Showing papers on "Activated alumina published in 2000"

Removing arsenic from groundwater

Abstract: Three treatment technologies for removing arsenic from groundwater in Albuquerque, N.M., were compared: ion exchange (IX), iron hydroxide coagulation followed by microfiltration (C/MF), and activated alumina (AA) adsorption. For an 8,700-m 3 /d (2.3-mgd) arsenic treatment facility, capital costs of the three processes were similar: $5.2 million, $4.1 million, and $4.6 million, respectively. Annual operations and maintenance costs were $447,000, $273,000 and $444,000, respectively. The principal differences were the result of large salt requirements for the IX process and the need to reduce the pH to 6 for AA adsorption, followed by base addition to stabilize the water. The C/MF system was selected for a demonstration facility in Albuquerque.

Use of an activated alumina for removing the CO2 from a gas

Abstract: A process, especially a PSA or TSA process, for purifying a gas containing at least carbon dioxide (CO 2 ) as impurity, in which the carbon dioxide is adsorbed on an adsorbent comprising particles of activated alumina. According to this process, the activated alumina has a specific surface area of between 200 m 2 /g and 299 m 2 /g and contains at least 80% aluminum oxide (Al 2 O 3 ), silicon oxide (SiO 2 ), iron oxide (Fe 2 O 3 ) and from 0.001% to 7.25% of at least one oxide of at least one alkali or alkaline-earth metal, such as sodium and potassium oxides. According to the invention, the gas stream to be purified is air or a synthesis gas.

Process for oxidation of H2S to sulphur

Abstract: PCT No. PCT/FR96/01699 Sec. 371 Date Aug. 25, 1997 Sec. 102(e) Date Aug. 25, 1997 PCT Filed Oct. 30, 1996 PCT Pub. No. WO97/17284 PCT Pub. Date May 15, 1997A process is provided for reducing the amount of hydrogen sulfide present in a tail gas from a sulfur recovery process. The hydrogen sulfide contaminated gas along with a gas containing free oxygen is passed through a series of hydrogen sulfide oxidation zones containing an oxidation catalyst, such as one or more oxides or salts of Ni, Co, Fe, Cu, Ag, Mn, Mo, Cr, W and V, deposited on a support, such as bauxite, activated alumina, titania and activated carbon. The initial and intermediate catalyst beds are operated adiabatically by injecting a substoichiometric amount of oxygen into the gas to be treated with respect to the amount of hydrogen sulfide present in the gas so that the temperature does not exceed 150 DEG C. The final catalyst bed is operated under conditions such that a superstoichiometric amount of oxygen is injected into the gas with respect to the hydrogen sulfide and cooling is provided so that the temperature does not exceed 150 DEG C. The invention is able to maintain an optimum selectivity toward sulfur during the catalytic oxidation of the hydrogen sulfide by controlling the temperature.

Defluorinator catalyst and process for removing fluorides from fluids

Abstract: The present invention constitutes a new method for removing HF and related organic fluorides from fluid streams in which the fluoride species exist as impurities and, in particular, from hydrocarbon fluid streams containing up to 1000 ppm combined fluorides. The method of the invention consists of contacting the fluid stream with an adsorbent consisting essentially of activated alumina promoted with a compound selected from the oxides and phosphates of alkali metals and alkaline earth metals, and mixtures thereof. Thus, in essence, the method of this invention utilizes a base-promoted alumina adsorbent in place of the prior art non-promoted aluminas.

Method for using activated alumina in order to remove co2 from gas

Abstract: PROBLEM TO BE SOLVED: To provide a gas refining process capable of effectively removing at least CO2 present in gas to be refined as impurities, pref., both of CO2 and steam. SOLUTION: In a refining process of gas containing carbon dioxide (CO2) as impurities, especially, a PSA(pressure-swing adsorption) or TSA(temperature- swing adsorption) process, carbon dioxide is adsorbed by an adsorbent containing activated alumina. Activated alumina has a specific surface area of 200-299 m2/g and contains at least 80% of aluminum oxide (Al2O3), silicon oxide (SiO2) and iron oxide (Fe2O3) and 0.001-7.25% of at least one oxide of alkali metal or alkaline earth metal, for example, sodium oxide or potassium oxide. Gas to be refined is air or synthetic gas.

Acidic activated alumina and its production

Abstract: PROBLEM TO BE SOLVED: To obtain the acidic activated alumina having pH on the acidic side and having adsorptivity to the metallic components and other basic components in addition to the adsorptivity of activated alumina by mixing aluminum hydroxide and ammonium chloride and/or ammonium sulfate and calcining the mixture. SOLUTION: At least one aluminum hydroxide among gibbsite-structure aluminum hydroxide, pseudoboehmite-structure aluminum hydroxide and bayerite- structure aluminum hydroxide is mixed with 0.5-3.0 wt.% ammonium chloride and/or ammonium sulfate on a 150 deg.C dry basis, and the mixture is calcined at 450-700 deg.C. The product contains >=97 wt.% Al2O3 when measured on a 150 deg.C dry basis and has 150-400 m2/g BET specific surface and 0.2-0.7 cc/g pore volume. The pH of its 2 wt.% aq. suspension of the acidic activated alumina is valued at 4.0-7.0. The product having 5-100 μm median diameter on a volume basis is preferable.

Transparent active alumina, its production and use

Abstract: PROBLEM TO BE SOLVED: To obtain a transparent activated alumina having an amorphous structure in terms of X-ray diffraction study, useful for a resin compounding agent, an adsorbent for a photocatalyst, a carrier, etc., and to provide a method for producing the alumina. SOLUTION: This transparent activated alumina is obtained by converting a hydrosol of a basic aluminum sulfate having a mol composition of SO3/Al2O3 of 0.90-1.00 into a gel, if required, neutralizing the gel or washing with water and drying or baking, is substantially amorphous in terms of X-ray diffraction study, has 100-500 m2/g BET specific surface area, is optically transparent substantially and maintains an amorphous structure even after heating at 600 deg.C for 3 hours.

Treatment method of fluorine-containing waste water

Abstract: PROBLEM TO BE SOLVED: To provide a method for separating and removing fluorine from waste water containing fluorine such as waste water generated by scrubbing smoke. SOLUTION: Powdery activated alumina is added and mixed to waste water to be treated containing fluorine as an adsorbent of a fluorine compound, and later the added activated alumina is separated by using a clarification sand filter. PH of the filtrate is preferred to prepare it in a range of 4.5 to 7 by adding a flocculant. As the flocculant, aluminum sulfate or polyaluminum chloride is preferred. Also, as the clarification sand filter, an upward counter flow current moving bed type sand filter is preferred. This method is useful to treatment of waste water generated by scrubbing smoke discharged from a waste incineration plant, etc.

Activated alumina compact for production of hydrogen peroxide, its production, and purification of operating liquid for production of hydrogen peroxide by using the same

Abstract: PROBLEM TO BE SOLVED: To obtain an activated alumina compact for production of hydrogen peroxide having the same or more initial removing ability for removing an epoxide from an operating liquid, and a longer life for sufficient removal compared to the conventional one, and further to provide a production method thereof, and a method for purifying the operating liquid for the production of the hydrogen peroxide by using the same. SOLUTION: This activated alumina compact for production of hydrogen peroxide has >=0.5 mm and =250 m2/g BET specific surface area, and 0.01-15 wt.% SiO2 concentration. The alumina compact is usable for removing an epoxide from a solution containing an anthraquinone compound in the process of producing the hydrogen peroxide by the oxidation and reduction of the anthraquinone compound. The method for producing the activated alumina compact for the production of the hydrogen peroxide comprises compacting activated alumina powder having rehydration, and 0.5-1.2 g/cm3 bulk density, rehydrating the obtained compact, and baking the rehydrated compact.

Hc1 adsorbent, method of making same and process for removing hc1 from fluids

Abstract: An adsorbent for removing HC1 from fluid streams comprising activated alumina impregnated with alkaline oxide and promoted with phosphate or organic amine or a mixture thereof. A method for making such adsorbent and a method of removing HC1 from fluid streams using such adsorbent.

Purification of monogermane gas

Abstract: PROBLEM TO BE SOLVED: To efficiently remove a sulfur-containing compound, Cl or the like and moisture by removing water soluble impurities by allowing monogermane gas having the impurities to contact with water and dehydrating entrained moisture with an adsorbent. SOLUTION: The monogermane gas containing the water soluble components as the main impurities is brought into contact with water to remove the water soluble components such as the sulfur-containing compound, Cl or the like. A bubbler, a cleaning tower or the like is used for a method of one contact with water. The contact time with water is controlled to 0.1-1000 sec, preferably 1-300 sec. The initial pH of water to be in contact is preferably controlled to 6-7. The monogermane gas removed in the water soluble components results in containing moisture and the moisture is adsorbed on the adsorbent non- reactive to the monogermane to be removed. As the adsorbent, dried natural zeolite, synthesized zeolite, silica gel, activated alumina, activated carbon and the like are mentioned.

Pore structure of activated alumina carrier

Abstract: Formation and types of activated alumina carrier were describedA network model for its pore structure was proposed and factors influencing the pore structure of activated alumina were discussedSeveral methods for controlling the pore structure were described and some suggestion were given on the basis of correlation ship of pore structure and other properties ship of activated alumina

Phosphorus doped activated alumina

Abstract: A process for producing granules of a phosphorus doped activated alumina from aluminium hydroxide and a phosphorus source is described. The granules can be used as growth regulator, especially as low phosphorus buffer in potted plants.

Hollow synthetic resin sheet

Abstract: PROBLEM TO BE SOLVED: To provide hollow synthetic resin sheets which are white or colored and have an effect of reducing CO concentration in exhaust gases upon incineration and preventing leakage of heavy metallic ions from the incinerated ashes buried in the ground. SOLUTION: Hollow synthetic resin sheets contain at least one inorganic compound having a BET specific surface area of not smaller than 30 m2/g after combustion and, at the same time an accumulated 90% diameter of not greater than 30 μm which is selected from aluminum hydroxide, zeolite, clay, a silicate, activated clay, and activated alumina. It is preferred that the inorganic compound is aluminum hydroxide and has an Fe2O3 content of not greater than 0.02%.

Porous activated alumina and its production

Abstract: PROBLEM TO BE SOLVED: To provide a method for producing porous activated alumina, enabling the easy adjustment of the diameters of pores. SOLUTION: This method for producing porous activated alumina in which many pores are formed comprises calcining an aluminum compound. Therein, the improvement comprises adding a water-soluble organic compound to the aqueous solution of a basic aluminum chloride used as the aluminum compound, subjecting the mixture to a hydrothermal treatment, gelling the obtained basic aluminum chloride aqueous solution, and then calcining the gelled product at a temperature not lower than the thermal decomposition temperature of the water-soluble organic compound left in the gelled product.

Composite inorganic oxide to remove anion in water and its production

Abstract: PROBLEM TO BE SOLVED: To adsorb and remove a minute amt. of anions such as arsenic and fluorine included in weak alkaline underground water or the like and to easily obtain water having equal pH to that of the raw water without a special process such as pH control by forming an aluminum magnesium multiple oxide layer on the surface of an inorg. oxide. SOLUTION: An aluminum magnesium multiple oxide layer is formed on the surface of an inorg. oxide to form a composite inorg. oxide to remove anions in water. As for inorg. oxides, at least one kind is selected from the group of activated alumina, manganese dioxide and cerium oxide. The inorg. oxide is preferably in a spherical form considering the handling property to add and recover the multiple inorg. oxide, and its particle size is controlled to about 0.1 to 10 mm. In the production of the composite oxide, the inorg, oxide is mixed with a mixture aq. soln. of aluminum salt and magnesium salt, aged and dried. To analyze the oxide layer on the surface, Mg on the cross section of the oxide is analyzed with beams.

Activated alumina molded article, process for producing the same, purification method of hydrogen peroxide solution using the same

Abstract: PURPOSE: An activated alumina molded article is provided which life time is long enough to eliminate byproducts and the initial eliminating performance for eliminating the byproducts such as an epoxide from a solution containing quinone compound is the same or more. CONSTITUTION: A activated alumina molded article have up to 0.5mm and less than 2mm of particle average diameter, up to 250m2/g of the BET non-surface area and 0.01-15wt% of SiO2 content. The activated alumina molded article is prepared by making the activated alumina being 0.5-1.2g/cm¬2 of bulky density.

Conversion of cis and trans-cyclododecene oxide to cyclododecanone

Abstract: PROBLEM TO BE SOLVED: To convert cis-and trans-cyclododecene oxide to cyclododecanone without causing a by-product unusable for a primary product and a final product. SOLUTION: Cis-and trans-Cyclododecene oxides are converted to cyclododecanone by using hydrogen excited by a catalyst in the presence of the copper catalyst containing 0.4-4 wt.% of chromium, 0.6-8 wt.% of barium and fine particle silicic acid or activated alumina as a carrier or constituted of copper or a copper compound and zinc oxide) at 150-260 deg.C under atmosphere or pressure a little higher than atmosphere. The conversion is advanced through cyclododecen-3-ol and cyclododecen-3-one to give cyclododecene as a by-product. Cyclododecene is separated by distillation and is used in the production of cis-and trans-cyclododecene oxide.

New alumina, its preparation, and its use as catalyst, catalyst carrier or adsorbent

Abstract: PROBLEM TO BE SOLVED: To give an optimized acidity to alumina and to suppress secondary reaction by mixing alumina produced by rapid dehydration of aluminum trihydroxide in a gibbsite phase and aluminum trihydroxide of bayerite phase, forming, ageing and firing them. SOLUTION: Alumina produced by rapid dehydration of aluminum trihydroxide in a gibbsite phase is mixed with aluminum trioxide of bayerite phase by the weight ratio of about 100/0.1 to 100/30. After the mixture is formed, if necessary, the formed body is aged till the proportion of aluminum trihydroxide of the bayerite phase is decreased to at least 5 wt.%. Then the body is fired at >=250 deg.C. Thereby, an activated alumina containing alumina having at least 5 wt.% of η-phase in the crystal structure and having 500 to 8000 wt.ppm alkali metals calculated as M2O is obtd. The obtd. activated alumina has at least 40 m2/g specific surface area.

Moisture retention material and its use

Abstract: PROBLEM TO BE SOLVED: To provide a moisture retention material obtained by using a solid component of a micro capsule containing a thermal storage medium that has functions to remove various uncomfortable odors derived from materials for the thermal storage medium and those necessary for microcapsulation and as heat generating materials having quick and stable temperature reproducibility by microwave when heating the microcapsule containing the thermal storage medium and a composition containing a water absorbable pigment by irradiation of microwave. SOLUTION: A composition containing the solid component of the microcapsule containing the thermal storage medium, a monolithic carbon compound and/or the water absorbable pigment with 3-60% of water absorption rate is used as the moisture retention material. It is favorable that the monolithic carbon compound comprises an activated carbon and the water absorbable pigment comprise silica gel, magnesium silicate, activated alumina, or zeolite. The moisture retention material is heated by irradiation of microwave.

The effect of competition by chloride and sulfate anions on the adsorption of arsenate ion onto activated alumina

Abstract: The Effect of Competition by Chloride and Sulfate Anions on the Adsorption of Arsenate Ion onto Activated Alumina. (May 2000) Patrick John Janis, B. A. , Texas A/kM University Chair of Advisory Committee: Dr. John P. Wagner Interactions of arsenate ions with sulfate and chloride anions in aqueous solutions containing various amounts of activated alumina were studied in the laboratory on a batch mode basis with the goal of understanding the competition of the anions for adsorption sites on the activated alumina. The results of this study showed that the presence of 15 meq/L chloride anion depresses the ability of the arsenate to be adsorbed by F-I activated alumina initial liquid phase arsenate ion concentration of 5 mg/L at pH 6. Alternatively, 30 meq/I. sulfate anion caused an increase in the arsenate ion adsorption. Additionally, the arsenate ion loading capacity of the activated alumina was lower with the presence of 15 meq/I. chloride anion than with the presence of 30 meq/L sulfate anion. In tests with no added anions, arsenate ion loading capacity was only slightly lower than tests with 30 meq/L

Removal of CO2 from gases using activated alumina

Abstract: The use of the activated adsorbent enables the simultaneous removal of carbon dioxide and water as a preliminary treatment of a gas mixture before a subsequent cryogenic separation. The purification of a gas containing carbon dioxide (CO2) as an impurity comprises adsorbing the CO2 on an adsorbent comprising particles of activated alumina. The alumina has a surface area of 200-299 m /g and contains at least 80% alumina, silica (SiO2), iron oxide (Fe2O3) and 0.001-7.25% of an alkali or alkaline earth oxide. An Independent claim is also included for the use of the process in the purification of air or synthesis gas.