Showing papers on "Activated alumina published in 2009"
TL;DR: The ability of activated alumina as synthetic adsorbent was investigated for adsorptive removal of Cd (II) and Pb(II) ions from aqueous solutions and showed the suitability ofactivated alumina in waste water treatment plant operation.
417 citations
TL;DR: This study reports usage of commercial grade activated alumina (aluminum oxide) as adsorbent for the removal of sulfur from model oil (dibenthiophene (DBT) dissolved in n-hexane).
233 citations
TL;DR: In this paper, the adsorption characteristics of fluoride on activated alumina (AA) were studied using batch methods, and the effects of reaction time, pH, ionic strength, and coexisting anions were determined.
141 citations
TL;DR: In this paper, the arsenite removal performance of manganese oxide-coated-alumina (MOCA) and its interaction with As(III) in drinking water was described.
140 citations
TL;DR: In this article, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adaption system and a fixed-bed flow adsoption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics.
Abstract: In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6-dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen...
137 citations
TL;DR: In this article, a series of batch adsorption experiments were carried out to assess parameters that influence the fluoride removal process and different parameters investigated include the effect of contact time, initial fluoride concentration, adsorbent dose, pH of the solution and coexisting anions.
Abstract: BACKGROUND: The present study has concentrated on investigating the fluoride removal potential of nano-scale aluminum oxide hydroxide (nano-AlOOH). A series of batch adsorption experiments were carried out to assess parameters that influence the adsorption process. The different parameters investigated include the effect of contact time, initial fluoride concentration, adsorbent dose, pH of the solution and co-existing anions.
RESULTS: Most of the adsorption took place during the first 30 min and kinetic and equilibrium adsorption data show that the process obeys a pseudo-second-order kinetic equation and the Langmuir adsorption model. The fluoride removal efficiency is greater than 90% between pH 6 and 8 and decreases as pH values increase to 11. The presence of SO42− or PO43− in aqueous solution was found to reduce the fluoride uptake. Desorption studies showed that the fluoride can easily be desorbed at pH 13.
CONCLUSION: Nano-AlOOH possesses a maximum fluoride capacity of 3259 mg F− kg−1, which is comparable with that of activated alumina. Maximum adsorption occurred at around pH 7, which makes nano-AlOOH a potential adsorbent for drinking water treatment. Copyright © 2009 Society of Chemical Industry
134 citations
TL;DR: In this article, a single column multilayered VSA unit was used with a guard-bed layer of superior desiccant and a main layer of 13X to simultaneously remove water (3-4% by volume) and capture CO2 (10-12%) at 30 ∘C within the same process.
113 citations
TL;DR: In this article, a new catalytic purification process for landfill gas conditioning, which may be supposed to be more competitive than state-of-the-art technologies and summarises some lab-scale results.
82 citations
TL;DR: A mesoporous hybrid adsorbent prepared by coating an activated alumina (AA) with a mercaptopropyl-functionalized silica was tested for removal of arsenite [As(III).
56 citations
TL;DR: The investigation has indicated that the hybrid adsorbents are very promising for As(III) removal from water and has been selected by consideration of not only the adsorption capacity but also its environmentally friendly and cost-effective production.
48 citations
TL;DR: In this paper, an improved method for the synthesis of 2,3-unsaturated-O-glycosides has been developed, using ZnCl2 impregnated on activated alumina.
TL;DR: In this article, the removal properties of As(III) and As(V) by the several metal oxides having different mineral type and content of metals were investigated in batch and column reactors.
TL;DR: In this paper, a low cost activated alumina based adsorbent prepared by partial thermal dehydration was used to remove arsenic from contaminated groundwater by low cost Activated Alumina Based Adsorbent with high surface area.
Abstract: Experimental investigations were carried out to remove arsenic from contaminated groundwater by low cost activated alumina based adsorbent prepared by partial thermal dehydration. Activated alumina based adsorbent with high surface area was prepared following partial thermal dehydration of gibbsite precursor and an attempt was made to study the effects of dehydration temperature, residence time, rate of increase of temperature and particle size on development of active surface area of the adsorbent. The operating parameters were found to have significant effect on active surface area development. BET Surface area (by nitrogen adsorption) and ignition losses were determined for all the samples. It was found that an adsorbent of surface area of around 335–340 m2/g could be developed when dehydrated at 500°C for a residence time of 30 min in a rapid heating system (rate of increase of temperature 200°C/min) with particle size of 200 mesh (85%). The arsenic adsorption capacity of this adsorbent was determined...
TL;DR: The effects of the crystalline structure and surface functional groups of porous inorganic materials on the adsorption of dichloroacetic acid (DCAA) were evaluated by using hexagonal mesoporous silicates, modified HMSs, faujasite Y zeolite and activated alumina as adsorbents, and compared with powdered activated carbon (PAC).
TL;DR: In this paper, the adsorptive capacity of activated alumina, silica sand and anthracite coal for phosphorus removal was investigated, and the results showed that the performance of three filter media were all in line with Langmuir isotherm.
Abstract: Experimental researches on adsorptive capacity of activated alumina, silica sand and anthracite coal for phosphorus were conducted. Results showed that performances of three filter media were all in line with Langmuir isotherm, and activated alumina adsorptive performance was much better than silica sand and an-thracite coal for phosphorus removal. The adsorptive capacity of activated alumina, silica sand and anthracite coal for phosphorus was 3333μg/g, 49μg/g and 100μg/g respectively. Activated alumina displayed adsorp-tive function well for phosphorus, because its inner porosity, specific surface area and surface isoelectric pH value were all higher than those of other two filter media. While activated alumina was used as filter material in water treatment process, phosphorus would be removed strongly because of adsorptive characteristic of activated alumina.
TL;DR: To study the rate-limiting step, the adsorption kinetic data of boron were analyzed using first-order (Lagergren) and second-order kinetic models and experimental results obtained showed that the Adsorption process followed a second- order kinetic model.
Abstract: Boron is widely distributed in the environment, mainly in the form of boric acid or borate salts, and its contamination of waters is a concern around the world. This study focuses on boron removal by means of adsorption onto activated alumina. Optimum adsorption was achieved in the pH range 8.0 to 8.5. Approximately 60% (by mass) boron removal was achieved using an adsorbent dose of 5 g at an initial boron concentration of 50 mg/L. Adsorption isotherms at 10, 20, and 30 degrees C were investigated. The results fitted with the Langmuir and Freundlich equations showed a monolayer adsorption onto a surface, with a finite number of identical sites. To study the rate-limiting step, the adsorption kinetic data of boron were analyzed using first-order (Lagergren) and second-order kinetic models. The experimental results obtained showed that the adsorption process followed a second-order kinetic model.
TL;DR: It is suggested that single-crystal host 1, because of its flexibility, can separate various gases by adjusting its channel structure according to the features of the guest gaseous molecules.
Abstract: To develop the application of the adsorption ability of our flexible single-crystal host [Cu(2)(bza)(4)(pyz)](n) (1) (bza = benzoate; pyz =pyrazine) possessing a 1D channel, we study the separation ability of a 1 packed column for various organic vapors and inorganic gases. A 1 packed column can detect various organic molecules with sharp signals although steric or nonpolar molecules give broad signals. Interestingly, 1 separates various organic mixtures even if the mixture contains nonpolar molecules. Comparing the separation properties with columns of other separation media, including zeolite, activated carbon, activated alumina, and silica gel, suggests that a 1 packed column separates various gaseous molecules under moderate conditions. Additionally, the eluted order of similar molecules, such as N(2)/O(2) and methanol/ethanol using the 1 packed column is different from the others (zeolite, activated carbon, activated alumina, and silica gel), which suggests a difference in the separation mechanism of 1. From GC measurements, the estimated changes in Gibbs free energy by gas adsorption, under diluted gas conditions, exhibits a large entropy dependence caused by regularity in the generated adsorption state, which enables the dynamic control of gas adsorption selectivity. Therefore, it is suggested that single-crystal host 1, because of its flexibility, can separate various gases by adjusting its channel structure according to the features of the guest gaseous molecules. This generates active controllability of the adsorption potential in addition to the intrinsic adsorption interaction.
Patent•
06 May 2009
TL;DR: In this paper, a Magnesia-based dry material for a tundish with aluminum hydroxide, which belongs to a refractory material, is described, which is used in the manufacturing of a working lining for receiving molten steel and steel slag.
Abstract: The invention discloses a magnesia-based dry material for a tundish with aluminum hydroxide, which belongs to a refractory material The magnesia-based dry material for the tundish with the aluminum hydroxide comprises the following compositions in percentage by weight: 1 to 15 percent of aluminum hydroxide fine powder, 82 to 89 percent of magnesia, and 15 to 65 percent of bonding agent During the baking and use, the aluminum hydroxide fine powder is decomposed to produce activated alumina and vapor, the vapor moistens the surfaces of particles inside the dry material to ensure that the surfaces of the magnesia and silica fume in the dry material are hydrated, and the bonding agent is partially dissolved and diffused to bond with the surface of the magnesia The generated activated alumina has a spinel reaction with magnesia fine powder at a temperature higher than 900 DEG C to form a large quantity of fine magnesium aluminate spinels, which remarkably improves the penetration-resistant action of the dry material on molten steel and steel slag and plays a role in ceramic bonding The dry material does not depend on carbon-containing bonding agents such as phenolic resin, asphalt, which avoids the carburization to molten steel of low carbon steel and also reduces the poisonous fume emission The construction of the magnesia-based dry material adopts a dry-press process, and then the dry material is subjected to heat conduction through the heating on a metal mold to make the bonding agent fused or solidified to form a fixed tundish working lining for receiving the molten steel
TL;DR: In this paper, two technologies were suggested: activated alumina and α-FeOOH (TehnoArz, TA) adsorption media, and experiments were performed on a laboratory scale.
Abstract: The drinking water from a small drinking water system contained arsenic in a concentration of about 50 μg/L. Chemical analyses showed that the pentavalent form of arsenic was present. Since the MCL value is 10 μg/L, it was necessary to implement a technological treatment to make the water suitable for drinking. In order to do so, two technologies were suggested: activated alumina and α-FeOOH (TehnoArz, TA) adsorption media. Experiments using both adsorption media were performed on a laboratory scale. It was possible to remove arsenic to below 1 μg/L. The maximal adsorption capacity was found to be 12.7 mg of As5+ per gram of α-FeOOH. Moreover, all the important physico-chemical parameters of the water remained practically unchanged after the treatment. Only a slight release of iron from the media was observed. The Fe-As bond was studied by means of chemical analysis and X-ray powder diffraction. Finally, in addition to showing the capability of arsenic removal by α-FeOOH, a comprehensive optimization of the technological parameters of the selected technology is provided.
Journal Article•
TL;DR: In this article, the effects of pH, temperature, initial concentration and flow rate on activated alumina performance were investigated in either a batch or column configuration, and the results demonstrate that activated AA is an effective adsorbent for selective removal of fluoride from base solution.
Abstract: An effective electrowinning process in hydrometallurgical industry requires fluoride levels in the base metal solution to be less than 10 mg/l. Selective removal of the fluoride ions from base solution isthus desired, if fluoride was added to control calcium and magnesium in the circuit. Consequently, adsorption of fluoride onto activated alumina was studied in a batch and a column set-up. Theeffects of base metal solution pH, temperature, initial concentration and flow rate on activated alumina performance were investigated in either a batch or column configuration. A two-level factorialexperimental design was implemented in studying column dynamics. Results demonstrate that activated alumina is an effective adsorbent for selective removal of fluoride from base solution. In the batch operation, fluoride was removed to values below the maximum allowable concentration (10 mg/l) when pH was = 8. In the column adsorption step at 55°C and 600mg/l initial concentration, up to 16 bed volumes were processed before breakthrough level was reached. Desorption step using 1% sodiumhydroxide solution achieved an elution of 8 bed volumes. The activated alumina (AA) had a capacity of 8.65 gF/l AA at the 10 mgF/l fluoride breakthrough level during the column adsorption test.
Journal Article•
TL;DR: In this article, the effect of activated alumina in reducing the fluoride concentration in drinking water was investigated and the results showed that with increasing of pH of solution, removal efficiency was decreased and optimum pH was found to be in the range of 5 to 7.
Abstract: Backgrounds and Objectives: Determination of Fluoride in drinking water has received increasing interest, duo to its beneifical and detrimental effects on health. The aim of this research is investigation of Effect of activated alumina in fluoride concentration reduction in drinking water. Materials and Methods: Expriment in batch system and with change effective parameters such as pH(5, 7,9), equilibration time (30, 60, 90, 120 minute), initial fluoride concentration(1.4, 2, 2.4 mg/l) and activated Alumina dosage (0.1, 0.2, 0.3 gr/l) was investigated. Also found data of this research were fited with Langmuir and Freundlich models, kinetic data with pseudofirst order, pseudosecond order and modifited pseudofirst order models. Results: The results showed that with increasing of pH of solution, removal efficiency was decreased and optimum pH was found to be in the range of 5 to 7. Also removal efficiency of fluoride was increased with increasing of adsorbent dosage and decreasing of initial concentration of fluoride. Adsorption isotherm data show that the fluoride sorption followed the Langmuir model (r2=0.98). Kinetics of sorption of fluoride onto Activated alumina was well described by pseudosecond order model. Conclusion: The concentration of Activated Alumina had significant effect on the reduction of fluoride ions concentration in water.The higher fluoride removals were observed for batch experiments at pH=5 because no free fluoride ion is present in the solutions, and it could be casued by electrostatic interactions between the surface of alumina and the dominant fluoride species in solution The kinetic model can adequately describe the removal behaviors of fluoride ion by alumina adsorption in the batch system. Key word: Activated Alumina, Fluoride, Water, Adsorption *Corresponding Author: dr.norozi@yahoo.com Tel: +98 171 4421651 Fax: +98 171 4423630 Iran. J. Health & Environ., 2009, Vol. 2, N0. 3 D ow nl oa de d fr om ij he .tu m s. ac .ir a t 7 :2 8 IR D T o n S un da y M ay 2 nd 2 02 1
Journal Article•
TL;DR: In this paper, the capacity of activated alumina to remove phosphorus with static experimental methods was evaluated and the best dosage of r-Al2O3 was 0.5 mg/50 mL, the most suitable pH was 2.8~3.8, adaption equilibrium time was 2 h and the largest adsorption capacity was 9.4 mg/g, the removal rate reached the highest when the initial concentration of phosphorus was 10 mg/L.
Abstract: Taken activated Alumina as adsorbents,the authors evaluated the capacity of activated alumina to remove phosphorus with static experimental methods.The result showed that the best dosage of r-Al2O3 was 0.5 mg/50 mL,the most suitable pH was 2.8~3.8,adsorption equilibrium time was 2 h and the largest adsorption capacity was 9.4 mg/g,the removal rate reached the highest when the initial concentration of phosphorus was 10 mg/L.
30 Mar 2009
TL;DR: In this paper, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adaption system and a fixed-bed flow adsoption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics.
Abstract: In order to explore the adsorptive denitrogenation of liquid hydrocarbon streams for producing ultraclean fuels, the adsorption performance of seven representative activated carbon samples and three activated alumina samples was evaluated in a batch adsorption system and a fixed-bed flow adsorption system for removing quinoline and indole from a model diesel fuel in the coexistence of sulfur compounds and aromatics. Different adsorbents show quite different selectivity toward basic and nonbasic nitrogen compounds (quinoline and indole) and sulfur compounds (dibenzothiophene and 4,6dimethyldibenzothiophene). The activated carbons generally show higher capacity than activated alumina samples for removing the nitrogen compounds. The adsorption capacity and selectivity of the activated carbons for nitrogen compounds were further correlated with their textural properties and oxygen content. It was found that (1) the microporous surface area and micropore volume are not a key factor for removal of the nitrogen compounds in the tested activated carbons; (2) the oxygen functionality of the activated carbons may play a more important role in determining the adsorption capacity for the nitrogen compounds since the adsorption capacity for nitrogen compounds increases with increase in the oxygen concentration of the activated carbons; and (3) the type of the oxygen-functional groups may be crucial in determining their selectivity for 40 various nitrogen or sulfur compounds. In addition, regeneration of the saturated adsorbents was conducted by the toluene washing followed by the heating to remove the remained toluene. The results show that the spent activated carbons can be regenerated to completely recover the adsorption capacity. The high capacity and selectivity of carbonbased adsorbents for the nitrogen compounds, along with their good regenerability, indicate that the activated carbons may be promising adsorbents for deep denitrogenation of liquid hydrocarbon streams.
Patent•
25 Nov 2009TL;DR: In this paper, a method for purifying hydrogen fluoride, capable of efficiently reducing the content of arsenic in hydrogen fluoride was proposed, which includes the steps of (a) bringing a crude hydrogen fluoride containing arsenic trifluoride into contact with an oxidizing agent of a metal fluoride in a liquid state in a reactor to obtain a reaction mixture, wherein arsenic pentafluorides is formed by oxidizing arsenic trifelectric acid with the oxidising agent of the metal fluoride through a liquid-liquid reaction; and (b) separating purified hydrogen fluoride from the reaction mixture
Abstract: A novel method for purifying hydrogen fluoride, capable of efficiently reducing the content of arsenic in hydrogen fluoride. The method includes the steps of (a) bringing a crude hydrogen fluoride containing arsenic trifluoride into contact with an oxidizing agent of a metal fluoride in a liquid state in a reactor to obtain a reaction mixture, wherein arsenic pentafluoride is formed by oxidizing arsenic trifluoride with the oxidizing agent of the metal fluoride through a liquid-liquid reaction; and (b) separating purified hydrogen fluoride from the reaction mixture by a separator, the thus obtained purified hydrogen fluoride having a lower content of arsenic than that of the crude hydrogen fluoride.
Patent•
04 Mar 2009
TL;DR: In this article, a regenerating and processing method for activated alumina used in the process of hydrogen peroxide working solution regeneration is presented, which is economical, environment-friendly and safe.
Abstract: The invention provides a regenerating and processing method for activated alumina used in the process of hydrogen peroxide working solution regeneration. The method comprises the following steps: inactivated alumina discharged from a solution regeneration bed in the process of hydrogen peroxide production and alumina inert for burning enter a tower reaction vessel from the upper part of the vessel, and move downwards according to the gravity, the gas containing oxygen enters a reaction vessel from the lower part of the tower reaction vessel and moves upwards; after reaction, the regenerated alumina and the alumina inert for burning are discharged from a material outlet device at the bottom part of the reaction vessel and tail gas is discharged from a tail gas outlet at the upper part of the reaction vessel; and the reaction temperature ranges from 360 to 800 DEG C, and the detention time of solid material in the reactor is 3 to 15 hours. The method of the invention is economical, environment-friendly and safe. In addition, the obtained regenerated alumina has no poisoning risk to the production of catalyst Pd and has low treatment cost, thereby having great value for popularization.
Journal Article•
TL;DR: In this article, the capability of activated alumina from bauxite compared with activated carbon adsorption capability to reduce the color content from Al-Hilla Textile Company wastewater was studied.
Abstract: This work was carried to study the capability of activated alumina from bauxite compared with activated carbon adsorption capability to reduce the color content from Al-Hilla Textile Company wastewater. Six dyes were studied from two types(reactive and dispersed) namely (blue, red, yellow) from wastewater and aqueous solutions.Forty eight experiments were carried out to study the effect of various initial conditions (bed height, flow rate, initial concentration, pH value, temperature, and competitive adsorption) on adsorption process.The results showed that the adsorption process using activated carbon insured a good degree of color reduction reaching (99.7%) and was better than activated bauxite which reached (95%).
Patent•
18 Nov 2009
TL;DR: In this paper, a magnesia-alumina spinel material prepared by waste activated alumina and a preparation method thereof is presented. But the preparation method is not suitable for high-quality refractories.
Abstract: The invention provides a magnesia-alumina spinel material prepared by waste activated alumina and a preparation method thereof. The raw material formula mainly comprises the waste activated alumina and basic magnesium carbonate; and the preparation method comprises the following steps of: taking the waste activated alumina and the basic magnesium carbonate as raw materials, mixing, pressing and forming the raw materials, leading the raw materials to react at high temperature, cooling the reaction products, thus obtaining the prepared magnesia-alumina spinel material. The material and the method are beneficial for waste utilization and solve the severe pollution of the waste activated alumina on the environment; the produced products have high-quality refractories which have high added value and no pollution, save the production cost, and have obvious economic benefits and popularization and application values.
Patent•
22 Jan 2009
TL;DR: In this article, the content ratio by weight of the adsorption material in the ad-sorption sheet becomes drastically high to result in the excellent adsorsorption performance for an organic solvent included in air and the high heat resistance of the annealing sheet.
Abstract: PROBLEM TO BE SOLVED: To provide an adsorption sheet and an adsorption element comprising an adsorption material, being excellent in adsorption performance and heat resistance. SOLUTION: The adsorption sheet includes the adsorption material such as zeolite, silica gel, activated alumina and activated carbon, and heat-resistant organic fibers having a self-consolidation property, whereby the content ratio by weight of the adsorption material in the adsorption sheet becomes drastically high to result in the excellent adsorption performance for an organic solvent included in air and the high heat resistance of the adsorption sheet. COPYRIGHT: (C)2009,JPO&INPIT
Patent•
18 Nov 2009
Abstract: The invention provides a cordierite material prepared by waste activated alumina and a preparation method thereof. The raw material formula mainly comprises the waste activated alumina, talcum and clay; and the preparation method comprises the following steps of: taking the waste activated alumina, the talcum and the clay as raw materials, mixing, pressing and forming the raw materials, leading the raw materials to react at high temperature, sintering and cooling the reaction products, thus obtaining the prepared titanate material. The material and the method are beneficial for waste utilization and solve the severe pollution of the waste activated alumina on the environment; the produced products have high-quality refractories which have high added value and no pollution, save the production cost, have obvious economic benefits and popularization and application values.
Patent•
18 Nov 2009
TL;DR: In this article, a mullite-corundum composite-phase material prepared by waste activated alumina and a preparation method thereof is presented, which is beneficial for waste utilization and solve the severe pollution of the waste activated aluminina on the environment.
Abstract: The invention provides a Mullite-corundum composite-phase material prepared by waste activated alumina and a preparation method thereof. The raw material formula mainly comprises the waste activated alumina and Longyan kaolin; and the preparation method comprises the following steps of: taking the waste activated alumina and the Longyan kaolin as raw materials, mixing, pressing and forming the raw materials, leading the raw materials to react at high temperature, cooling the reaction products, thus obtaining the prepared mullite-corundum composite-phase material. The material and the method are beneficial for waste utilization and solve the severe pollution of the waste activated alumina on the environment; and the produced products have high-quality refractories which have high added value and no pollution, save the production cost, have obvious economic benefits and have values for popularization and application.