriethoxysilane (FAS) brushes and dopamine can form a stable hierarchical surface which sustained superhydrophobicity/superoleophilicity when immersed in aqueous solutions at different pH values. Meanwhile, FAS brushes can serve as steric obstacles to efficiently repel water droplets during oil/water separation. The fabricated membrane possesses a high permeation flux and excellent separation properties (> 98%). In addition, this highly adhesive coating modification and hierarchical design can be widely applied on the surfaces of different materials, giving an attractive potential application prospect, such as oil/water separation, antifouling surface, and superwetting materials.

[formula omitted] tracking control for de-oiling hydrocyclone systems via event-triggered reinforcement learning

De-oiling hydrocyclone system is a crucial device in offshore oil and gas production. To reduce action frequency of actuators as well as energy costs, it is desired to apply event-triggered control (ETC) technique for coordination control of de-oiling hydrocyclone systems. However, the triggering errors and slugging disturbances will greatly affect oil-water separation efficiency and need to be well treated. Towards this end, this work studies the coordination control problem of de-oiling hydrocyclone systems subject to slugging disturbances and unknown system dynamics. Robust H∞ control approach is applied to reduce disturbances sensitivity and guaranteeing satisfactory oil-water separation performance. The coordination control problem is transformed into a 2-player zero-sum game problem. A model-based solution by solving the game algebraic Riccati equation (GARE) is obtained and an event-triggered (ET) off-policy reinforcement learning (RL) algorithm is developed to implement the model-based solution. The salient feature of the proposed algorithm is that the proposed model-free H∞ control method alleviates the affects of both triggering errors and slugging disturbances, which are handled together as a generalized disturbance in the algorithm. Stability and Zeno behavior avoidance of the proposed algorithm are analyzed. Simulation studies demonstrate the effectiveness of the proposed algorithm.

Robust superhydrophobic fabrics: Rapid preparation and outstanding photothermal-induced performance

Developing material that can separate oil-water mixture and absorb spilled crude oil efficiently has become a pressing challenge. To this end, we prepared a polydopamine@octamine nano-capsules based superhydrophobic fabric with photothermal effect rapidly using UV-assisted preparation. The prepared superhydrophobic fabric exhibits excellent photothermal-induced oil absorption and oil-water separation performance. Not only oils with low viscosity can be absorbed efficiently, but also oils with high viscosity can be absorbed quickly. POS fabric could absorb crude oil up to 6.5 times of its own weight. The oil-water separation efficiency and flux could reach more than 98.8 % and 16,900 L·m−2·h−1, respectively. Moreover, the separation efficiency remained unchanged even after 50 separation cycles while the separation flux rose gradually with the increase of oil-water separation cycle. Meanwhile, the as-prepared superhydrophobic fabric reveals outstanding durability and stability. It maintains superhydrophobic performance even after exposed to various harsh conditions such as acids, alkalis, salts, organic solvents, UV light, and mechanical abrasion. Additionally, the fabric has outstanding self-healing ability and which can extend its service life. Therefore, this simple, fast, and environment-friendly preparation method together with the excellent performance of resultant materials is expected to have broad application prospects in the treatment of oily wastewater and offshore crude oil spills.

Copper Nanoparticles Modified Superhydrophobic Electrospun Carbon Nanofiber Membranes with Enhanced the Oil–water Separation Performance

Copper Nanoparticles Modified Superhydrophobic Electrospun Carbon Nanofiber Membranes with Enhanced the Oil–water Separation Performance

Biomimetic dendritic‐networks‐inspired oil-water separation fiber membrane based on TBAC and CNC/PVDF porous nanostructures

Inspired by the multi-level structure of trees in nature, using cellulose nanocrystals/polyvinylidene fluoride (CNC/PVDF) fibers as the support layer and CNC/PVDF/organic branched salt (TBAC) fibers as the filtering layer, to construct oil–water separation membrane with tree-like structure. The membrane's surface (nano spherical) and internal (interconnected pores) structures were regulated by phase separation of CNC induced. The high conductivity of TBAC was utilized to construct branched fibers (d = 53.3 nm) on the backbone fibers (d = 1.2 μm). The impact of TBAC on the microstructure, wetting behavior, and oil–water separation performance of membranes was investigated. Note, TBAC concentration was 0.02 mol/L, the membrane exhibits a highly porous dendritic network structure (with porosity of 85 % and pore size of 6.1 nm), and outstanding wetting properties (water contact angle underoil ˃ 150°). This distinctive structure endows membranes with a high oil adsorption capacity (64.1 g/g of engine oil), oil flux (22873 L/m−2h−1 of toluene). Following ten testing cycles, the toluene adsorption capacity remains at 83.1 % of the initial adsorption, while the separation flux of emulsion (5645 L/m−2h−1) remains nearly constant. Overall, successfully fabricating CNC/PVDF/T-0.02 fibers with a tree-like structure provides a novel approach to designing and developing efficient membrane separation materials.

Preparation and performance study of environmentally friendly and durable kaolin/PDMS/cotton fabrics superhydrophobic surface

In this research work, a fluorine-free, durable, and excellent self-cleaning and oil-water separation performance kaolin/polydimethylsiloxane/cotton fabrics (Kaolin/PDMS/cotton) superhydrophobic surface was successfully prepared. The morphology, wettability, and phase composition of the coating were characterized and tested using scanning electron microscopy (SEM), dynamic contact angle measuring instrument, and X-ray diffraction (XRD). The experimental results showed that the organic composite of hydrophobic modified kaolin particles and cotton fabrics was successfully achieved through the bridging effect of PDMS. A dense superhydrophobic micro-nano structure coating was constructed on the surface of cotton fibers, and the tested performance was excellent. Has good local anti-pollution performance for common coffee, Coca-Cola, dyeing water, and simulated dust; After being worn for a distance of 1200 centimeters under a load of 10KPa, the contact angle with water remained above 150°, indicating excellent durability of the coating; In addition, kaolin/PDMS/cotton also exhibited good oil/water separation performance. After 15 cycles of oil-water separation tests, the separation efficiency for gasoline and dichloromethane both exceeded 96%.

Sustainable and efficient oil-water separation using bio tin oxide-based superhydrophobic membrane

IntroductionSuperhydrophobic materials are considered an ideal method for oil-water separation. However, existing oil-water separation methods have the problem of manufacturing complex and toxic chemical reagents. To address the limitation, we proposed a novel approach to sustainable and efficient oil-water separation using a superhydrophobic membrane based on the Bio Tin oxide nanoparticles (Bio-SnO2 NPs).MethodsThe study involves synthesizing Bio-SnO2 NPs from the sunflower leaf extract which was natural and non-toxic and modifying textile fabric with a superhydrophobic coating (S.T.F.). Characterization techniques including SEM, FTIR, and BET analysis are employed to assess the structural and textural properties of the modified membrane.Results and DiscussionThe textile fabric was modified with a superhydrophobic coating (S.T.F.), demonstrating enhanced wettability, oil absorption capacity, and oil-water separation performance. The Bio-SnO2 NPs exhibited crystalline structures with a length of 90 nm and a diameter of 20 nm, as confirmed by SEM analysis. FTIR results revealed characteristic peaks at 3410 cm-1 and 642 cm-1, indicating the presence of hydroxyl group and Sn-O bonds confirming the successful synthesis of Bio-SnO2 NPs. BET analysis showed a substantial specific surface area of 413 m2/g and a pore volume of 0.19 cm3/g, emphasizing the textural properties. The FTIR and SEM techniques were used to study the characteristics of the textile fabric before and after modification with the superhydrophobic coat. The S.T.F. exhibited remarkable superhydrophobicity with a water contact angle of 152° and a water sliding angle of 4°. Absorption capacities for coconut oil, diesel, and hexane were found to be 70.4 g/g, 63.5 g/g, and 49.6 g/g, respectively, with excellent cyclic stability. Separation efficiency for hexane, diesel, and coconut oil was found to be 99.5, 97.1%, and 96.3%, respectively, with excellent cyclic stability. Mechanical stability test revealed superhydrophobicity retention even after an abrasion length of 200 mm. The chemical stability test indicated that the superhydrophobicity was maintained in the pH range of 3-11. Moreover, the flux for hexane, diesel, and coconut oil was 9400 L m−2 h−1, 8800 L m−2 h−1, and 8100 L m−2 h−1, respectively, highlighting the membrane’s efficient oil-water separation capabilities. These results collectively position the developed S.T.F. as a promising and sustainable solution for diverse oil-water separation applications.

Directional self-assembly of octavinyl polyhedral oligomeric silsesquioxane on the surface of melamine sponge: Establishing hydrophobic surfaces to improve oil–water separation performance

The continuous increase in industrial organic pollutants has seriously contaminated the natural environment, posing a threat to natural ecosystems and human survival. The preparation of hydrophobic materials with corrosion resistance is crucial for the efficient treatment of emulsified oil–water mixtures in industrial wastewater.Octavinyl polyhedral oligomeric silsesquioxane-coated melamine foam (OV-POSS@MF), possessing hydrophobic properties, was synthesized through a two-step process: initially, a sulfhydryl layer was built up on the surface of the melamine foam, followed by the subsequent assembly of octavinyl POSS onto the melamine foam's surface via a free radical polymerization reaction between sulfhydryl groups and vinyl moieties. OV-POSS@MF achieves a static water contact angle of 141°, demonstrating its pronounced hydrophobic nature. Moreover, the corrosion resistance, adsorption capacity, oil–water separation efficiency, deformation resistance, and flame retardancy of OV-POSS@MF were thoroughly examined. The results indicate that OV-POSS@MF exhibits strong corrosion resistance and maintains good hydrophobicity even after prolonged exposure to highly acidic and alkaline conditions. Notably, OV-POSS@MF possesses the capability to efficiently and rapidly separate emulsified oil–water mixtures. Furthermore, it retains excellent hydrophobicity even after undergoing up to 100 consecutive compressions or distortions, highlighting its remarkable mechanical resilience. Additionally, OV-POSS@MF demonstrates superior flame retardant properties compared to unmodified melamine foam (MF).

Porous silicate cement membrane: Unraveling the effect of triethanolamine on ice crystal changing, pore structure, and performance

Triethanolamine (TEA) has been broadly used as the organic amine conditioning agent to modify the workability of cement-based materials. However, the effect of TEA on the structure and property of porous silicate cement membranes has not been reported. In this paper, TEA was applied to study its effect on parameters of porous silicate cement membranes based on the preparation method combining freeze casting and heat-dry curing, because it is easy to form complexes with cement particles. The effect and acting mechanism of TEA on porous silicate cement membranes were researched using a series of characterizations and molecular dynamics (MD) simulation. Results showed that TEA significantly improved the performance of porous silicate cement membranes. The addition of TEA changed the pore morphology of porous silicate cement membranes from lamellar structures to cellular structures, with mesoporous size distribution focusing on 2.5–4.5 nm at TEA doping ratio of 0.16 wt%. The oil-water separation performance could reach up to 99.6 %. Through comprehensive comparison, the porous silicate cement membrane with 1.0 wt% TEA showed better holistic preponderance of oil-water separation and permeation flux. Quantum chemistry calculation and MD simulation were used to briefly explain the influence of TEA on phase transformation. MD showed that adding TEA changed the morphology and structure of ice crystals. The percentage of the Ih structure significantly increased from 53 % to 86 % after adding TEA. This study might expand the application of TEA in other aspects and enlighten relevant workers in new experimental designs.

Facile construction of multifunctional 3D smart MOF-based polyurethane sponges with photocatalytic ability for efficient separation of oil-in-water emulsions and co-existing organic pollutant

Water resources are increasingly being damaged by human activities, and it is crucial to deal effectively with polluted water resources. Due to the diversity of pollution sources (oil, organic dyes, and other complex pollutants), it makes sense to develop a material that can handle these pollutants simultaneously. In this article, we construct a simple and fast method to fabricate multifunctional superhydrophobic polyurethane sponges (PU). A superhydrophobic composite coating constructed from ZIF-8, polydimethylsiloxane (PDMS), and stearic acid (SA) was attached to the surface of the polyurethane sponge by a simple impregnation method. Through the above process, we have successfully integrated oil–water separation, photocatalysis, and superhydrophobicity into a polyurethane sponge. The results showed that the PDMS/SA/ZIF-8 polyurethane sponge (PSZPU) had a high hydrophobicity angle (162.9 ± 1.1°). In addition, PSZPU maintains high oil–water separation performance (mean value of separation efficiency > 94.24 %) and superhydrophobicity after oil–water separation cycling tests and a series of harsh environmental tests in acidic and alkaline solutions, high temperatures, abrasion, and UV aging irradiation. Overall, the creation of PSZPU provides a new application for superhydrophobic sponges in water resource treatment.

Multifunctional hydrophobic MOFs modified by rosin acid with oil–water separation and room temperature catalysis

Metal-organic frameworks (MOFs) are high surface area porous materials with uniform pores. MOFs are among the widely investigated porous materials because of their potential applications in adsorption, oil–water separation, catalysis, and other such applications. However, MOFs are not stable enough in aqueous environments, which restricts their application in practice. We converted hydrophilic UiO-66-SH into hydrophobic UiO-66-RA by introducing rosin acid into organic linkers. The material was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The superhydrophobic UiO-66-RA was successfully constructed and the water droplet contacts angle reached 157.2°. Importantly, the obtained UiO-66-RA demonstrated stable oil–water separation performance, with separation efficiencies of up to 96.1% and 96.8% for both light and heavy oils. The separation efficiencies also reached more than 95.1% after five repetitions. For stable oil–water emulsions, UiO-66-RA also achieved effective separation. In addition, the catalyst Pd@UiO-66-RA was successfully prepared by hybridization of palladium chloride with UiO-66-RA. The catalytic yields of Pd@UiO-66-RA was 95.4%. And the yield could also be kept above 60% after five cycles of Sonogashira reaction catalyzed. This work offers a new type of superhydrophobic MOFs, the multifunctional MOFs has the potential for environmentally benign catalysis and purification of wastewater.

Trabecular bone-inspired tung oil-derived spongy cellular networks with intelligent pH-responsive wettability and superelasticity for efficient multitasking separation

Development of new biomass sponges with controllable wettability and excellent resilience is urgent while challenging for multitasking and effective oil–water separation because incorporating these performances into conventional biomass sponges is complicated and even contradictory. Herein, a hypersalinity-confined thermopolymerization strategy is presented for fabricating the tung oil-derived spongy cellular network (TSN), during which its interconnected porous skeleton with ionizable carboxyl groups is formed due to the self-initiated thermal polymerization and crosslinking of tung oil precursors enclosed in the stacking space of sodium chloride (NaCl) particles. By mimicking trabecular bone architecture with good energy transfer/dissipation, high porosity and strong capillary absorption, the resultant TSN with carboxylic acid groups exhibits reversible pH-responsive wettability (transition from hydrophobicity/lipophilicity to hydrophilicity/oleophobicity), superelasticity (nearly 100 % stress and height retention after 1000 cycles), good thermal/chemical stability and efficient oil–water separation performance (>99.4 % separation efficiency) in multitasking situations. This study provides an encouraging insight for the tailored fabrication of smart sponge materials derived from renewable vegetable oils for oil–water separation in multitasking and complex situations.

Silica-Based Superhydrophobic and Superoleophilic Cotton Fabric with Enhanced Self-Cleaning Properties for Oil-Water Separation and Methylene Blue Degradation.

Superhydrophobic textiles with multifunctional characteristics are highly desired and have attracted tremendous research attention. This research employs a simple dip-coating method to obtain a fluorine-free silica-based superhydrophobic and superoleophilic cotton fabric. Pristine cotton fabric is coated with SiO2 nanoparticles and octadecylamine. SiO2 nanoparticles are anchored on the cotton fabric to increase surface roughness, and octadecyl amine lowers the surface energy, turning the hydrophilic cotton fabric into superhydrophobic. The designed cotton fabric exhibits a water contact angle of 159° and a sliding angle of 7°. The prepared cotton fabric is characterized by attenuated total reflectance-fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. In addition, the coated fabric reveals excellent features, including mechanical and chemical stability, superhydrophobicity, superoleophilicity, and the self-cleaning ability. SiO2 nanoparticles and octadecylamine-coated cotton fabric demonstrate exceptional oil-water separation and wastewater remediation performance by degrading the methylene blue solution up to 89% under visible light. The oil-water separation ability is tested against five different oils with more than 90% separation efficiency. This strategy has the advantages of low-cost precursors, a simple and scalable coating method, enhanced superhydrophobicity and superoleophilicity, self-cleaning ability, efficient oil-water separation, and exceptional wastewater remediation performance.

Synthesis of a composite Fe3O4@SiO2/poly(SMA-co-BA-co-BZMA-co-DMC) and evaluation of its oil-water separation performance

To obtain a demulsification material with convenient recovery, high oil-water separation capacity, and excellent reusability, Fe3O4@SiO2 core-shell particles and hydrophilic DMC were introduced into the acrylic ester-based polymer system to prepare a magnetic amphiphilic composite demulsifier, Fe3O4@SiO2/poly(SMA-co-BA-co-BZMA-co-DMC) (Fe3O4@SiO2/PAMCs-P). The molecular structure of Fe3O4@SiO2/PAMCs-P was characterized using FT-IR and XPS, while the morphology was observed using SEM. Additionally, the effects of TEOS, Fe3O4@SiO2 core-shell particles, and DMC dosage on the demulsification performance of the composites were discussed in detail. Fe3O4@SiO2/PAMCs-P exhibited excellent demulsification, oil-water separation, and reusability properties for CTAB-toluene emulsions. Under magnetic field conditions, Fe3O4@SiO2/PAMCs-P achieved saturated separation within 2 h with a separation efficiency of 97.9%. After five consecutive separations, the separation efficiency decreased to 39.1%, but it could be restored to 91.5% of the initial separation efficiency after desorption. These results indicate that Fe3O4@SiO2/PAMCs-P has valuable application potential in emulsified wastewater treatment.

Design and fabrication of superhydrophobic photothermal coating on copper mesh and its applications on anti-corrosion, anti-icing and oil-water separation

The discharge of oily wastewater, the leakage of high-viscosity oils as well as corrosion and freezing of metal equipment surfaces have not only caused large economic losses, but also posed a major threat to environmental safety, which has sparked international concern. Superhydrophobic materials inspired by lotus leaves were great options for addressing these problems because of their special surface wettability. In this study, a simple hydrothermal approach (in-situ CuxS growth) and post-modification technique (stearic acid modification) was used to create a superhydrophobic-superoleophilic-photothermal (SHPB-SOPI-PT) coating on the surface of copper mesh. The SHPB-SOPI-PT coating was found to be good self-cleaning ability, mechanical durability (ultrasonic vibration, sandpaper abrasion, tape peeling, surface bending), chemical stability (pH = 1, pH = 13, and 3.5 wt% NaCl solution) and environmental adaptability (thermal, UV aging, acid rain and long-term unprotected storage). Meanwhile, the SHPB-SOPI-PT coating offered ideal corrosion protection (η = 97.7 %), passive anti-icing performance (1800 % longer freezing time), oil-water separation performance. More importantly, the SHPB-SOPI-PT coating also provided active de-icing and high-efficient separation of high viscosity oils due to the photothermal effect of CuxS. This method of constructing multifunctional coating was easy to produce and utilize on a large scale, which could expand the serviceable range of copper-based materials.

Multi-functional self-cleaning superhydrophobic cotton fabric as photothermal-reinforced crude oil separator, oil skimmer and underwater oil absorbent

Removing oil pollution from seawater prior to its desalination helps in saving time and cost. In this study, a novel superhydrophobic cotton fabric with photothermal effect and self-cleaning property was prepared via the incorporation of Fe3+-polydopamine (PDA) coating and carbon nanotubes (CNTs) on the fabric surface (termed as CF@PDA/CNT), followed by the grafting of (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and octadecylamine (ODA) (termed as the CF@PDA/CNT-GPTMS-ODA). CF@PDA/CNT exhibits good desalination with photothermal conversion capability on the high-salinity water (evaporation rate > 1.11 kg/(m2⋅h)), providing an effective basis for the preparation of the photothermal-assisted oil–water separator (CF@PDA/CNT-GPTMS-ODA), with which the crude oil permeation time was improved from 58 s without light to only 9 s with light, showing the pronounced contribution of the photothermal effect on the oil permeation. In addition, CF@PDA/CNT-GPTMS-ODA used in the form of oil skimmer and underwater oil absorbent demonstrates excellent oil–water separation performance (separation efficiency > 97 %). Notably, the fabric can isolate various oil phases from both pure water and simulated seawater, with separation efficiencies exceeding 97 %. This novel material offers a promising solution for addressing complex water pollution issues and introduces a potential approach for integrating photothermal conversion effect into the field of oil–water separation.

Facile construction of robust superhydrophobic ZIF‐8@pulp/cellulose nanofiber (CNF) membrane for multifunctional applications

Given the increasing contamination of freshwater supplies, it is essential to effectively treat industrial wastewater. However, treating industrial wastewater using a single method is challenging due to the presence of complex contaminants like petroleum, organic dyes, bacteria, and other complex contaminants. In this study, we present a straightforward and scalable approach to prepare multifunctional nanocellulose-based membranes (NM) that exhibit superhydrophobicity, self-cleaning, oil/water separation, photocatalysis, and anti-bioadhesion properties. To begin with, we created NM by extruding fiber slurry onto a stencil and drying it. Next, we built a polyurethane (PU)/ZIF‐8/1H, 1H, 2H, 2H‐perfluorooctyltriethoxysilane (POTS)-based superhydrophobic layer by spraying it over the NM's surface. By employing the aforementioned processes, we successfully integrated multiple functions into a single superhydrophobic NM. Our results demonstrate that the NM-PU/ZIF-8/POTS membrane exhibits superior hydrophobicity performance, with a high-water contact angle (166.8 ± 0.8°) and a low rolling angle (5 ± 0.3°). Moreover, these samples retain high-water contact angles and low rolling angles even in harsh environments such as acid and alkali solutions, high temperatures, abrasion resistance, UV aging resistance, bending and folding, tape peeling, and self-cleaning. The NM-PU/ZIF-8/POTS membrane also exhibits high and stable oil-water separation performance, with a separation efficiency of 94.6% and a relatively high separation flux (133.2 L·m−2·h−1). At the same time, the NM-PU/ZIF-8/POTS membrane exhibits water-in-oil emulsion separation ability. The membrane’s stability, effectiveness, and reusability were demonstrated through ten repetitions of degradation experiments using aqueous methylene blue solution, with the NM-PU/ZIF-8/POTS membrane exhibiting an excellent degradation rate (>94%). Finally, the bioadhesion resistance test indicated a reduction of 69.1% in the adhesion rate of the NM-PU/ZIF-8/POTS membrane. Overall, the creation of the NM-PU/ZIF-8/POTS membrane serves as a useful inspiration for the practical application of superhydrophobic NM in multifunctional integration, while also broadening the scope of membrane applications.

The optimized microbial-induced calcium carbonate precipitation process to fabricate underwater superoleophobic mesh for efficient oil-water separation

Microbial-induced calcium carbonate precipitation (MICP) is an environmentally-friendly and easy operation technique for separating oil-water mixtures. However, the effect of environmental factors on the wettability and oil-water separation performance of MICP remains unclear. In this study, three primary factors including mineralization solution (MS) concentration, bacterial suspension (BS) concentration, and temperature were carefully investigated. Under these varying conditions, stainless steel meshes (SSM) were chosen as the substrates for the growth of CaCO3 precipitations. Experimental results demonstrate a strong dependence of the morphology and wettability of CaCO3 precipitations on these factors. Higher MS concentration and temperature contribute to enhanced hydrophilicity of CaCO3 coatings due to the increased surface roughness. The water flux of MICP-coated SSMs decreases with the increase of BS concentration, MS concentration, and temperature. The MICP-coated SSM obtained with MS concentration of 0.15 M, BS concentration of 0.1 × 108 cells/mL, and mineralization reaction at 25 ℃ for 24 hours demonstrated the optimal comprehensive performance, exhibiting underwater superoleophobicity with an underwater oil contact angle (UWOCA) exceeding 151°, an ultra-high oil intrusion pressure (> 3.0 kPa), ultrahigh flux (28,644 L m−2 h−1), and a preferable oil rejection rate (> 99.9%). Additionally, the as-prepared mesh exhibited superior anti-oil-fouling property and reusability, while concurrently demonstrating excellent chemical and thermal stability. This work contributes to advancing our knowledge of the influence of various environmental factors on the wetting characteristics of MICP and provides a feasible solution for the highly efficient and low-cost preparation of oil-water separation membranes based on the MICP process.

Fabrication of bio-based biodegradable poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composite foams for highly efficient oil-water separation

The open-cell bio-based biodegradable polymer foams show good application prospect in dealing with the serious environmental issue caused by oil spill and organic solvents spills, while the cell structures and hydrophobic properties of the foams limit their performance. In this work, the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was selected to help prepare bio-based biodegradable poly(lactic acid) (PLA) foams. Based on a two-step foaming method, the crystallization ability of different samples was regulated by the “original crystals” together with PHBV in the foaming process, where skeleton structures were provided to facilitate the open-cell structures and promote their mechanical property. As illustrated, PHBV facilitated the formation of open-cell PLA foams, where the foams displayed superior oil-water separation capacity. The maximum volume expansion ratio of the foams was 80.08, the contact angle of deionized water reached to 134.5°, the adsorption capacity for oil or organic solvents was 10.8 g/g-51.8 g/g, and the adsorption capacity for CCl4 can still maintained 83.5 % of the initial value after 10 adsorption-desorption cycles. This work not only clarified the foaming mechanism of open-cell foams, but also provided a green and simple method for preparing bio-based biodegradable foams possessing excellent oil-water separation performance.

Structure Optimization and Performance Evaluation of Downhole Oil–Water Separation Tools: A Novel Hydrocyclone

Abstract Based on the principle of cyclone separation and 3D printing technology, a novel variable pitch hydrocyclone structure was proposed for the axial flow hydrocyclone separators of oil wells. The structural parameters of this variable pitch hydrocyclone were optimized via a combined approach of the Plackett–Burman design, response surface design, and computational fluid dynamics. A quadratic polynomial mathematical relationship between significant structural parameters and separation efficiency was established. The effects of the inlet flowrate, split ratio, and oil phase volume fraction on oil–water separation performance were systematically analyzed. A laboratory test system for oil–water swirl separation was constructed to verify the accuracy of numerical simulation results and the efficiency of the optimized structure. The optimal overflow split ratio, inlet flowrate, and oil concentration for the hydrocyclone are 30%, 96 m3/day, and 2%, respectively. The combination of these optimal parameters results in an experimental separation efficiency of 99.38%, which is higher than that of the conventional structure (98.8%). The experimental results are in good agreement with the simulation results.