Adsorption of sodium oleate at the microfine hematite/aqueous solution interface and its consequences for flotation

The adsorption of sodium oleate(NaOL)at the microfine hematite/aqueous solution interface was investigated in this paper.Experimental research indicated that negative effects stemmed from the dissolution of the microfine hematite(D50=19.21μm)could be effectively eliminated via the appropriate dosage of NaOL at alkali pH conditions.Solution chemistry calculation and adsorption test results indicated that RCOO
and(RCOO)_(2)^(2-) ions were responsible for microfine hematite flotation at pH 8.2.Zeta potential and FTIR measurements confirmed the co-adsorption of molecular and ionic oleate species occurred at pH 8.2.X-ray photoelectron spectroscopy(XPS)results further indicated that oleate species interacted with hematite surfaces mainly through chemisorption,giving rise to molecule/colloid formation of oleate and Fe―OL complex compound.Time-of-flight secondary ion mass spectrometry(ToF-SIMS)results demonstrated that oleate species adsorbed onto the hematite surfaces with a thickness of a few nanometers.Furthermore,the normalized peak intensity of C4H7+ions on the hematite sample at pH 8.2 increased remarkably comparing with corresponding result of hematite sample at pH 6.8.The new findings of the present study well revealed the dissolution of microfine hematite and the pH effects on the hematite flotation,as well as the adsorption characteristics of oleate species.

Insights into the influence of temperature on the adsorption behavior of sodium oleate and its response to flotation of quartz

Temperature affects the flotation of quartz in the calcium/sodium oleate(Na OL)system,while there is a lack of understanding of its potential mechanism.Therefore,in this work,the flotation response of quartz to temperature was investigated via micro-flotation experiments,interface property analyses,and theoretical calculations.Flotation results demonstrated that increasing temperature contributed to higher flotation recovery of quartz,which enhanced the removal of quartz from hematite.Surface tension results revealed that higher temperatures lowered the critical micelle concentration(CMC)and surface tension of the Na OL solution,and thus enhanced its surface activity.Solution chemistry calculations and X-ray photoelectron spectroscopy(XPS)measurements confirmed that the increased content of Ca(OH)+achieved by increasing temperatures enhanced the adsorption amounts of calcium species(acting as activation sites)on the quartz surface.Dynamic light scattering(DLS)measurements verified that the association degree of RCOOàto form(RCOO)22àwas strengthened.Furthermore,adsorption density measurements and molecular dynamics(MD)simulations confirmed that increasing the temperature facilitated Na OL adsorption toward the surface of the quartz,which was attributed to the stronger interaction between Na OL and the calcium-activated quartz surface at higher temperatures.As a result,quartz flotation was improved by increasing temperatures.Accordingly,a possible adsorption model was proposed.

Aquathermolysis of heavy crude oil with ferric oleate catalyst

Oil-soluble catalysts could be of special significance for reducing the viscosity of heavy crude oil, because of their good dispersion in crude oil and high catalytic efficiency toward aquathermolysis. Ferric oleate was synthesized and applied as catalyst in the aquathermolysis reaction of Shengli heavy oil. It was found that ferric oleate was more efficient for heavy oil cracking than Co and Ni oleates. Besides, it was superior to oleic acid and inorganic ferric nitrate and achieved the highest viscosity reduction rate of up to 86.1%. In addition, the changes in the components of Shengli heavy oil before and after aquathermolysis were investigated by elemental analysis, Fourier transform infrared spectrometry, and ^1H nuclear magnetic resonance spectroscopy. Results indicated that ferric oleate contributed to a significant increase in the content of light components and decrease in the content of resin, N and S. The as-prepared ferric oleate showed good activity for reducing the viscosity and improving the quality of the heavy crude oil, showing promising application potential in aquathermolysis of heavy crude oil.

Synthesis of Ethyl Oleate Catalyzed by Solid Superacid SO_4^(2-)/TiO_2/La^(3+)

Rare-earth compound solid superacid SO4^2 -/TiO2/La3＋ was prepared. Its catalytic activity was examined under different synthetic conditions for the esterification of propanoic acid and n-butyl alcohol as probing reaction. The optimum conditions were also found, which were the pH=8, the depositing time was 24 h, the mass fraction of La（NO3）3 used in solid superacid was 5%, the concentration of H2SO4 was 1.25 mol/L, the soaking time in H2SO4 was 16 h and the calcining temperature was 500℃. The ethyl oleate was synthesized from oleic acid and ethanol in the presence of SO4^2-/TiO2/La3＋. The optimum reaction conditions were obtained which were the reaction time was 6 h, molar ratio of oleic acid to ethanol was 1：4 and the mass fraction of catalyst was 4%.

EFFECT OF SODIUM OLEATE ON FLOTATION OF MAGNESITE

Laboratory studies were made on the floatabil-ity of magnesite and dolomite with sodium oieate as the collector. The adsorption mechanism of sodium oieate on the surface of minerals was examined. The results show that the ion-molecule association polymer of oieate in the pulp is a main active component of the collector . In both neutral and basic media , the adsorption type of sodium oieate on the surface of carbonate minerals is mainly chemisorp-tion, forming Mg(Ol)2 and Mg(Ol)2·HOl.

Evalution of Thermal Oxidative Degradation of Trimethylol-propane Trioleate by TG/DTA/DSC

In order to evaluate the thermal oxidation degradation behavior of lubricant with different antioxidants,the thermal kinetics equation based on the anlyses of thermogravimetry(TG),differential thermal analysis(DTA),and differential scanning calorimetry(DSC)was established,respectively,to calculate the activation energy of lubricant thermal-oxidative reaction.The thermal analyses of TG and DTA were employed to determine the thermal decomposition properties of ester oils trimethylolpropane trioleate(TMPTO)with butyl-octyl-diphenylamine/octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate/amine-phenol combination antioxidant.The activation energy of the lubricating oil adding antioxidant is increased relative to the TMPTO base oil,and the order of activation energy are Ec(93.732 kJ·mol^(-1))>Ed(88.71 kJ·mol^(-1))>Eb(58.41 kJ·mol^(-1))>Ea(46.32 kJ·mol^(-1)).The experimental results show that octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate in TMPTO has favorable resistance to thermal oxidation and decomposition.The thermal analysis method of DSC accurately reflects the heat exchange of lubricant thermal-oxidative reaction.The order of activation energy is calculated to ED(144.385 kJ·mol^(-1))>EC(110.05 kJ·mol^(-1))>EB(97.187 kJ·mol^(-1))>EA(66.02 kJ·mol^(-1)).It is illustrated that the amine-phenol combination antioxidant has the best thermal oxidation resistance,which is the same as what the oxidation onset temperature effected.

Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

The effects of carbonate minerals（dolomite and siderite） on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared（FTIR） spectroscopic studies, and X-ray photoelectron spectroscopy（XPS） analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations（Ca^（2＋） and Mg^（2＋）） and CO_3^（2＋）ions dissolved from dolomite depressed hematite flotation, whereas only the 23CO-ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca^（2＋）, Mg^（2＋）, and CO_3^（2-）（HCO_3^-） could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.

Adsorption effect mechanism of sodium oleate on feldspar and quartz

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Metal–Oleate Complex?Derived Bimetallic Oxides Nanoparticles Encapsulated in 3D Graphene Networks as Anodes for Efficient Lithium Storage with Pseudocapacitance

In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4  GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4  GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4  GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4  GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4  GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.

Effect of Sodium Oleate Concentration Variations on Froth Flotation of Manganese Ore

Each type of a manganese deposit is a problem by itself in the matter of selection of a proper method of concentration, depending on the manganese minerals and their gangue constituents. Hence, this work studied the effect of sodium oleate concentration variation on the froth flotation of manganese ore obtained from Madaka, Niger State, Nigeria. The chemical analysis of the ore shows that it contains 48.4% MnO (37.5% Mn). Peaks were identified in XRD analysis of the crude sample as that of magnosite (MnO), hausmannite (Mn3O4), spessartine and vemuculite (Mg, Fe2+, Fe3+)3[(AlSiO4)O10](OH)2·4H2O. The ore was beneficiated by froth flotation using sodium oleate as collector at varied concentrations of 3 g/kg, 7 g/kg and 10 g/kg. Other chemical reagents used were sodium silicate, fuel oil and calcium hydroxide as dispersant, frother and pH modifier respectively. Results obtained showed percentage metal recoveries of 9.29%, 14.30% and 19.61%, assaying 65.20%, 62.03% and 61.30% Mn respectively. This indicates that at sodium oleate concentration of 3 g/kg, high grade-concentrate can be obtained.

Sustainable conversion regenerated cellulose into cellulose oleate by sonochemistry

Derivatization has great potential for the high-value utilization of cellulose by enhancing its processability and functionality.However,due to the low reactivity of natural cellulose,it remains challenging to rapidly prepare cellulose derivatives with high degrees of substitution.The“cavitation effect”of ultrasound can reduce the particle size and crystalline index of cellulose,which provides a possible method for preparing cellulose derivatives.Herein,a feasible method was proposed for efficiently converting regenerated cellulose to cellulose oleate with the assistance of ultrasonic treatment.By adjusting the reaction conditions including ultrasonic intensity,feeding ratios of oleic acid,reaction time,and reaction solvent,a series of cellulose oleates with degrees of substitution ranging from 0.37 to 1.71 were synthesized.Additionally,the effects of different reaction conditions on the chemical structures,crystalline structures,and thermal behaviors were investigated thoroughly.Cellulose oleates with degrees of substitution exceeding 1.23 exhibited amorphous structures and thermoplasticity with glass transition temperatures at 159.8 to 172.6℃.This study presented a sustainable and practicable method for effectively derivatizing cellulose.

Role of CD36 in central nervous system diseases

CD36 is a highly glycosylated integral membrane protein that belongs to the scavenger receptor class B family and regulates the pathological progress of metabolic diseases.CD36 was recently found to be widely expressed in various cell types in the nervous system,including endothelial cells,pericytes,astrocytes,and microglia.CD36 mediates a number of regulatory processes,such as endothelial dysfunction,oxidative stress,mitochondrial dysfunction,and inflammatory responses,which are involved in many central nervous system diseases,such as stroke,Alzheimer’s disease,Parkinson’s disease,and spinal cord injury.CD36 antagonists can suppress CD36 expression or prevent CD36 binding to its ligand,thereby achieving inhibition of CD36-mediated pathways or functions.Here,we reviewed the mechanisms of action of CD36 antagonists,such as Salvianolic acid B,tanshinone IIA,curcumin,sulfosuccinimidyl oleate,antioxidants,and small-molecule compounds.Moreover,we predicted the structures of binding sites between CD36 and antagonists.These sites can provide targets for more efficient and safer CD36 antagonists for the treatment of central nervous system diseases.

Flotation behavior and electronic simulations of rare earth minerals in the presence of dolomite supernatant using sodium oleate collector

Common rare earth (RE) minerals, such as bastnasite and monazite, may be formed in deposits associated with carbonate gangue, such as calcite and dolomite. Sodium oleate is a widely used collector for the flotation of both RE and gangue minerals, which might, therefore, be an inefficient process due to the lack of selectivity of this collector. Since these minerals are also sparingly soluble in solution, they could release their constituent ions into the solution, which could affect the floatability of other minerals. In this study, the interactions of sodium oleate with bastn(a|¨)site and monazite in the presence of dissolved dolomite species have been investigated. Micro flotation tests were carried out to explore the effects of these dissolved species on the floatability of the RE minerals. Zeta potential measurements and XPS characterization were carried out to understand how the species affect the collector adsorption. To complement these characterizations, density functional theory (DFT) simulations were conducted to investigate the collector-mineral and collector-adsorbed species (on the mineral surface) interactions.The results show that collector-dolomite interaction energy is greater than that of collector-adsorbed species, but lower than collector-monazite interaction energy, explaining the decrease in the minerals’recovery upon exposure to the dissolved mineral species. It is also shown that oleate ions (OI^-) have the strongest interaction with the minerals compared to other oleate species such as acid soap (HOI_2^-) and oleate dimer (Ol_2^(2-)). The behavior (strength and selectivity) of sodium oleate towards RE minerals and dolomite, as compared to other RE mineral collectors (such as aromatic hydroxamate), is attributed mainly to the collector's and the minerals'structure. The long hydrocarbon chain of sodium oleate which imparts hydrophobic characteristic to the minerals, makes it stronger collector than benzohydroxamate.Moreover, sodium oleate (with linear structure), unlike the aromatic hydroxamate, can approach the mineral easier due to lesser steric hindrance effect and higher reactivity of O involved in the interaction,making it less selective. In addition, it can interact easily with dolomite due to the presence of more exposed active sites than RE minerals.

Rheological behavior of mixed system of ionic liquid [C8mim]Br and sodium oleate in water

Abstract We report on the rheological behavior of wormlike micelles constructed by ionic liquid surfactant [Csmim]Br （1-octyl-3-methylimidazolium bromide） and anionic surfactant sodium oleate （NaOA） in aqueous solution. The effects of surfactant composition, total surfactant concentration, added salts, and temperature were investigated. The prevailing surfactant effect at lower concentration and the leading cosolvent effect at higher concentration of [Csmim]Br may be the main reasons for appearance of well-established maximum in key rheologi- cal parameters with variation of surfactant composition and total surfactant concentration. The Cole-Cole plots demon- strate that the systems （total surfactant concentration falls within 0.17-0.35 mol. L- 1 and molar ratio 0.33≤R ≤ 0.50） fit the Maxwell＇s mechanical model as linear viscoelastic fluid. The addition of NaBr or sodium salicylate decreases significantly the viscosity and the relaxation time of the wormlike micelle solution but cannot change the value of plateau modulus Go. The present system has low rheological tolerance to temperature. The increase of temperature decreases the average contour length and viscosity of wormlike micelles and thus strengthens the relaxation progress of diffusion and weakens the relaxation progress of reptation. Increasing the temperature also decreases the value of plateau modulus G0 and shifts the minimum value of the loss modulus G″min to higher frequencies.

Lamellar liquid crystal polymerization of sodium oleate/oleic acid/octadiene/water system

In the lamellar liquid crystallization (LLC) phase of NaOL/ OLA/H2O system, the small angle X-ray diffraction measurements show that the oleic add is solubilized in the oil layer at first and men into the amphiphile layer. The octadiene added is also located partly in the oil layer and partly in the amphiphile layer in the LLC. With the addition of octadiene as cross-linking agent, roe LLC phase of NaOL/OLA/H2O system was polymerized under the initiation of AIBN with the protection of pure nitrogen at 60°C. Most of the double bond absorption of the monomers in IR spectra disappeared after polymerization. The polymerization takes place not only in the middle of the amphiphile layer between the double bonds of NaOL or OLA and those of octadiene, but also in the oil layer of LLC between the double bonds of OLA and those of octadiene. Interlayer spacing measurements on the copolymer proved d values decreased by about 1 - 2 nm compared with those of the corresponding system before the polymerization, indicating a disruption of the ordered structure by the polymerization. The copolymer still has superior surface activity with the critical micellar concentration (CMC) decreased almost to the half of the value for the system before the polymerization.

Emergency balloon-occluded retrograde transvenous obliteration of ruptured gastric varices

AIM: To evaluate the effectiveness and safety of emergency balloon-occluded retrograde transvenous obliteration(BRTO) for ruptured gastric varices.METHODS: Emergency BRTO was performed in 17 patients with gastric varices and gastrorenal or gastrocaval shunts within 24 h of hematemesis and/or tarry stool.The gastric varices were confirmed by endoscopy,and the gastrorenal or gastrocaval shunts were identified by contrast-enhanced computed tomography(CE-CT).A 6-Fr balloon catheter(Cobra type) was inserted into the gastrorenal shunt via the right internal jugular vein,or into the gastrocaval shunt via the right femoral vein,depending on the varices drainage route.The sclerosant,5% ethanolamine oleate iopamidol,was injected into the gastric varices through the catheter during balloon occlusion.In patients with incom plete thrombosis of the varices after the first BRTO,a second BRTO was performed the following day.Patients were followed up by endoscopy and CE-CT at 1 d,1 wk,and 1,3 and 6 mo after the procedure,and every 6 mo thereafter.RESULTS: Complete thrombosis of the gastric varices was not achieved with the first BRTO in 7/17 patients because of large gastric varices.These patients underwent a second BRTO on the next day,and additional sclerosant was injected through the catheter.Complete thrombosis which led to disappearance of the varices was achieved in 16/17 patients,while the remaining patient had incomplete thrombosis of the varices.None of the patients experienced rebleeding or recurrence of the gastric varices after a median follow-up of 1130 d(range 8-2739 d).No major complications occurred after the procedure.However,esophageal varices worsened in 5/17 patients after a mean follow-up of 8.6 mo.CONCLUSION: Emergency BRTO is an effective and safe treatment for ruptured gastric varices.

STUDY ON BONDING MECHANISM BETWEEN SILLIMANITE AND COLLECTORS BY QUANTUM CHEMISTRY CALCULATION

The charge distribution of ions in sillimanite crystal, diatomic energy, and the heat of absorption of sillimanite on collectors such as sodium oleate,sodium dodecyl sulfonate, and tetradecyl amine are evaluated in the light of quantum chemistry CNDO/2 m

Improving chemical and sensory quality of high-oleic peanut by application of foliar fertilizer

High-oleic peanut is favored by consumers because its a longer shelf life and benefits for cardiovascular health.Up to the high-oleic standard and with good taste is essential for peanut products in food processing.The aim of present study was to explore the effect of foliar fertilizers on chemical and eating quality of high-oleic peanuts.Three high-oleic peanut cultivars,namely Huayu 09C2,Huayu 9621,and Huayu 962,were used as materials.Huayu 09C2 and Huayu 9621 were planted in Fuxin,Liaoning,foliar sprayed with Fosforil at 2250 mL/ha,and Huayu 962 was sown in Jvnan,Shandong,foliar sprayed with Foliplus at 1500/3000 mL/ha.The chemical and sensory quality of peanut harvested from the treatment plots and controls was evaluated.Results showed that,Huayu 09C2 and Huayu 9621,foliar spraying with Fosforil in Fuxin,Huayu 962,foliar spraying with Foliplus in Jvnan,all still maintained high oleate content levels,and the Fosforil treatment was effective in raising the intensity of sweetness of roasted kernels.This study demonstrated the feasibility of improving chemical and sensory quality of high-oleic peanut through foliar fertilizer.

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand,thereby posing a non-negligible threat to peanut production in north and northeast China.Five high-oleic(HO)peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period.High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait.Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant.Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points.Four of the 5 HO peanut cultivars yielded satisfactory results.For Huayu 665,Huayu 668 and Huayu 965,Huweisanbao may be the best option;for Huayu 962,Weilidan was highly acceptable.These combinations will be evaluated further in multiple environments before large-scale extension.

DRIFT SPECTROSCOPIC STUDY OF THE MECHANISM OF SELECTIVE SHEAR-FLOCCULATION OF HEMATITE FROM KAOLINITE

The mechanism of separating hematite from kaolinite by shear-flocculation and the reason responsible for the selectivity of shear-flocculation was studied by using diffuse reflectance infrared Fourier transform (DRIFT) spec-troscopy, which was found to be effective for analysing adsorbed oleate species on the highly absorbing mineral hematite. The spectra suggest that chemisorption of oleate on hematite took place under shear-flocculation condition and that the chemisorbed species was bridged bidentate, corresponding to a peak at 1580 cm-1. Dimers of oleic acid, corresponding to a peak at 1710 cm-1, adsorbed via hydrocarbon chain association with the chemisorbed oleate. The coexistance of physically adsorbed oleic acid dimers and chemisorbed oleate ions made the surface of hematite hydrophobic, which would remain under the shear field. Under the same condition , the surface of kaolinite did not adsorb oleic acid or oleate and remained hydrophilic. The shear field of sufficient magnitude made the hydrophobic ultrafine particles of hematite to aggregate, whereas the hydrophilic ultrafine particles of kaolinite remained suspended in solution. This explains the mechanism of selective shear-flocculation of hematite from kaolinite.