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Showing papers on "Activated alumina published in 2004"


Journal ArticleDOI
TL;DR: In this article, mesoprous alumina (MA) with a wide surface area (307 m2/g) and uniform pore size (3.5 nm) was prepared, and a spongelike interlinked pore system was developed through a post-hydrolysis method.
Abstract: The health threat of arsenic is well-known, and the U.S. EPA recommends the maximum contaminant level to be 0.01 ppm or less for arsenic in drinking water. Therefore, advanced treatment processes are needed for finished water to meet the required regulations. Adsorption is considered to be a less expensive procedure that is safer to handle than precipitation, ion exchange, and membrane filtration. Activated alumina (AA) is the most commonly used adsorbent for the removal of arsenic from aqueous solutions. However, conventional porous solids including AA have ill-defined pore structures and, typically, low adsorption capacities and act in a kinetically slow manner. An ideal adsorbent should have uniformly accessible pores, an interlinked pore system, a high surface area, and physical and/or chemical stability. To meet this requirement, mesoprous alumina (MA) with a wide surface area (307 m2/g) and uniform pore size (3.5 nm) was prepared, and a spongelike interlinked pore system was developed through a post-hydrolysis method. The resulting MA was insoluble and stable within the range of pH 3-7. The maximum uptake of As(V) by MA was found to be 7 times higher [121 mg of As(V)/g and 47 mg of As(III)/ g] than that of conventional AA, and the kinetics of adsorption were also rapid with complete adsorption in less than 5 h as compared to the conventional AA (about 2 d to reach half of the equilibrium value). A desorption study using sodium hydroxide solutions (0.01-1 M) was conducted, and 0.05 M NaOH was found to be the most suitable desorption agent. More than 85% of the arsenic adsorbed to the MA was desorbed in less than 1 h. Several other activated aluminas with different pore properties were also tested. The results show that the surface area of the adsorbents does not greatly influence on the adsorption capacity. In fact, the key factor is a uniform pore size and an interlinked pore system. These studies show that MA with a wide surface area, uniform pore size, and interlinked pore system can be used as an efficient adsorbent for the removal of arsenic.

592 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of adsorbent dose, solution pH, and contact time has been investigated to remove arsenite ions [As(III)] by activated alumina.

519 citations


Journal ArticleDOI
TL;DR: The amounts of Cr(VI) adsorbed increased with increase in dose of both adsorbents and their contact time, and the maximum removal occurred at pH 2 by activated rice husk and at pH 4 by activated alumina.

358 citations


Journal ArticleDOI
TL;DR: In this article, the removal of fluoride ions using activated alumina (AA) was investigated in batch and continuous operations, and the fluoride removal performance was investigated as a function of the fluoride concentration, flow rate, amount of adsorbent dose and pH.

312 citations


Journal ArticleDOI
TL;DR: The advanced phosphorus removal by adsorption was studied for its suitability as a post-treatment step for membrane bioreactor effluents low in P concentration and particle content and dissolved organic carbon appears to be the strongest competitor for adsorbents.

275 citations


Journal ArticleDOI
TL;DR: High phosphate adsorption capacities of the Al-impregnated mesoporous materials were attributed to not only the increase of surface hydroxyl density on Al oxide due to well-dispersed impregnation of Al components but also the decrease in stoichiometry of surface Hydroxyl ions to phosphate by the formation of monodentate surface complexes.
Abstract: Phosphorus from excess fertilizers and detergents ends up washing into lakes, creeks, and rivers. This overabundance of phosphorus causes excessive aquatic plant and algae growth and depletes the dissolved oxygen supply in the water. In this study, aluminum-impregnated mesoporous adsorbents were tested for their ability to remove phosphate from water. The surface structure of the materials was investigated with X-ray diffraction (XRD), a N2 adsorption-desorption technique, Fourier transform-infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) to understand the effect of surface properties on the adsorption behavior of phosphate. The mesoporous materials were loaded with Al components by reaction with surface silanol groups. In the adsorption test, the Al-impregnated mesoporous materials showed fast adsorption kinetics as well as high adsorption capacities, compared with activated alumina. The uniform mesopores of the Al-impregnated mesoporous materials caused the diffusion rate in the adsorption process to increase, which in turn caused the fast adsorption kinetics. High phosphate adsorption capacities of the Al-impregnated mesoporous materials were attributed to not only the increase of surface hydroxyl density on Al oxide due to well-dispersed impregnation of Al components but also the decrease in stoichiometry of surface hydroxyl ions to phosphate by the formation of monodentate surface complexes.

266 citations


Journal ArticleDOI
TL;DR: This study quantifies leaching of arsenic from Activated Alumina and Granular Ferric Hydroxide, two sorbents expected to be widely used for arsenic removal, and indicates the WET may also underestimate arsenic mobilization in landfills.
Abstract: Recent revision of the arsenic in drinking water standard will cause many utilities to implement removal technologies. Most of the affected utilities are expected to use adsorption onto solid media for arsenic removal. The arsenic-bearing solid residuals (ABSR) from adsorption processes are to be disposed of in nonhazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) tests whether a waste is hazardous or nonhazardous; most solid residuals pass the TCLP. However, the TCLP poorly simulates the alkaline pH, low redox potential, biological activity, long retention time, and organic composition of mature landfills. These same conditions are likely to favor mobilization of arsenic from metal oxide sorbents. This study quantifies leaching of arsenic from Activated Alumina (AA) and Granular Ferric Hydroxide (GFH), two sorbents expected to be widely used for arsenic removal. The sorbents were subjected to the TCLP, the Waste Extraction Test (WET), an actual landfill leachate, and two synthetic...

167 citations


Journal ArticleDOI
TL;DR: In this article, a fixed-bed adsorber operated at ambient temperature and pressure was used for diesel fuel desulfurization by different nickel-exchanged faujasite zeolites.
Abstract: Desulfurization of a commercial diesel fuel (2972 ppmw S) by different nickel(II)-exchanged faujasite zeolites was studied in a fixed-bed adsorber operated at ambient temperature and pressure The zeolites were prepared by both liquid-phase (LP) and solid-state (SS) ion-exchange (IE) methods In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough followed the order: Selexsorb CDX (alumina)/Ni(II)-Y (SSIE-500) > Selexsorb CDX (alumina)/Ni(II)-X (LPIE-RT) > Ni(II)-Y (SSIE-500) > Ni(II)-X (LPIE-RT) > Ni(II)-Y (LPIE-135) The best adsorbent, Selexsorb CDX (alumina)/Ni(II)-Y (SSIE-500) [layered bed of 25 wt % activated alumina followed by Ni(II)-Y] is capable of producing 19 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 022 ppmw S These low-sulfur fuels are suitable for fuel cell applications The sorbents were fully regenerated in one step using air at 350 °C, which simplifies possible implementation for many applications GC−FPD results showed

134 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the desulfurization of diesel fuel by different layered adsorbents and regeneration of the latter in a fixed-bed unit operated at ambient temperature and pressure.
Abstract: Desulfurization of a commercial diesel fuel by different layered adsorbents and regeneration of the latter were studied in a fixed-bed unit operated at ambient temperature and pressure. In general, a layered bed consisting of 12 wt % activated carbon, 22 wt % of activated alumina (Selexsorb CDX), followed by Cu(I)−Y, activated carbon/Selexsorb CDX/Cu(I)−Y, is capable of producing 41 cm3 of desulfurized diesel fuel/g of adsorbent. The matrix is capable of processing 27 cm3 of deep-desulfurized diesel with a weighted average content of 76 ppbw S. These low-sulfur fuels are suitable for fuel cell applications. For layered-bed regeneration, it was determined that calcination of the adsorbed sulfur moieties with air at 350 °C followed by autoreduction of the copper species recovered all of the original desulfurization capacity when activated aluminas are used as a guard layer. Solvent elution experiments indicate that carbon tetrachloride and N,N-dimethylformamide are suitable solvents to recover all of the ad...

125 citations


Journal ArticleDOI
TL;DR: In this paper, the synthesis and fluoride adsorption behavior of hydrous ferric oxide (HFO) are reported, and it is found that the highest adorption density for fluoride is found to be at pH 4.0.
Abstract: Groundwaters contaminated with excess fluoride (above 1.5 mg/L) posed some risks to the public health in India. Methods available for fluoride contaminated water treatment are cogaulation–filtration using alum + lime + bleaching powder (Nalgonda technique) and adsorption using activated alumina. Use of aluminium compounds for water treatment purpose needs replacement on neurological health problem. Objective to this, the synthesis and fluoride adsorption behavior of hydrous ferric oxide (HFO) are reported here. It is seen that fluoride adsorption density varies as a function of pH, contact time, aging time, drying temperature and particle size of HFO. Highest adsorption density for fluoride is found to be at pH 4.0. Effects of competing anions in removing fluoride from solution were tested. Arsenite, arsenate, phosphate and sulfate show strong interfering effect at high anions to fluoride molar ratio in solution. Adsorption of fluoride on HFO follows the Freundlich isotherm and the Lagergren first-order kinetic model. It was also determined that HFO is a better adsorbent in removing fluoride from high fluoride groundwater than some other adsorbents. Regeneration of fluoride-rich HFO results showed that 1.0 M NaOH solution could be used up to a maximum of 75% regeneration.

104 citations


Journal ArticleDOI
TL;DR: In this paper, the optimal parameters affecting the adsorption of arsenic ions As(III) on iron oxide impregnated activated alumina (IOIAA) were determined by conducting batch and column experiments.
Abstract: The optimal parameters affecting the adsorption of arsenic ions As(III) on iron oxide impregnated activated alumina (IOIAA) were determined by conducting batch and column experiments. The adsorption of As(III) was strongly dependent on pH, temperature and initial adsorbate concentration. The adsorption process satisfied the Langmuir and Freundlich isotherms. Equilibrium studies were conducted to obtain the thermodynamic parameters and data showed the endothermic nature of adsorption. Kinetics studies showed that a pseudo first-order rate equation successfully described the adsorption process. Equilibrium was attained within 10 h and the time taken to attain equilibrium was independent of initial arsenite concentration. Column studies showed that adsorption was strongly dependent on empty bed contact time. Column design parameters such as the time taken for the establishment of primary adsorption zone, fractional capacity, length of primary adsorption zone and the percentage saturation at breakpoint were calculated to be in the range of 18.3 to 70.4 h, 0.39 to 0.63, 3.0 to 3.85 cm and 69.6 to 81.5%, respectively. The observations mentioned above provide a direct relationship between the length of the adsorption zone (δ) and percent saturation at break point.

Journal ArticleDOI
TL;DR: Results showed that MO could be degraded by ultrasonic irradiation at 130 kHz with the first order rate constant of 8x10(-4) and 5x10 (-4) sec(-1), in acidic and basic conditions, respectively, without adsorbents.

Journal ArticleDOI
TL;DR: Mameri et al. as discussed by the authors developed a new activation technique using alumina for the removal of fluoride from water, and the optimum activation parameters (potential and contact time) were determined, and an activation time of about 120 min and a potential of +lOO mV/SCE were then selected.

Journal Article
TL;DR: In this article, the adsorption of fluoride ions on activated alumina was studied in the temperature range of 303-333 K by the hatch equilibration method and the results indicated that the adorption process is endothermic and occurs spontaneously which substantiate the proposed mechanism for the adoration of fluoride at the alumina solution interface.

Journal Article
TL;DR: The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper and it is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy, X-ray diffraction, andX-ray fluorescence is essential to establish its surface bonding.
Abstract: Various options are applicable for the removal of water pollutants included reverse osmosis, ion exchange, coagulation, co-precipitation, catalytic reduction, herbal filtration, electrodialysis and adsorption. This paper deals with the sorption phenomena for the removal of pollutants from drinking water. Attempts have been made to use low cost sorbents developed by pretreatment/activation/impregnation with alkalis, acids, iron oxide, manganese dioxide, ferric chloride, alum, lime, aluminum salts with natural products/indigenous minerals viz. activated alumina, activated carbon, groundnut husk, saw dust, chemically coated sand, fly ash, zeolites, clay minerals and other plant products. Application of Freundich and Langmuir isotherms were used to assess the adsorption capacity. Equilibrium isotherms were determined at optimum temperature and pH to characterize the sorption process. Statistical parameters such as mass transfer coefficients, multiple regression analysis were applied to establish the mechanism. It is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) is essential to establish its surface bonding. Scope for safety evaluation and risk assessment to human and biosphere may provide the guideline and predication to the regulatory agencies for its sustainable use and safe disposal The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper.

Journal ArticleDOI
TL;DR: A novel adsorbent, which had been developed for phosphate adsorption, was adopted for arsenic removal from groundwater and it was found that twice the bed volume, i.e., total volume of effluent divided by empty column volume, was achieved till breakthrough by using this novel ads Orbent.

DOI
01 Jan 2004
TL;DR: In this paper, the authors describe the different adsorption types of some classes of porous materials containing Si and Al such as silica, alumina, zeolite, and, more recently, silsesquioxane-derived.
Abstract: A main step in many industrial processes is often found in the separation and purification of products. Adsorption technology has an important role in the removal of undesired components, for instance, wastewater and air streams. There are many materials, natural or synthesized, that have sorption capacity. The most important commercial adsorbents are silica gel, activated alumina, activated carbon, and molecular sieve zeolites. The applications for these adsorbents depend on their intrinsic sorptive properties. Silica gel and activated alumina are used for the drying of gases, organic solvents, and transformer oils. Applications of zeolites are distinct from other adsorbents in that for each type, there is no distribution of pore size because the crystal lattice into which the adsorbate molecules can or cannot enter is precisely uniform. For this reason, zeolites are capable of separating effectively on the basis of molecular size. They are used, among others, for the separation of oxygen and argon, the separation of normal from branched paraffins, the drying of gases, and for the removal of water from azeotropic mixtures. Surface polarity corresponds to affinity with polar substances such as water or alcohols. Polar adsorbents are thus called ‘‘hydrophilic,’’ and aluminosilicates, such as zeolites, porous alumina, silica gel, or silica–alumina, are examples of adsorbents of this type. On the other hand, nonpolar adsorbents are generally ‘‘hydrophobic’’ such as silicalite and a new related material-type group called silsesquioxane-derived. These adsorbents have more affinity with oil or hydrocarbons than water. The basic objective of this article is to describe the different adsorption types of some classes of porous materials containing Si and Al such as silica, alumina, zeolite, and, more recently, silsesquioxane-derived. Special attention is given to matrix effect phenomena of compounds on the organoand inorganofunctionalized silica gel surface.

Journal ArticleDOI
TL;DR: In this paper, the efficiency of the sonochemical coating process was determined by UV photodecolourisation of the aqueous methyl orange solution, and the results indicated that the direct immersion horn results in uniform, as well as a maximum number of TiO2 particles to be adsorbed on an activated alumina surface.
Abstract: Nanosized TiO2 supported on activated alumina was prepared using a sonochemical method. To prepare this supported material, direct immersion horn and cup horn ultrasonic systems were used. The efficiency of the sonochemical coating process was determined by UV photodecolourisation of the aqueous methyl orange solution. It was found that TiO2 supported on activated alumina prepared by the sonochemical method gave the maximum decolourisation efficiency. In that method itself, direct immersion horn gave a higher photodecolourisation activity as compared to the cup horn. The obtained results suggest that the direct immersion horn results in uniform, as well as a maximum number of TiO2 particles to be adsorbed on an activated alumina surface.

Journal ArticleDOI
TL;DR: It was observed that activated rice husk is an efficient adsorbent and comparable to commercially available activated alumina and there was a decrease in Cr(VI) removal compared to aqueous sample due to the presence of other metal ions in the wastewater sample.
Abstract: The aim of this work was to investigate the use of activated rice husk carbon prepared by thermal activation and activated alumina in the removal of Cr(VI) from aqueous solution and electroplating wastewater through column studies. The optimum solution pH was found to be 2 for activated rice husk carbon and 4 for activated alumina in the batch process. This was further applied to the aqueous solution to optimise the column bed height, diameter and flow rate of solute. These optimised conditions were applied to the electroplating wastewater. It was observed that activated rice husk is an efficient adsorbent and comparable to commercially available activated alumina. The percent Cr(VI) removal from wastewater was 73.3% with activated rice husk and 75.3% with activated alumina after 1 h continuous flow at the rate of 5 ml min-1 from 7.5 cm bed height of adsorbent in a column having diameter 2.5 cm. A long contact time of the samples with adsorbents resulted in desorption of Cr(VI) from the adsorbent surfaces...

01 Nov 2004
TL;DR: In this article, an Army installation was faced with treating groundwater to reduce arsenic and fluoride concentrations, and various water treatment technologies were evaluated based on engineering, economic, and regulatory criteria.
Abstract: : The revised arsenic maximum contaminant level (MCL) of 0.010 mg/L is expected to impact many water utility systems, particularly those in western states, where high levels of naturally-occurring arsenic are more common. An Army installation was faced with treating groundwater (GW) to reduce arsenic and fluoride concentrations. Various water treatment technologies were evaluated based on engineering, economic, and regulatory criteria. Water conservation and source water quality issues also impacted treatment technology selection. Ultimately, activated alumina was deemed most feasible, and will be pilot tested to verify arsenic and fluoride removal efficiencies and to develop full-scale design data.

Patent
08 Jan 2004
TL;DR: In this article, a method of manufacturing a polyether, a crude polyether obtained by adding polymerizing a cyclic ether to an active hydrogen-containing compound having a double bond in the presence of a Lewis acid catalyst is neutralized by adding an alkali metal hydroxide and/or an alkaline earth metal hydride.
Abstract: PROBLEM TO BE SOLVED: To obtain a polymerizable polyether which is manufactured using a Lewis acid catalyst, has a double bond and enables a reaction to form a polyurethane stably. SOLUTION: In this method of manufacturing a polyether, a crude polyether obtained by addition polymerizing a cyclic ether to an active hydrogen-containing compound having a double bond in the presence of a Lewis acid catalyst is neutralized by adding an alkali metal hydroxide and/or an alkaline earth metal hydroxide. After at least one adsorbent selected from the group consisting of a synthetic silicate, hydrotalcite, magnesium-aluminum oxide, an activated clay, activated alumina, a synthetic zeolite and an ion exchange resin and water are blended, the polyether is filtered. COPYRIGHT: (C)2004,JPO

Patent
17 Mar 2004
TL;DR: In this paper, the authors provided a method by which high strength activated alumina having a low alkali content can be produced from activated aluminets containing alkali metal components by washing the activated aluminets while maintaining the hydrogen ion concentration in an acidic washing solution.
Abstract: PROBLEM TO BE SOLVED: To provide a method, by which high strength activated alumina having a low alkali content can be produced from activated alumina containing alkali metal components. SOLUTION: The method is characterized by washing the activated alumina while maintaining the hydrogen ion concentration in an acidic washing solution to be pH 4-6. Rehydrated alumina is preferably used as the activated alumina. The use amount of the aqueous acidic solution is 1-25 times by mass of the amount of the activated alumina containing the alkali metal components. After washing, the obtained alumina may be fired at 400-900°C. The activated alumina having a low alkali content and characterized in that the content of the alkali metal is ≤0.05 mass % and the BET specific surface area is 100-400 m 2 /g is obtained. Further, α alumina having a low alkali content and a BET specific surface area of 1-10 m 2 /g is also obtained by firing at 1,300-1,400°C. COPYRIGHT: (C)2005,JPO&NCIPI

Journal Article
TL;DR: The synthetic water performance in the light of fluoride removal was studied and compared with the actual fluoride contaminated water of different selected water collection stations.
Abstract: The synthetic water performance in the light of fluoride removal was studied and compared with the actual fluoride contaminated water of different selected water collection stations. An indegeneous activated alumina was used as adsorbent. The performance of the column for fluoride contaminated water was about 94% fluoride reduction at a pH value of 7.0 and the presence of total dissolved solids (T.D.S.). 2114 mg/L in subsoil water decreased the fluoride removal by 5%.

Patent
08 Dec 2004
TL;DR: In this paper, the authors proposed an adsorbent having zeolite, which is able to simultaneously remove various kinds of odors and provide an optimum filter, minimize unnecessary waste of a filter media and provide functionality to the filter media.
Abstract: PURPOSE: To provide an adsorbent having zeolite, which is able to simultaneously remove various kinds of odors and provide an optimum filter, minimize unnecessary waste of a filter media and provide functionality to the filter media. CONSTITUTION: The device comprises a housing (100) that has a predetermined space and forms a flow path from a lower part to an upper part by using a fan (110) and a filtering means that is installed inside of the housing and has a shell layer (150a), a bio-ball layer (150b), a zeolite layer (150c), an activated carbon layer (150d), an activated alumina layer (150e) and a zinc oxide layer in sequence from the lower part to the upper part of the housing. The adsorbent comprises a mixture of a zeolite having a diameter of 2-5 millimeters, an activated carbon, an activated alumina and a photocatalyst carrier.

Patent
16 Sep 2004
TL;DR: In this paper, a method for easily manufacturing an activated alumina-shaped article that has a large macroporous volume and a high BET specific surface area is proposed, which comprises steps of mixing a rehydratable alumina powder with a water absorbing resin powder having a main particle size of 50 μm or more.
Abstract: PROBLEM TO BE SOLVED: To provide a method for easily manufacturing an activated alumina shaped article that has a large macroporous volume and a high BET specific surface area. SOLUTION: The method comprises steps of mixing a rehydratable alumina powder with a water absorbing resin powder having a main particle size of 50 μm or more and grinding the resultant mixture to obtain a mixed pulverized material having a Blaine specific surface area of 13,500 cm 2 /g or less, adding water to the resultant mixed pulverized material and shaping the same to produce a rehydratable alumina powder shaped article, rehydrating the resultant rehydratable alumina powder shaped article to obtain a rehydrated alumina shaped article and firing the same. Preferably, the main particle diameter of the rehydratable alumina powder is 10-100 μm. The amount to be used of the water absorbing resin powder is 0.1-0.5 pts.mass based on 100 pts.mass of the rehydratable alumina powder. The rehydrated alumina shaped article is fired at 300-1,000°C. COPYRIGHT: (C)2004,JPO&NCIPI

Patent
26 Oct 2004
TL;DR: In this article, the content of fluoride ions in aqueous solutions of calcium chloride is reduced by contacting with activated alumina, which can be accomplished either as a batch slurry process or a continuous process using a fixed bed.
Abstract: The content of fluoride ions in aqueous solutions of calcium chloride is reduced by contacting with activated alumina. The contacting can be accomplished either as a batch slurry process or a continuous process using a fixed bed. The adsorption rate of fluoride ions by the activated alumina is increased by pre-treating the alumina with either an aqueous acid or a sulfate solution. Spent alumina can be regenerated by washing with dilute caustic.

Patent
24 Dec 2004
TL;DR: In this article, an air cleaning filter is provided with adsorption sheets 10, 11 having at least one of diatomaceous earth, silica, alumina, a mixture of silica and alumina.
Abstract: PROBLEM TO BE SOLVED: To efficiently remove organic matter causing problems in an atmosphere in a clean room of semiconductor and LCD manufacturing for long term, with little pressure loss. SOLUTION: This air cleaning filter is provided with adsorption sheets 10, 11 having at least one of diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, activated clay, activated bentonite, synthetic zeolite, and activated carbon. A thickness of the sheets 10, 11 is 0.4 mm or less, and total volume of fine holes with diameters 20 Å or less measured by a gas adsorption method using argon gas, is 46 cc/m 2 or more per unit area of the sheet 10, 11. COPYRIGHT: (C)2005,JPO&NCIPI

Patent
Junpei Tsuji1
10 Sep 2004
TL;DR: In this article, a process for α-methylstyrene which comprises dehydrating cumyl alcohol in the presence of activated alumina is described, characterized in that the concentration of propylene oxide in a raw material containing cumyl Alcohol is 0 to 10,000 wt.ppm.
Abstract: A process for producing α-methylstyrene which comprises dehydrating cumyl alcohol in the presence of activated alumina, characterized in that the concentration of propylene oxide in a raw material containing cumyl alcohol is 0 to 10,000 wt.ppm.

18 Aug 2004
TL;DR: The use of catalysts to improve the exchange kinetics between hydrogen isotope in the gas phase and that in the solid phase was investigated in this paper, where granules of activated alumina, silica and molecular sieve were coated with platinum or palladium as the catalyst.
Abstract: Porous solids such as activated alumina, silica and molecular sieves generally contain significant amounts of hydrogen atoms in the form of H2O or OH even at high temperature and low humidity environment. A significant amount of this hydrogen is available for reversible isotopic exchange. This exchange reaction is slow under normal conditions and does not render itself to practical applications. But if the exchange kinetics is improved this reaction has the potential to be used for tritium removal from gas streams or for hydrogen isotopic separation.The use of catalysts to improve the exchange kinetics between hydrogen isotope in the gas phase and that in the solid phase was investigated. Granules of alumina, silica and molecular sieve were coated with platinum or palladium as the catalyst. The granules were packed in a 2-cm diameter column for isotope exchange tests. Gas streams containing different concentrations of deuterium in nitrogen or argon were fed through the protium saturated column. Isotope concentration in column effluent was monitored to generate isotope break-through curves. The curves were analyzed to produce information on the kinetics and capacity of the material. The results showed that all materials tested provided some extent of isotope exchange but some were superior both in kinetics and capacity. This paper will present the test results.

Patent
27 May 2004
TL;DR: In this article, styrene is adsorbed on activated alumina in aromatic or aliphatic solvent with contact time within 1 to 12 h at temperature between -5(r) and 10(r).
Abstract: FIELD: industrial organic synthesis. SUBSTANCE: styrene is adsorbed on activated alumina in aromatic or aliphatic solvent with contact time within 1 to 12 h at temperature between -5(r) and 10(r). Weight ratio of styrene solution to adsorbent ranges from 5:1 to 10:1. Adsorbent is then subjected to multiple regeneration cycles (up to 30 cycles). EFFECT: improved purity of styrene to a degree allowing its use as monomer in anionic copolymerization processes. 1 tbl, 7 ex