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Registros recuperados: 8
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Adsorção de cádmio e chumbo em solos tropicais altamente intemperizados. Repositório Alice
LINHARES, L.A.; EGREJA FILHO, F.B.; OLIVEIRA, C.V. de; BELLIS, V.M. de..
O objetivo deste trabalho foi determinar a capacidade de adsorção de cádmio e de chumbo e avaliar a influência das propriedades dos solos sobre os parâmetros de adsorção desses elementos em solos tropicais altamente intemperizados. Foram utilizados quatro Latossolos e um Argissolo. Amostras de 1 g de solo foram agitadas por 16 horas, com soluções de CaCl2 0,01 mol L-1, às quais foram adicionadas 0, 10, 20, 30, 40, 60 e 80 ?gámL-1 de cádmio e 0, 10, 20, 40, 60, 80, 100 e 120 ?gámL-1 de chumbo na forma de nitrato. As quantidades adsorvidas foram determinadas mediante análise dos elementos no sobrenadante, e os dados foram ajustados às isotermas de Langmuir e de Freundlich. Os resultados experimentais ajustaram-se aos modelos estudados. A adsorção máxima de...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Argissolo; Latossolo; Isoterma de adsorção; Metal pesado; Ultisol; Oxisol; Adsorption isotherm; Heavy metals.
Ano: 2009 URL: http://www.alice.cnptia.embrapa.br/handle/doc/125775
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Adsorption of amyloglucosidase from Aspergillus niger NRRL 3122 using ion exchange resin BABT
Manera,Ana Paula; Kamimura,Eliana Setsuko; Brites,Luciana Machado; Kalil,Susana Juliano.
Amyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature) in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Amyloglucosidase; Adsorption isotherm; Kinetics adsorption; Ion exchange resin; Purification.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000500019
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Comparison of adsorption equilibrium of fructose, glucose and sucrose on potassium gel-type and macroporous sodium ion-exchange resins IPB - Escola Superior Agrária
Nobre, Clarisse; Santos, M.J.; Dominguez, Ana; Torres, Duarte; Rocha, Orlando; Peres, António M.; Rocha, Isabel; Ferreira, Eugénio C.; Teixeira, José A.; Rodrigues, Lígia R..
Adsorption equilibrium of fructose, glucose and sucrose was evaluated on sulfonated poly(styrene-codivinylbenzene) cation-exchange resins. Two types of resins were used: potassium (K+) gel-type and sodium (Na+) macroporous resins. Influence of the cation and effect of the resin structure on adsorption were studied. The adsorption isotherms were determined by the static method in batch mode for monocomponent and multi-component sugar mixtures, at 25 and 40 ◦C, in a range of concentrations between 5 and 250 g L−1. All adsorption isotherms were fitted by a linear model in this range of concentrations. Sugars were adsorbed in both resins by the following order: fructose > glucose > sucrose. Sucrose was more adsorbed in the Na+ macroporous resin, glucose...
Tipo: Article Palavras-chave: Adsorption isotherm; Macroporous resin; Gel-type resin; Cations; Sugars.
Ano: 2010 URL: http://hdl.handle.net/10198/3818
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Equilibrium sorption isotherm studies of Cd(II), Pb(II) and Zn(II) ions detoxification from waste water using unmodified and EDTA-modified maize husk Electron. J. Biotechnol.
Igwe,Jude C; Abia,Augustin A.
The mobilization of heavy metals in the environment due to industrial activities is of serious concern due to the toxicity of these metals in humans and other forms of life. The equilibrium adsorption isotherms of Cd(II), Pb(II) and Zn(II) ions, detoxification from waste water using unmodified and EDTA-modified maize husk have been studied. Maize husk was found to be an excellent adsorbent for the removal of these metal ions. The amount of these metal ions adsorbed increased as the initial concentration increased. Also, EDTA-modification enhanced the adsorption capacity of maize husk due to the chelating ability of ethylenediamine tetra acetic acid (EDTA). Among the three adsorption isotherms tested, Dubinin-Radushkevich isotherm gave the best fit with R²...
Tipo: Journal article Palavras-chave: Adsorption isotherm; EDTA; Heavy metals; Maize husk; Waste water.
Ano: 2007 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582007000400007
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Study of adsorption isotherms and physicochemical characterization of natural food colourants Ciênc. Tecnol. Aliment.
VIANA,Kéllen Wanessa Coutinho; OLIVEIRA,Isadora Rebouças Nolasco de; ROCHA,Juliana de Cássia Gomes; BARROS,Frederico Augusto Ribeiro de; STRINGHETA,Paulo César.
Abstract Synthetic colourants are widely used for colouring foods. However, their safety has been questioned. Due to this limitation and the global trend of consuming healthy foods, the industry is faced with the need to replace artificial colourings, which has given rise to a growing interest in colourants from natural sources. Thus, this work obtained the moisture adsorption isotherms of the natural food dyes of anthocyanins, betalains and curcumin and evaluated the humidity, water activity (aw), hygroscopicity, colour and antioxidant capacity in vitro. Isotherms were determined by the static gravimetric method with saturated salt solutions (LiCl. H2O, MgCl2.6H 2O, Mg(NO3)2.6H2O, NaCl, KCl and K2 SO4) at 25 °C. Experimental data were adjusted by GAB,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Natural dyes; Anthocyanins; Betalains; Curcumin; Adsorption isotherm.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000500074
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Zinc adsorption in highly weathered soils. Repositório Alice
CASAGRANDE, J.C.; SOARES, M.R.; MOUTA, E.R..
The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0?80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59?810 mg kg-1, and Zn affinity was greater in subsoil (0.13?0.81 L kg-1) than in the...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: PH; Adsorption envelope; Adsorption isotherm; Ionic strength; Trace element; Envelope de adsorção; Isoterma de adsorção; Força iônica; Elemento-traço.
Ano: 2008 URL: http://www.alice.cnptia.embrapa.br/handle/doc/123240
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Zinc adsorption in highly weathered soils PAB
Casagrande,José Carlos; Soares,Marcio Roberto; Mouta,Ernesto Rinaldi.
The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0-80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59-810 mg kg-1, and Zn affinity was greater in subsoil (0.13-0.81 L kg-1) than in the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: PH; Adsorption envelope; Adsorption isotherm; Ionic strength; Trace element.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2008000100017
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烏龍茶葉吸濕性及其品質維持之應用研究 Taiwan Agricultural Research Institute
陳加忠; 賴建洲; 曹之祖; C. C. Chen; C. C. Lai; C. T. Tsao.
[[abstract]]在此研究中量測兩種烏龍茶葉的平衡相對濕度物性,實驗結果顯示電子式相對濕度計可適用於此種物性量測。溫度對等溫水份線的主要效應發生於70 RH%下範圍。修正Oswin模式適用於此項物性,此研究所得茶葉安定含水率範圍為3─4%。自GAB模式計算所得之安定含水率數值顯著地高於來自BET模式之數值。利用量測的平衡相對濕度和溫度數值計算所得之含水率其誤差約為0.5%。 The equilibrium relative humidity properties of the adsorption isotherms for two types of Oolong tea were measured in this study. The results indicated that electronic RH sensor can serve as good device on ERH measurement. The main effect of temp erature shirt on isotherm were found below the range of 50%RH. The Modified-Oswin equation was the adequate model for two types of Oolong tea. The critical M. C. value for maintaining quality of Oolong tea was 3%-4%. The Mo values calculated by GAB model was signficantly higher than those of BET model. The moisture content of...
Palavras-chave: 烏龍茶葉; 吸濕性; 單層水份; ERH模式 Oolong tea; Adsorption isotherm; Monolayer value; ERH model [[classification]]8.
Ano: 1990
Registros recuperados: 8
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