Showing papers on "Activated alumina published in 1987"

Removing Arsenic From Drinking Water

Abstract: Pilot-plant tests of two treatment methods, activated alumina and ion exchange, for removing arsenic from drinking water were evaluated at the Fallon, Nevada, Naval Air Station (NAS). The arsenic concentration was 0.080-0.116 mg/liter, exceeding the 0.05 mg/liter maximum contaminant level. Although the valence of arsenic was not determined, in prechlorination process and test results suggest it was probably arsenic V. Chlorinated drinking water from the NAS was used for evaluating the efficacy of treatment under several different conditions. The activated alumina and ion exchange systems were operated through three different loading and regeneration cycles each. The major water quality factors affecting the removal of arsenic by these methods were pH of feedwater, arsenic concentration, sulfate concentration, and alkalinity. The major operational factors affecting removal were flow rate, down time, and media clogging. Capital and operating costs for arsenic removal are estimated for the activated alumina method at optimum pH (5.5) for each of the three small community systems drawing water from the same aquifer. In addition, several containers of the regeneration waste were used for a special study to characterize, dewater, and render the waste non-toxic for disposal in a sanitary landfill.

Process for pretreatment of light hydrocarbons to remove sulfur, water, and oxygen-containing compounds

Abstract: A pretreatment process for removal of contaminants from a light hydrocarbon feedstock is presented. The feedstock is passed to a first adsorption zone containing a molecular sieve and thereafter passed to a second adsorption zone containing activated alumina. The process produces a hydrocarbon feedstock substantially free of sulfur compounds, oxygenates, and water. Such a process finds utility as a feed pretreatment step preceding a catalytic isomerization process.

Catalyst for purifying exhaust gas

Abstract: PURPOSE:To improve heat resistance and to prevent the activity reduction by depositing Rh on a carrier which has a second wash coated layer incorporating different kind of activated alumina on a first wash coated layer incorporating activated alumina. CONSTITUTION:A carrier is obtained by impregnating activated alumina with a rare earth salt aq. soln. incorporating La as an essential component and thereafter drying and calcining it at about 600 deg.C at about 1hr. This carrier is impregnated with a palladium chloride aq. soln., dried and thereafter calcined, and after mixing this carrier with alumina sol and crushing the mixture, a wash coat of a first layer is obtained by sticking it on the base body of a monolithic carrier. Then activated alumina is impregnated with a rare earth salt aq. soln. incorporating Ce as the essential component, dried and calcined to obtain the carrier and thereafter this carrier is mixed with alumina sol and zirconium oxide powder and the mixture is crushed and stuck on the first wash coat. Further a catalyst for purifying exhaust gas is obtained by depositing Pt or the like thereon.

Controlling arsenic, fluoride, and uranium by point-of-use treatment

Abstract: Arsenic and other inorganic contaminants are found in the water supplies of many small communities. One possible solution for the problem of inorganic contaminants is point-of-use treatment, which can be used by individual homes or small communities. Ion exchange, activated alumina, and reverse osmosis point-of-use treatment units have been evaluated by the U.S. Environmental Protection Agency, and each system was found to be effective under certain operating conditions. Data from various field projects are presented, along with laboratory data on the removal of specific contaminants.

Process for removal of carbonyl sulfide from organic liquid by adsorption using alumina adsorbent capable of regeneration

Abstract: An adsorption process is disclosed for removal of carbonyl sulfide (COS) from a liquid hydrocarbon which comprises providing an activated alumina adsorbent which has preferably impregnated with a compound selected from the class consisting of one or more alkali metal compounds, one or more alkaline earth metal compounds, or a mixture of such compounds; passing a liquid hydrocarbon containing COS through the activated alumina adsorbent at a flow rate sufficient to adsorb enough COS in the liquid hydrocarbon to lower the COS content of the liquid hydrocarbon to less than 1 ppm; monitoring the effluent liquid hydrocarbon to determine when the capacity of the adsorbent to adsorb the COS has been reached; and then regenerating the activated alumina adsorbent by passing a gas, heated to a temperature of from about 150° to about 300° C., through the adsorbent for a period of time sufficient to remove a substantial amount of the sulfur adsorbed thereon.

Microwave regeneration of adsorbent materials for reuse as drying agents

Abstract: Porous desiccant material, such as silica gel, activated alumina, molecular sieves or mixtures thereof, is efficiently regenerated for reuse as a drying agent by irradiating a bed of the desiccant material with microwave energy preferably having a frequency of from 2400 MHz to 2500 MHz or from 900 to 915 MHz to heat and substantially affect only moisture adsorbed by the material and to vaporize the moisture in consequence of the heating of the moisture, the vaporized moisture being purged out of the bed with a forced draft of scavenging air while the bed undergoes irradiation by the microwave energy, and the resulting mixture of scavenging air and vapor being disposed of by discharging the mixture to an effluent receiving region isolated from the bed. As the moisture adsorbed on the pore, capillary and other surfaces of the desiccant material is preferentially heated by energy taken up from the microwave energy, moisture conversion from a liquid phase to a vapor phase is achieved directly, thereby to obviate raising the temperature of the desiccant material itself sufficiently to achieve the phase conversion of the adsorbate indirectly.

Activated alumina adsorption of dissolved organic compounds before and after ozonation

Abstract: L'elimination de substances organiques par l'alumine activee peut etre amelioree par une preoxydation a l'ozone

Ethylene oxide monitoring device

Abstract: Monitoring exposure to ethylene oxide using a dosimeter or monitoring device avoids using devices that collect a sample for future testing or devices that must be sent away for lab analysis. The device comprises a reactive coating including a layer of activated alumina particles coated with p-nitrobenzyl pyridine and ammonium chloride, and is adapted to instantly produce a color intensity change directly related to the dosage of the reactive coating to ethylene oxide upon the addition of a developer.

Color filter with a porous activated film layer having dye fixed in the minute pores to form color or pattern

Abstract: The color filter of this invention comprises a transparent substrate, a porous activated film layer formed on the substrate and made of activated alumina or activated silica or a mixture thereof, a colored area or a pattern formed by the dye fixed in the minute pores of the activated film layer, and a coating layer sealingly closing the upper portions of the minute pores of said activated film layer. This color filter is relatively simple and easy to manufacture, superior in resistivity to heat, water, chemicals, solvents, etc. and suitable for use as a color filter in various display devices, particularly liquid crystal display devices.

Producing alumina granules in a fluidized bed

Abstract: The process of the present invention for preparing granules of alumina includes pretreating an alumina powder by admixing with cold water in a mixer at a temperature below room temperature, eg, such as below about 20° C, to form a pretreated alumina having a pore volume saturated with water and further having a surface area of gel structure, and agglomerating the pretreated alumina in a fluidized bed to form granules The process is particularly suited to producing activated alumina in macroporous granules The process in one aspect further includes a cold hopper for cooling alumina powder prior to the pretreating step

A surface complex model for adsorption of trace components from wastewater

Abstract: A surface complex adsorption model is used to describe the results of batch equilibrium experiments investigating adsorption of hydrogen ion, chromate, phosphate, lead, and total organic carbon (TOC) onto activated alumina. These tests were conducted using domestic waste water treated by the activated sludge process, and lime coagulation. Surface complex models describe adsorption as formation of surface complexes between a component of the solid and the adsorbate in a manner analogous to formation of complexes in solution. The surface complex model applied to this work was able to adequately describe adsorption of the hydrogen, chromate, and phosphate ions onto alumina. However, the model did not adequately describe adsorption of lead and total organic carbon.

Improved catalyst compositions and methods of making same

Abstract: A method of making a catalyst composition comprising an activated alumina coating stabilized against thermal de­gradation includes applying a coating of alumina having one or more platinum group metal catalytic components dispersed thereon onto a carrier substrate and calcining the coating. The calcined coating is then impregnated with a solution of a thermal stabilizer-precursor and calcined again to provide a thermal stabilizer in the alumina. Bulk ceria, optionally an aluminum-stabilized bulk ceria, may also be added to the composition, preferably at specified minimum levels, includ­ing a high purity bulk ceria on which one or more non-rhod­ium platinum group metal catalytic components, e.g., platin­um, optionally, are dispersed. A separate aspect of the in­vention provides for a method of making a catalyst composi­tion including dispersing one or more platinum group metal catalytic components on an activated alumina and calcining the combined alumina and platinum group metal catalytic components. The steps are carried out under limited acidi­fication conditions whereby at least minimum dispersions of the platinum group metal catalytic components are attained. The invention also provides for catalyst compositions re­sulting from either or both the foregoing methods.

Waste gas purifying catalyst

Abstract: PURPOSE:To improve purifying capacity for hydrocarbons, CO, and NOX of a waste gas purifying catalyst by providing a coated layer consisting of powder of perovskite type compound oxide, activated alumina, etc. to the surface of a monolithic carrier, and depositing at least one kind among Pt, Rh, and Pd to the coated layer. CONSTITUTION:A specified amt. of aq. soln. of nitrate of a rare earth metal is immersed in an activated alumina carrier by the immersion method, and the carrier is after drying calcined at 600-650 deg.C in the air. Then, a slurry prepd. by crushing a mixture of powder of rare earth metal oxide, said activated alumina carrier, and perovskite type compound oxide powder is coated on a base material of monolithic carrier comprising cordierite. A catalyst carrier is obtd. by calcining the coated product at 650-850 deg.C after drying the coated product. Obtd. carrier is immersed in aq. soln. of at least one kind of salt of Pt, Rh, or Pd. After drying the immersed product, it is calcined at 500-700 deg.C for 0.5-2hr to obtain thus a waste gas purifying catalyst.

Production of catalyst for purifying exhaust gas

Abstract: PURPOSE:To obtain the title catalyst having excellent purification performance, durability, etc, by depositing a slurry contg zirconium oxide contg rhodium, activated alumina contg cerium, cerium oxide, and an alumina sol on a carrier, drying and baking the obtained material, and then depositing platinum on the material CONSTITUTION:About 015-7wt% rhodium is incorporated into zirconium oxide by impregnation, etc, and about 1-5wt% cerium is incorporated into activated alumina The zirconium oxide and the activated alumina are crushed and mixed in an alumina sol to obtain a slurry, and a carrier is impregnated with the slurry, dried, and baked to form composite oxide coated film contg rhodium on the carrier Pt is then deposited on the coated film to obtain the catalyst The catalyst has excellent purification performance, heat resistance, durability, etc, and is appropriately used as the catalyst for removing carbon monoxide, hydrocarbons, and nitrogen oxides in the exhaust gas from an automobile, etc

Separation and removing method for oxygen

Abstract: PURPOSE:To prevent the reduction of adsorbed amount of N2 due to the adsorption of moisture on zeolite by providing packed beds in the order of activated carbon, activated alumina and zeolite from the feed side of air as a raw material and performing a pressure fluctuation adsorption method in the packed bed having such three-layer structure. CONSTITUTION:The air a raw material, is fed to an adsorption tower 1 under pressurization with a blower 10. The air is passed in the order of activated carbon, activated alumina and zeolite; water is adsorbed by activated carbon and activated alumina; N2 is adsorbed by zeolite; and concentrated O2 is flowed out and stored in a tank 14. After finishing the adsorbing process, the adsorption tower 1 is subjected to pressure equalization together with an adsorption tower 2 and furthermore decompressed with a vacuum pump 11 to desorb the adsorbed gas. Thus two adsorption towers 1, 2 are successively changed over and used.

Production of catalyst for cleaning exhaust gas

Abstract: PURPOSE: To increase high temp. durability of a catalyst by preparing a slurry by adding activated alumina contg. the platinum group element, selenium oxide and barium nitrate, etc., sticking the slurry on a carrier having an integrated structure and thereafter calcining it. CONSTITUTION: The slurry contg. activated alumina contg. platinum group element, selenium oxide and barium nitrate, and/or barium formate is prepared. The catalyst for cleaning exhaust gas is produced by sticking the slurry on the carrier having the integrated structure and thereafter calcining it. Said carrier consists of refractory metal oxide or durable metal and its monolithic or three-dimensional network structure is preferable as the form of the carrier. Selenium oxide content is preferably 10W200g/1l catalyst obtd. COPYRIGHT: (C)1988,JPO&Japio

Fluidized bed granulation of rehydratable alumina

Abstract: The process of the present invention for preparing granules of alumina includes pretreating an alumina powder by admixing with cold water in a mixer at a temperature below room temperature, e.g., such as below about 20° C., to form a pretreated alumina having a pore volume saturated with water and further having a surface area of gel structure, and agglomerating the pretreated alumina in a fluidized bed to form granules sized in the range of about 1-3 mm. The process is particularly suited to producing activated alumina in macroporous granules. The process in one aspect further includes a cold hopper for cooling alumina powder prior to the pretreating step.

Method for removing acids from organophosphate functional fluids

Abstract: A method for reducing the acidity and moisture content of used organophosphate functional fluids. The used functional fluid is contacted with a solid composite adsorbent and then separated from the adsorbent. The composite adsorbent is preferably a powder having an average particle size of about 20-500 microns and total pore volume of at least about 0.40 cm 3 /g and it comprises about 40-90 wt % alumina and about 10-60 wt % Y zeolite wherein the molar ratio of SiO 2 to Al 2 O 3 is about 4.5-6.0. The adsorbent is produced by agglomerating particles of activated alumina and Y zeolite into a composite agglomerate, aging the agglomerate, activating at an elevated temperature, and then comminuting to form a powder.

Exhaust gas purifying monolith catalyst

Abstract: PURPOSE:To prevent the deterioration in the purifying activity of the titled catalyst by depositing rhodium on an upstream coating bed consisting of a highly heat-resistant alpha-alumina, and depositing a catalytic metal such as platinum on the downstream coating bed consisting of activated alumina. CONSTITUTION:In the monolith catalyst for purifying the exhaust gas from an internal combustion engine, the upstream coating bed 1 consisting of alpha-alumina and the downstream coating bed 2 consisting of activated alumina such as gamma-alumina and theta-alumina are provided in a monolith carrier based material. Rhodium is deposited on the upstream coating bed 1, and a catalytic material such as platinum and palladium is deposited on the downstream coating bed 2. Consequently, the detrioration in the catalytic activity due to the transformation of alumina under high-temp. conditions is prevented, and the deterioration in the purifying activity due to the formation of a solid soln. between rhodium and alumina under high-temp. conditions is prevented.

Dynamic modelling of water vapor adsorption by activated alumina

Abstract: Prediction of water vapor adsorption by activated alumina in a packed bed operated adiabatically is accomplished through the use of a simplified mathematical model. The model accounts for the heat and mass convection in the axial direction, and characterizes the heat and mass transfer associated with the adsorption process by a linear driving force. A linear isotherm was applied to approximate the equilibrium relationship of water vapor on activated alumina. Experimental data using Alcoa's commercial activated alumina, obtained from a 6 x 48 inch adiabatic column, were compared with model prediction; and a reasonably good agreement between these two was obtained. @KEYWORDS: Mathematical modeling, Adsorption, Activated alumina, Gas drying, Desiccant, Packed column.

Method for purifying sulfamide

Abstract: PURPOSE:To easily obtain high purity sulfamide useful to produce intermediates of dyes and pharmaceuticals by bringing a soln. of sulfamide contg. impurities in an org. solvent into contact with a specified inorg. solid absorbent. CONSTITUTION:Sulfamide contg. impurities is dissolved in a polar org. solvent such as methyl acetate, acetonitrile or 1,4-dioxane to prepare a soln., and one or more kinds of inorg. solid absorbents selected among activated alumina, zeolite and a molecular sieve each having >=7 pH surface acidity measured with a Nishicater indicator are added to the soln. The soln, is brought into contact with the adsorbents by stirring to allow the impurities to be adsorbed on the adsorbents. The adsorbents are then filtered off, the resulting filtrate is heated under reduced pressure to remove the org. solvent, and the remainder is vacuum-dried to obtain high purity sulfamide.

Preparation of catalyst carrier for purifying exhaust gas

Abstract: PURPOSE:To stabilize a catalyst support layer and to enhance catalytic activity, by a method wherein a slurry mixture of an activated alumina powder, a water soluble rare earth metal salt and water is adhered to the surface of a catalyst carrier and dried and baked to form an activated alumina layer to the surface of the carrier CONSTITUTION:A slurry mixture of an activated alumina powder, a water soluble rare earth metal salt and water is prepared to be adhered to the surface of a catalyst carrier base material and subsequently dried and baked to obtain an exhaust gas purifying catalyst carrier wherein an activated alumina layer containing at least a rare earth metal element is formed to the surface of the catalyst carrier base material In the obtained catalyst carrier, the rare earth metal element, for example, La is diffused during stirring and the La-ion enters the lattice of activated alumina such as gamma-alumina, delta-alumina or theta-alumina having a large gap to stabilize the crystal structure of the carrier

Apparaus for reduction of COD in water

Abstract: A method and apparatus for reducing chemical oxygen demand levels in water which includes the steps of: (a) mixing the water to be treated with at least one oxygen source; (b) contacting the water with a first, activated alumina catalyst; (c) contacting the water with a catalyst selected from the group consisting of Group VIIIB metals, Group IB metals, or mixtures thereof; (d) reacting chemical contaminants in the water with the oxgen source; and finally (e) contacting the water with an adsorptive material such as activated carbon. The present invention also includes a method and apparatus for regenerating the catalyst in situ by contacting the catalyst with alkaline and acidic aqueous inorganic regeneration solutions.

Production of adsorbent for phosphoric ion, fluoride ion or the like

Abstract: PURPOSE:To remarkably improve the efficiency in adsorbing phosphoric ions, fluoride ions, etc., by impregnating activated alumina with a titanium salt soln. and heating the material at % titanium sulfate (IV). The material is heated at 250-350 deg.C for about 2hr, allowed to cool, washed with water and dried to produce the adsorbent for phosphoric ions. Meanwhile, 1kg of granular activated alumina is impregnated with 1l of an aq. soln. of 1.0-2.5wt.V % titanium sulfate (IV). The material is heated at 300-500 deg.C for about 2hr, allowed to cool, washed with water and dried to produce the adsorbent for fluoride ions.

Production of unsaturated carboxylic acid or ester thereof

Abstract: PURPOSE:To obtain the titled compound in high selectivity without causing deterioration in activity by change in physical properties of a catalyst in decoking, by reacting a carboxylic acid with formaldehyde in the presence of an activated alumina-supported catalyst, having a high catalyst strength and subjected to specific treatment. CONSTITUTION:A carboxylic acid expressed by formula I (R1 and R2 are H or 1-5C alkyl) or an ester thereof is reacted with formaldehyde in the presence of a catalyst pepared by supporting an alkali metal, e.g. K, Rb or Cs, on activated alumina obtained by previously firing at 800-1,200 deg.C, preferably 900-1,000 deg.C for 5-10hr, as necessary, in an inert solvent, e.g. trioxane, at 250-400 deg.C under 0.5-3kg/cm pressure in the vapor phase at 1-10 weight hourly space velocity (WHSV, g raw material/g catalyst/hr) to afford the aimed compound expressed by formula II. The catalyst is supported on a carrier by a method for impregnating the above-mentioned fired carrier with 0.5-15% alkali metal, drying the impregnated carrier and supporting the alkali metal thereon.

Preparation of activated alumina carrier having high pore void volume

Abstract: PURPOSE:To easily form desired fine pore distribution, by granulating hydraulic alumina, obtained by treating aluminum hydroxide having specific particle size distribution and a specific average particle size in a hot air stream at specific temp., while water is sprayed to said alumina. CONSTITUTION:Aluminum hydroxide wherein the content of particles with a particle size of 5mum or less is 80% or more and an average particle size is 0.5-5mum is thrown in a hot air stream with temp. of 400-1,200 deg.C for 0.1-10sec to form hydraulic alumina. This hydraulic alumina is granulated while water is sprayed to prepare an activated alumina carrier wherein an entire void volume is 0.5-1.5cc/g and the volume of a pore size of 1,000-10,000Angstrom is 0.2-0.6cc/g. In the aforementioned method, for example, when granulation is performed by a pan type granulator, a powder is fine and filling property becomes inferior and, therefore, the filling density of the carrier can be regulated by the spray amount of water.

Treatment of chemical vapor deposition exhaust gas

Abstract: PURPOSE:To perform the dry treatment of exhaust gas adaptable to chemical vapor deposition treatment, by almost removing volatile fluorides by cooling exhaust gas resulting from chemical vapor deposition treatment by condensation or coagulation and removing the remaining fluorides by an adsorbent. CONSTITUTION:The exhaust gas from a chemical vapor deposition treatment apparatus is cooled to -100--170 deg.C using liquid nitrogen to almost condensate or coagulate volatile fluorides in the exhaust gas and fluorides not coagulated are removed by an adsorbent. As the adsorbent, sodium fluoride, soda lime and, according to circumstances, activated alumina are used in combination. Sodium fluoride mainly removes hydrogen fluoride and soda lime removes other volatile fluorides by chemical absorption. Alumina absorbs and removes the powder of soda lime and moisture and also absorbs moisture mixed by reverse diffusion.

Metal carrier catalyst

Abstract: PURPOSE:To eliminate an alumina layer, by a method wherein alumina hydrate is laminated to the surface of a heat resistant metal carrier and baked to be converted to the activated alumina layer and a catalyst metal or a metal compound is supported by said activated layer. CONSTITUTION:An aluminum layer is formed to the surface of a heat resistant metal carrier comprising a heat resistant metal material such as heat resistant steel by a molten Al plating method. Subsequently, the aluminum layer is treated by a treatment method such as an anodic oxidation method or a boehmite chemical forming treatment method to convert aluminum of the surface layer to alumina hydrate and, after sealing is further performed desirably, said alumina hydrate is forcibly dehydrated by baking under heating to prepare a catalyst carrier. At this time, the surface of the carrier is coated with a gamma-alumina layer having a high specific surface area and a desired catalyst including a platinum catalyst is supported by said alumina layer to obtain a metal supported catalyst for purifying combustion exhaust gas.

A method of removing impurities from n-methyl-pyrrolidone used for solvent extraction of lube oil fractions using activated alumina

Abstract: N-methyl pyrrolidone solvent used to extract aromatic components from lubricating oil distillates is purified by contacting the solvent with activated alumina.