摘要:

AbstractThe interfacial activities of triisooctylamine, dihexyl sulphide and dodecylmethyl sulphide were studied and used to discuss the mechanism of palladium (II) extraction from acidic chloride solutions by a mixture of dialkyl sulphide with triisooctylamine. The surface excess isotherms were computed and amine association was considered. The extraction occurs probably according to a complex interfacial‐bulk mechanism in which the reaction between palladium and protonated amine occurs mainly in the bulk of the aqueous phase but the intermediate complex R3NHPdCl3adsorbs at the interface and reacts with dialkylsulphide in the limiting ste

ISSN:0268-2575    

DOI:10.1002/jctb.280480102

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractTreatment of cotton cellulose with 3 M sodium hydroxide solution at 260°C and 280°C gave a mixture of carboxylic acids with a yield of>95%. The identified 50 carboxylic acids included both hydroxy monocarboxylic acids and dicarboxylic acids; their routes of formation are discussed. Among the main compounds were lactic, glycolic, 2‐hydroxy‐2‐methylpropanoic, 2‐hydroxybutanoic, 3,4‐dideoxypentonic, anhydroisosaccharinic, 2,3‐dideoxypentaric, and 3,4‐dideoxyhexaric acids. Technical utilisation of this kind of acid mixture requires further studies.Investigations of the cyclic compounds, formed in small amounts only, resulted in identification of mainly alkyl‐substituted 2

ISSN:0268-2575    

DOI:10.1002/jctb.280480103

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractImmobilized, inactive mycelia of Rhizopus arrhizus are preferential to native biomass for use in the biosorption of metal ions. Refinement of a proprietary immobilization technique previously developed at McMaster University enabled production of particles of immobilized Rhizopus arrhizus biomass having a 12–23% wt of polymer additive. The effects of production stage parameters on the intrinsic uptake capacity of the immobilized biomass were examined. Kinetic experiments showed the following trends: a decrease in the weight percent of the added polymer leads to an increase in the apparent uranium uptake capacity of the immobilized biomass particles far a given contact time. A decrease in the particle size improved the kinetics of metal uptake and led to an increase in the apparent uranium uptake capacity for the same contact time. An increase in the initial concentration of the uranium solution caused equilibrium conditions to be attained faste

ISSN:0268-2575    

DOI:10.1002/jctb.280480104

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractColloidal gas aphrons(CGAs),generated from dilute solutions of four surfactants, were used to clarify palm oil mill effluent(POME),suspensions of microalgae and suspensions of three inorganic minerals.In POME and the algal suspensions, each CGA was most effective at a pH value close to the pK value of the surfactant concerned. This effect was not tested in the inorganic suspensions.The efficiency of air utilization was directly related to the concentration of solids in the suspensions, the size, density and nature of the solids having secondary effects. Comparison with data in the literature led to a general correlation embracing a variety of suspensions and flotation systems.Shedding of collected material from the foam layer was also a direct function of solids concentration.CGAs offer advantages over other systems of air‐assisted flotation in relation to the requirements for equipment and to the management of process operation

ISSN:0268-2575    

DOI:10.1002/jctb.280480105

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractBiomass production at high temperature by Hansenula polymorpha as part of a lignocellulosic utilizing process was studied. Compromise growth conditions (45°C and pH = 4.8) with an eventual saccharification step were established. The effects of stirring rate and initial glucose concentration on biomass yield coefficient, volumetric productivity and maximal cell density were determined. Process optimization led to a fed‐batch fermentation process: high yield (0.63 g dry cell g−1glucose), volumetric productivity (1.3 g dry cell dm−3h−1) and cell concentration (60 g dry cell dm−3) were obtained. At these conditions, significant arabitol excretion (18 g dm−3) as a unique by‐product associated with cell mass production was obtained, making more interesting a high temperature ope

ISSN:0268-2575    

DOI:10.1002/jctb.280480106

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractA novel bioprocess using micelle biocatalysts was developed to minimize several disadvantages of conventional microbial coal desulfurization processes. The multiphase biocatalysis process consists of an organic medium (mineral oil or a mixture with n‐heptane), a surfactant and an aqueous phase containing Thiobacillus ferrooxidans organisms or their cell‐free enzyme extracts. Water‐in‐oil emulsion and reverse micelle processes have been successful for removing sulfur from bituminous coal. The preliminary results indicated that, in the case of water‐in‐oil emulsion, the process that used the cell‐free enzyme extracts of T. ferrooxidans showed higher sulfur reduction than that containing whole cells, and reverse micells were more effective than water‐in‐oil emulsion. With a high concentration of bacteria, more than 50% total sulfur removal was achieved through the reverse micelle system. These results indicate that multiphase biocatalysis may have a significant potential for developing biotechnical coal desulfur

ISSN:0268-2575    

DOI:10.1002/jctb.280480107

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

摘要:

AbstractRecirculation and flow structures of gas in the downcomer section of a concentric cylindrical airlift reactor for air‐water systems were studied, using an optical probe and the cross‐covariance technique. A semiempirical model for predicting the gas recirculation rates in airlift reactors was developed based on the concept of ideal bubble flow. The entrained gas rate and the gas recirculation rate increased as the superficial gas velocity increased. There were nonuniform radial distributions of local gas holdup and air flow rates in the downcomer. Air flow rates in the downcomer depended on the superficial gas velocity and the distance from the top of the draft tube, but not on the superficial liquid velocity for this experimental ra

ISSN:0268-2575    

DOI:10.1002/jctb.280480108

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280480109

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280480110

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY

ISSN:0268-2575    

DOI:10.1002/jctb.280480111

出版商:John Wiley&Sons, Ltd.    

年代:1990

数据来源: WILEY