Showing papers on "Activated alumina published in 1996"

Environment purifying material

Abstract: The present invention is directed to a sheet-form environment purifying material comprising particles of metal and/or metal oxide consisting essentially of at least one member being selected from the group consisting of manganese, copper, zinc, iron, vanadium, nickel, titanium, palladium, platinum, manganese oxide, copper oxide, zinc oxide, iron oxide, vanadium oxide, nickel oxide, titanium oxide, palladium oxide, and platinum oxide, adsorbent particles consisting essentially of at least one member selected from the group consisting of activated carbon, zeolite, silica gel, sepiolite, activated alumina and activated clay, thermoplastic resin particles being selected from ultrahigh-molecular weight polyethylene, polyethylene, polycarbonate, polyamide acrylonitrile-butadiene-styrene resins, polyimide, polyvinyl chloride, cellulose acetate, polysulfone, polystyrene phthalate and polypropylene, and an air-permeable sheet of fibrous. The metal and/or metal oxide particles and the adsorbent particles are respectively bound to the thermoplastic resin particles while retaining their inherent surface areas and performances without being covered by the thermoplastic resin layers, and the thermoplastic resin particles are joined to the fibrous substrate. The present invention is also directed to a process for making the environment purifying material which comprises the steps of mixing all the particles and heating the mixture at a temperature not lower than the melting point of the thermoplastic resin and not higher than the thermal decomposition temperature thereof. The environment purifying material of the present invention is useful as deodorizers and harmful gas removers.

Chapter 2.12 Drying of gases and liquids by activated alumina

Abstract: Publisher Summary Removal of trace and bulk water from a fluid (gas or liquid) stream is a major unit operation in the chemical and petrochemical industries. The drying process is necessary to (1) prevent condensation and freeze-out of water in plant pipeline and equipment, (2) eliminate corrosion in process equipment, (3) protect against undesirable chemical reactions such as hydration and hydrolysis, (4) prevent catalyst poisoning, and (5) meet product fluid composition specification. Selective adsorption of water on a solid desiccant such as zeolites, silica gels, and activated aluminas is often used as the method of drying the fluid stream. Various forms of cyclic pressure swing adsorption (PSA) and thermal swing adsorption (TSA) concepts are generally used as the drying process. These processes utilize regenerative schemes consisting of adsorption and desorption steps so that the adsorbent can be repeatedly used for drying the fluid stream. The design and cost of operation of these processes demand certain properties for adsorption of water by the adsorbent that facilitate the adsorption and desorption steps. Activated aluminas often provide a large spectrum of desirable adsorptive properties for such drying applications. These properties include adsorption equilibria, adsorption kinetics, heats of adsorption, and adsorption and desorption column dynamics, which govern the performance of the drying process. This chapter briefly describes these properties for adsorption of water on various forms of alumina and illustrates several conventional drying processes using alumina.

Treatability of inorganic arsenic and organoarsenicals in groundwater

Abstract: A 2-year three-phase study into methods for treatment of mixed inorganic and organic arsenic species to drinking water levels was conducted at a former pesticide facility in Houston, Tex. The species present include monomethylarsinic acid, dimethylarsinic acid, arsenate, and arsenite. Phase One studies reported here included the evaluation of four adsorbents using bottle roll and column flow through techniques, oxidation through the application of Fenton's reagent followed by coprecipitation, coprecipitation without oxidation, and ultraviolet (UV)/ ozone tests. The four adsorbents tested were activated carbon, activated alumina, ferrous sulfide, and a strongly basic ion exchange resin. All adsorbents removed some arsenic, but none except ferrous sulfide was sufficiently effective to warrant follow-up studies. Two small ferrous sulfide column tests, run under different conditions, removed arsenic but not to the levels and loading capacities needed to make this method practical. Organic compound destruction was tested using Fenton's reagent (a mixture of hydrogen peroxide and ferrous iron) before coprecipitation. Arsenic was reduced to 170 ppb in the treated liquor. Coprecipitation without oxidative pretreatment produced a liquor containing 260 ppb arsenic. A two-stage Fenton-type coprecipitation procedure produced a supematant containing 110 ppb total arsenic. Preliminary tests with a second-stage oxidative process, using ozone and UV radiation, showed approximately 80% destruction of an organic-arsenic surrogate (cacodylic acid) in I hour. Water Environ. Res., 68, 946 (1996).

Sorption of SFG and SFG decomposition products by activated alumina and molecular sieve 13X

Abstract: This paper presents measurements of the adsorption characteristics of various SF6 decomposition products on activated alumina and on a molecular sieve type 13X (synthetic zeolite). The adsorption process is analysed by measuring the concentrations of the gas component to be adsorbed as well as its desorbed reaction products by IR absorption in a 2.5 litre stainless steel cell. The adsorption characteristics (adsorption isotherms) and the chemical reactions in the adsorber were determined for the pure gases SF4, SOF2, S02, SOF4, S02F2, S2F10, S202F10 and SF6. "Precharging" the adsorber with humidity has been shown to lower the adsorption. The importance of the chemical reaction energy associated with chemisorption processes was established by measuring the temperature of the adsorher substances during the adsorption process. The transport mechanisms responsible for the transfer of the adsorbable gas from the volume into the adsorber (adsorption kinetics, diffusion, convection) were identified by comparing the measured decay times of pure SO2 as well as SO2 in SF6 with and without forced convection. A preliminary attempt is made to understand the physical chemistry of the observed phenomena.

Catalyst for producing high calorie gas and its production

Abstract: PROBLEM TO BE SOLVED: To provide a catalyst used to a process for producing an alternate natural gas high in calorie by subjecting hydrocarbon to steam reforming and to provide a production method of the catalyst. SOLUTION: The catalyst is obtained by depositing 1.5-4wt.% ruthenium on an activated alumina composite carrier obtained by burning at 450-600 deg.C a carrier base stock obtd. by compacting aluminum hydroxide, at least one kind carbonate selected form among group II, group III and lanthanoide metal in periodic table and oxy acid as a starting material, insolubilizing and fixing the ruthenium with an alkali aq. soln, and subjecting the material to reducing treatment at 80-500 deg.C, and the catalyst has >=60% ruthenium dispersibility. After the reducing treatment, a ruthenium retention rate on the catalyst is >=95%, and a specific surface area of the catalyst is preferably >=180m /g, and before the reducing treatment, the material is preferably dried at <=100 deg.C under reduced pressure or normal pressure.

Apparatus for removing arsenic in water

Abstract: PROBLEM TO BE SOLVED: To stably obtain treated water of good quality low in the concn. of residual arsenic over a long period of time and capable of economically removing arsenic in an apparatus for adsorption-removing arsenic in water by using an adsorbent. SOLUTION: A rough removing adsorbent and a cerium or zirconium type adsorbent are used to roughly remove arsenic in water to be treated by the rough removing adsorbent and, subsequently, arsenic in water to be treated is finally removed by the cerium or zirconium type adsorbent. For example, the tower 8 on the upstream side in a water passing direction among two towers 8, 10 is packed with activated alumina 4 as the rough removing adsorbent and the downstream tower 10 is packed with the cerium type adsorbent 6 and water to be treated is successively passed through two towers 8, 10. COPYRIGHT: (C)1998,JPO

Production of phosgene

Abstract: PROBLEM TO BE SOLVED: To obtain colorless phosgene in a high yield by reacting chlorine with carbon monoxide reduced in the content of hydrogen in the presence of an activated carbon catalyst. SOLUTION: This method for producing phosgene comprises reacting chlorine with carbon monoxide having a hydrogen gas content of ≤6mol.% in an amount excessive by 1-30mol.% based on a stoichiometric amount in the presence of an activated carbon catalyst in an amount of 800-1300kg based on 1000m 2 /hr of the carbon monoxide. The carbon monoxide reduced in the hydrogen gas content is produced by bringing carbon monoxide having a hydrogen gas content of ≥6.0mol.% into contact with an adsorbent such as silica gel, calcium chloride or activated alumina or by heating the carbon monoxide in the presence of a catalyst such as copper-activated carbon catalyst or copper-manganese- activated carbon catalyst at 40-100°C to convert the hydrogen into water, and subsequently bringing the water-containing carbon monoxide into contact with an adsorbent. COPYRIGHT: (C)1998,JPO

Catalytic material for cleaning of exhaust gas, catalyst for cleaning of exhaust gas and its production

Abstract: PROBLEM TO BE SOLVED: To prevent the thermal deterioration of Ba in a Ba-contg. catalyst by forming Ba oxide by heating on the surface of ceria particles and fixing Ba as oxide on the ceria particles. SOLUTION: A coating layer contg. ceria particles with fixed Ba, activated alumina particles and a noble metal is formed on the surface of a catalyst carrier to obtain a honeycomb catalyst for purification of exhaust gas from an automobile. As this time, in order to prevent the thermal deterioration of the fixed Ba, a Ba compd. is mixed with ceria particles, Ba oxide is formed on the surfaces of the ceria particles by heating at 400-1,100°C and this Ba oxide is fixed on the ceria particles. The fixation of the Ba oxide on the ceria particles is strengthened, and even when the resultant catalytic material is heated to a high temp., the release of Ba, the diffusion of Ba in other substance or the formation of a compd. or solid soln. is avoided until the material is heated to a temp. close to the decomposition temp. of Ba oxide. COPYRIGHT: (C)1997,JPO

Method for producing activated alumina catalyst

Abstract: A method of making activated alumina including the steps of dissolving a double salt of aluminum in a solution of pure water at 85°C, recrystalizing the double salt at a pressure about 250 psi and temperature ranging from 200°C to 250°C, precipitating out the purified basic double salt, drying the precipitated double salt to drive off water and roasting it at 850°C to 950°C to drive off the sulfate, washing to remove the potassium sulfate and then drying the remaining alumina to yield activated alumina for use as a high-grade catalyst.

Catalytic production of butyrolactone or tetrahydrofuran

Abstract: A process for the preparation of supported bimetallic catalyst useful for the hydrogenation of esters of dicarboxylic acids, which comprises impregnating activated alumina powder with transition metal by contacting the said solid alumina powder with an aqueous solution of a salt of a transition metal, treating the said transition metal salt impregnated alumina powder with an aqueous solution of a salt of group (IV) metal in acidic medium so as to have ratio of transition metal to group (IV) A metal in the range of 1:5 to 1:20, further treating the bimetallic impregnated alumina powder with an alkali solution followed by a solution of boron containing compound, finally washing and drying the resultant supported catalyst.

Process for removing peroxide impurities from acrylonitrile monomers

Abstract: A process is provided for removing peroxide contamination from acrylonitrile. The process includes contacting the acrylonitrile with an activated alumina adsorbent and separating the acrylonitrile product from the alumina. The contaminated acrylonitrile is contacted with the activated alumina adsorbent for a time sufficient for the peroxide contaminate to be adsorbed by the activated alumina. The activated alumina may also be used to selectively remove color promoting contaminates in an acrylonitrile product.

Denitration catalyst and denitration method using the same

Abstract: PURPOSE:To provide a denitration catalyst and to denitrate NOx in exhaust gas of an internal combustion engine of a lean air/fuel ratio with a high efficiency and high reliability by using the catalyst. CONSTITUTION:Activated alumina is used as a carrier and strontium or barium and silver and/or silver oxide are supported on the carrier to obtain the denitration catalyst. In this catalyst, the pore distribution in the activated alumina is characterized by that B is 30% or more of A and C is 15% or less of A when the sum total value of pore vol. occupied by pores with a pore radius of 300Angstrom or less is set to A and the sum total value of pore vol. occupied by pores with a pore radius of 50Angstrom or less is set to B and the sum total value of pore vol. occupied by pores with a pore radius of 100-300A is set to C in the relation between a pore radius and pore vol. measured by a nitrogen gas adsorbing method. When exhaust gas of an internal combustion engine operated in a lean air/fuel ratio passes through the denitration catalyst bed, the inlet temp. of the catalyst bed is set to 400-600V.

Production of denitration catalyst and denitration method using obtained catalyst

Abstract: PURPOSE:To efficiently remove NOx in exhaust gas of an internal combustion engine of a lean air/fuel ratio at a sufficiently high spatial velocity by using activated alumina having a specific pore distribution as the carrier and supporting a silver salt on the carrier to dry and bake the supporting carrier. CONSTITUTION:In the production of the denitration catalyst, at first, an alumina hydrate is formed by dripping an aq. aluminum salt soln. and an aq. alkali soln. at the same time and subsequently dried and baked to obtain activated alumina having such a pore distribution that B is 30% or more of A and C is 15% or less of A when the sum total value of pore vol. occupied by pores with a pore radius of 300Angstrom or less is set to A and the sum total value of pore vol. occupied by pores with a pore radius of 50Angstrom or less is set to B and the sum total value of pore vol. occupied by pores with a pore radius of 100-300Angstrom is set to C in the relation between a pore radius and pore vol. measured by a nitrogen gas adsorbing method. This activated alumina is used as the carrier and a silver salt is supported on the carrier and the supporting carrier is dried and baked to produce the denitration catalyst.

Determination of adsorbed species in the surface hydrolysis of SOF/sub 2/ on activated alumina

Abstract: The nature of the species adsorbed in the hydrolysis of SOF/sub 2/ on activated alumina has been investigated using spectroscopic XPS and FTIR techniques. XPS technique proved to be a convenient tool for determining the amount of adsorbed species, especially when they are strongly bonded. The amount of fluorine detected by XPS confirmed its strong interaction with alumina, although the formation of an alumina-fluorine complex was not observed. With regards to the adsorbed sulfur complexes, the S 2p XPS binding energy (BE) associated with the features of the FTIR spectra (around 1000-1200 cm/sup -1/) suggests the presence of both chemisorbed SO/sub 3/ (sulfite) and SO/sub 2/F (fluorosulfite) species on alumina. Lastly, the decreasing amount of oxygenated species detected by XPS suggests that the presence of adsorbed fluorine has a significant impact on the retention capability of alumina toward moisture.

Catalyst for purification of exhaust gas and exhaust gas purifying system

Abstract: PROBLEM TO BE SOLVED: To enhance hydrocarbon removing ability in a rich atmosphere at a low temp. by carrying a catalytic layer contg. at least one kind of noble, and Ba and Cs on a carrier by coating. SOLUTION: At least one kind of noble metal selected from among Pd, Pt and Rh, Ba as an electron donative substance causing removal reaction at a relatively low temp. when it exists near the noble metal and Cs further improving low-temp. ignitability as compared with the case where only Ba is added to a catalytic layer are deposited on activated alumina powder as a substrate and the alumina powder is carried on a carrier by coating and fired. When the noble metal and the electron donative substance are deposited on the same activated alumina powder, it is preferable that the noble metal is first deposited so that it is brought into direct contact with the surface of the alumina powder. Hydrocarbons discharged in large quantities at the time of cold starting are effectively removed. COPYRIGHT: (C)1998,JPO

Manufacture of very low arsenic hydrogen fluoride

Abstract: The invention provides a process for the preparation of hydrogen fluoride having a very low arsenic level. More specifically, the invention provides a process in which industrial grade anhydrous hydrogen fluoride, or an intermediate product obtained during the hydrogen fluoride manufacturing process, is contacted with an oxidizer in order to oxidize the arsenic impurity to produce anhydrous hydrogen fluoride with a level of arsenic impurity that is at least less than two parts per billion, or aqueous hydrogen fluoride with a correspondingly low level of arsenic.

Field sampling and microcolumn preconcentration techniques in inductively coupled plasma spectrometry

Abstract: This thesis is concerned with analytical studies on the trace analytes barium, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, vanadium and zinc, present in high purity and highly complex matrices. The technique utilises activated alumina microcolumns in a flow injection (FI) system, to perform analyte enrichment and matrix removal. The analytes, after retention on the microcolumn are subsequently eluted and quantified by inductively coupled plasma-emission spectrometry (ICP-ES).Initial studies focus on trace analytes in caesium iodide, however a selection of the alkali metal salts, lithium nitrate, potassium bromide, sodium fluoride and sodium chloride, are investigated. New methodology for the ultratrace determination of high purity alkali metal salts is thus provided. The microcolumn enrichment technique with ICP-ES detection is robust, utilises limited sample handling and simultaneously preconcentrates and separates the analytes from matrix components. Hence possible matrix interferences are eliminated and limits of detection are significantly improved, in comparison to conventional ICP-ES analysis.A technique for the determination of the total content of eleven trace analytes present in natural waters (mineral, reservoir), using microcolumns of activated alumina in a FI-ICP-ES is investigated. The use of the complexing agent tartaric acid is shown to be effective in improving analyte retention. The procedure is successfully applied to determination of these analytes in a certified river water reference material (SLRS-1). Due to low retention and elution efficiencies, the total content of the analytes Fe and V present in Buxton, Redmires and Langsett samples could not be accurately determined by this technique.Activated alumina microcolumns are utilised as a new field sampling tools. Samples are collected in the field and processed through the alumina microcolumns for the effective retention of desired analytes. Hence, an alumina microcolumn sampling stage to effect concentration and isolation prior to analytical measurement is at the core of the investigation. The overall aim is to extend the application of alumina microcolumns, and in particular to provide a new multi-element field sampling device, which gives high sample integrity and preconcentration.