摘要:

AbstractAn electrochemical oxidation cell is used to reduce the concentrations of organic dyes and chemical oxygen demand in an aqueous effluent. The importance of the presence of an electrolyte is recorded and the effects of changing both electrolyte concentration and initial dye concentration are reported. The rate of the electrooxidation process is shown to be a pseudo‐first‐order kinetic process with the rate constant being affected by both the electrolyte concentration and the dye concentration. The use of different electrolytes is repor

ISSN:0268-2575    

DOI:10.1002/jctb.280620202

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractLarge‐scale animal cell operation is costly both in terms of facilities and consumables. Hence developmental studies with animal cells normally start at laboratory scale, often using small stirred tanks. In order to better optimise cell performance, it is necessary to know the physical conditions under which the cells are grown. In this study a laboratory‐scale vessel (2 dm3working volume) with two large‐bladed paddle impellers was characterised hydrodynamically. Three different aeration methods (surface, sparging and membrane aeration) were investigated and compared. Power input and oxygen transfer rates to culture medium were determined as a function of agitation and gas flow rates. Non‐dimensional correlations were established for each case, which can be useful for scale‐up purposes. The results obtained indicate that power input is quite dependent on the vessel accessories: for the same agitation rate, the maximum power is required for the membrane structure and the minimum for surface aeration, with the addition of the sparger leading to an intermediate situation. Predictions found in the literature can be used for simple vessels, but may not be applicable when accessories are added to the vessel structure; in such cases, the use of experimental relationships are required. Oxygen transfer rate was dependent on the aeration method and working conditions (agitation and gas flow rates), particularly for sparger aeration. Membrane aeration gave larger oxygen transfer but higher gas pressure and flow rates were required. Surface aeration was the least effective method, nevertheless requiring gas flow rates similar to those used for membrane aeration. The aeration method of choice depends upon the culture and work specificities: surface aeration is limited to small cell concentrations and low oxygen consumption rates. For higher cell concentrations and oxygen consumption rates, both membrane and sparger aeration methods can be applied: the use of the sparger is limited to cells that are not affected by the presence of bubbles or the addition of surfactants, whereas the membrane aeration basket should not be used when a hydrodynamically controlled stirred tank is

ISSN:0268-2575    

DOI:10.1002/jctb.280620203

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractKinetic measurements were made for the sorption of copper ions from aqueous sulfate solutions with di(2‐ethylhexyl)phosphoric acid‐impregnated Amberlite XAD macroporous resins in finite bath by a batch‐contact time method. The sorption process of copper was first determined to be controlled by particle diffusion using a modified shrinking‐core mechanism, which considered reversibility of the sorption. A more rigorous model based on Fick's law was then applied to justify the applicability of the modified shrinking‐core model to the present sorption systems. The effective particle diffusivity had an order of 10−12(in m2s−1), which was in agreement with those obtained for chelating ion‐exc

ISSN:0268-2575    

DOI:10.1002/jctb.280620204

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe rates of the sorption of zinc ions from aqueous sulfate solutions with di(2‐ethylhexyl)phosphoric acid‐impregnated Amberlite XAD macroporous resins were measured in finite bath by a batch‐contact time method. The sorption process was initially found to be controlled by a combined chemical reaction and particle diffusion process using a provable modified shrinking‐core model. A more rigorous model based on Fick's law was then developed to elucidate the sorption mechanism, and a procedure was suggested to simultaneously determine the reaction rate constant and effective particle diff

ISSN:0268-2575    

DOI:10.1002/jctb.280620205

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe influence of temperature on the growth and fatty‐acid composition of the microalgaSkeletonema costatum(CCAP 1077/b) has been studied. The maximum specific rates of growth (μm) and productivity (PB) were reached between 293 and 298 K. The experimental values of μm–Twere adjusted to the function: μ = μ′o·T· exp(‐Ea/RT) − μd· exp(‐Ed/RT). The total content of the saturated acids reached a minimum at 293 K, wheras the maximum amounts of polyunsaturated acids and Σn− 3 HUFA (highly unsaturatedn− 3 fatty acids) occurred at 293 a

ISSN:0268-2575    

DOI:10.1002/jctb.280620206

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper deals with the use of iron felt as a reducing agent for the removal of mercury from aqueous dilute solutions containing chloride ions. The kinetic behavior of the mercuric ion reduction was analyzed and its diffusion coefficient was determined with the use of a rotating disk electrode. Experimental results of the removal of mercury from aqueous sodium chloride solutions containing 100 ppm mercury by contact with iron felt are reported. The mercury concentration was decreased to values lower than 0·1 ppm. The recovery of metallic mercury by chemical attack of the residual iron felt was also analyzed

ISSN:0268-2575    

DOI:10.1002/jctb.280620207

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSpirulina platensisgrew mixotrophically on glucose in the light, ehancing biomass and pigment production. Under light‐limited conditions, biomass production was enhanced by supplemental microbial synthesis from heterotrophic metabolism of glucose. Biomass and photosynthetic pigment production were increased 1·5–2·0‐fold compared with those in autotrophic

ISSN:0268-2575    

DOI:10.1002/jctb.280620208

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractTen variously substituted derivatives (IIa–j) of 3′‐(benzimidazol‐2‐yl)‐4′‐hydroxyazobenzene were prepared. The effects of the nature and orientation of the substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres

ISSN:0268-2575    

DOI:10.1002/jctb.280620209

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractFifteen variously substituted derivatives (IVa–o) of 2‐styrylquinazolone have been prepared for use as dye‐stuffs. The effects of the nature and orientation of substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres were ass

ISSN:0268-2575    

DOI:10.1002/jctb.280620210

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractSequential biological anaerobic–aerobic treatment of oil shale ash dump leachate was studied using laboratory‐scale reactors and bioassays. The COD of the leachate was 2·0–3·0 g dm−3. The leachate was known to contain several phenolic compounds and to have a high sulphur concentration. The proportion of the leachate in the feed of the biological process was gradually increased during a 309 day test period. With 100% leachate in the feed, COD removal was 35% in the anaerobic stage while in the combined process the COD and BOD7removals were up to 75% and 99%, respectively. The removal of total phenols was insignificant in the anaerobic stage, while up to 85% removal was obtained by the combined anaerobic–aerobic process. In the anaerobic stage, degradation of organic compounds was mainly a result of sulphide production. The results demonstrated that the leachates were amenable to biologica

ISSN:0268-2575    

DOI:10.1002/jctb.280620211

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY