ABSTRACT
RESUMO Neste estudo foram realizadas as cinéticas e isotermas de adsorção dos íons Fe (III) presentes em afluentes sintéticos utilizando como adsorvente carvão ativado de casca de coco. O objetivo foi a obtenção dos parâmetros cinéticos e de equilíbrio do processo para assim simular diferentes condições operacionais em uma coluna de adsorção em leito fixo. Foram avaliadas a influência de três diferentes temperaturas na adsorção de Fe (III), sendo que o aumento da temperatura indicou adsorção exotérmica. A isoterma de Freundlich representou melhor os dados experimentais. Também foi realizado o estudo cinético e o modelo que apresentou melhor os dados experimentais foi o modelo de Pseudo-Primeira Ordem para as três concentrações estudadas. O método de Volumes Finitos foi utilizado na discretização das equações matemáticas e um algoritmo computacional foi implementado em linguagem FORTRAN. O código computacional foi validado com dados experimentais encontrados na literatura (erro máximo de 6,2%) podendo-se assim simular diferentes condições operacionais do sistema de adsorção com aplicação na indústria alimentícia.
ABSTRACT In this study were performed the kinetics and isotherms of adsorption of the ions Fe (III) from synthetic affluent using activated carbon from coconut shell as adsorbent. The objective was to obtain the equilibrium and kinetic parameters of the process and thereby simulating different operating conditions in a adsorption column fixed bed. It was evaluated the influence of three temperatures different on the adsorption of Fe (III), in which the temperature increase indicated adsorption exotherm. The Freundlich isotherm showed the best fit to the experimental data. At the kinetic study the model that best fit to the experimental data was the model Pseudo-First Order for the three concentrations studied. The finite volume method was used for discretization of the mathematical equations and a computational algorithm was implemented in FORTRAN. The computational code was validated with experimental data found in the literature (maximum error of 6.2%) can thus simulate different operating conditions of the system.
ABSTRACT
OBJECTIVE: To prepare Polygonatum odoratum polysaccharide-iron (III) complex (POPFe) and study its physico-chemical properties. METHODS: POPFe was synthesized by neutralization of FeCl3 carbohydrate solution. Orthogonal design was used to optimize the preparation process. The content of iron (III) in POPFe was determined with o-phenanthroline spectrophotometry and iodometry. The surface structure of POPFe was studied by infrared spectroscopic technique. The deoxidization of POPFe was tested with colorimetric analysis. RESULTS: The optimal preparation conditions were found as follows: the ratio of polysaccharides aqueous solution to sodium citrate solution as 4:1, temperature 70°C and pH 8-9. POPFe showed qualitatively identified reactions of Fe (III). The content of Fe (III) in POPFe was 30.13%. The complex was stable at pH 3-12 without precipitation and dissociation. At 37°C, Fe (III) in the complex was completely reduced to Fe (II) by ascorbic acid in about 5 h. CONCLUSION: POPFe can be developed as a new iron supplementary. Copyright 2012 by the Chinese Pharmaceutical Association.
ABSTRACT
Electricigens play an important role in microbial fuel cell(MFC) . This review provides an introduction of different electricigens on theirs taxonomical group,biochemical,physiological and morphological characteristics. The ability of electricity production of electricigens and electron transfer mechanisms in microbial fuel cells are also concluded. The prospect of waste water treatment and bio-electricity production is underlined,it is point out in this review that the future research of microorganism for MFC should be focused on enrichment,adaptation,modification and optimization by multi-strains application to improve the performances of MFC.