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Activated alumina

About: Activated alumina is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 31090 citations.


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01 Jan 2013
TL;DR: In this article, a nanoscale adsorbent, called Maghemite-Magnetic Nanoadsorbent (MAGMAG), was proposed for arsenic removal from water with laboratory-scale batch experiments.
Abstract: Arsenic is a poisonous and carcinogenic heavy metal that exists naturally on the earth’s crust, from where it can leach into the groundwater – a common water source worldwide. Therefore, arsenic-rich areas pose the risk of chronic exposure, which is prevented by removing arsenic from water using various technologies. Adsorption with conventional adsorbents, as activated alumina and iron-based adsorbents, is commonly applied for arsenic removal. This study introduces a nanoscale adsorbent, maghemite-magnetic nanoadsorbent, for arsenic removal. The overall aim of the study was to compile fundamental information on novel maghemite nanoparticles and their suitability for arsenic removal from water with laboratory—scale batch experiments. The study was conducted with three kinds of maghemites: sol-gel, mechanochemical, and commercial maghemite. Sol-gel maghemite was the main research target; the others were studied for reference. The research consisted of the preparation of maghemite nanoparticles and their characterization, the study of adsorption kinetics, an investigation of arsenate adsorption properties on maghemite, a determination of the adsorption mechanism, and the evaluation of maghemite stability and regeneration properties. The results indicated the applicability of sol-gel maghemite for arsenic removal by adsorption. The reasons are several: sol-gel maghemite synthesis is fast, convenient to work with and produces repeatedly high-quality particles, adsorbs arsenate satisfactorily, and there is no need for preliminary treatments prior to adsorption experiments: it is easy to handle and separate via an external magnet, it maintains its initial arsenate uptake capacity after six regeneration cycles, and it is stable, which are important factors for cost-effectiveness. And it produces only a small amount of “arsenate-maghemite” waste. Moreover, sol-gel maghemite is competitive with activated alumina in adsorbent properties. Both adsorbents need careful monitoring due to pH control, interference of other ions, and regeneration. Activated alumina can remove slightly more arsenate than sol-gel maghemite, but sol-gel maghemite is more stable, forms less waste, and is separated simply and rapidly by external magnet. ; Arseeni on myrkyllinen ja karsinogeeninen raskasmetalli, jota esiintyy kallio- ja maaperassa. Sielta arseenia voi liueta pohjaveteen, joka on yleinen juomaveden lahde maailmanlaajuisesti. Arseenipitoisilla pohjavesialueilla kroonisen altistumisen riski on merkittava ja altistumisen estamiseksi arseenia poistetaan juomavedesta erilaisilla tekniikoilla. Adsorptio perinteisilla adsorbenteilla, kuten aktivoidulla alumiinilla ja rautapohjaisilla adsorbenteilla, on yleisesti kaytossa oleva arseenin poistomenetelma. Tassa tutkimuksessa esitetaan nanomittakaavan adsorbentti – maghemiitti – magneettinen nanoadsorbentti – arseenin poistoon. Tutkimuksen tavoitteena oli koota perustietoa uudesta maghemiittinanohiukkasesta ja sen soveltuvuudesta arsenaatin (As(V)), poistoon vedesta laboratoriomittakaavan kokeilla.…

3 citations

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

3 citations

Patent
10 Jan 1968
TL;DR: In this article, a VAPOR PHASE PROCESS at ATMOSPHERIC PRESSURE by CYCLODEHYDRATION of the CORRESPONDING N-SUBSTITUTED ETHANOLAMINE in the PRESENCE of an ACTIVATED ALUMINA CATYLST.
Abstract: N,N''-DISUBSTITUTED PIPERAZINES ARE PREPARED IN A VAPOR PHASE PROCESS AT ATMOSPHERIC PRESSURE BY CYCLODEHYDRATION OF THE CORRESPONDING N-SUBSTITUTED ETHANOLAMINE IN THE PRESENCE OF AN ACTIVATED ALUMINA CATYLST.

3 citations

Patent
11 Jan 1968
TL;DR: In this article, the authors describe a continuous process for the removal of the catalyst from the sulphur depositing zone to the sulfur removing zone and thereafter recycling the catalyst, is described.
Abstract: 1,211,033. Removing SO 2 from waste gases. ONTARIO RESEARCH FOUNDATION. 10 Jan., 1969 [11 Jan., 1968], No. 1741/68. Heading C1A. Sulphur dioxide containing effluent gas is contacted with a reducing gas comprising H 2 S in the presence of a catalyst at a temperature of 50- 150‹ C. whereby the SO 2 is at least partially reduced to sulphur in accordance with the equation: and the sulphur is deposited on the catalyst, and removing the sulphur from the catalyst at least partially by reaction with carbon monoxide at a temperature of from 250-500‹ C. in order to provide regenerated, substantially sulphur free catalyst. The reaction with carbon monoxide preferably occurs at 300-450‹ C. The carbonyl sulphide produced may in turn be hydrolysed to CO 2 and H 2 S which is recycled, further H 2 S being produced if a mixture of CO and H 2 is used for removing the sulphur, steam (removing the necessity for subsequent hydrolysis) and an inert gas, such as N 2 , may also be present. Sufficient H 2 S is used in order to react with all the SO 2 , sufficient CO with or without H 2 is used to react with 2/3 of the sulphur produced, the rest being removed as sulphur vapour in the COS and subsequently removed; sufficient steam is used to hydrolyse all the COS produced. A continuous process for the removal of the catalyst from the sulphur depositing zone to the sulphur removing zone and: thereafter recycling the catalyst, is described. Catalysts disclosed for the sulphur producing stage are Pd, Pt, Rh, promoted iron oxide but preferably activated alumina or bauxite is used. This stage may be broken up into 2 parts: (a) reaction with H 2 S at 250-400‹ C. (b) completion of the reaction at 50-150‹ C. Some CS 2 may be produced especially if hydrocarbons are present in the CO or H 2 . This need not be hydrolysed since CS 2 will reduce SO 2 to S if recycled.

3 citations

Patent
20 Jun 1989
TL;DR: An exhaust gas purifying catalyst suppressing the generation of hydrogen sulfide obtained by coating and supporting on a honeycomb carrier of a monolithic structure is defined in this article, which is an example of such an approach.
Abstract: An exhaust gas purifying catalyst suppressing the generation of hydrogen sulfide obtained by coating and supporting on a honeycomb carrier of a monolithic structure a catalyst composition containing (a) activated alumina supporting platinum and/or palladium in the range of 5 to 30 weight % and rhodium in the range of 1 to 20 weight %, (b) a cerium oxide and (c) activated alumina, and optionally (d) an alkali metal and/or (e) a nickel oxide.

3 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202218
202118
202031
201941
201839