Effect Of Sodium Oleate Research Articles

Quantifying bubble-scheelite interaction under the effect of sodium oleate

Scheelite (CaWO4) is mainly collected through froth flotation. It has significant applications in the manufacturing of alloys and steels. To better understand bubble-scheelite attachment mechanisms, we probed the interaction force between a bubble and a scheelite surface using an atomic force microscope (AFM) and investigated the way in which sodium oleate and calcium ions affected how the bubble attached. The results showed that the electrical double layer (EDL) force was the main repulsive force that inhibited the scheelite-bubble attachment. Adding 0.01 mM of sodium oleate (NaOl) to the solution could hydrophobize the scheelite surface, allowing the hydrophobic attraction to dominate bubble-scheelite interaction. Increasing the NaOl concentration from 0.01 mM NaO1 to 0.02 mM made the scheelite and bubble’s zeta potential more negative, resulting in a stronger EDL repulsion. Increasing the NaOl concentration also reduced the interfacial tension of the bubble, which could inhibit the bubble-scheelite attachment; accordingly, the air bubble cannot attach to the scheelite surface when NaOl concentration was 0.02 mM. Adding calcium ions significantly reduced the magnitude of the scheelite and bubble’s zeta potential, which was increased by adding the NaOl. Reducing the magnitude weakened the EDL repulsive force and facilitated the bubble attachment. The interfacial tension for the air bubble was significantly increased from 39.5 to 69.8 mM/m, when the calcium ions concentration was only 1 mM, which could increase the Laplace pressure and benefit the bubble attachment. The weakened repulsive force and the increased interfacial tension led to the scheelite-bubble attachment. Micro-flotation tests also verified that the excessive NaOl concentration was detrimental for scheelite flotation and that the adverse effects could be eliminated by adding calcium ions. This study yielded quantitative data on the interaction forces between a scheelite surface and a bubble, providing a better understanding of the fundamental interaction mechanisms for bubble-scheelite attachment in mineral flotation.

Effect of Sodium Oleate on the Adsorption Morphology and Mechanism of Nanobubbles on the Mica Surface.

Nanobubbles promote the flotation of fine-grained minerals. In the associated mechanism, the aggregation of fine particles is first promoted, which increases the probability of collision between particles and bubbles. However, the interaction between nanobubbles and mineral particles is often neglected, especially when the surface properties of the nanobubbles are modified by flotation collectors. In this study, the interaction mechanism between nanobubbles and the mica surface is investigated by nanoparticle tracking analysis, zeta potential measurement, and atomic force microscopy. The results reveal that the hydrophobic group of sodium oleate points toward the inside of the nanobubble and the hydrophilic group faces outward after the interaction of sodium oleate molecules and nanobubbles. A surfactant micelle with nanobubbles as the core is formed, thus considerably reducing the concentration of sodium oleate to form micelles. The adsorption of the modified nanobubbles on the mineral surface is carried out by the specific adsorption of the exposed hydrophilic group and the mineral surface. This adsorption method is superior to the hydrophobic interaction between the nanobubbles and the hydrophobic mineral surface. Further, the nanobubbles are highly selective for the activation sites on the mineral surface in the adsorption mode. This study will help understand the interaction between nanobubbles and collectors to further apply nanobubbles to treat fine-grained mineral particles.

Sodium Oleate Increases Ampicillin Sensitivity in Methylophilus quaylei Biofilms on Teflon and Polypropylene

Drug combination is a new therapy to improve antibiotic deficiency treatment towards biofilm resistance. This study was conducted to determine the potential effect of sodium oleate to inhibit established biofilms of two strains, methylotrophic bacteria Methylophilus quaylei in combination with ampicillin. Minimum inhibitory concentration (MIC) of ampicillin was determined and added in combination with sodium oleate and examined on planktonic and established biofilms of two strains M. quaylei were characterized by different properties of cell surface hydrophobicity. The effect on biofilms was evaluated by the number of colony forming units (CFUs), crystal violet assay, light and scanning electron microscopy. The study demonstrates that sodium oleate has a promoting activity against planktonic growth of M. quaylei strains and has a slight inhibitory effect on biofilm. Addition of sodium oleate enhances the bactericidal effect of ampicillin against biofilm cells. Combination of ampicillin 0.1 mg/ml (MIC) and sodium oleate 0.03 mg/ml showed a remarkable destruction effect on established biofilms. Combination of ampicillin 0.1 mg/ml (MIC) and sodium oleate 0.03 mg/ml showed a remarkable destruction effect on established biofilms. Overall, results indicated that sodium oleate in combination with ampicillin enhances the inhibition of M. quaylei biofilms and this combination can be utilized for combating bacterial biofilm resistance. Overall, results indicated that sodium oleate in combination with ampicillin enhances the inhibition of M. quaylei biofilms and this combination can be utilized for combating bacterial biofilm resistance.

Preparation and characterization of ultra-hydrophobic calcium carbonate nanoparticles

Anionic surfactants based on fatty acids are usually used to modify the particle surface properties of CaCO3 with the aim to enhance its dispersion and compatibility with polymer matrices. In this study sodium oleate was used for the preparation of ultrahydrophobic CaCO3 nanoparticles using a wet carbonation route. The effect of sodium oleate on the characteristics, particle size, morphology, surface potential, thermal decomposition and hydrophobicity of CaCO3, was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), Zeta potential, thermogravimetric analysis (TGA) and water contact angle measurement (WCA). The results showed that the addition of 2 wt% sodium oleate helps in reducing the particle size from 2 μm length scalenohedral particles to 45 nm rhombohedral particles and modifying of the hydrophobic property of CaCO3.

Flotabilidade da apatita e minerais de ganga provenientes de minério sílico-carbonatado com oleato de sódio

O beneficiamento dos minérios fosfáticos com ganga silicatada e carbonatada é estritamente necessário para aumentar a produção de concentrados fosfáticos e para suprir a demanda nacional de fertilizantes. Visando a processar esses minérios, esse trabalho estudou, através de testes de microflotação e medidas de potencial zeta, o efeito do oleato de sódio, do amido de milho e da carboximetilcelulose (CMC) na superfície dos minerais puros originários do minério sílico-carbonatado de Catalão/GO. Os resultados obtidos mostraram a possibilidade de separação seletiva da apatita, por flotação direta em pH igual a 9, usando-se oleato de sódio como coletor, na ausência de depressores, o que seria inviável industrialmente. Tanto a CMC como o amido deprimem a dolomita, mas não são seletivos, pois deprimem, também, a apatita. O amido apresenta ação depressora sobre a apatita mais forte que a CMC.

Effect of sodium oleate as a buffer on the synthesis of superparamagnetic magnetite colloids

In this study, superparamagnetic monodisperse magnetite colloids, around 5 nm in size, were prepared by dissolving iron chlorides, sodium hydroxide (NaOH) and sodium oleate (NaOL), in toluene/ethanol/water mixtures and refluxing for 4 h. The concentrations of NaOH and NaOL were varied to systematically investigate the effect on the surface properties, size, dispersion, and magnetic properties of magnetite nanoparticles (MNPs). The samples were characterized via XRD, FTIR, TGA, TEM, SAED, DLS, and VSM. The results indicated that the surface coatings of MNPs could be manipulated from oleate to hydroxyl groups via increasing the molar ratio of NaOH/Fe(II) more than 8. The amount of NaOH had no obvious influence on the size and the saturation magnetization of MNPs. Therefore NaOH was not a necessary reactant for forming magnetite crystals. On the contrary, NaOL was shown to be the most important component for synthesizing stable magnetite colloids. The NaOL acted as both a key reactant to buffer the pH environment and a surfactant to keep the MNPs stable in nonpolar solvent media.

OPTIMIZATION OF ALUMINA FLOTATION FROM GIBBSITE BEARING-SHALE OF SOUTH WESTERN SINAI, EGYPT BY USING SODIUM OLEATE AS A COLLECTOR

The effect of sodium oleate on the flotation of alumina was studied using samples of gibbsite bearing–shale of south western Sinai, Egypt. The assays of the samples are 18.98% Al2O3, 15.45% SiO2, 12.83% Fe2O3, 14.87% CaO, 5.74% P2O5, 5.34% MnO, 0.86% K2O, 0.76% Na2O, 1.50% trace elements and 23.65% loss on ignition. The aim of this research is to upgrade alumina in the concentrate to be suitable for the industrial applications. Various operating variables (i. e. pH, pulp density, collector dosage, and particle size) affecting the flotation process of gibbsite were studied. Sodium oleate used as an anionic collector; as well as, sodium hydroxide was used as a pH modifier. The optimum conditions obtained were as follows: pH = 11, collector dosage = 2000 g/t, pulp density = 250 g/l and particle size = (-100+80) µm. At these conditions, a concentrate having a grade of 40.1% alumina with component recovery of 96.1% was obtained. The grades of the other ore constituents in final concentrate were as follows: SiO2 was decreased from 14.2% to 5.9%, CaO was decreased from 14.1% to 4.8%, Fe2O3 was decreased from 13.1% to 5.4%, P2O5 was decreased from 4.3% to 3.2%, MnO was decreased from 4.2% to 3.5%, while K2O was increased from 0.89% to 1.3%, Na2O was also increased from 0.69% to 1.2%, traces were increased from 1.6% to 2.7%, and loss on ignition was increased from 25.4% to 31.9%. The component recoveries of SiO2, CaO, Fe2O3, P2O5, MnO, K2O, Na2O, and traces of the final concentrate were 21.4%, 17.5%, 21.2%, 38.4%, 42.9%, 75.3%, 89.6%, and 86.9%, respectively. The mass recovery of final concentrate was 51.5%.

Two stage flotation of sodium feldspar – from laboratory to industrial application

In this study, results are presented of laboratory flotation tests and industrial application to separate colouring minerals (muscovite, biotite, rutile, sphene), some iron oxides and clays from Çine-Ceyhan sodium feldspar ore owned by Kalemaden A.S. In the first stage, conventional mica flotation was carried out at pH 2·5–3 by using tallow amine acetate as collector together with a frother mixture of 50% MIBC and 50% pine oil. Following mica flotation, in the second stage, the effect of sodium oleate, pH and the fineness of grind were tested. Experimental studies indicated that the ore should be ground to –300 μm and clayey slimes (–25μm) washed out prior to flotation so as to separate colouring gangue minerals effectively. Under optimum conditions, a high quality concentrate containing 0.1% TiO2 + Fe2O3 and giving very glossy white firing test button at 1260°C was obtained by two stage flotation at pH 2·5–3 with 225 g/t Armac TD for micas and at pH 5·5–6·5 with 2000 g/t Na-oleate for titanium and iron oxides. Based on the extensive experimental data, a flotation plant was designed, built and started up in November 1999.

Effect of sodium oleate on inhibiting pyrite oxidation

The oxidation and acid production behavior of both ore and coal pyrites with and without a hydrophobic surface coating of sodium oleate was investigated. The results showed that pyrite surface was passivated by sodium oleate coating, which substantially reduced or even eliminated moist air oxidation. Without the hydrophobic surface coating, coal pyrite displayed higher oxidation and acid production rate than ore pyrite. It was also found that the acid production by pyrite in aqueous solution obeys a zeroth order dissolution reaction with respect to hydrogen ions. The nature of the surface coating was characterized by electrochemical, contact angle and zeta potential measurements.

Effects of oleate and fatty acids from omental adipocytes on insulin uptake in rat liver cells.

Hyperinsulinemia in central type (upper body) obesity has been related to reduced hepatic insulin uptake caused by fatty acids reaching the portal vein directly from the omental (visceral) fat depot. We investigated the effect of sodium oleate and fatty acid-rich buffer recovered from incubation of omental adipocytes with 10(-7) M epinephrine on specific [125I]insulin uptake (at 37 C) in freshly prepared and cultured hepatocytes and nonparenchymal liver cells isolated from 200-250 g rats. In hepatocytes, insulin uptake was studied after standard cell isolation and washing and after additional repeated 30-min washings at 37 C. In the vigorously washed hepatocytes, both fatty acid rich buffer (from 0.08-1.3 mM) and sodium oleate (from 0.0125-1.2 mM) decreased insulin uptake maximally by approximately 30% and approximately 40%, respectively (P < 0.005); a biphasic effect of fatty acids was observed, with maximal inhibition occurring at 0.08-0.1 mM. Without vigorous washing, oleate had no effect on insulin uptake in either freshly prepared or cultured hepatocytes and nonparenchymal cells. The reason for the observed inhibitory effect of fatty acids on insulin uptake in vigorously washed cells remains unknown, but the effect is unlikely to be physiologically important. Thus, our data do not support the hypothesis that the increased concentration of fatty acids in the portal vein is responsible for reduced hepatic insulin uptake and hyperinsulinemia in upper body obesity.

The influence of the sodium oleate adsorption on the behavior of calcite suspensions

The effect of sodium oleate (SOL) on the behavior of calcite suspension has been investigated. The stability of dilute calcite suspension dramatically increases at 3 10 −3kmol/m 3 of SOL. It correlates well with the vertical part of the adsorption isotherm of SOL on the calcite surface. The hindered settling technique was used for the concentrated calcite suspension tests. The maximum of mean equivalent Stokes radius corresponds with the onset of flocculation of mineral suspensions. Also, the Bingham yield values attains the maximum at the flocculation area of calcite suspension. The spherical agglomeration of calcite suspension occurs at high surfactant concentrations (3 10 −3 kmol/m 3). Also the specific resistance of calcite cakes was investigated. The results show that the specific resistance of the calcite cake created after mechanical agitation is higher than that of the cake made by flocculation.

Incorporation of mitochondrial l-glycerol-3-phosphate dehydrogenase into liposomes; effect of sodium oleate and calcium ions

FAD-linked l-glycerol-3-phosphate dehydrogenase purified from liver mitochondria of hyperthyroid rats was incorporated into unilamellar phospholipid liposomes. The incorporation influenced both V max,app and K m,app values of the enzyme for its substrate, l-glycerol 3-phosphate. The K m,app for the electron acceptor remained unchanged with a simultaneous slight enhancement of the corresponding V max,app value. The steady-state fluorescence anisotropies of the fluorescein isothiocyanate and trimethylammoniumdiphenylhexatriene labels were affected by sodium oleate and calcium ions in the case of both solubilized and liposome-incorporated l-glycerol-3-phosphate dehydrogenase. These results indicate that calcium ions cause a significant alteration of the enzyme conformation. Sodium oleate (used as a model of free fatty acids), besides its direct action on the enzyme itself, affects the enzyme indirectly as well, via alteration of the physical properties of the membrane.

Effect of sodium oleate on plasma secretin concentration and pancreatic secretion in dog

The effects of sodium oleate and triglyceride infused into the duodenum of dogs with chronic pancreatic fistulas on pancreatic secretion and plasma immunoreactive secretin were investigated. The responses were compared with those following intravenous secretin infusions. Oleate markedly increased pancreatic water and bicarbonate secretion in a dose-related fashion, and these increases were accompanied by a small, but significant rise in the level of circulating immunoreactive secretin. No change in pancreatic secretion or in plasma secretin level was observed by the administration of triglyceride. Comparison of the bicarbonate response after oleate infusion with that after secretin administration suggests that the pancreatic stimulatory effect of intraduodenal sodium oleate is mediated to a major extent by the release of endogenous secretin.

The effect of sodium oleate on cholesterol solubility in bile salt-lecithin model systems.

Reflux of pancreatic secretions and bacterial infection have been suggested as important factors in gallstone formation in some instances by introducing into bile phospholipases hydrolyzing lecithin to lysolecithin, mono- and diglycerides, and free fatty acids. Since there is little data on free fatty acids, we studied the effect of sodium oleate, the soap of one of the major fatty acid derivatives of lecithin, on cholesterol solubility in unconjugated bile salt-lecithin model solutions to see if an increase in this component might lead to saturation of bile with cholesterol. In the absence of lecithin, sodium oleate decreased cholesterol solubility in bile salt solutions at concentrations physiologic for bile, although cholesterol solubility was increased by oleate at higher oleate-bile salt ratios. In the presence of lecithin, sodium oleate decreased cholesterol solubility at all concentrations studied. Significant differences in cholesterol solubility were found for all comparable concentrations of sodium cholate and deoxycholate studied, both in the presence and absence of lecithin. Our studies showed that an increase in free fatty acid concentration can increase cholesterol saturation significantly in unconjugated bile salt-lecithin model solutions. Whether or not free fatty acid concentrations in pathologic bile reach levels sufficient to contribute to cholesterol saturation and gallstone formation cannot be determined until more adequate data on the minor lipid composition of bile becomes available.

The effect of lipid on chymotrypsin assay in stools.

The sodium salt of oleic acid has been demonstrated to interfere with the measurement of the esterolytic activity of chymotrypsin on a specific substrate, ATEE, utilizing automatic titration. The inhibitory effect of sodium oleate has been attributed in part to its ability to act as a buffering agent in an assay system, since nonlipid buffers (tris)—in increasing concentration—exerted a similar effect. Fecal samples with high lipid content decreased the recovery of added chymotrypsin. Successive dilutions of fecal samples resulted in an increase in assayable native chymotrypsin activity. Stool samples varying in lipid content and buffer capacity may help explain low fecal chymotrypsin recoveries observed in nonpancreatogenous steatorrhea.

ENZYMES IN ONTOGENESIS (ORTHOPTERA)

1. Glycerol extracts of the grasshopper egg (Melanoplus differentialis) have been tested for hydrolytic activity on methyl butyrate, tributyrin and olive oil during various stages in the development of the egg. The ability to hydrolyze methyl butyrate is high when the egg is laid; this value declines between the tenth and fifteenth day of development, remains constant during diapause and slowly declines again during the post-diapause period. The action of extracts on tributyrin is much stronger, remains constant from the time of laying until the cessation of the diapause and then declines markedly. No action on olive oil could be demonstrated.2. Optimum activity in hydrolysis of tributyrin is at pH 6; the activity of the enzyme reacting with methyl butyrate is only slightly affected by changes in the H-ion concentration.3. Temperature affected the methyl butyrinase and tributyrinase activity in a different manner. Exposure to tempetatures above 55° C. depressed the activity of the former while the activity of the latter persisted to 65° C.4. The hydrolytic action on tributyrin increased with temperature between 5° and 25° C. and declined at higher temperatures. Methyl butyrinase activity increased with temperature between 0° and 45° C.5. The esterases seemed to be associated with the yolk until just before hatching.6. The effect of sodium oleate, calcium ion and various inhibitors of lipolytic enzymes on the extracts used were determined.