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Separation of light naphtha for the octane upgrading of gasoline: adsorption and membrane technologies and new adsorbents

Bárcia, Patrick da Silva
Fonte: FEUP Publicador: FEUP
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
391.63547%
The aim of this work is to contribute for the development of adsorption based separation processes with considerable potential for commercial application on the refining industry, namely, in the separation of high research octane number (HRON) paraffins from light naphtha fractions. The development of an adsorption process requires first a detailed knowledge of equilibria and kinetics of adsorption and their impact on the dynamic response of an adsorption column. Accordingly, we start collecting single and mixture adsorption equilibrium isotherms of C6 isomers, n-hexane (nHEX), 3-methylpentane (3MP), 2,3-dimethylbutane (23DMB), and 2,2- dimethylbutane (22DMB), from breakthrough experiments in zeolite beta. This adsorbent was selected because its pore system posses interesting characteristics for the separation of HRON dibranched C6 from their low research octane number (LRON) monobranched isomers. It was found that the sorption hierarchy in zeolite beta was most favourable towards the linear isomer and least favourable towards the dibranched ones. Zeolite beta demonstrated significant selectivity to discriminate between mono and dibranched C6 isomers, especially at low coverage. Based on an analysis of sorption events at the molecular level...

Adsorption of phenylalanine onto polymeric resins: equilibrium, kinetics and operation of a parametric pumping unit

Díez, Sergi; Leitão, Anabela; Ferreira, Licínio; Rodrigues, Alírio
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
487.58086%
Adsorption of -Phenylalanine onto polymeric adsorbents (Amberlite XAD-4 and XAD-16; Sephabeads SP206 and SP207) was studied. Adsorption equilibrium isotherms were measured by batch equilibration at 15 and 40°C, showing the possibility of using a parametric pumping technique for aminoacid purification/recovery. Dynamic studies in a laboratory adsorption column Amicon Column (22 × 500 mm) were carried out to further screen adsorbents and obtain mass transfer parameters to be used in the modeling, simulation and operation of the pilot parametric pumping unit. The pilot plant includes a Amicon Columnn (90 × 1000 mm) and is completely automated. A package for the simulation of this cyclic operation was developed. Simulated and experimental results using Sephabeads SP206 (Mitsubishi Kasei Corporation, Japan) are in good agreement.; http://www.sciencedirect.com/science/article/B6THJ-3V7PF1M-3/1/790b48ad004d05db3bbf0582f73002e8

Cromatografia a líquido por injeção sequencial para a determinação de herbicidas triazínicos e metabólitos da atrazina explorando o uso de cela de longo caminho óptico e monitoramento on-line em estudos de adsorção; Sequential injection liquid chromatography for the determination of triazine herbicides and metabolites of atrazine exploring the use of long optical pathlength flow cell and on line monitoring of adsorption studies

Urio, Ricardo de Prá
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/05/2011 PT
Relevância na Pesquisa
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Estudou-se o emprego da Cromatografia a Líquido por Injeção Seqüencial (SIC) explorando o uso de uma cela de longo caminho óptico com guia de onda (LCW) de 100 cm para a melhora dos limites de detecção (LOD) e quantificação (LOQ) na determinação de atrazina (ATR), propazina (PRO) e simazina (SIM). Para isto, utilizou-se uma fase móvel com composição de 44:56 (v v-1) metanol : tampão acetato de amônio 1,25 mM, pH 4,7, coluna monolítica e a detecção espectrofotométrica em 238 nm. Obtiveram-se valores de LOD e LOQ, respectivamente, de 1,76 e 5,86 µg L-1 para ATR, 4,51 e 15 µg L-1 para PRO e 2,25 e 7,5 µg L-1 para SIM. Com o emprego da cela de longo caminho óptico os valores de LOD ficaram abaixo dos recomendados pela US-EPA, que permite para águas potáveis uma concentração de 3 µg L-1 para ATR, 4 µg L-1 para SIM e 10 µg L-1 para PRO. Realizaram-se estudos de adsorção de SIM, PRO e ATR e seus metabólitos desisopropilatrazina (DIA), desetilatrazina (DEA) e 2-hidroxiatrazina (HAT) em solo, ácido húmico e solo modificado com ácido húmico. Para isso foi utilizado um sistema de monitoramento on-line composto por um filtro tangencial e uma bomba peristáltica para circulação da suspensão. Foram realizados estudos cinéticos em duas etapas e...

Síntese de zeólitas de cinzas de carvão modificada por surfactante e aplicação na remoção de ácido laranja 8 de solução aquosa: estudo em leito móvel, coluna de leito fixo e avaliação ecotoxicológica; Synthesis of zeolites coal ash in surfactant modified in application and removal of orange 8 acid solution: study in batch, fixed bed column and evaluation ecotoxicological

Magdalena, Carina Pitwak
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/01/2015 PT
Relevância na Pesquisa
396.7458%
No presente estudo, material zeolítico sintetizado a partir de cinzas de carvão e modificado por surfactante catiônico foi utilizado na remoção do corante ácido laranja 8 (AL8) por processo de adsorção utilizando leito móvel e coluna de leito fixo. As matérias primas e os adsorventes foram caracterizados por diferentes técnicas, tais como: difração de raios-x, fluorescência de raios-X, entre outras. A adsorção do AL8 foi realizada por leito móvel com o objetivo de otimizar os resultados quando lançados em leito fixo. Os efeitos na adsorção do AL8 sobre zeólita foram comparados: (1) efeito dos contra-íons Br- e Cl- do surfactante usado na modificação da zeólita; (2) efeito do tipo de cinzas de carvão usada como matéria prima na síntese das zeólitas (leve e pesada). Os seguintes adsorventes foram utilizados no estudo: zeólita leve e pesada modificada por surfactante brometo de hexadeciltrimetilamônio (ZLMS-Br e ZPMS-Br) e zeólita leve modificada por surfactante cloreto de hexadeciltrimetilamônio (ZLMS-Cl). A cinética de pseudo-segunda-ordem descreveu a adsorção do corante sobre todos os adsorventes. O tempo de equilíbrio alcançado foi 40, 60 e 120 min para ZLMS-Br, ZLMS-Cl e ZPMS-Br, respectivamente. O equilíbrio de adsorção foi analisado pelas equações dos modelos das isotermas lineares e não lineares de Langmuir...

Difusão de Al, Mn, Fe e F por um solo laterítico visando a aplicação como barreira impermeabilizante para a bacia de captação de drenagem ácida gerada pela pilha de estéril 4 da UTM-Caldas; Diffusion and adsorption of Al, Fe, Mn and F by a lateritic soil, aiming at its application as waterproofing barrier for the impoundment basin of acid drainage generated by wste rock pile 4 at UTM-Caldas

Rodrigo Paiva Barreto
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/12/2011 PT
Relevância na Pesquisa
392.457%
A primeira mina de extração de urânio do Brasil, atualmente em fase de descomissionamento, gerou vários impactos ambientais negativos em sua área, em decorrência dos processos de lavra, tratamento e beneficiamento. A geração de drenagem ácida na pilha de estéril número 4 (PE-4) é um dos impactos negativos gerados com a situação mais crítica. A água ácida, produto desta drenagem, apresenta metais pesados e elementos radioativos e pode estar sendo infiltrada pela base da bacia de captação, onde é feita a coleta desta água para tratamento. O objetivo deste trabalho foi selecionar um solo da área, visando a sua utilização como barreira impermeabilizante de base da bacia de captação desta água ácida, a fim de evitar a contaminação do ambiente. Dessa maneira, foram realizados ensaios geotécnicos e químico-mineralógicos para caracterização de seis solos coletados na área. Um dos solos estudados, coletado próximo à bacia, foi usado em um ensaio de coluna. O solo que obteve o melhor desempenho com relação aos ensaios geotécnicos e químico - mineralógicos com consideração aos limites recomendados pela literatura científica foi escolhido para ser submetido aos ensaios de adsorção em lote e difusão...

ADSORPTION OF CHROMOPHORE CHEMICAL SPECIES PRESENT IN AN REAL INDUSTRUAL EFFLUENT USING ACTIVATED CARBONS

Nabais, Joao; Carrott, Peter; Ribeiro Carrott, Manuela; Marques, Liliana
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Aula Formato: 14175 bytes; application/pdf
ENG
Relevância na Pesquisa
394.1747%
The use of 5 commercial activated carbons with different shapes, origins and characteristics (Norit Azo, Merck granular, DCL GDC 753 from Sutcliffe Speakman (DCL) and X2MH 6/8 from Takeda) were tested for the adsorption of the chromophore compounds present in a pulp mill effluent using batch and dynamic trials. The colour removal achieved is within the range 30-90%. The highest removal is obtained with Norit AZO and the smallest with Takeda X2MH. From the batch trials we can draw the following conclusions: - Iodine index can be used as a guide for the effluent colour removal efficiency but for this propose the methylene blue index is useless. - Acidic groups are more important than the basic groups on the adsorption mechanisms involved in the activated carbon adsorption of the chemical species that gave colour to the effluent. - The adsorption is proportional to the pzc and V0 samples values. - For small values of SBET this parameter has a significant impact on the adsorption but for sample with SBET bigger than 900m2g-1 the adsorption is apparently independent of the BET surface area. The column tests performed with X2MH, DCL and MERCK samples showed that we can obtain similar results as in batch tests, as expected. The breakthrough curves reveal that X2MH sample has a very fast saturation while DCL and MERCK sample have good efficiency with 90% colour removal when the effluent volume that passes through the column is 10 and 20 times the activated carbon volume...

Comparative study of hydrodynamic behavior of liquid expanded bed adsorption: mathematical and short-cut methods

Jahanshahi,M.; Ghoreishi,A. A.; Vasheghani-F,E.; Khavarpour,M.; Abedijaber,A.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
390.3%
Liquid fluidized/expanded bed adsorption (LF/EBA) is a novel chromatography technique for capturing target biomolecules directly from crude feedstock in downstream processing. To widely extend the LF/EBA technology in biological industries, a better understanding of the expanded-bed behavior is necessary to maximize its efficient applications. In this study, streamline adsorbent was loaded into the column and the bed was subjected to physical and hydrodynamical experiments. Hydrodynamic characteristics of the bed (e.g., Daxl and Bo) with different settled bed height (SBH=5,6,7,8,9,10,11,12cm) along with a variety of column diameters (1,1.6,2.5 cm) have been investigated based on exact mathematical as well as approximate short-cut methods. It was found that the increasing column diameter promoted bed mixing, which was undesirable, and the optimal values for the bed expansion and SBH based on minimal liquid mixing were 80%-130% and 8-10 cm, respectively. However, exploiting the short-cut method for the bed hydrodynamic assessments also demonstrated results as good as the mathematical method. Hydrodynamic behavior of liquid fluidized bed adsorption and the generic application of the short-cut method and its potential as a simple method for study of hydrodynamic performance is discussed.

Numerical study of n-pentane separation using adsorption column

Silva,Adriano da; Mariani,Viviana Cocco; Souza,Antônio Augusto Ulson de; Souza,Selene Maria de Arruda Guelli Ulson
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2005 EN
Relevância na Pesquisa
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This work simulated numerically the n-pentane separation of a mixture of iso-pentane, n-pentane and nitrogen, using an adsorption column with zeolite 5A. The mathematical model equations of the mass and heat transfer in the adsorption column are presented, as well as the boundary and initials conditions, beyond some hypotheses and considerations. The Volume Finite Method was used in the discretization of the equations to get the system of algebraic equations and posterior development of the computational algorithm. The numerical results using the Differencing Central (CDS) and Upwind (UDS) interpolations were compared with experimental results found in the literature. The influence of the partial pressure in the adsorption column performance was also analyzed.

Simultaneous Production and Recovery of Fumaric Acid from Immobilized Rhizopus oryzae with a Rotary Biofilm Contactor and an Adsorption Column

Cao, N.; Du, J.; Gong, C. S.; Tsao, G. T.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1996 EN
Relevância na Pesquisa
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An integrated system of simultaneous fermentation-adsorption for the production and recovery of fumaric acid from glucose by Rhizopus oryzae was investigated. The system was constructed such that growing Rhizopus mycelia were self-immobilized on the plastic discs of a rotary biofilm contactor during the nitrogen-rich growth phase. During the nongrowth, production phase, the biofilm was alternately exposed to liquid medium and air upon rotation of the discs in the horizontal fermentation vessel. The product of fermentation, fumaric acid, was removed simultaneously and continuously by a coupled adsorption column, thereby moderating inhibition, enhancing the fermentation rate, and sustaining cell viability. Another beneficial effect of the removal of fumaric acid is release of hydroxyl ions from a polyvinyl pyridine adsorbent into the circulating fermentation broth. This moderates the decrease in pH that would otherwise occur. Polyvinyl pyridine and IRA-900 gave the highest loading for this type of fermentation. This fermentation system is capable of producing fumaric acid with an average yield of 85 g/liter from 100 g of glucose per liter within 20 h under repetitive fed-batch cycles. On a weight yield basis, 91% of the theoretical maximum was obtained with a productivity of 4.25 g/liter/h. This is in contrast to stirred-tank fermentation supplemented with calcium carbonate...

Mathematical modeling and experimental breakthrough curves of cephalosporin C adsorption in a fixed-bed column

Burkert, Carlos André Veiga; Barbosa, Geraldo Nazareno de Oliveira; Mazutti, Marcio Antônio; Maugeri, Francisco
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
390.3%
This work presents the mathematical modeling of the cephalosporin C (CPC) adsorption process in a fixed-bed column. The application of Particle Swarm Optimization (PSO) algorithm for parameter estimation was first considered, which shows to be a useful tool for parameter estimation in adsorption processes. Modeling and simulation of CPC purification showed a good performance during both estimation and validation step. After this, a central composite rotational design (CCRD) was conceived taking into account both the superficial velocity of liquid and column length as process variables with the responses obtained from the application of the model, which works as a process simulator affording a process answer from a given input. It has been shown that the response surface methodology was an efficient optimization tool, since few simulations were required to find the optimum region for independent variables.

Recuperação e purificação de quitosanases usando adsorção em leito expandido com streamline DEAE com modelagem e simulação usando redes neurais; Recovery and Purification of Chitosanases using Expanded Bed Adsorption with Streamline DEAE with Modeling and Simulation using Neural Networks

Padilha, Carlos Eduardo de Araújo
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
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Expanded Bed Adsorption (EBA) is an integrative process that combines concepts of chromatography and fluidization of solids. The many parameters involved and their synergistic effects complicate the optimization of the process. Fortunately, some mathematical tools have been developed in order to guide the investigation of the EBA system. In this work the application of experimental design, phenomenological modeling and artificial neural networks (ANN) in understanding chitosanases adsorption on ion exchange resin Streamline® DEAE have been investigated. The strain Paenibacillus ehimensis NRRL B-23118 was used for chitosanase production. EBA experiments were carried out using a column of 2.6 cm inner diameter with 30.0 cm in height that was coupled to a peristaltic pump. At the bottom of the column there was a distributor of glass beads having a height of 3.0 cm. Assays for residence time distribution (RTD) revelead a high degree of mixing, however, the Richardson-Zaki coefficients showed that the column was on the threshold of stability. Isotherm models fitted the adsorption equilibrium data in the presence of lyotropic salts. The results of experiment design indicated that the ionic strength and superficial velocity are important to the recovery and purity of chitosanases. The molecular mass of the two chitosanases were approximately 23 kDa and 52 kDa as estimated by SDS-PAGE. The phenomenological modeling was aimed to describe the operations in batch and column chromatography. The simulations were performed in Microsoft Visual Studio. The kinetic rate constant model set to kinetic curves efficiently under conditions of initial enzyme activity 0.232...

Remoção de alumínio em sistema contínuo por adsorção em coluna de leito fixo com carvão ativado

Oliveira, Letícia Raquel de
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
Relevância na Pesquisa
496.7458%
A poluição do ambiente aquático é uma questão séria e ponto central de debates no mundo todo, pois a água é um recurso vital e de extrema importância também para o desenvolvimento industrial e econômico. Dentre a vasta gama de poluentes da água encontram-se metais como o alumínio que, apesar de não ser classificado como metal pesado, interfere significativamente no ecossistema aquático quando em excesso. A principal fonte de alumínio na água é devida ao residual encontrado após o tratamento com sais de alumínio como sulfato de alumínio. Essa crescente preocupação com o meio ambiente tem intensificado o estudo de técnicas de remoção de metais de efluentes e da água bruta. Neste sentido, a adsorção tem atraido atenção, pois se apresenta como um método eficaz, econômico, de baixo custo e baixo consumo energético. Outro ponto que chama atenção é o destino do sólido adsorvente após o seu uso e saturação. Neste sentido, o carvão ativado destaca-se como adsorvente pela possibilidade de regeneração e reutilização deste material em processos de adsorção. Além disso, apresenta uma área superficial elevada e seu uso como adsorvente está consolidado a décadas. Sendo assim, o objetivo do presente trabalho foi investigar a capacidade de adsorção do carvão ativado na remoção de alumínio residual de um efluente tratado pelo método convencional de coagulação/precipitação com sulfato de alumínio...

Discriminating and assessing adsorption and biodegradation removal mechanisms during granular activated carbon filtration of microcystin toxins

Wang, H.; Ho, L.; Lewis, D.; Brookes, J.; Newcombe, G.
Fonte: Pergamon-Elsevier Science Ltd Publicador: Pergamon-Elsevier Science Ltd
Tipo: Artigo de Revista Científica
Publicado em //2007 EN
Relevância na Pesquisa
398.86867%
Microcystins are cyanobacterial toxins that are problematic for water authorities due to their resistance to conventional water treatment. Granular activated carbon (GAC) filtration has been shown to be effective in removing microcystin from water using both adsorption and biodegradation removal mechanisms; however, little is known regarding which removal mechanism predominates and to what extent. In this study, microcystin removal due to adsorption and biodegradation in GAC filtration were discriminated and assessed by commissioning three parallel laboratory columns, including a sterile GAC column, a conventional GAC column and a sand column. The results demonstrate that biodegradation is an efficient removal mechanism once it commences and that the rate of biodegradation was dependent upon temperature and initial bacterial concentration. Adsorption of microcystins was prevalent during the initial stages of the GAC columns and was modelled using the homogeneous surface diffusion model (HSDM). The HSDM provided evidence that an active biofilm present on the surface of the conventional GAC hindered adsorption of microcystin compared with the sterile GAC with no active biofilm. Up to 70% removal of microcystin-LR was still observed after 6 months of operation of the sterile GAC column...

BATCH AND BENCH-SCALE FIXED-BED COLUMN EVALUATIONS OF HEAVY METAL REMOVALS FROM AQUEOUS SOLUTIONS AND SYNTHETIC LANDFILL LEACHATE USING LOW-COST NATURAL ADSORBENTS

Li, Chenxi
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 5000314 bytes; application/pdf
EN; EN
Relevância na Pesquisa
391.63547%
In this project, three separate experiments were conducted to assess heavy metal removal from metal aqueous solutions and synthetic landfill leachate by adsorption using low-cost natural adsorbents. Fundamental batch investigations indicated that the 4.0-4.75 mm crushed mollusk shells and the Sphagnum peat moss were the best adsorbents for cadmium and nickel removal, respectively. Peat moss was also found to have the highest adsorption capacities for manganese and cobalt adsorption. The adsorption capacities of the peat moss and crushed mollusk shells used as natural adsorbents for the adsorption of cadmium and nickel from binary aqueous solutions in fixed-bed columns under continuous flow conditions were investigated. The life expectancy of each adsorbent in the fixed-bed columns was also assessed for different hydraulic loading rates. The flow rate of 1.5 mL/min (surface loading of 27.52 cm3/cm2•day) and bed depth of 15 cm were identified as the better operational conditions from the column testing. The results indicated that 47.9% and 42.7% cadmium and nickel removal efficiencies could obtained under these operational conditions, respectively. Finally, the peat moss and the crushed mollusk shells were packed in bench-scale down-flow fixed-bed columns to evaluate their adsorption capacities as natural low-cost adsorbents for the removal of heavy metals from aerated and non-aerated synthetic landfill leachate. The flow rate applied in this operation was 1.5 mL/min (surface loading of 27.52 cm3/cm2•day). Peat was found to have the best adsorption capacities in columns treating aerated synthetic leachate for cadmium (78.6%) and nickel (83.8%) removal efficiencies.; Thesis (Master...

Remoção de cadmio, chumbo e cobre utilizando zeolita natural clinoptilolita em coluna de leito fixo; Cadmium lead and Cooper removal using zeolite clinoptilolite in a fixed bed column

Sirlei Jaiana Kleinübing
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/07/2006 PT
Relevância na Pesquisa
387.58086%
Neste trabalho foi estudada a remoção do íon cádmio, chumbo e cobre pela zeólita natural Clinoptilolita. Este estudo foi realizado em coluna de leito fixo construído em acnlico nas dimensões de 13,3 em de altura e 1,4 em de diâmetro interno. O estudo de pH foi feito visando a determinação dos valores no qual não ocorre à precipitação dos metais, sendo adotado o pH de 5,0. Utilizou-se a técnica de planejamento experimental 22 com 3 pontos centrais para o estudo do processo de adsorção de cada metal individualmente, avaliando as variáveis, vazão de operação e concentração de alimentação na resposta capacidade total de metal removida. Foram efetuados vários planejamentos experimentais, o planejamento 1 foi realizado para o cádmio, nas condições de concentração de 200 e 600 ppm e vazão de 10 e 50mL/min, no entanto os resultados não foram satisfatórios. Definiu-se então o planejamento experimental 2, nas condições de 400 e 600 ppm e 15 e 25 rnL/min, para cádmio, chumbo e cobre, encontrando-se a variável concentração como sendo a mais significativa e maior quantidade de metal é removido em maior concentração. Fez-se análise da zona de transferência de massa (ZTM) para o processo de adsorção de chumbo...

Selective cation-exchange adsorption of the two major whey proteins

El-Sayed, Mayyada
Fonte: University of Cambridge; Department of Chemical Engineering and Biotechnology Publicador: University of Cambridge; Department of Chemical Engineering and Biotechnology
Tipo: Thesis; doctoral; PhD
EN
Relevância na Pesquisa
401.3869%
Whey is a by-product of cheese manufacture, containing a mixture of proteins of commercial value, each having unique attributes for nutritional, biological and food ingredient applications. A tremendous amount of whey, normally treated as a waste product, is produced worldwide each year. This work describes the cation-exchange adsorption of the two major whey proteins, alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) with the purpose of optimising a process for isolating them from whey. Adsorption of pure BLG and ALA was studied onto SP Sepharose FF using 0.1M acetate buffer. Batch experiments were carried out at various pH values for ALA and BLG, and the relevant Langmuir isotherm parameters, dissociation constant, Kd, and maximum binding capacity, qm, were determined. The optimum pH for separation was chosen to be pH 3.7. At pH 3.7, both Kd and qm pertaining to ALA were found to have higher numerical values than those of BLG, implying different characteristics of adsorption of the two proteins on this adsorbent. The Kd for the former protein was almost four times larger than the latter, while qm was 1.3 times higher. Packed-bed column adsorption was performed using a 1-ml column at pH 3.7, flow rate 1 ml/min and initial concentration of 3 mg/ml for BLG and 1.5 mg/ml for ALA both in 0.1M sodium acetate buffer. The t1/2 for the resulting ALA breakthrough was 75% longer than its BLG counterpart. The above results suggest the possibility of the occurrence of competitive adsorption between the proteins when adsorbed simultaneously. In traditional batch uptake experiments...

CHARACTERIZATION AND COLUMN ADSORPTIVE TREATMENT FOR COD AND COLOR REMOVAL USING ACTIVATED NEEM LEAF POWDER FROM TEXTILE WASTEWATER

Patel, Himanshu; Vashi, R. T.
Fonte: JUEE Press Publicador: JUEE Press
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 27/12/2015 ENG
Relevância na Pesquisa
399.5049%
The textile wastewater samples before treatment processes has been collected and characterized using standard methods, in which COD, color and other contaminations are high and prior to remove before discharge. Feasibility of column adsorption of components contributing COD and color onto activated Neem Leaf Powder using sulphuric acid (a-NLP) from textile wastewater has been studied in this investigation. The effect of process parameters like different flow rate, bed-height and pH for COD and color removal has been analyzed, in which adsorption reached saturation faster with increasing the flow rate and pH; while it was the advantage of column adsorption with the increase in the a-NLP bed. The data were applied to Thomas, Yoon-Nelson, Bed Depth Service Time (BDST) and Adams and Bohart Model to evaluation of efficacy of the column. The maximum adsorption capacity related to Adams and Bohart model was found to be 725.7 and 380.4 mg/g for COD and color respectively at flow rate of 5 ml/min and bed height of 15 cm when a-NLP was used.

ADSORPTION AND DESORPTION CHARACTERISTICS OF CRYSTAL VIOLET IN BOTTOM ASH COLUMN (doi: 10.4090/juee.2012.v6n1.018029)

Nidheesh, Puthiya Veetil; Gandhimathi, Rajan; Ramesh, Sreekrishnaperumal Thanga; Anantha Singh, Tangappan Sarasvathy
Fonte: JUEE Press Publicador: JUEE Press
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 29/06/2012 ENG
Relevância na Pesquisa
502.84242%
This study described adsorption of Crystal Violet (CV) by bottom ash in fixed-bed column mode. Equilibrium of adsorption was studied in batch mode for finding adsorption capacity of bottom ash. In fixed bed column adsorption, the effects of bed height, feed flow rate, and initial concentration were studied by assessing breakthrough curve. The slope of the breakthrough curve decreased with increasing bed height. The breakthrough time and exhaustion time were decreased with increasing influent CV concentration and flow rates. The effect of bed depth, flow rate and CV concentration on the adsorption column design parameters were analyzed. Bed depth service time (BDST) model was applied for analysis of crystal violet adsorption in the column. The adsorption capacity of bottom ash was calculated at 10% breakthrough point for different flow rates and concentrations. Desorption studies reveals that recovery of CV from bottom ash was effective by using CH3COOH than H2SO4, NaOH, HCl and NaCl solutions.

Fixed-bed column of surface modified activated carbons for adsorption of mercury (II) in aqueous solution

Silva,H.S.; Granados,D.L.; Ruiz,S.V.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2012 EN
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Activated carbons are universal adsorbents that can be obtained from a wide variety of raw materials, and have been found to be very effective for mercury removal from water. This contribution presents a comparative adsorption in column study of activated carbons obtained by physical activation of carbonized eucalyptus wood with water vapour, as adsorbents of mercury in liquid phase. Two samples were treated with sulphuric acid and with carbon disulphide, in order to introduce sulphur as a heteroatom onto the adsorbent surface. Adsorption in column assays was performed and the breakthrough curves were used to compare their performance. The sulphurization treatments produce important variations on the textural properties of the solid, on the zero charge point, and on the number of acid and basic surface groups. From the analysis of these factors, the dependency of the adsorption capacity of a solid with the pH of the solution can be explained.

Activated alumina-based adsorption and recovery of excess fluoride ions subsequent to calcium and magnesium removal in base metal leach circuits

Lorenzen,L.; Eksteen,J.J.; Pelser,M.; Aldrich,C.; Georgalli,G.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2009 EN
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An effective electrowinning process in hydrometallurgical industry requires fluoride levels in the base metal solution to be less than 10 mg/ Selective removal of the fluoride ions from base solution is thus 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. The effects 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 factorial experimental 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/) when pH was 8. In the column adsorption step at 55°C and 600mg/ initial concentration, up to 16 bed volumes were processed before breakthrough level was reached. Desorption step using 1% sodium hydroxide solution achieved an elution of 8 bed volumes. The activated alumina (AA) had a capacity of 8.65 gF/AA at the 10 mgF/ fluoride breakthrough level during the column adsorption test.