Anti-abrasion collagen fiber-based membrane functionalized by UiO-66-NH_(2)with ultra-high efficiency and stability for oil-in-water emulsions separation

Membrane separation strategies offer promising platform for the emulsion separation.However,the low mechanical strength of membrane separation layers and the trade-off between separation flux and efficiency present significant challenges.In this study,we report a CFM@UiO-66-NH_(2)membrane with high separation flux,efficiency and stability,through utilizing a robust anti-abrasion collagen fiber membrane(CFM)as the multifunctional support and UiO-66-NH_(2)by an in-situ growth as the separation layer.The high mechanical strength of the CFM compensated for the weakness of the separation layer,while the charge-breaking effect of UiO-66-NH_(2),along with the size sieving of its constituent separating layers and the capillary effect of the collagen fibers,contributed to the potential for efficient separation.Additionally,the CFM@UiO-66-NH_(2)membrane exhibited superhydrophilic properties,making it suitable for separating oil-in-water microemulsions and nanoemulsions stabilized by anionic surfactants.The membrane demonstrated remarkable separation efficiencies of up to 99.960%and a separation flux of370.05 L·m^(-2)·h^(-1).Moreover,it exhibits stability,durability,and abrasion resistance,maintaining excellent separation performance even when exposed to strong acids and alkalis without any damage to its structure and performance.After six cycles of reuse,it achieved a separation flux of 417.97 L·m^(-2)·h^(-1)and a separation efficiency of 99.747%.Furthermore,after undergoing 500 cycles of strong abrasion,the separation flux remained at 124.39 L·m^(-2)·h^(-1),with a separation efficiency of 99.992%.These properties make it suitable for the long-term use in harsh operating environments.We attribute these properties to the electrostatic effect resulting from the amino group on UiO-66-NH_(2)and its in-situ growth on the CFM,which forms a size-screening separation layer.Our work highlights the potential of the CFM@UiO-66-NH_(2)membrane as an environmentally friendly size-screening material for the efficient emulsion wastewater separation.

Demulsification Behavior, Characteristics, and Performance of Surfactant Stabilized Oil-in-Water Emulsion under Bidirectional Pulsed Electric Field

As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.

Development and applications of solids-free oil-in-water drilling fluids

The increasing application of near balanced drilling technology to low-pressure and depleted fractured reservoirs requires the use of low-density drilling fluids to avoid formation damage. Solidsfree oil-in-water （O/W） emulsion drilling fluid is one type of low-density drilling fluid suitable for depleted fractured reservoirs. In this paper, the solids-free O/W drilling fluid was developed and has been successfully used in the Bozhong 28-1 oil and gas field, by which lost circulation, a severe problem occurred previously when drilling into fractured reservoir beds, was controlled, thereby minimizing formation damage. The O/W emulsion drilling fluid was prepared by adding 20% （by volume） No. 5 mineral oil （with high flash point, as dispersed phase） into seawater （as continuous phase）. Surfactant HTO-1 （as a primary emulsifier） and non-ionic surfactant HTO-2 （as a secondary emulsifier） were added into the drilling fluid system to stabilize the emulsion; and YJD polymer was also added to seawater to improve the viscosity of the continuous phase （seawater）. The drilling fluid was characterized by high flash point, good thermal stability and high stability to crude oil contamination.

Enhanced coalescence separation of oil-in-water emulsions using electrospun PVDF nanofibers

A novel and high-efficiency coalescence membrane enhanced by nano-sized polyvinylidene fluoride(PVDF)nanofibers based on polyester(PET)substrate was fabricated using electrospinning method.The properties of the electrospun nanofibers such as roughness and surface morphology greatly affected the oil droplet interception efficiency and surface wettability of the membrane.A series of coalescence units were prepared with different layers of nanofibrous membrane and the separation efficiencies at different initial concentrations,flow rates,and oil types were tested.It is very interesting that the obtained nanofibrous membrane exhibited superoleophilicity in air but poor oleophilicity under water,which was beneficial to the coalescence process.The coalescence unit with four membrane layers had excellent performances under different initial concentrations and flow rates.The separation efficiency of the 4-layers unit remained above 98.2%when the initial concentration reached up to 2000 mg·L-1.Furthermore,the unit also exhibited good performance with the increasing oil density and viscosity,which is promising for large-scale oil wastewater treatment.

Effects of Different Heavy Crude Oil Fractions on the Stability of Oil-in-water Emulsions—the film properties of heavy crude functional components and water system

A series of π-A isotherms are drawn to study the film properties of the components with Langmuir-Blodgett technique. The effects of the aromaticity of spread solvents and pH value on the air/water film formed by the components are investigated. Acid fraction and asphaltene can form stable two-dimensional insoluble films on an air/water surface. The surface film pressure of acid fraction and asphaltene is higher and more stable than that of the other fractions. The surface film pressure of the fraction increases evidently under the basic condition (pH=12). The results show that the interfacial activity of acid fraction and asphaltene is superior to that of the other fractions and the basic condition is favorable to the stability of the O/W emulsion.

Impact of sesame lignan on physical and oxidative stability of flaxseed oil-in-water emulsion

Recent studies have shown that the highly susceptibility to oxidation ofα-linolenic acid(ALA)enriched emulsion delivery system was harmful for human health which limited their incorporation into functional food.Impacts of natural sesamol(SOH)and sesamin(SES)on stability of flaxseed oil-in-water emulsion were investigated.Results showed that SOH indicated higher antioxidant activity and significantly prolonged the time of emulsion oil-off by retarding oil droplet aggregation in a dose dependent manner throughout storage.Moreover,SOH showed substantial extended lag phase of lipid oxidation products,especially for secondary oxidation products(thiobarbituric acid-reactive substances,TBARS),with a maximum reduction of 70%with 800 M dosage.The antioxidative efficiency of SOH might relate to its strong ability of scavenging free radical and chelate transition metal.Furthermore,SOH significantly enhanced interfacial barrier property and reduced permeation rate of peroxyl radical across emulsion interface by hydrogen bonds between sugar groups of saponin molecules and SOH.However,no obvious change in barrier property of emulsion was observed in SES.SOH improved physicochemical property of flaxseed oil-in-water emulsion with higher antioxidant activity and stronger interfacial barrier property,so that it could be serve as plant-based antioxidant in oil-in-water emulsion delivery system.

An antifouling catechol/chitosan-modified polyvinylidene fluoride membrane for sustainable oil-in-water emulsions separation

Low-pressure membrane filtrations are considered as effective technologies for sustainable oil/water separation.However,conventional membranes usually suffer from severe pore clogging and surface fouling,and thus,novel membranes with superior wettability and antifouling features are urgently required.Herein,we report a facile green approach for the development of an underwater superoleophobic microfiltration membrane via one-step oxidant-induced ultrafast co-deposition of naturally available catechol/chitosan on a porous polyvinylidene fluoride(PVDF)substrate.Membrane morphology and surface chemistry were studied using a series of characterization techniques.The as-prepared membrane retained the original pore structure due to the ultrathin and uniform catechol/chitosan coating.It exhibited ultrahigh pure water permeability and robust chemical stability under harsh pH conditions.Moreover,the catechol/chitosan hydrophilic coating on the membrane surface acting as an energetic barrier for oil droplets could minimize oil adhesion on the surface,which endowed the membrane with remarkable antifouling property and reusability in a cyclic oil-in-water(O/W)emulsion separation.The modified membrane exhibited a competitive flux of~428 L/(m^(2)·h·bar)after three filtration cycles,which was 70%higher than that of the pristine PVDF membrane.These results suggest that the novel underwatersuperoleophobic membrane can potentially be used for sustainable O/W emulsions separation,and the proposed green facile modification approach can also be applied to other water-remediation materials considering its low cost and simplicity.

Sustainable oil-in-water analysis using a supercritical fluid carbon dioxide extraction system directly interfaced with infrared spectroscopy

A direct aqueous supercritical fluid extraction （SFE） system using carbon dioxide provides a sustainable means by which a vast range of industries may continue to depend on well established infrared （IR） techniques to determine oil-in-water. The SFE-IR method provides an environmentally friendly substitute for current national standard IR reference methods for measuring oil-in-water that rely on using increasingly restricted ozone depleting solvents whose manufacture is being phased out in accordance with international law. The SFE-IR analysis of a 500 mL water sample can be accomplished in 15 min. A rapid on-line SFE-IR calibration method has been implemented. With this calibration method, SFE-IR accuracy for determining diesel oil in 500 mL spiked water samples using single wave number measurement was 86.0%-98.8% with precision （RSD） ranging from 2.5%-7.0%. Using a general purpose calculation which involves measuring infrared absorbance values at three different wave numbers, SFE-IR method accuracy for determining diesel oil in 500 mL spiked water samples was 83.7%-92.2% with RSD 1.0%-9.3%. Data is presented that indicates current long established national standard IR reference methods involving three wave number calculations should be reviewed since, without careful consideration, the inclusion of calculated aromatic hydrocarbon species contributions to final oil-in-water concentration values may provide less accurate results.

MILP synthesis of separation processes for waste oil-in-water emulsions treatment

This paper presents a novel synthesis method for designing integrated processes for oil-in-water （O/W） emulsions treatment. General superstructure involving alternative separation technologies is developed and modelled as a mixed integer linear programming （MILP） model for maximum annual profit. Separation processes in the superstructure are divided into three main sections of which the pretreatment and final treatment are limited to the selection of one altemative （or bypass） only, while within the intermediate section various combinations of different technologies in series can be selected. Integrated processes composed of selected separation techniques for given ranges of input chemical oxygen demand （COD） can be proposed by applying parametric analyses within the superstructure approach. This approach has been applied to an existing industrial case study for deriving optimal combinations of technologies for treating diverse oil-in- water emulsions within the range of input COD values between 1000 mg-L-1 and 145000 mgL t. The optimal solution represents a flexible and profitable process for reducing the COD values below maximal allowable limits for discharging effluent into surface water.

Selective separation of oil-in-water emulsion with high efficiency by bio-inspired Janus membrane

The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply controlling the surface wettability is difficult.Controlling the pore size of the membrane surface to achieve separation will lead to a sharp decrease in flux.Herein,inspired by cell membrane transportation,a hydrophilic/hydrophobic bifunctional Janus membrane for stable oil-in-water separation was prepared by simple surface polymerization and vapor diffusion.The prepared Janus membrane contained a hydrophobic side and hydrophilic polyamine layer.When used for oil-in-water emulsion separation,the polyamine layer accumulated micro/nanometer oil droplets,forming an oil layer on the hydrophobic surface.Water was retained by the 1H,1H,2H,2H-perfluorooctyl trichlorosilane layer,allowing oil droplets to selectively permeate through the membrane,achieving the separation effect.As the pore size of the modified fabric was basically unchanged,the permeation flux was fast(1.53×10^(3) Lm^(−2) h^(−1)).Furthermore,the poly(N,N-dimethylaminoethyl methacrylate)layer destroyed the emulsion stability,making the emulsion droplets aggregate without affecting the separation efficiency with fast permeation flux.Therefore,the prepared bifunctional Janus membrane shows great potential for actual wastewater treatment.

Effects of the original state of sodium-based additives on microstructure,surface characteristics and filtration performance of SiC membranes

Sodium-contained compounds are promising sintering additives for the low-temperature preparation of reaction bonded SiC membranes.Although sodium-based sintering additives in various original states were attempted,their effects on microstructure and surface properties have rarely been studied.In this work,three types of sodium-based additives,including solid-state NaA zeolite residue(NaA)and liquidstate dodecylbenzene sulfonate(SDBS)and water glass(WG),were separately adopted to prepare SiC membranes,and the microstructure,surface characteristics and filtration performance of these SiC membranes were comparatively studied.Results showed that the SiC membranes prepared with liquid-state SDBS and WG(S-SDBS and S-WG)showed lower open porosity yet higher bending strength compared to those prepared with solid-state NaA(S-NaA).The observed differences in bending strength were further interpreted by analyzing the reaction process of each sintering additive and the composition of the bonding phase in the reaction bonded SiC membranes.Meanwhile,the microstructural differentiation was correlated to the original state of the additives.In addition,their surface characteristics and filtration performance for oil-in-water emulsion were examined and correlated to the membrane microstructure.The S-NaA samples showed higher hydrophilicity,lower surface roughness(1.80μm)and higher rejection ratio(99.99%)in O/W emulsion separation than those of S-WG and S-SDBS.This can be attributed to the smaller mean pore size and higher open porosity,resulting from the originally solid-state NaA additives.Therefore,this work revealed the comprehensive effects of original state of sintering additives on the prepared SiC membranes,which could be helpful for the application-oriented fabrication by choosing additives in suitable state.

Emulsification of Indian heavy crude oil using a novel surfactant for pipeline transportation

The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this research,a novel surfactant,tri-triethanolamine monosunflower ester,was synthesized in the laboratory by extracting fatty acids present in sunflower（Helianthus annuus）oil.Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India.After emulsification,a dramatic decrease in pour point as well as viscosity was observed.All the prepared emulsions were found to be flowing even at 1°C.The emulsion developed with 60%oil content and 2wt%surfactant showed a decrease in viscosity of 96%.The stability of the emulsion was investigated at different temperatures,and it was found to be highly stable.The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension（IFT）between the crude oil（diluted）and the aqueous phase along with zeta potential of emulsions.2wt%surfactant decreased IFT by almost nine times that of no surfactant.These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.

Experimental investigation of the effects of various parameters on viscosity reduction of heavy crude by oil-water emulsion

The effects of water content, shear rate, temperature, and solid particle concentration on viscosity reduction （VR） caused by forming stable emulsions were investigated using Omani heavy crude oil. The viscosity of the crude oil was initially measured with respect to shear rates at different temperatures from 20 to 70℃. The crude oil exhibited a shear thinning behavior at all the temperatures. The strongest shear thinning was observed at 20℃. A non-ionic water soluble surfactant （Triton X-100） was used to form and stabilize crude oil emulsions. The emulsification process has significantly reduced the crude oil viscosity. The degree of VR was found to increase with an increase in water content and reach its maximum value at 50 % water content. The phase inversion from oil- oil emulsion occurred at 30 in-water emulsion to water-in- % water content. The results indicated that the VR was inversely proportional to temperature and concentration of silica nanoparticles. For water-in-oil emulsions, VR increased with shear rate and eventually reached a plateau at a shear rate of around 350 s^-1. This was attributed to the thinning behavior of the continuous phase. The VR of oil-in-water emulsions remained almost constant as the shear rate increased due to the Newtonian behavior of water, the continuous phase.

DEVELOPMENT AND APPLICATION OF WATER-IN-OIL EMULSIONS FOR ZINC HOT ROLLING

ＤＥＶＥＬＯＰＭＥＮＴＡＮＤＡＰＰＬＩＣＡＴＩＯＮＯＦＷＡＴＥＲ－ＩＮ－ＯＩＬ ＥＭＵＬＳＩＯＮＳＦＯＲＺＩＮＣＨＯＴＲＯＬＬＩＮＧＪｉａｎｇ；ＪｉａｎｃｈｕｎＭａｏ；Ｄａｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｃｈｉｎｅＥｎｇｉｎｅｅｒｉｎｇ，Ｃｅｎ...

Coconut Press Cake Alkaline Extract—Protein Solubility and Emulsification Properties

The solubility and the emulsification properties of a crude freeze dried alkaline protein extract (APE), 30% protein, obtained from coconut milk press cake by one step extraction at pH 11, were characterized at pH 2 to 11, and the cream and subnatant fractions of the emulsion studied by SDS-PAGE electrophoresis. The protein solubility followed U profile, showing a minimum at pH 3 to 4, close to but not identical to reported iso-electric points of 4 - 5 for many coconut protein fractions. The extract showed good capacity to form oil-in-water emulsion outside the low solubility pH range. The bands that appeared to play a role in the emulsification were found at 32 and 42 kDa in SDS-PAGE electrophoresis, but the most predominant absorbed band was at 23 kDa.

炼油催化裂化催化剂生产废水零排放处理的工业化应用

文章对炼油催化裂化催化剂生产废水类型进行分析,并对炼油催化裂化催化剂生产废水零排放处理工艺的具体工业化应用的工艺和炼油催化裂化催化剂生产废水零排放处理系统加以阐述,助力炼油催化裂化催化剂生产废水零排放的实现。