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.

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.

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.

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.

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。