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The combined use of n-nonane preadsorption and CO 2 adsorption at 273 K allows interpretation of the mechanism of adsorption of CO 2 in narrow micropores of a series of CO 2 -activated carbons prepared from an anthracite. The mechanism depends on the shape and size of the pores. In narrow micropores of molecular dimensions (1σ), CO 2 is probably adsorbed by micropore...
The solute-solid adsorption isotherms (SSA) of asphaltenes and resins were measured using the inorganic fraction (97% SiO 2 ) of the deposit that plugged the tubing of a production well as an inorganic adsorbent. In other experiments, Ceuta asphaltenes and the product (HA) of heating them at 350°C for 11 h were used as organic adsorbents in heptane, toluene and heptane-toluene at 26°C. Ceuta...
Much of the natural gas in the Devonian shales in the Appalachian basin is stored as a condensed phase, which may be in solution in organic material or adsorbed on surfaces. A laboratory apparatus and measurement procedures for accurate determination of the relatively small amounts of condensed phase typical of Devonian shale samples have been designed. A temperature control system was developed...
The objective of this study was to determine whether activated char produced from Illinois coal could be used effectively to remove sulfur dioxide from coal combustion flue gas. Chars were prepared from a high-volatile Illinois bituminous coal under a wide range of pyrolysis and activation conditions. A novel char preparation technique was developed to prepare chars with SO 2 adsorption...
The effect of low-concentration SO 2 on the adsorption of NO over activated carbon was studied using adsorption--desorption profiles obtained during thermal analysis-mass spectrometry. Using three different gas mixtures and adsorption temperatures between 293 and 413 K with NO and SO 2 as the reactants, it was determined that NO 2 and SO 2 were the primary adsorbed...
Composite carbons were produced by combining, and subsequently pyrolysing, polyvinylidene copolymer latexes and AX-21 carbon. These carbons were produced in a monolithic form, enabling them to fit compactly into a given storage volume. The composites demonstrated that the latex polymer could enter the undesirable large voids and interparticle spaces in the superactivated carbon and remain there...
Utilization of biomass-pyrolysis char for adsorption purposes is of bonus advantage and importance considering the ubiquitous need for a cheap source of carbon adsorbent for various small-scale industries for waste water treatment. Experimental studies were conducted in this context, to characterize the biomass-pyrolysis char to explain their specificity as conditioned by their individual adsorptive...
Vacuum filtration of clean coal slurries and flocculated slurries with cationic, anionic and nonionic surfactants has been investigated. Significant reductions in filter cake moisture content were obtained for all types of surfactant. The most effective surfactant was CTAB. The final moisture content of filter cakes was reduced from 21 to 11.7 wt% by using a moderate dosage of flocculant followed...
This paper describes the adsorption kinetics and isotherms for cationic and anionic surfactants on coal surfaces. Both types of surfactants adsorb significantly rapidly; although the cationic surfactant achieved much higher levels of adsorption than the anionic one. The adsorption isotherms are of typical Langmuir type and employed for calculation of free energies. The results indicate that adsorption...
NO adsorption and reduction with NH 3 over activated coke at low temperatures were studied by temperature-programmed desoption (TPD) and step-response experiments. NO adsorption is inhibited by competitive adsorption of NH 3 in the absence of oxygen, and is significantly increased in the presence of oxygen. This phenomenon cannot be explained by either the oxidation of NO in the gas...
In order to improve the understanding of the mechanisms involved in the adsorption of volatile organic compounds (VOCs) on coal materials, and in order to predict selectivity values between given pairs of VOCs, an LSER (Linear Solvation Energy Relationship) approach has been used. Gas-solid partition coefficients at infinite dilution of 14 VOCs on a commercial coal material have been obtained by the...
The adsorption of water vapor and carbon dioxide at room temperature in relation to carboxylic functional groups on the surfaces of 20 different types of coal was examined.The carboxylic functional groups on the surface of coal may be considered the preferential sites of adsorption when compared with the other groups. The adsorption of water vapor and carbon dioxide was found to increase in proportion...
The catalytic activity of a pitch-based activated carbon fiber (ACF) of very large surface area (OG-20A) was studied for NO-NH 3 reaction in a flow reactor at ambient temperatures. The ACF exhibited the highest activity in wet as well as dry gas among heat-treated ACFs so far examined by the present authors. The calcination at 1100 o C was essential to exhibit the highest activity...
The presence of polar species in transformer insulating oil may cause degradation and electric discharges in the power transformer. Such oil polar fraction can originate either from the neat oil and/or from its oxidative degradation in the power transformer. The aim of this study is to examine the relation between the insulating oil and the electrical properties of its polar fraction in order to predict...
In situ FTIR spectroscopy was used to identify the adsorbed species and the intermediates during methanol dehydrogenation over Cu/SiO 2 catalyst, and a schematic reaction network was proposed. Methoxy species on copper, which were derived from adsorbed methanol, dehydrogenated into formaldehyde. Then several competitive pathways took place. The adsorbed formaldehyde could desorb to the gas...
In the power transformer, the presence of polar or charged species in the insulating oil can cause failure and electric discharges. Solid substrates such as silica can be used to extract the polar species and to refine the oil in order to prevent future failure in the power transformer. However, the use of silica for petroleum oil separation and refining will depend on the silica characteristics such...
The accuracy of the European Emissions Standard Method to determine the amount of diesel particulate matter (DPM) emitted to the atmosphere is questioned. Results obtained using an experimental fixed bed installation show that the main mechanism involved in the formation of DPM is gas phase saturation and later liquid adsorption, and that gas adsorption is not important under the mini-tunnel sampling...
Perfluorosulfonate ionomer membranes (PFSIs) were cast from Nafion ® propanol–water solutions of varying equivalent weights (950, 1100, and 1200Da) and all annealed at 100°C under vacuum. Sulfonate group surface concentration on the various membranes and its effect on the adsorption of a cationic polyacrylamide were investigated utilizing X-ray photoelectron spectroscopy (XPS). The cationic...
Coal combustion in power plant produces fly ash. Fly ash may be used in water treatment to remove mercury (Hg 2+ ) from water or to immobilize mercury mobile forms in silts and soils. Experiments were carried out on two kinds of fly ashes produced by two circulating fluidized bed plants with different chemical composition: silico-aluminous fly ashes and sulfo-calcic fly ashes. For the two...
Mathematical fitting of experimental emission data from five different fuels and three mixtures of biodiesel and reference diesel operating under diverse conditions allows to propose an easy equation to calculate both the insoluble and soluble fractions in Diesel Particulate Matter.The relative importance of each mechanism involved in the DPM formation process is also mathematically quantified. Two...
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