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.

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.

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.

scholarly journals THE DISPERSION-FLOCCULATION BEHAVIOUR OF THE NATURAL RAW CLAY SAMPLES FROM OMARSKA MINE

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ljiljana Tankosić ◽  
Svjetlana Sredić ◽  
Pavle Tančić ◽  
Zoran Nedić
Keyword(s):  
Zeta Potential ◽  
Clay Minerals ◽  
Bosnia And Herzegovina ◽  
Iron Ore ◽  
Sodium Pyrophosphate ◽  
Sodium Hexametaphosphate ◽  
Selective Flocculation ◽  
Iron Minerals ◽  
Waste Sludge ◽  
The Individual

In present paper, studied were the dispersion-flocculation behaviour of the primary natural raw „clay samples” from Omarska mine (Republic of Srpska, Bosnia and Herzegovina). Namely, our previous results showed that during the processing of iron ore in the Omarska mine, large quantities of fine sized (15μm) waste sludge, with relatively high Fe concentrations, were generated. Sludge samples are composed of major goethite and quartz, less clay minerals, and minor magnetite and todorokite. Selective flocculation is one of the methods that can be applied for the separation of fine class iron minerals from impurities and depends on the individual components of the sludge and their behaviour. This paper presents part of the research of the individual components of the sludge. The „clay samples” are composed of major quartz and clay minerals, which dominate over minor contents of feldspars, amphiboles, goethite and hematite. The clay minerals were identified as mostly illite-sericite which prevails over kaolinite, and with chlorites which appears only sporadically. The dispersion-flocculation behaviour was studied by settling and flocculation experiments and Zeta potential measurements. A three different dispersants (sodium hexametaphosphate, sodium-pyrophosphate and sodiumsilicate), and anionic and non-ionic polyacrylamide (PAM) flocculants were used. It was established that the best results were achieved with sodium-hexametaphosphate (1000 g/t) and anionic A100 PAM.

scholarly journals Effect of Chitosan/BSA Addition on the Physical Stability of Sunflower Oil Emulsions

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Fengyan Zhou ◽  
Guo Li ◽  
Jianying Huang
Keyword(s):  
Particle Size ◽  
Bovine Serum Albumin ◽  
Zeta Potential ◽  
Sunflower Oil ◽  
Storage Stability ◽  
Emulsion Stability ◽  
Ph Value ◽  
Physical Stability ◽  
Ph Values ◽  
Oil Emulsions

Proteins and polysaccharides are important ingredients and additives in food field. The aim of this study was to study the effect of chitosan and bovine serum albumin (BSA) solution on the physical stability of sunflower oil emulsions at different pH values, temperatures, and BSA/chitosan ratios during 20-day storage in terms of their storage stability, zeta potential, particle size, and microstructure. The results showed that pH, protein/polysaccharide ratio, and temperature significantly influenced the physical stability of emulsions at lower pH. The emulsion stability decreased as the test temperatures increased, and the storage stability of BSA/chitosan coated oil emulsions was obtained when the ratio was from 8 : 1 to 1 : 1 under 4°C for 20-day storage when pH values were 3.0 and 4.0. Droplet flocculation happened with the increase of chitosan addition and pH value.

Characteristics of wood-silica composites influenced by the pH value of silica sols

Holzforschung ◽  
2018 ◽  
Vol 72 (4) ◽  
pp. 311-319 ◽  
Author(s):  
Jun Jiang ◽  
Jinzhen Cao ◽  
Wang Wang
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Dimensional Stability ◽  
Colloidal Particle ◽  
Ph Value ◽  
Surface Hardness ◽  
X Ray ◽  
Ph Values ◽  
First Case ◽  
Silica Sols

AbstractSouthern pine (Pinusspp.) sapwood samples were impregnated with silica sols with known zeta potential and particle size distribution at various pH values (3, 5, 7, 9, 11 and 13) to produce wood-silica composites (WSiCs). The morphological and chemical properties of the composites were evaluated by scanning electron microscopy-energy dispersive X-ray (SEM-EDXA) and Fourier transform infrared (FTIR) spectroscopy. The overall performance of the composites was characterized by X-ray diffraction (XRD) and thermogravimetric (TG) analysis, and dynamic wettability tests, and their dimensional stability and surface hardness were also investigated as well. The pH value of the sols had a remarkable effect on the distribution of zeta potential and colloidal particle size, and on their penetration and distribution in the wood. The composites produced at pH 5 and pH 11 show relatively better impregnability and overall properties. In the first case the compatibility with the wood pH (ca. 5) is relevant, and at these pH values are the sol’s particle sizes low. Sols with pH around 13 resulted in inferior properties, such as increased water absorption, high thermal degradation and poor dimensional stability. This could be ascribed to wood degradation under high alkaline conditions. The results were discussed in view of the colloidal particle redistribution and the interaction between silica sol and wood.

Electrokinetic Properties and Their Effect on Thermal Conductivity of Nanofluids

2008 ◽  
Author(s):  
S. M. Sohel Murshed ◽  
Kai Choong Leong ◽  
Chun Yang
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Effective Thermal Conductivity ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Deionized Water ◽  
Ph Values ◽  
Nacl Concentration ◽  
Effects Of Ph ◽  
Similar Decrease

This paper presents the effects of pH value, surfactant, and electrolyte concentration on zeta potential and effective thermal conductivity of nanofluids. The zeta potential of TiO2 (15 nm) nanoparticles in deionized water of different pH values was measured and the iso-electrical point was found to be between 4.9 and 5.2. The results show that the higher the electrolyte concentration, the smaller the particle zeta potential, which results in increased agglomeration of particles. The enhanced thermal conductivity of TiO2/deionized water-based nanofluids was found to decrease with increasing pH value or electrolyte concentration. For example, for 0.2 volume %, the thermal conductivity of this nanofluid was found to decrease from 5.5% to 2.5% when the pH value was increased from 3.4 to 9. A similar decrease (≈ 2%) in thermal conductivity was observed when NaCl concentration was increased from 0.01 mM to 10 mM. The presence of a surfactant showed considerably larger enhancement of the effective thermal conductivity compared to that of nanofluids without surfactant.

scholarly journals Critical importance of pH and collector type on the flotation of sphalerite and galena from a low-grade lead–zinc ore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdolrahim Foroutan ◽  
Majid Abbas Zadeh Haji Abadi ◽  
Yaser Kianinia ◽  
Mahdi Ghadiri
Keyword(s):  
Iron Ore ◽  
Low Grade ◽  
Zinc Recovery ◽  
Flotation Process ◽  
Ph Values ◽  
Lead And Zinc ◽  
Optimum Ph ◽  
Iron And Zinc ◽  
Lead Zinc ◽  
Zinc Concentrate

AbstractCollector type and pulp pH play an important role in the lead–zinc ore flotation process. In the current study, the effect of pulp pH and the collector type parameters on the galena and sphalerite flotation from a complex lead–zinc–iron ore was investigated. The ethyl xanthate and Aero 3418 collectors were used for lead flotation and Aero 3477 and amyl xanthate for zinc flotation. It was found that maximum lead grade could be achieved by using Aero 3418 as collector at pH 8. Also, iron and zinc recoveries and grades were increased in the lead concentrate at lower pH which caused zinc recovery reduction in the zinc concentrate and decrease the lead grade concentrate. Furthermore, the results showed that the maximum zinc grade and recovery of 42.9% and 76.7% were achieved at pH 6 in the presence of Aero 3477 as collector. For both collectors at pH 5, Zinc recovery was increased around 2–3%; however, the iron recovery was also increased at this pH which reduced the zinc concentrate quality. Finally, pH 8 and pH 6 were selected as optimum pH values for lead and zinc flotation circuits, respectively.

scholarly journals Bonding of Selected Hardwoods with PVAc Adhesive

2020 ◽  
Vol 11 (1) ◽  
pp. 67
Author(s):  
Ján Iždinský ◽  
Ladislav Reinprecht ◽  
Ján Sedliačik ◽  
Jozef Kúdela ◽  
Viera Kučerová
Keyword(s):  
Adhesion Strength ◽  
Cold Water ◽  
Ph Value ◽  
Water Extract ◽  
Solid Wood ◽  
Contact Angles ◽  
Water Contact ◽  
Ph Values ◽  
Positive Tendency ◽  
The Impact

The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion strength was significantly with positive tendency influenced by their higher densities, lower roughness parameters perpendicular to the grain, and lower water contact angles.

scholarly journals Microstructure and Properties of Self-Assembly Graphene Microcapsules: Effect of the pH Value

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 587 ◽  
Author(s):  
Yan-Dong Guo ◽  
Jun-Feng Su ◽  
Ru Mu ◽  
Xin-Yu Wang ◽  
Xiao-Long Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Engineering ◽  
Ph Value ◽  
Liquid Paraffin ◽  
Energy Dispersive Spectrometer ◽  
Core Material ◽  
Microstructure And Properties ◽  
Ph Values

Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.

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