Showing papers on "Activated alumina published in 2011"
TL;DR: This review briefly presents iron and aluminium based adsorbents for arsenic removal and point-of-use adsorptive remediation methods indicate that Sono Arsenic filter and Kanchan™ ArsenIC filter are in operation at various locations of Bangladesh and Nepal.
294 citations
TL;DR: A novel cost effective defluoridation method based on surface modification of rice husk ash (RHA) by coating aluminum hydroxide is presented that showed excellent fluoride removal efficiency and the adsorption capacity was found to be between 9 and 10mg/g.
190 citations
TL;DR: In this paper, two low-cost adsorbents, iron-doped activated alumina (Al2O3/Fe) and lotus stalk-based activated carbon (LAC), were employed to remove norfloxacin from aqueous solutions.
185 citations
TL;DR: The viscosity profile of the spent grains indicated that activated alumina could promote liquefaction and prevent charring of the structure between 400 and 460 °C, which could meet about 9% of the renewable obligation in the UK.
72 citations
TL;DR: In this paper, two 13X-type zeolites, activated alumina and highly pure silica, were compared in terms of capacity for water vapor and carbon dioxide removal from air.
Abstract: Pretreatment stage is usually a requirement for any adsorption based air separation process. Carbon dioxide and water vapor present in the atmosphere act as contaminants, deactivating adsorbents, particularly zeolites used in oxygen pressure swing adsorption processes. Such systems usually present one or more prelayers to ensure full removal of these two contaminants, protecting the oxygen/nitrogen selective layer. In the present study, two 13X-type zeolites—one activated alumina and one highly pure silica—are compared in terms of capacity for water vapor and carbon dioxide removal from air. Water and carbon dioxide adsorb irreversibly on these adsorbents up to a certain extension and then effective adsorption isotherms and breakthroughs curves were obtained. The effective properties were attained after three cycles under close to vacuum pressure swing adsorption conditions. A combination of two layers for the precolumns is suggested: the first, composed by either silica or alumina to remove most of the w...
60 citations
TL;DR: In this article, the effect of various parameters on batch adsorption process such as pH, contact time, adsorbent dosage, particle size, temperature, and initial metal ions concentration were studied to optimize the conditions for maximum metal ion removal.
Abstract: The possible use of activated alumina powder (AAP) as adsorbent for Cr(III), Ni(II), and Cu(II) from synthetic solutions was investigated. The effect of various parameters on batch adsorption process such as pH, contact time, adsorbent dosage, particle size, temperature, and initial metal ions concentration were studied to optimize the conditions for maximum metal ion removal. Both higher (molar) and lower (ppm) initial metal ion concentration sets were subjected to adsorption on AAP. Adsorption process revealed that equilibrium was established in 50 min for Cr(III) at pH 4.70, 80 min for Ni(II) at pH 7.00, and 40 min for Cu(II) at pH 3.02. Percentage removal was found to be highest at 55°C for Cr(III) and Ni(II) with 420 µm and 45°C for Cu(II) with 250-µm particle size AAP. A dosage of 2 g for Cr(III), 8 g for Ni(II), and 10 g Cu(II) gave promising data in the metal ion removal. The adsorption process followed Langmuir as well as Freundlich models. The thermodynamics of adsorption of these metal ions on activated aluminum indicated that the adsorption was spontaneous and endothermic in nature. Present study indicates that AAP can act as a promising adsorbent for industrial wastewater treatment.
41 citations
TL;DR: In this article, an experimental investigation on the performance of radial flow desiccant bed using activated alumina has been carried out, and the experimental tests were carried out at different conditions of inlet air and initial bed parameters.
30 citations
TL;DR: In this paper, the removal of chromium (VI) from aqueous solutions by activated alumina has been investigated as a function of solution pH, initial chromium concentration, adsorbent dose, and temperature.
Abstract: The removal of chromium (VI) from aqueous solutions by activated alumina has been investigated as a function of solution pH, initial chromium concentration, adsorbent dose of activated alumina and temperature. The pH and the adsorbent dose of activated alumina are the most significant parameters affecting chromium (VI) adsorption. The chromium concentrations were analyzed by reaction with 1,5-diphenylcarbazide. This method has been validated according to the French standard XPT-90-210. In order to optimize the effect of the main parameters and their mutual interaction for the adsorption process, a full factor design of the type nk has been used. Thus, the total number of trial experiments needed for an investigation is 24. The Freundlich and Langmuir models have been applied and the equilibrium adsorption data were found to best fit the Freundlich and Langmuir adsorption isotherm. A comparison of kinetic models applied to the adsorption of chromium (VI) on activated alumina was evaluated for the first-ord...
28 citations
TL;DR: In this article, a natural clinoptilolite zeolite was used as the filtration media to remove arsenic-containing HFO/HAO co-precipitates.
24 citations
01 Jan 2011
TL;DR: In this paper, an attempt is made to study the various materials available with special reference to different methods of defluoridation and different natural adsorbents used for defluodoridation by adsorption technique.
Abstract: Fluoride is an essential constituents for both humans and animals depending on the total amount ingested or its concentration in drinking water. The presence of fluoride in drinking water, within permissible limits of 0.5-1.0 mg/l, is beneficial for the production and maintenance of healthy bones and teeth, while excessive intake of fluoride causes dental and skeletal fluorosis. An attempt is made to study the various materials available with special reference to different methods of defluoridation and different natural adsorbents used for defluoridation by adsorption technique. Different activated adsorbent samples like activated alumina, activated bauxite, Activated rice husk were taken and equilibrium studies were conducted to find a suitable adsorbent. The results obtained from these studies are presented in this report .
20 citations
TL;DR: In this article, the equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water.
Abstract: The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of Ceq = 10 µg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95%.
TL;DR: In this article, the adsorption equilibrium of a fluoride solution on 1-2 mm granular activated alumina modified by Fe 2 (SO 4 ) 3 solution was investigated using a wide range of initial fluoride concentrations (0.5 to 180 mg·L −1 at pH ∼7.0).
TL;DR: In this paper, the authors measured water vapor on a commercially available activated alumina, Selexsorb-CDX, and fitted the measured data to the dual mechanism adsorption potential (DMAP) equation.
Abstract: Adsorption equilibrium data of water vapor on a commercially available activated alumina, Selexsorb-CDX, were measured by a static gravimetric technique. The relative humidity and temperature were varied between 0 % and 90 % and between (5 and 35) °C, respectively. The measured data were fitted to the dual mechanism adsorption potential (DMAP) equation. The pore structure of the adsorbent material was characterized by nitrogen adsorption and mercury intrusion measurements. The DMAP equation predicted that the first 50 % of the total water adsorbed was held on the adsorbent by the combined action of chemisorption and physisorption, which was attributed to filling of the micropores and the first adsorbed layers in the mesopores. The remainder of the adsorbed water was attributed to capillary condensation in the mesopores. The heat of adsorption as a function of fractional loading was calculated using the fitted DMAP equation parameters in conjunction with the van't Hoff equation, with and without an assumpt...
01 Jan 2011
TL;DR: In this paper, the results showed that the chrome and bronze plating wastewater might be combined together and the composite sample could be treated with Activated Alumina to remove chromium, copper and colour appreciably.
Abstract: The wastewater treatment process was evaluated in an Electroplating unit that practiced chrome and bronze plating. With a view to recycle and reuse the wastewater, adsorption process was adopted as single stage treatment instead of the existing chemical methods. Wastewater was collected from chrome and bronze plating unit and analyzed for the relevant parameters. On the basis of characteristics, adsorption process was selected and materials such as wood charcoal, coconut shell carbon, activated carbon etc. were not proved to be effective for acceptable removal of chromium and copper as well as colour. Later, Activated Alumina (AS 37 of grain size 0.6 mm - 0.9 mm) was opted and its performance was examined by several batch and column studies. The results showed that the chrome and bronze plating wastewater might be combined together and the composite sample could be treated with Activated Alumina to remove chromium, copper and colour appreciably. Under the existing pollution load in terms of chromium and copper, an adsorption column made of activated alumina was designed following the classical Bed Depth Service Time (BDST) relationship. Keywords—activated Alumina, adsorption, chrome-bronze plating, electroplating wastewater
Patent•
24 Jun 2011
TL;DR: In this paper, a method and system for drying coal using activated alumina is presented, where coal is combined with activated alginin to achieve surface contact between the activated alumin and the coal.
Abstract: The present invention provides a method and system for drying coal using activated alumina. The method and system dries the coal by combining coal with the activated alumina. While in combination, the mixture is agitated to maximize surface contact between the activated alumina and the coal. As the coal contact the activated alumina, the surfactant moisture on the coal is then absorbed by the activated alumina. The activated alumina allow for the water molecules to pass into the sieves, thus being removed from the coal. After a period of agitation, the method and system thereby separates the activated alumina and the coal.
TL;DR: In this paper, the catalytic ozonation of fenofibric and clofiberric acids and the herbicides atrazine and linuron was studied using titanium dioxide, alumina, and manganese oxide supported on activated alumina and on silica SBA-15.
Abstract: The catalytic ozonation of fenofibric and clofibric acids and the herbicides atrazine and linuron was studied using titanium dioxide, alumina, and manganese oxide supported on activated alumina and on silica SBA-15 The organics studied did not adsorb significantly either in wastewater or in phosphate-buffered water The catalysts did not modify the rate of the hydroxyl-mediated ozonation with respect to the homogeneous value The mode of action of metal oxide catalysts would be an enhanced generation of oxidant species from the catalytic decomposition of ozone All catalysts increased the efficiency in the production of hydroxyl radicals from ozone
Journal Article•
TL;DR: In this article, a composite porous resins was prepared via a foaming method, in which aluminum hydroxide was decomposed into activated alumina and water vapor was released simultaneously at high temperature.
Abstract: As intelligent humidity control materials,porous resins have more advantages,such as high moisture content and fast absorption-desorption rate than traditional porous silica gels.A composite porous resin was prepared via a foaming method in this study,in which aluminum hydroxide was decomposed into activated alumina and water vapor was released simultaneously at high temperature.The morphology and pore structure of the composite porous resins were characterized by thermogravimetry(TG),scanning electron microscopy(SEM),X-ray diffractomer(XRD),Fourier transform infrared spectroscopy(FTIR) and nitrogen adsorption.Humidity control capability and saturation moisture content of the composite porous resins were tested under high humidity and low humidity conditions.Humidity control performance at various temperatures and trace formaldehyde adsorption ability at 25 ℃ of the composite porous resins were investigated particularly.The results show that porous structure is successfully formed in the resin.The composite porous resin has good performances on humidity control and formaldehyde adsorption.Through controlling the pore parameters of the resin by changing preparation processes,we could adjust the humidity-controlling range of the resin between 50% and 60% relative humidity(RH) in 4 h free from the influence of temperature,and the formaldehyde adsorption content of the resin was about 2.50×105 mol/(L\5g).The composite porous resin could be applied as intelligent humidity control material and create a clean micro-environment for cultural relic conservation.
Patent•
22 Aug 2011
TL;DR: In this paper, an activated alumina block filter media was proposed for use in gravity fed water filters and pressurized water filters for efficiently filtering particulate contaminants including microorganisms like cysts, bacteria and virus apart from removal of chemical contaminants while at the same time providing relatively high flow rates.
Abstract: The present invention relates to an activated alumina block filter media and a process for preparation of the alumina block, for use in gravity fed water filters and pressurized water filters for efficiently filtering particulate contaminants including microorganisms like cysts, bacteria and virus apart from removal of chemical contaminants while at the same time providing for relatively high flow rates. The alumina block filter media for use in gravity fed water filters and pressurized water filters comprises (a) activated alumina having a particle size in the range of 100 to 1000 microns and with a BET surface area in the range 200 to 1000 m 2 /g and (b) a binder material having a Melt Flow Rate (MFR) of less than 5 wherein the ratio of activated alumina particles to the binder is in the range of 1:1 to 20:1 by weight.
01 Jan 2011
TL;DR: In this paper, the authors evaluated the use of activated alumina, granular bone and bone chart for removing fluoride from water in order to propose the most feasible one for its domestic use.
Abstract: Oxide of magnesium, activated alumina, granular bone and bone chart were evaluated as methods of elimination of fluoride from water in order to propose the most feasible one for its domestic use. The water from the wells of the study area presents fluoride concentrations from 0.53 to 8.9 mg/l. The results indicate that activated alumina removes 42% of fluoride in 10 min, and the calcined bones removes 43% of fluoride in 5 minutes, from water with 8.7 mg/l of fluoride. Both methods could be considered as viable options. To increase the removal of fluoride with activated alumina is necessary to vary the pH being this more complicated at domestic environment. Also, the treated water could absorb aluminum from the alumina solution, which does not occur with the bone chart. The calcined bone is the best option since it does not cause alterations in the characteristics of the treated water, and this material is easy to obtain.
01 Sep 2011
TL;DR: In this paper, a method of cleaning solvents using activated alumina is discussed in which a degradation sample of 30% TBP/n-dodecane was prepared by irradiating (1.6 MGy) with a 60Co gamma-source.
Abstract: Abstract The PUREX process is used to extract uranium and plutonium from dissolved solutions (spent nuclear fuel liquor). The extractant is 30% tributyl phosphate in n-dodecane, which is known to be degradable by radiation and nitric acid. Tributyl phosphate degradation products can generally be washed in alkali solutions like sodium carbonate solution; however, it is more difficult to remove n-dodecane degradation products using this method. A method of cleaning solvents using activated alumina is discussed in this study. A degradation sample of 30% TBP/n-dodecane was prepared by irradiating (1.6 MGy) with a 60Co gamma-source. The degradation products were then qualitatively analyzed using a gas chromatography-mass spectrometer (GC-MS). After being irradiated the solvents were cleaned with activated alumina, and a phase separation test with performed in evaluating the cleaned solvent. This resulted in the discovery of a procedure for the removal of n-dodecane degradation products of dodecanol and dodecanone, with about 70% of the degradation products, and the phase separation performance could be clearly improved through use of activated alumina.
Patent•
27 Apr 2011
TL;DR: In this paper, a faujasite/Al2O3 composite material and a preparation method of faujaite molecular sieve is presented. But the preparation method is not suitable for the use of catalytic cracking.
Abstract: The invention discloses a faujasite/Al2O3 composite material and a preparation method thereof. The composite material is prepared by taking activated alumina as an aluminum source, and adding guide agent, water and a silicon source to carry out crystallization reaction. The BET specific surface of the composite material is less than or equal to 650m /g, the relative crystallinity of the contained active component faujasite is less than or equal to 50 percent, and the balance of the activated alumina. In addition to reserve the good pore structure and surface performance of the activated alumina, the faujasite/Al2O3 composite material prepared by the method generates an active component faujasite molecular sieve, has more reasonable acidity, can improve the catalytic cracking product distribution and has good heavy oil catalytic cracking properties.
Journal Article•
TL;DR: In this paper, an evaluation method of adsorbents on the adsorption performance to low concentration volatile organic compounds was established, and the equivalent partition coefficient and mass diffusion coefficient were obtained.
Abstract: Porous adsorption materials can adsorb harmful gases in indoor air.In this paper,an evaluation method of adsorbents on the adsorption performance to low concentration volatile organic compounds was established.By fast breakthrough experiment,equivalent partition coefficient and mass diffusion coefficient were obtained.This method was more efficient than traditional methods but with the same accuracy.Silica gel,activated alumina and 13X zeolite were tested and evaluated by adsorbing benzene,toluene and formaldehyde of typical indoor level.
TL;DR: In this article, the potential of removing arsenic from groundwater by using two process categories (activated alumina and lime softening) was investigated and its effi ciency was surveyed and its correlation coeffi cient > 0.93.
Abstract: Arsenic may be found in water that has fl owed through arsenic-rich rocks. Arsenic is a toxic, trace element that is ubiquitous in nature. It can easily be transported from the sediment to the surrounding pore-water. Severe health effects have been observed in populations drinking arsenic-rich water over long periods in countries worldwide. A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water. In groundwater, arsenic combines with oxygen to form inorganic pentavalent arsenate and trivalent arsenite. Most arsenic treatments fall into four process categories: ion exchange, membrane process, adsorption, or chemical precipitation. This study investigates the potential of removing arsenic from groundwater by using two process categories ‐ activated alumina and lime softening. Arsenic adsorption by commercially available activated alumina is surveyed and its effi ciency investigated. We have incorporated some of the valuable literature on arsenic remediation by adsorption. According to results of three activated alumina pilot studies, considering infl uence of adsorption time, temperature, pH, alumina quantity, arsenic concentration, and different alumina production resources, it has high effi ciency for arsenic removal. Adsorption isotherm for both species of arsenic (III and V) is compatible with both Freundlich and Langmuir models (correlation coeffi cient >0.93). The prevalent pH range for arsenate was between 6 and 8. Modifi ed activated alumina can remove arsenate at the infl uent pH of 8.1 ± 0.4 to below the maximum concentration level (MCL). The exhausted media passed the Toxicity Characteristic Leaching Procedure (TCLP) test with respect to arsenic. Lime softening operated within the optimum pH range of more than 10.5 is likely to provide a high percentage of arsenic removal (90%) for infl uent concentrations of up to 0.05 mg/L. It may be diffi cult to reduce consistently to 0.01 mg/L by lime softening alone. Systems using lime softening may require secondary treatment to meet that goal.
Journal Article•
TL;DR: In this paper, the authors used activated alumina and activated carbon as adsorbents of Cr(Ⅵ) from aqueous solutions and investigated the effect of operating parameters.
Abstract: Cr(Ⅵ) is considered to be potentially carcinogenic to mankind,and has the potential pollution to water.Activated alumina and activated carbon were used as adsorbents of Cr(Ⅵ) from aqueous solutions and the effect of operating parameters were investigated.The results show that pH value,adsorbent concentration and contact time were important effect parameters.The maximum removal rate of Cr(Ⅵ) was found at pH 2 for activated carbon and at pH 3 for activated alumina,96.06% and 84.18%,respectively.Adsorption performance increased with dosage and adsorption time increased and then remained constant when reaching to equilibrium.Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated.
TL;DR: In this article, the effect of calcination temperature and time on the activity of active alumina (Al2O3) was studied, and the best calcination process of acquiring activated alumina admixture was 500°C1.0h.
Abstract: Through calcining bauxite, the preparation of active alumina (Al2O3) admixture was investigated. The effect of calcination temperature and time on the activity of alumina was studied. Calcination production species and crystalline state were determined by X-ray diffractometer, and the specific surface area referred as an important parameter was also determined. The results showed that the best calcination process of acquiring activated alumina admixture was 500°C1.0h. Alkali-aggregate reaction was inhibited effectively by the active alumina admixture.
Patent•
12 Dec 2011
TL;DR: In this paper, an economical and simplified method of removing an acetylene-based impurity for purification in an olefin raw material, which does not use an expensive catalyst noble metal, does not supply a hydrogen gas, and is free of residual hydrogen gas.
Abstract: PROBLEM TO BE SOLVED: To provide an economical and simplified method of removing an acetylene-based impurity for purification in an olefin raw material, which does not use an expensive catalyst noble metal, does not supply a hydrogen gas, and is free of residual hydrogen gas, thus performing olefin polymerization efficiently.SOLUTION: An olefin raw material containing an acetylene-based compound is brought into contact with a hybrid adsorbent consisting of an activated alumina and zeolite to remove the acetylene-based compound, thus purifying an olefin.
Journal Article•
TL;DR: The effects of adsorption time, pH, initial concentration of wastewater, modified dosage and other factors on the phosphorus removal from wastewater were studied in this article, and the results showed that the specific surface area of modified activated alumina was 398.364 m2/g and was improved by 14.22%.
Abstract: In order to improve activated alumina's performance of phosphorus removal in waste water,the activated alumina as a carrier was modified with aluminum sulfate solution by impregnation method.Pore volume,average pore size and BET surface area were determined.The effects of adsorption time,pH,initial concentration of wastewater,modified dosage and other factors on the phosphorus removal from wastewater were studied.Modified activated alumina's adsorption mechanism of phosphorus was discussed.The results showed that the specific surface area of modified activated alumina was 398.364 m2/g and was improved by 14.22% than the unmodified activated alumina's.The adsorption equilibrium came after four hours and the adsorption capacity of phosphorus improved by 30.4%.The best adsorption pH was 5~7.It was also found that with the increase of initial concentration of wastewater,the removal rate of phosphorus decreased instead,while the removal rate of phosphorus increased with the increasing modified dosage,the optimal dosage of modified activated alumina was 3.0 g/L.Both Freundlich and Langmuir model of adsorption isotherms could reflect the adsorption behavior of modified activated alumina for phosphorus,while the Langmuir model was more proper.
03 Nov 2011
TL;DR: In this article, the effects of activated alumina on biogas production from corn straw hydrolysate were investigated in an up-flow anaerobic sludge blanket (UASB).
Abstract: The effects of the activated alumina on biogas production from corn straw hydrolysate were investigated in an up-flow anaerobic sludge blanket (UASB). The biogas fermentation was initiated by inoculation of the mixture of activated alumina and sludge (1 to 19 ratios) into the UASB, and operated at 37 _ for two month. The results showed that the activated alumina enabled 10 days earlier (10 days vs 20 days) of the start-up period for maximum methane production and increased the methane content of the biogas produced by 23% (86% vs 70%) when compared to those of the control With the added activated alumina, the biogas fermentation of corn straw hydrolysate achieved chemical oxygen demand (COD) removal rate, organic load rate (OLR), methane yield, and the percentage of methane in the biogas produced by 82.3%, 15.01 g/L d COD, 304 ml CH4/g COD, and 86%, respectively.
25 Oct 2011
TL;DR: In this paper, the authors investigated the efficiency of removing bromate from aqueous solution using activated alumina and found that the removal efficiency was about 90% for bromates ion with acidic activated ion and over 95% with silver or aluminum treated activated ion without any treatments of neutral water within 1 2 min.
Abstract: The efficient removal of bromate () from aqueous solutions was investigated using activated alumina. Bromate is a disinfection by-product, generally formed by the reaction of ozone and bromide in drinking water during ozonation process. The removal efficiency was about 90% for bromate (500 ng/mL) ion with acidic activated alumina but over 95% with silver or aluminum treated acidic activated alumina without any treatments of neutral water within 1~2 min.