Stability of Suspensions and Emulsions Containing Illitic Clays

2016 ◽  
Vol 721 ◽  
pp. 337-342 ◽  
Author(s):  
Inga Jurgelane ◽  
Agnese Stunda-Zujeva ◽  
Liga Berzina-Cimdina
Keyword(s):  
Zeta Potential ◽  
Clay Minerals ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Safflower Oil ◽  
Iron Compounds ◽  
Oil In Water ◽  
Increasing Demand ◽  
The Stability

There are a lot of studies about colloidal stability of suspensions and emulsions containing clay minerals, but only few about illite containing clays. Due to increasing demand for eco cosmetics, research about the possibility to use natural colloidal particles (clay minerals) as stabilizers also increases. In this study illitic clays were used to investigate the stability of glycerol containing suspensions and safflower oil-in-water emulsions. Three types of clay samples were used – chemically untreated, after removal of carbonates and iron compounds. Viscosity and zeta potential of glycerol suspensions was determined. Samples with the highest viscosity were also the most stable. The removal of iron compounds significantly decreased the viscosity of suspensions and increased the zeta potential

Thin Films of Europium (III) Doped-TiO2 Prepared by Electrophoretic Deposition from Nanoparticulate Sols

2012 ◽  
Vol 507 ◽  
pp. 73-77 ◽  
Author(s):  
Mario Borlaf ◽  
Maria Teresa Colomer ◽  
Howard Titzel ◽  
James H. Dickerson ◽  
Rodrigo Moreno
Keyword(s):  
Thin Films ◽  
Zeta Potential ◽  
Electrophoretic Deposition ◽  
Colloidal Stability ◽  
Sol Gel ◽  
Complete Characterization ◽  
Constant Current ◽  
Molar Ratio ◽  
Versatile Technique ◽  
The Stability

Colloidal sol-gel is a common method used for the preparation of stable and homogeneous sols and thin films. The nanoparticulate sols can be easily deposited by EPD, which is a versatile technique for producing denser and thicker coatings than those produced by other techniques like dipping. A complete characterization of the sols, such as colloidal stability and electrophoretic mobility, which can be determined through zeta potential measurements, as well as the influence of deflocculants in the surface properties, is needed before using electrophoretic deposition. In this work, we have prepared sols of TiO2with an alkoxide:water molar ratio of 50:1 and Eu (III) doped-TiO2(2 mole % Eu (III)) using as precursors titanium (IV) isopropoxide and europium (III) acetate hydrate, respectively. The stability of the particulate sols was studied in terms of conductivity, zeta potential and viscosity evolution. Anatase stable sols, after peptization and without the use of any additive, were deposited on stainless steel substrates by electrophoretic deposition under both constant current and constant voltage conditions. Using different intensities and deposition times we have obtained thin films with different features (thicknesses and morphology) and different optical properties. The presence of europium (III) increases particle size, viscosity and peptization time and decreases the band gap of TiO2.

scholarly journals Characterization and Nanofluid Stability of CoFe2O4-APTES and CoFe2O4-PVA Nanoparticles

2020 ◽  
Vol 78 (1) ◽  
pp. 79-87
Author(s):  
Anis Arisa Roslan ◽  
Hasnah Mohd Zaid ◽  
Siti Nur Azella Zaine ◽  
Mursyidah Umar ◽  
Beh Hoe Guan
Keyword(s):  
Surface Modification ◽  
Zeta Potential ◽  
Performance Studies ◽  
Colloidal Stability ◽  
Amino Silane ◽  
Cobalt Iron Oxide ◽  
One Step ◽  
The Stability ◽  
Surface Modified ◽  
Surface Modified Nanoparticles

Nanofluid contains nanoparticles that enhanced the property of the base fluid. However, the separating layer between the nanoparticles and base fluids may interfere the nanofluids performance. Studies have been made that surface modification of nanoparticles may improve the dispersion of nanoparticles in base fluids. This paper reports the study of the colloidal stability of surface modified nanoparticles using a polymer and an amino-silane. The nanoparticles were prepared by one-step and two-step methods using cobalt iron oxide nanoparticles with brine solution and deionized water as the base fluids. Functionalization by surface modification of the nanoparticles to enhance the nanofluids stability was carried out using (3-aminopropyl) triethoxysilane (APTES) and polyvinyl alcohol (PVA). Characterization using Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscope (FESEM) and X-ray Powder Diffraction (XRD) were performed to study the functionality and morphology of the synthesized nanoparticles. The extra IR peaks such as Si-O-Si at 1063 cm-1 for CoFe2O4-APTES and C=O at 1742 cm-1 for CoFe2O4-PVA showed that there are additional elements in the cobalt ferrite due to functionalization. The size of synthesized CoFe2O4-APTES ranged between 15.99 nm to 26.89 nm while CoFe2O4-PVA is from 25.70 nm to 54.16 nm. The stability of the nanofluid were determined via zeta potential measurements. CoFe2O4-APTES nanofluid has zeta potential of -35.7 mV compared to CoFe2O4-PVA at -15.5 mV.

scholarly journals Nanomagnetit-bentonit vizes közegű diszperz rendszereinek zeta-potenciáljának vizsgálata

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Ákos Pintér-Móricz ◽  
Renáta Dr. Zákányiné Dr. Mészáros
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Colloidal Stability ◽  
Salt Content ◽  
Fluid Loss ◽  
Drilling Process ◽  
Hybrid Particles ◽  
The Stability ◽  
Application Fields ◽  
Drilling Muds

The stability of different type nanomaterials play an important role among recent scientific and industrial challenges, including the examination of the effect of polymers, surfactants and their mixture on surface and electric surface properties and aggregation extent of dispersed particles, which are of utmost importance. Bentonite and its composite with different nanomaterials are frequently used for instance in environmental protection for wastewater treatment, since due to their great specific surface area they have excellent sorption properties. There are several publications in the literature for the application of bentonite in drilling muds. By using them the fluid loss can be decreased during the drilling process, the filtration of the fluid can be increased, it also improves the rheological properties and the formation damage can also be mitigated. During research the investigation and the analysis of the zeta-potential of nanoparticles and their composites at different pH and salt content can be an interesting topic. During our experiments the electric surface properties of nanomagnetite synthetized in laboratory (NM), cation exchanged bentonite from Mád (Be) and the composite particles of these particles were investigated. Hybrid particles of different compositions (9:1, 7:3, 1:1, 3:7, 1:9) were analyzed at different potassium chloride concentrations (0.1 – 0.0001 M). The surface adsorption on the surface, i.e. the change in the surface charge can be traced well by analyzing the obtained zeta-potential values. The behavior of such systems was observed in the full pH interval, thus, valuable data were obtained regarding the colloidal stability. As for the stability, different requirements may emerge in practice, there are application fields where the colloidally stable system is advantageous, on the other hand, in some cases, ceasing the stabile system is the goal. Our investigations are of high importance in terms of stability and its characterization [1].

Effect of PEG on Stability of Alkalinity Silica Sol

2011 ◽  
Vol 399-401 ◽  
pp. 2314-2317
Author(s):  
Juan Wang ◽  
Ming Sun ◽  
Bao Hong Gao ◽  
Ru Wang ◽  
Yu Ling Liu
Keyword(s):  
Molecular Weight ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Silica Sol ◽  
Kinetic Stability ◽  
Solution Ph ◽  
Factors Affecting ◽  
Main Factors ◽  
Silica Dispersion ◽  
The Stability

It is known that the rate of coagulation depends mainly on the stability of the colloidal particles and that the solution pH and potential are the main factors affecting the colloidal stability. The stability of dispersion (the ability of the dispersion to resist coagulation) may be related to its kinetic stability, which in turn depends on the force barrier preventing collision between the particles and thus preventing their coagulation. The addition of surfactant can change the pH and the potential of silica sol. So PEG is select to improve the stability of silica sol. The results presented here show that surfactant, PEG, has a strong consequence on the stability of silica dispersion. With the molecular weight increasing, the stability of silica sol is weakening.

Study on the Stability of Alkaline Silica Sol

2012 ◽  
Vol 430-432 ◽  
pp. 764-767
Author(s):  
Juan Wang ◽  
Yan Yan Huang ◽  
Ru Wang ◽  
Ming Sun ◽  
Yu Ling Liu
Keyword(s):  
Colloidal Particles ◽  
Colloidal Stability ◽  
Silica Sol ◽  
Low Molecular Weight ◽  
Solution Ph ◽  
Factors Affecting ◽  
Main Factors ◽  
Silica Dispersion ◽  
The Stability ◽  
Silicon Sol

The stability of slurry has a great effect upon the stability of polishing quality. At present the slurry of CMP includes SiO2 is applied in different fields respectively. But silicon sol is not enough to meet the requirement of CMP because of its instability. So the stability of silica sol is studied in this paper. It is known that the rate of coagulation depends mainly on the stability of the colloidal particles and that the solution pH and potential are the main factors affecting the colloidal stability. The stability of dispersion (the ability of the dispersion to resist coagulation) may be related to its kinetic stability, which in turn depends on the force barrier preventing collision between the particles and thus preventing their coagulation. The addition of surfactant can change the pH and the potential of silica sol. So o-20、JFC and PEG are selected to improve the stability of silica sol. The results presented here show that surfactant, PEG with low molecular weight, has a strong consequence on the stability of silica dispersion.

scholarly journals Effect of Tris and acetic acid on the stability of titania nanoparticles in different alcohols and their electrophoretic deposition process

2018 ◽  
Vol 12 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Morteza Farrokhi-Rad
Keyword(s):  
Acetic Acid ◽  
Zeta Potential ◽  
Electrophoretic Deposition ◽  
Colloidal Stability ◽  
Optimum Concentration ◽  
Titania Nanoparticles ◽  
Potential Measurement ◽  
The Stability ◽  
Kinetics Of ◽  
Titania Coating

Tris (tris(hydroxymethyl)aminomethane) was used as the dispersant to enhance the colloidal stability of titania nanoparticles in different alcohols (methanol, ethanol, isopropanol and butanol). Acetic acid (AA) was also used to increase the ionization of Tris via acid-base reaction. The effect of Tris on the stability of suspensions in the absence as well as the presence of AA was investigated by different analysis, such as conductivity and zeta potential measurement as well as FTIR analysis. It was found that Tris is protonated and adsorbed on the titania nanoparticles. It enhances their zeta potential and thus colloidal stability. The optimum concentration of Tris increased with molecular weight of alcohol (0.1, 0.2, 0.3 and 0.6 g/l for methanolic, ethanolic, isopropanolic and butanolic suspensions, respectively). The optimum concentration of Tris decreased to 0.1 g/ l for all AA containing suspensions except the methanolic ones. Titania coating was obtained by electrophoretic deposition (EPD) performed at 60 V. The current density and in-situ kinetics of deposition were recorded during EPD. It was found that the kinetics of EPD is the fastest for the suspensions with the optimum concentration of Tris (the highest zeta potential). Calcium phosphate phases were formed on the surface of titania coating after its immersion for one week in SBF at 37.5?C.

How to use alum with cationic dispersed rosin size

TAPPI Journal ◽  
2016 ◽  
Vol 15 (5) ◽  
pp. 331-335 ◽  
Author(s):  
LEBO XU ◽  
JEREMY MYERS ◽  
PETER HART
Keyword(s):  
Zeta Potential ◽  
Colloidal Particles ◽  
Streaming Potential ◽  
Excessive Amount ◽  
Paper Machine ◽  
Optimum Amount ◽  
Potential Measurement ◽  
Streaming Current ◽  
Wide Range ◽  
Laboratory Results

Retention of cationic dispersed rosin size was studied via turbidity measurements on stock filtrate with different alum and dispersed rosin size dosages. Stock charge characteristics were analyzed using both an analysis of charge demand determined via a streaming current detector and an evaluation of zeta potential of the fibers by streaming potential measurement. The results indicated that an optimum amount of alum existed such that good sizing retention was maintained throughout a wide range of dispersed rosin size dosages. However, when an excessive amount of alum was used and fines and colloidal particles were transitioned from anionic to cationic, the cationic size retention was reduced. Laboratory results were confirmed with a paper machine trial. All data suggested that a stock charge study was necessary to identify optimal alum dosage for a cationic dispersed rosin sizing program.

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
A.M. Zetty Akhtar ◽  
M.M. Rahman ◽  
K. Kadirgama ◽  
M.A. Maleque
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Base Fluid ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Cutting Zone ◽  
Observation Method ◽  
The Stability ◽  
The Relationship ◽  
Zeta Potential Analysis

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

scholarly journals New approach in process intensification based on subcritical water, as green solvent, in propolis oil in water nanoemulsion preparation

2021 ◽  
Vol 10 (1) ◽  
pp. 208-218
Author(s):  
Fatemeh Ghavidel ◽  
Afshin Javadi ◽  
Navideh Anarjan ◽  
Hoda Jafarizadeh-Malmiri
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Zeta Potential ◽  
Subcritical Water ◽  
Process Intensification ◽  
Processing Parameters ◽  
Bioactive Materials ◽  
Propolis Extract ◽  
High Antibacterial Activity ◽  
Oil In Water

Abstract Subcritical water was used to provide propolis oil in water (O/W) nanoemulsions. To monitor and detect the main bioactive compounds of the prepared propolis extract, gas chromatography demonstrated that there were 47 bioactive materials in the propolis extract, among which pinostrobin chalcone and pinocembrin were the two key components. Effectiveness of two processing parameters such as the amount of saponin (0.5–2.0 g) and propolis extract (0.1–0.6 g), on particle size, polydispersity index (PDI), zeta potential, and antioxidant activity of the provided nanoemulsions, was evaluated. Results demonstrated that more desirable propolis O/W nanoemulsion, with minimum particle size (144.06 nm) and PDI (0.286), and maximum zeta potential (−21.71 mV) and antioxidant activity (90.86%) were made using 0.50 g of saponin and 0.53 g of propolis extract. Further analysis revealed that the prepared nanoemulsion based on optimum processing conditions had spherical shaped propolis nanodroplets in the colloidal solution with turbidity and maximum broad absorption peak of 0.08 a.u. and 292 nm, respectively. The prepared nanoemulsion had high antibacterial activity against both selected bacteria strains namely, Staphylococcus aureus and Escherichia coli.

scholarly journals Influence of Whey Protein Micro-Gel Particles and Whey Protein Micro-Gel Particles-Xanthan Gum Complexes on the Stability of O/W Emulsions

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2301
Author(s):  
Man Zhang ◽  
Bin Liang ◽  
Hongjun He ◽  
Changjian Ji ◽  
Tingting Cui ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Whey Protein ◽  
High Speed ◽  
Xanthan Gum ◽  
Physical Stability ◽  
Theoretical Support ◽  
Gel Particles ◽  
Oil In Water ◽  
The Stability ◽  
The Impact

Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation.

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