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].

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 Research of Bare-Free Drilling Fluids

2021 ◽  
Vol 21 (3) ◽  
pp. 123-130
Author(s):  
Ekaterina L. Leusheva ◽  
Nazim T. Alikhanov
Keyword(s):  
Drilling Fluid ◽  
Inhibitory Effect ◽  
Rheological Parameters ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Geological Conditions ◽  
Water Based ◽  
Environmental Requirements ◽  
The Stability

Mining and geological conditions for the development of new fields are becoming more difficult every year. Accordingly, the requirements for ensuring the environmental and technological safety of the drilling process are becoming more and more important. To ensure such a process, it is necessary to use correctly selected drilling fluids with proper characteristics: rheological parameters sufficient for effective cleaning of the well bottom, density sufficient to create back pressure, fluid loss to ensure a high-quality filter cake. Modern environmental requirements dictate the abandonment of hydrocarbon-based solutions. But when using water-based solutions, there are no suitable solutions, especially with their high density, since the use of barite can lead to a decrease in reservoir productivity. In this regard, the analysis of the problem and the search for options for creating water-based drilling fluids, weighted without the addition of barite, having the properties of maintaining the stability of the wellbore, ensuring safe drilling and opening productive formations without damaging the reservoir characteristics, was carried out. Such a solution was found in changing the base of the drilling fluid - highly mineralized fluids or solutions based on saturated brines. Brines must be created on the basis of inorganic salts that have good solubility, for example, chlorides, bromides. Due to the content of salts, the fluids have an inhibitory effect, and depending on the volume of dissolution, the density of the drilling fluids can be controlled. The scientific works of foreign and domestic scientists analyzed in the article have been published over the past five years, which indicates the relevance of this development. The selected compositions are presented and theoretically investigated, which were also tested in the field conditions.

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

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.

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 Dye Separation and Antibacterial Activities of Polyaniline Thin Film-Coated Poly(phenyl sulfone) Membranes

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Javed Alam ◽  
Arun Kumar Shukla ◽  
Mohammad Azam Ansari ◽  
Fekri Abdulraqeb Ahmed Ali ◽  
Mansour Alhoshan
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Antibacterial Activities ◽  
Pani Film ◽  
Force Microscopy ◽  
Water Permeation ◽  
Membrane Pores ◽  
Membrane Performance ◽  
Phenyl Sulfone ◽  
The Impact

We fabricated a nanofiltration membrane consisting of a polyaniline (PANI) film on a polyphenylsulfone (PPSU) substrate membrane. The PANI film acted as a potent separation enhancer and antimicrobial coating. The membrane was analyzed via scanning electron microscopy and atomic force microscopy to examine its morphology, topography, contact angle, and zeta potential. We aimed to investigate the impact of the PANI film on the surface properties of the membrane. Membrane performance was then evaluated in terms of water permeation and rejection of methylene blue (MB), an organic dye. Coating the PPSU membrane with a PANI film imparted significant advantages, including finely tuned nanometer-scale membrane pores and tailored surface properties, including increased hydrophilicity and zeta potential. The PANI film also significantly enhanced separation of the MB dye. The PANI-coated membrane rejected over 90% of MB with little compromise in membrane permeability. The PANI film also enhanced the antimicrobial activity of the membrane. The bacteriostasis (BR) values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Escherichia coli were 63.5% and 95.2%, respectively. The BR values of PANI-coated PPSU membranes after six and sixteen hours of incubation with Staphylococcus aureus were 70.6% and 88.0%, respectively.

scholarly journals The Effect of pH and Storage Temperature on the Stability of Emulsions Stabilized by Rapeseed Proteins

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1657
Author(s):  
Karolina Östbring ◽  
María Matos ◽  
Ali Marefati ◽  
Cecilia Ahlström ◽  
Gemma Gutiérrez
Keyword(s):  
Zeta Potential ◽  
Storage Temperature ◽  
Emulsion Stability ◽  
Press Cake ◽  
Strong Impact ◽  
Soy Lecithin ◽  
Rapeseed Protein ◽  
Rapeseed Proteins ◽  
Precipitation Ph ◽  
The Stability

Rapeseed press cake (RPC), the by-product of rapeseed oil production, contains proteins with emulsifying properties, which can be used in food applications. Proteins from industrially produced RPC were extracted at pH 10.5 and precipitated at pH 3 (RPP3) and 6.5 (RPP6.5). Emulsions were formulated at three different pHs (pH 3, 4.5, and 6) with soy lecithin as control, and were stored for six months at either 4 °C or 30 °C. Zeta potential and droplet size distribution were analyzed prior to incubation, and emulsion stability was assessed over time by a Turbiscan instrument. Soy lecithin had significantly larger zeta potential (−49 mV to 66 mV) than rapeseed protein (−19 mV to 20 mV). Rapeseed protein stabilized emulsions with smaller droplets at pH close to neutral, whereas soy lecithin was more efficient at lower pHs. Emulsions stabilized by rapeseed protein had higher stability during storage compared to emulsions prepared by soy lecithin. Precipitation pH during the protein extraction process had a strong impact on the emulsion stability. RPP3 stabilized emulsions with higher stability in pHs close to neutral, whereas the opposite was found for RPP6.5, which stabilized more stable emulsions in acidic conditions. Rapeseed proteins recovered from cold-pressed RPC could be a suitable natural emulsifier and precipitation pH can be used to monitor the stability in emulsions with different pHs.

Novel Fiber-Optic Sensing System for Detection of Methane

2013 ◽  
Vol 562-565 ◽  
pp. 1008-1015 ◽  
Author(s):  
Shu Tao Wang ◽  
Peng Wei Zhang ◽  
Quan Min Zhu
Keyword(s):  
Fiber Optic ◽  
Detection System ◽  
Step Motor ◽  
Harmonic Detection ◽  
Distributed Feedback Laser ◽  
Gas Cell ◽  
Response Characteristics ◽  
The Stability ◽  
Application Fields ◽  
Methane Detection

Based on DFBLD (Distributed Feedback Laser Diode) and harmonic detection technique, a novel fiber-optic methane detection system is constructed. The system can be applied to broad-range concentration detection of methane. Based on the approximation express of the law of Beer-Lambert, detection of methane with various concentration from 0% to 20% is completed using subtraction of background and ratio processing method, as the atmosphere surroundings are treated as background noise. The direct absorption spectra for various concentration is measured using GRIN gas cell, combined with DFBLD. The R5 line of the 2v3 band of methane is selected as the absorption peak. The system is tested online during gas mixing process and the linear relationship between system indication and concentration variation is validated. Also the stability and dynamic response characteristics are confirmed by the experiments. The sensitivity of the system can be adjusted according to the concentration level of various field environments by changing the prism distance using step motor. In the range of 0% to 20% the sensitivity of methane detection can arrive at 0.001%. So the system can be applied to various application fields and adopted as monitoring instruments for coalmine tunnel and natural pipeline.

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