Biomolecules as selective dispersants for carbon nanotubes
Simon E. MoultonAndrew I. MinettRobert L. MurphyKevin P. RyanDenis N. McCarthyJonathan N. ColemanWerner J. BlauGordon G. Wallace
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Biomolecule
Carbon nanobud
Abstract This paper evaluated dispersants for high densityinvert-emulsion drilling fluids weighted with manganese tetroxide (Mn3O4) particles for high temperature applications. Additionally, the use of dispersants to control the reaction of cleaning fluid with Mn3O4-based filter cake was studied. The dispersants selectedare non-toxic to aquatic organisms and biodegradable. Adding dispersants to the drilling fluid will result in reduced sag, rheological properties, and low fluid-loss. Three dispersants (A, B, and C)improved the flow behavior Oil-based drilling fluids weighted mainly with manganese tetraoxide particles. They are based on ethoxylated alcohol and polyether carboxylic acid. Dispersant A was anionic and dispersants B and C were non-ionic. In addition, three dispersants (D, E, and F) showed excellent results in controlling the reaction rate of cleaning fluids with manganese tetraoxide particles. Dispersant D was based on sulfonic acid, dispersant E was based on phosphate ester, and dispersant F was based on malic acid copolymer. Dispersant B showed improved the rheological/filtration properties and sag before/after heat aging at 400°F and 16 hours aging time for Mn3O4 oil-based drilling fluids (1.9 SG) than fluids with or without dispersants A or C. Combination of ionic and non-ionic dispersants improved the filtration properties of oil-based drilling fluids (2.1 SG) weighted mainly with manganese tetraoxide particles. Using dispersant E, the reaction rate of lactic acid/Mn3O4 system was the lowest, followed by dispersant F, and then dispersant D. Dispersants D, E, and F can be used as additives in the cleaning fluid formulation to control the reaction with Mn3O4-based filter cake.
Filtration (mathematics)
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The influences of several anionic dispersants on the colloidal and rheological properties of nanosized Y-TZP suspensions were investigated. Isothermal adsorption was conducted to study the interaction between the dispersant and the powder. It was found that these dispersants adsorbed chemically on the powder. The zeta potential of Y-TZP powder at alkaline region changed from -20mV to -40-50mV after the addition of dispersants. Rheological measurements showed that the dispersant addition significantly enhanced the fluidity of the slurry. The deflocculation mechanism of the dispersant for the suspension was finally discussed.
Zeta potential
Suspension
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We investigated the effects of particle concentration and an additive amount of a dispersant on the adsorption behavior of dispersant. Ammonium polycarboxylate, one of the typical polyelectrolyte was used as a dispersant in this study. Alumina slurries were prepared by changing the concentrations of both the particle and dispersant and kept in a test tube for at least 2 d. After that, the adsorbed dispersant amount was calculated from the residual dispersant concentration measured by a total organic carbon analyzer. It was found that the adsorbed dispersant amount strongly depends on the additive dispersant amount on the basis of the unit mass of particles in the slurry regardless of the particle concentration. It was also shown that polycarboxylic acid strongly absorbs onto an alumina surface and can not be desorbed by dilution, suggesting that its adsorption behavior differs from physical adsorption.
Particle (ecology)
Dilution
Suspension
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Dispersion mechanisms of different dispersants were introduced briefly, and the aid-grinding, stable dsipersing, diluting and water reducing, and energy consumption reducing effects of the dispersant during the preparation of the ferrite were also discussed. The dispersive effect of four kins of dispersants in the ferrite slurry were investigated with a fixed content of 1% for the dispersants. The results showed that the dispersive effect of different dispersants is different. For the dispersant A with a better dispersive effect, the effect of its content on the dispersion was further investigated. The results indicated that an optinal amount of dispersant exists. Therefore, the proper dispersant and its content used for dispersing the ferrite slurry with different composition and prepared by different process should be determined by experiments.
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The synthesis,performance and application of new pigment dispersant for iron phthalein green were introduced.The influences of amount of acrylic monomers and different initiator on the performance of dispersant were discussed.The optimum amount of the dispersant was determined,and the performance of iron phthalein green product was tested.
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It is necessary to improve the soot dispersancy of the lubricating oil. The soot formation process and the interaction mechanism of soot and dispersant were described in this paper.The progress of soot dispersant preparation and research in recent years were also summed. On the one hand, production process of the soot dispersant has been improved; on the other hand, its structure was modified,all tyoe of new soot dispersant products have been prepared.
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ABSTRACT Laboratory studies on dispersant effectiveness were conducted to assess the effects of several variables and to determine the action mechanisms of dispersants. The variables examined were temperature, salinity, and dispersant quantity. Dispersant effectiveness was measured as a function of the five oil bulk components: asphaltenes, aromatics, polar compounds, saturate compounds, and waxes. The effect of water temperature variation is logarithmically correlated with dispersant effectiveness. With regard to salinity, effectiveness is at a peak when salinity is about 40%c (parts per thousand) of typical commercial dispersant formulations and falls to nearly 0 as salinity decreases to 0. Effectiveness also falls to 0 as salinity rises from 40 to 80%o. This behavior is explained by the necessity for a certain level of ionic strength to stabilize the surfactant between the oil droplet and the water. Dispersant quantity was also found to be an important factor. Dispersant-to-oil ratios greater than about 1:40 or 1:60 result in very low dispersant effectiveness. Effectiveness is logarithmic with respect to dispersant-to-oil ratio. Dispersion experiments wee conducted to investigate the effects of oil composition. Dispersant effectiveness is positively and strongly correlated with the saturate concentration in the oil and is negatively correlated with aromatic, asphaltene, and polar compound contents of the oil. Dispersant effectiveness is only weakly correlated with oil viscosity. Dispersant effectiveness is primarily limited by oil composition.
Asphaltene
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Mechanism of powder modified by hyper-dispersant was introduced in this paper and synthesized the SML hyper-dispersant.Activation index of modified calcium sulphate powder was investigated,and discussed the effect of SML hyper-dispersant on mechanics property of PE/calcium sulphate composite.Finally,the broken surface of specimen was observed with SEM.The results show that: SML hyper-dispersant excells the F-2 dispersant,when the amount of modifier is 3%,the activation index reaches 97% and the tensile strength,impact strength and flexural strength of composite enhances 28.7%,20.7%,4.9%,respectively.
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ABSTRACT Previously, anomalous results from various laboratory dispersant effectiveness tests were believed due to the historic difficulties of replicating field conditions in the laboratory. Some variables were reported to cause differences in dispersant performance, such as the oil viscosity—i.e., both dispersant A and dispersant B exhibited poorer performance as the oil viscosity increased. Other test results showed an opposite trend. For example, dispersant A performed more effectively than dispersant B for Murban crude oil but B was better than A for the more viscous La Rosa crude oil. It is now believed that these inconsistent results are actually due to the chemical compositions of the crude oils. Various factors influence dispersant performance and some initial research directed at determining the mechanism of water-in-oil emulsion (mousse) formation has identified naturally occurring surfactants in the various crude oils. This will provide insight as to how these indigenous agents interacted with the surfactant package in the test dispersant to affect overall performance. Variations in dispersant performance for different crude oils are thus likely to be related to the water-in-oil emulsion formation of the particular crude oil. The results of this work indicate that dispersant treatment should be evaluated during spill situations even if the crude oil physical properties, such as high viscosity, might suggest that dispersant treatment would not be effective.
Oil droplet
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ABSTRACT This study evaluated the effectiveness of three dispersants in simulated seawater on five different fuel oils (both intermediate fuel oils (IFOs) and heavy fuel oils (HFOs)) with viscosities ranging from 1,079 to 6,615 cSt and densities ranging from 0.995 to 0.998 g/cc. The three dispersants were COREXIT® 9500 dispersant, a dispersant under development by ExxonMobil – ED-6™ gel dispersant, and FINASOL™ OSR 52 dispersant. Testing was done at two dispersant-to-oil ratios (DOR) – 1:20 and 1:10. All three dispersants were effective (70%+ dispersant effectiveness (DE)) for fuel oils with a viscosity less than 2,000 cSt - IFOs 180 and 380. The dispersants were less effective (16 to 58% DE) for the higher viscosity oils (ranging in viscosity from 4,258 to 6,615 cSt). Increasing the amount of dispersant from a DOR of 1:20 to 1:10 significantly improved DE. For example, the DE of the two HFOs studied increased from less than 42% to greater than 56% using COREXIT 9500™ dispersant. The results of our bench-scale study indicate that dispersants can disperse heavy fuel oils and, therefore, could be a response option for spills of these products in a marine environment.
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