scholarly journals EFFECT OF PH CONDITIONS ON GOETHITE BEHAVIOR IN THE PRESENCE/ABSENCE OF DIFFERENT DISPERSANTS

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Svjetlana Sredić ◽  
Ljiljana Tankosić
Keyword(s):  
Zeta Potential ◽  
Surface Charge ◽  
Sodium Silicate ◽  
Ph Value ◽  
Sodium Hexametaphosphate ◽  
Surface Charges ◽  
Effect Of Ph ◽  
Ph Values ◽  
Ph Conditions ◽  
Settling Behavior

Dispersion and settling behavior of goethite has been studied and effect of pH values on surface properties of goethite particles with /without dispersants has been discussed. A prerequisite for the successful flocculation is the stabilization of the system which is achieved by the good dispersion of particles. The effect of pH, sodium silicate (Na2SiO3), sodium hexametaphosphate (Na6P6O18) and sodium pyrophosphate (Na4P2O7), on the surface charges of goethite was studied. The IEP of natural goethite was found by measuring zeta potential at pH value of 6.6. With the use of sodium silicate the IEP of goethite moves to pH 4.95. An IEP could not be detected when the poly-phosphates were used and the surface charge is negative from pH 2 to pH 12. The relatively high zeta potential values indicate a fairly stable dispersion, especially when the sodium hexametaphosphate were used as dispersant.

scholarly journals Kaolinite-Magnesite Based Ceramics. Part I: Surface Charge and Rheological Properties Optimization of the Suspensions for the Processing of Cordierite-mullite Tapes

2019 ◽  
Author(s):  
Aghiles Hammas ◽  
Gisèle Laure Lecomte-Nana ◽  
Nadjet Azril ◽  
Imane Daou ◽  
Claire Peyratout ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Sodium Silicate ◽  
Ph Value ◽  
Tape Casting ◽  
Casting Process ◽  
Sodium Hexametaphosphate ◽  
Cohesion Energy ◽  
Limit Values ◽  
Clay Slurry ◽  
Kaolinitic Clay

The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.

scholarly journals Kaolinite-Magnesite Based Ceramics. Part I: Surface Charge and Rheological Properties Optimization of the Suspensions for the Processing of Cordierite-Mullite Tapes

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 757 ◽  
Author(s):  
Aghiles Hammas ◽  
Gisèle Lecomte-Nana ◽  
Nadjet Azril ◽  
Imane Daou ◽  
Claire Peyratout ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Sodium Silicate ◽  
Ph Value ◽  
Tape Casting ◽  
Casting Process ◽  
Sodium Hexametaphosphate ◽  
Cohesion Energy ◽  
Limit Values ◽  
Clay Slurry ◽  
Kaolinitic Clay

The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite this, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by the Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate, respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.

scholarly journals Comparison of the influence of polyacrylamide and sodium oleate on selective flocculation of goethite from sludge

2021 ◽  
Vol 57 (1) ◽  
pp. 43-51
Author(s):  
Ljiljana Tankosić ◽  
S. Sredić
Keyword(s):  
Zeta Potential ◽  
Sodium Oleate ◽  
Iron Ore ◽  
Ph Value ◽  
Settling Rate ◽  
Selective Flocculation ◽  
Ph Values ◽  
Settling Behavior

The paper represents a part of research conducted with the aim of examining the possibility of applying selective flocculation of goethite from sludge that occurs in the process of iron ore production. The aim of this study was to compare the influence of polyacrylamide and sodium oleate as a flocculant on the settling behavior of goethite under different conditions. The paper presents the results of the research on the influence of the flocculants based on polyacrylamide and sodium oleate, as well as pH values on the settling rate of a natural goethite sample. The results showed that the settling rate of goethite was influenced by pH value and the type of flocculant, while the concentration of flocculant did not significantly affect the settling rate. Measurements of zeta potential showed the effect of flocculants on the surface of the goethite.

Adsorption of Organic Compounds on Refined Latvian Clay

2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka
Keyword(s):  
Methyl Orange ◽  
Zeta Potential ◽  
Adsorption Capacity ◽  
Clay Minerals ◽  
Organic Compounds ◽  
Clay Mineral ◽  
Rhodamine B ◽  
Ph Value ◽  
Ftir Spectra ◽  
Ph Values

Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.

Deflocculation of Alumina Suspensions Using Polyelectrolyte Dispersants

2007 ◽  
Vol 352 ◽  
pp. 81-84
Author(s):  
Yang Qiao Liu ◽  
Lian Gao
Keyword(s):  
Acrylic Acid ◽  
Zeta Potential ◽  
Synergistic Effect ◽  
Surface Charge ◽  
Functional Groups ◽  
Ph Value ◽  
Rheological Measurements ◽  
Gel Casting ◽  
Ph Range ◽  
Poly Acrylic Acid

In this paper, the dispersing abilities of three polyelectrolytes, poly (acrylic acid), poly (acrylic acid-co-acrylate), and a four-member copolymer containing various anionic functional groups were tested for aqueous Al2O3 suspensions. The influence of the dispersants on the surface charge of the powder was evaluated by measuring the zeta potential in dilute Al2O3 suspensions. It was found that all the three dispersants shifted the isoelectric point to a lower pH value. Rheological measurements showed that the four-member dispersant decreased the viscosity in the widest pH range, which should be ascribed to the synergistic effect of different functional groups. The 58vol% concentrated Al2O3 slurry using the four-member dispersant was further consolidated using gel casting and was fully sintered at 1600oC.

Effect of pH and Chemical Surfactant on Thermal Conductivity Enhancement of Cu-H2O Nanofluids

2008 ◽  
Author(s):  
Xinfang Li ◽  
Dongsheng Zhu ◽  
Xianju Wang ◽  
Nan Wang ◽  
Zhengdong Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Ph Value ◽  
Combined Treatment ◽  
Weight Fraction ◽  
Effect Of Ph ◽  
Conductivity Enhancement ◽  
Practical Applications ◽  
Heat Transfer Fluids ◽  
Ph Values ◽  
Thermal Constants

Nanofluids have been attractive for the last few years with the enormous potential to improve the efficiency of heat transfer fluids. This work focuses on the effect of pH and sodium dodecylbenzenesulfonate (SDBS) surfactant on the thermal conductivity of nanofluids.The thermal conductivity was measured by a Hot Disk Thermal Constants Anlyser. The results showed that the thermal conductivity enhancements of Cu–H2O nanofluids are highly dependent on the weight fraction of nanoparticle, pH values and SDBS surfactant concentration of nano-suspensions. The Cu–H2O nanofluids with an ounce of Cu have noticeably higher thermal conductivity than the base fluid without nanoparticles, For Cu nanoparticles at a weight fraction of 0.001 (0.1 wt %), thermal conductivity was enhanced by up to 10.7%, with an optimal pH value and SDBS concentration for the highest thermal conductivity. Therefore, the combined treatment with both the pH and chemical surfactant is recommended to improve the thermal conductivity for practical applications of nanofluid.

scholarly journals Effect of the Acidic and Alkaline Solutions on K2CrO4 and K2Cr2O7 by Ultraviolet and Visible Measurement

2019 ◽  
Vol 30 (1) ◽  
pp. 221
Author(s):  
Mohammad Radi Mohammad ◽  
Hasanain Saad Azeez
Keyword(s):  
Ph Value ◽  
Red Shift ◽  
Alkaline Solutions ◽  
Visible Spectroscopy ◽  
Solution Ph ◽  
Effect Of Ph ◽  
Ph Values ◽  
Uv Visible

In this work different amount of acidic (HCl) and alkaline (NaOH) solutions were added to stoke solutions of K2CrO4 and K2Cr2O7 to show the effect of pH values on their spectra. The results of UV-Visible spectroscopy shows that, the Changing of solution pH value when drops of HCl were added led to shift wavelength of K2CrO4 spectrum while no change has been occurred in K2Cr2O7 spectrum. However, Changing PH values solution by adding drops of NaOH led to change in wavelength red shift for K2Cr2O7 while no changes has been occurred in spectrum of K2CrO4.

scholarly journals The Flotation Separation of Magnesite and Limonite Using an Amine Collector

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiahong Han ◽  
Xiaoan Li ◽  
Shujuan Dai ◽  
Guozhen Liu
Keyword(s):  
Infrared Spectroscopy ◽  
Zeta Potential ◽  
Sodium Silicate ◽  
Carboxymethyl Cellulose ◽  
Sodium Carboxymethyl Cellulose ◽  
Sodium Hexametaphosphate ◽  
Electrostatic Adsorption ◽  
Adsorption Mechanisms ◽  
The Difference ◽  
Soluble Components

In order to reduce the iron impurities in magnesite ore and improve the purity of magnesium products, the difference in floatability between magnesite and limonite has been studied by using mixtures with a collecting agent—KD (cationic amine collectors, containing soluble components). Sodium hexametaphosphate, pH, sodium silicate, and sodium carboxymethyl cellulose were used as regulators. Adsorption mechanisms of the reagents on minerals were analyzed by a zeta potential analyzer and infrared spectroscopy. Sodium silicate increased the floatability of both minerals at 11.6. All the three regulators reduced the zeta potential of both minerals, while KD increased the zeta potential of magnesite and decreased the zeta potential of limonite. All the three regulators were likely chemically adsorbed on the surface of both minerals; KD has electrostatic adsorption on the surface of the minerals.

Effect of pH Values on Conversion of Calcite Crystals into Calcium Phosphate Phases in Buffer Solutions

2007 ◽  
Vol 353-358 ◽  
pp. 2183-2186 ◽  
Author(s):  
Ya Ping Guo ◽  
Bao Qiang Li ◽  
Yu Zhou ◽  
De Chang Jia
Keyword(s):  
Calcium Phosphate ◽  
Ph Value ◽  
Octacalcium Phosphate ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
Effect Of Ph ◽  
X Ray ◽  
Buffer Solutions ◽  
Ph Values

Calcium phosphate phases with laminar-plate structure were converted from calcite powders after soaking in phosphate buffer solutions of pH’s 6.0-8.0 at 37 °C for 9 days. The effect of pH values on the conversion of calcite crystals was investigated by X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. If the pH value of a buffer solution is kept at 6.0, calcite powders are converted mainly to dicalcium phosphate dehydrate (DCPD) or octacalcium phosphate (OCP). If the pH value is kept at 6.4 or 7.0, calcite powders are converted mainly to OCP. Hydroxyapatite (HAP) with poorly crystalline can be obtained from calcite powders both by treatment of a basic buffer solution, and by treatment of an acid buffer solution without regulating its pH value during the reaction. The conversion mechanism of calcite crystals is a dissolution-precipitation reaction.

scholarly journals The Proliferation Rule of Microcystis Aeruginosa Under Different Initial pH Conditions and its Influence on the pH Value of the Environment

2021 ◽  
Author(s):  
Sijie Wei ◽  
Guanjie Zhuang ◽  
Lirijian Cheng ◽  
Shoubing Wang
Keyword(s):  
Microcystis Aeruginosa ◽  
Ph Value ◽  
Control Strategies ◽  
Scientific Basis ◽  
Cyanobacterial Blooms ◽  
Ph Values ◽  
Inoculation Density ◽  
Initial Ph ◽  
Ph Conditions ◽  
Optimal Ph

Abstract This study investigated the characteristics of the proliferation process of Microcystis aeruginosa and its changes to environmental pH values under different initial pH values and different initial inoculation densities. The results showed that although the initial pH value or the initial inoculation density was different, the pH values of the culture systems fluctuated up and down throughout the proliferation of M. aeruginosa, both on a daily and hourly time scale, and then tended to stabilize around the same value of 10.0 at the end of proliferation. The optimal pH value for the proliferation of M. aeruginosa was 9.56. This study creatively proposes that the period when the environmental pH value starts to rise rapidly toward 9.0 could be selected as an early warning period for a cyanobacterial outbreak, and the environmental pH value could be adjusted to below 8.0 to delay the outbreak. These results provide a scientific basis for further understanding the mechanism of cyanobacterial blooms and formulating pH-based control strategies.

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