Showing papers on "Activated alumina published in 1997"
TL;DR: A new technique based on the combination of an activated alumina column and an electrochemical system for fluoride removal from water is reported in this article. But it is not shown that it is more efficient than the former in removing fluoride from water.
125 citations
TL;DR: In this article, the adsorption characteristics of activated alumina treated with aluminum sulfate were studied to develop a new removal process for low concentration phosphorus in the waters of rivers and lakes.
82 citations
TL;DR: The surface complexation model as previously applied to pure anion and pure cation exchange equilibria has been extended to the description of the amphotheric sorption of inorganic ions onto activated alumina as mentioned in this paper.
31 citations
Patent•
02 Jul 1997
TL;DR: In this paper, a method of preparing an alumina-based bodies suitable for use as an adsorbent or catalyst was proposed, the method comprising providing a source of activated alumina powder for forming into bodies and providing an aqueous solution containing at least two different alkali metals, at least one alkali metal derived from a soluble carboxylic acid alkali salt.
Abstract: A method of preparing an alumina-based bodies suitable for use as an adsorbent or catalyst, the method comprising providing a source of activated alumina powder for forming into bodies and providing an aqueous solution containing at least two different alkali metals, at least one alkali metal derived from a soluble carboxylic acid alkali metal salt. As said powder is formed into said bodies, the bodies are contacted or sprayed with the aqueous solution to provide composite bodies containing the alumina powder and the alkali metals and the soluble carboxylic acid alkali metal salt. Alternatively, the alumina bodies may be formed first and then contacted, e.g., soaked in the aqueous solution. Or, a viscous slurry of the activated alumina powder and the aqueous solution may be made. The viscous slurry may be made into bodies by extrusion or by the oil drop method. Thereafter, the bodies are thermally treated to activate alumina therein and remove or decompose the organic part, e.g., carboxylic acid, of the soluble carboxylic acid alkali metal salt.
29 citations
Patent•
23 May 1997
TL;DR: In this article, a method of producing activated alumina bodies having alkali or alkaline earth metal compounds incorporated therein, the bodies suitable for adsorption and having increased capacity for gases and the like.
Abstract: A method of producing activated alumina bodies having alkali or alkaline earth metal compounds incorporated therein, the bodies suitable for adsorption and having increased capacity for adsorption of gases and the like. The method comprises providing a source of activated alumina powder and further providing an aqueous solution having an alkali or alkaline earth metal hydroxide and a water soluble alkali or alkaline earth metal salt of an organic compound dissolved therein. The activated alumina powder is formed into bodies which are treated with the aqueous solution to provide alumina bodies having alkali or alkaline earth metal compounds incorporated therein. The alumina bodies are heated for purposes of activation to provide said activated alumina bodies capable of having increased adsorption capacity.
20 citations
Patent•
19 Dec 1997
TL;DR: In this paper, a methanation catalyst with sulfur poisoning resistance, carbon deposition resistance, high activity, high selectivity and sufficient mechanical strength is presented. But the methanization catalyst is not suitable for the use in the industrial setting.
Abstract: PROBLEM TO BE SOLVED: To produce a methanation catalyst having sulfur poisoning resistance, carbon deposition resistance, high activity, high selectivity and sufficient mechanical strength. SOLUTION: Aluminum oxide or its precursor and an oxyacid are fired at 400-600 deg.C to prepare an activated alumina carrier and 0.5-4 wt.% ruthenium is carried on the carrier, insolubilzied and fixed with an aq. alkali soln. and then subjected to reduction treatment at 80-500 deg.C to obtain the objective methanation catalyst.
8 citations
TL;DR: In this article, the liquid phase adsorption/desorption characteristics of 1,1-dichloro-1-fluoroethane (HCFC-141b) by activated alumina, molecular sieve, granular activated carbon, extruded activated carbon (EAC), and activated carbon fiber (ACF) were examined.
Abstract: Experiments have been conducted to examine the liquid-phase adsorption/desorption characteristics of 1,1-dichloro-1-fluoroethane (HCFC-141b) by activated alumina, molecular sieve, granular activated carbon (GAC), extruded activated carbon (EAC), and activated carbon fiber (ACF). HCFC-141b is currently regarded as an excellent replacement for CFC-11, a foaming agent widely used in the rigid polyurethane foam industries. The experimental results of adsorption and desorption were analyzed in terms of the equilibrium adsorption capacity, time to reach equilibrium, and desorption efficiency of the adsorbent and with an aim to assess the viability of the use of all adsorbents for possible HCFC-141b recovery. Adsorption isotherms of the Langmuir and Freundlich types were employed to examine the equilibrium adsorption data. A mass-transfer model based on the pseudo-steady-state driving force was adopted to describe the HCFC-141b adsorption process.
7 citations
Patent•
23 May 1997TL;DR: In this paper, a method of producing activated alumina bodies having alkali or alkaline earth metal compounds incorporated therein, the bodies having increased surface area and crush resistance, was proposed.
Abstract: A method of producing activated alumina bodies having alkali or alkaline earth metal compounds incorporated therein, the bodies having increased surface area and crush resistance, the method comprising providing a source of activated alumina powder and an aqueous solution having an alkali or alkaline metal hydroxide dissolved therein, the solution having a pH in the range of 12 to 13.5. The activated alumina powder is formed into bodies, and are treated with the aqueous solution to form alumina bodies having alkali or alkaline earth metal compounds incorporated therein. The alumina bodies are heated to provide activated alumina bodies having increased surface area and crush resistance.
7 citations
Patent•
28 Oct 1997
TL;DR: In this paper, a silent discharge plasma is generated between the outer wall of a dielectric 3 by applying an AC high voltage to an area between an outer electrode 1 and an inner electrode 2 as constituents forming the area through the dielectrics 3.
Abstract: PROBLEM TO BE SOLVED: To efficiently oxidize NO into NO2 by a silent discharge plasma and remove NO2 by adsorption with the help of an adsorbent. SOLUTION: A silent discharge plasma is generated between the outer wall of a dielectric 3 by applying an AC high voltage to an area between an outer electrode 1 and an inner electrode 2 as constituents forming the area through the dielectric 3. In addition, NO is oxidized into NO2 by a generated ozone and NO2 is removed by adsorption with the help of activated alumina.
5 citations
Patent•
18 Mar 1997
TL;DR: A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160° F..
Abstract: A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160° F. and a surface-chilled temperature of 60° F. Crystals of aluminum sulphate are precipitated and recrystalized by evaporation in a vacuum and at an elevated temperature. Purified crystals of aluminum sulphate are then dried at 50°-60° C. The dried aluminum sulphate crystals are then dehydrated at 400°-450° C. after a rise rate of 50°-60° C. per minute to drive off most of the water. A roasting and recalcination step at 1000° C.-1050° C. after a rise rate of 50°-60° C. per minute is used drive off the sulphate. The remaining alumina is smelted by electrolysis for aluminum.
5 citations
01 May 1997
TL;DR: In this paper, the adsorption of selenium from a mine leachate was evaluated to develop design parameters for a full-scale activated alumina process, and it was shown that 68% of the seenium in the leachates could be removed by alumina at pH levels greater than 5.0.
Abstract: Leachates from gold heap-leaching mines may contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina from relatively “clean” drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for a full-scale activated alumina process. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH levels greater than 5.0. At pH levels less than 4, silica was poorly adsorbed by alumina, and selenium adsorption was improved. Silica adversely affected the selenium adsorption capacity.
Patent•
25 Mar 1997
TL;DR: In this article, the authors proposed spherical activated alumina having a specified Na2 O content and a specified wear rate to satisfy all of cost, handleability and treating effect as an adsorbent by bringing an adorbent made of the alumina into contact with water contg. arsenate ions.
Abstract: PROBLEM TO BE SOLVED: To allow spherical activated alumina having a specified Na2 O content and a specified wear rate to satisfy all of cost, handleability and treating effect as an adsorbent by bringing an adsorbent made of the alumina into contact with water contg. arsenate ions and removing the arsenate ions from the water. SOLUTION: Aluminum hydroxide such as gibbsite is calcined for 0.1sec to several min in a flow of hot air at 500-1,200 deg.C, the calcined body is separated and cooled and the resultant activated alumina powder having rehydratability is pulverized and compacted in a sphere shape to obtain spherical activated alumina having <=0.3wt.% Na2 O content and <=1% wear rate. An adsorbent made of the alumina is brought into contact with water contg. arsenate ions and the arsenate ions are removed from the water. The alumina can satisfy all of cost, handleability and treating effect as an adsorbent.
Patent•
25 Mar 1997
TL;DR: In this article, a mixture packed layer of granular activated alumina and granular zeolite mineral was used to remove phosphorus and ammonia by adsorption, then supplying an alkali soln. to the packed layer to regenerate and adding magnesium ion to the regenerated liquid to recover phosphorus.
Abstract: PROBLEM TO BE SOLVED: To recover phosphorus as a resource by passing the feed water through a mixture packed layer of granular zeolite and granular activated alumina to remove phosphorus and ammonia by adsorption, then supplying an alkali soln. to the packed layer to regenerate and adding magnesium, ion to the regenerated liquid to recover phosphorus. SOLUTION: After an org. waste water such as sewage containing phosphorus and nitrogen is subjected to biological treatment and the like, the biologically treated water is passed through a packed layer 2 prepared by mixing granular activated alumina and granular zeolite mineral. In this process, phosphorus and ammonia are adsorbed and removed by the granular alumina and the zeolite mineral, respectively. When the packed layer is to be regenerated, an alkali- based sodium chloride soln. or alkaline sea water is used as a regenerating agent and passed through the packed layer to desorb ammonia and phosphorus. Air 6 is blown into the regenerated alkaline waste water 5, and further magnesium ion 7 is added to the waste water to produce ammonium magnesium phosphate 9 which is valuable as a soluble fertilizer.
Patent•
15 Apr 1997
TL;DR: In this article, the authors proposed a method to produce a catalyst composition having excellent properties with respect to platinum group metal dispersion on activated alumina, where the stages are performed under restricted acidifying conditions to allow at least one of platinum, rhodium and palladium catalyst components to exist in the composition and to produce the objective catalyst composition on the carrier base body.
Abstract: PROBLEM TO BE SOLVED: To provide the production of a catalyst composition having excellent properties with respect to platinum group metal dispersion. SOLUTION: This production of a catalyst composition comprises a stage (a) for dispersing at least one platinum group metal catalyst component on activated alumna and a stage (b) for coating a carrier base body with the resulting activated alumina having the platinum group metal catalyst component on it and calcining the formed coating material on the carrier base body, where the stages (a) and (b) are performed under restricted acidifying conditions to allow at least one of platinum, rhodium and palladium catalyst components to exist in the composition and to produce the objective catalyst composition on the carrier base body. At this time, the degree of dispersion of each of these platinum group metal catalyst components on the activated alumina is maintained at about >=0.3CO/PM (number of carbon monoxide molecules adsorbed on one atom of the platinum group metal), wherein the measurement of the degree of dispersion is performed by using a catalyst composition sample treated as follows: (1) when the catalyst component metals(s) is platinum and/or rhodium, the sample is reduced in gaseous hydrogen at 750 deg.C for 1hr; or (2) when the catalyst component metal is palladium, the sample is heated in air at 750 deg.C for 1hr and then, reduced in gaseous hydrogen at 350 deg.C for 1hr.
TL;DR: In this article, a KF/Al2O3 neutral KG/A3 neutral (KF/AO3)-neutral) KG-neutral KG was proposed.
Abstract: 有機合成において, 交差アルドール縮合は炭素-炭素結合形成反応として重要な反応の一つである。我々は, 種々のフッ化塩を無機固体に担持させた固体塩基触媒を用いたベンズアルデヒド (1) と2-ブタノン (2) の交差アルドール縮合反応の検討を行った。結果, フッ化カリウムを中性アルミナに担持させた触媒 (KF/Al2O3-neutral) が (1) と (2) の交差アルドール縮合反応に有効に働くことを見いだした。又, この触媒は種々の芳香族アルデヒド, ケトンの交差アルドール縮合反応やカルコン類, ジスチリルケトン類の合成にも適用可能である。
Patent•
31 Mar 1997
TL;DR: In this paper, the problem of recovering phosphate ions as solid particles of magnesium ammonium phosphate by mixing an activated alumina desorbed soln. with sludge treatment return flow water was addressed.
Abstract: PROBLEM TO BE SOLVED: To effectively recover phosphate ions as solid particles of magnesium ammonium phosphate by mixing an activated alumina desorbed soln. with sludge treatment return flow water in a method for treating phosphorus in activated alumina desorbed soln. generated at a time of the purification of sewage secondary treated water and adjusting the pH of the mixed soln. to a specific value to add a magnesium compd. SOLUTION: When sewage secondary treated water 1 is supplied to an activated alumina packed bed 3, phosphate ions in treated water 1 are adsorbed by the activated alumina packed bed 3 to obtain activated alumina adsorbed treated water 2. After this treatment, an acidic soln. or alkaline soln. 4 is supplied in order to desorb phosphoric acid and a desorbed soln. 5 is subsequently mixed with sludge treated return flow water 7 so that [NH4 ]/[PO4 ] becomes 1 or more. Subsequently, a magnesium compd. 9 is added to a granulated dephosphorizing tower 8 so that [Mg ]/[PO4 ] becomes 1 or more and pH is adjusted to 7.5-10. Formed solid particles 13 of magnesium ammonium phosphate are utilized as a compd. fertilizer.
Patent•
18 Mar 1997
TL;DR: A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160° F..
Abstract: A method of making activated alumina includes beginning with a leach liquor of potassium and aluminum sulphates that is subjected to a surface-cooled crystallizer with a heat-exchanger input temperature of 160° F. and a surface-chilled temperature of 60° F. to 80° F. Crystals of aluminum sulphate are precipitated and recrystalized by evaporation in a vacuum and at an elevated temperature. Purified crystals of aluminum sulphate are then dried at 50°-60° C. The dried aluminum sulphate crystals are then dehydrated at 400°-450° C. after a rise rate of 10°-20° C. per minute to drive off most of the water. A roasting and recalcination step at 900° C.-950° C. after a rise rate of 10°-20° C. per minute is used drive off the sulphate. The remaining alumina is useful as a high-grade catalyst.
Journal Article•