摘要:

AbstractA Clean Technology is a means of providing a human benefit which, overall, uses less resources and causes less environmental damage than alternative means with which it is economically competitive. Life Cycle Assessment is central to Clean Technology, as the way to identify overall resource usage and environmental damage. Pollution Prevention and Waste Minimisation are important parts of Clean Technology, but more fundamental is the shift from selling products to providing services. Some specific technological challenges for the chemical and biotechnology industries are identified.

ISSN:0268-2575    

DOI:10.1002/jctb.280620402

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThree geometric configurations of gas–liquid separators were used in split‐channel airlift reactors (0·1 m3liquid volume; riser‐to‐downcomer cross‐sectional area ratio = 0·7; aspect ratio = 3.6) to test the effect of geometry on hydrodynamic performance and oxygen transfer behaviour. For otherwise fixed conditions, the design of gas–liquid separators affected the induced liquid circulation rate, the depth of penetration of the bubble layer in the downcomer, the gas holdup in the downcomer, the mixing time and the overall volumetric gas–liquid oxygen transfer coefficient. The gas holdup in the riser was only marginally affected by the design of the separator. The impact of the various separator designs on hydrodynamic behaviour could be explained as emanating from a combination of the gas–liquid separating ability of the design and its hyd

ISSN:0268-2575    

DOI:10.1002/jctb.280620403

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe redox properties of HCoO 2−on a glassy carbon electrode in the absence and presence of hydrogen peroxide have been investigated by using cyclic voltammetry and UV‐Vis spectroscopy in alkaline solution. Corresponding rotating ring‐disk experiments showed that the disk current increased by about 60% in the presence of HCoO 2−, confirming the important role played by HCoO 2−in the homogeneous decomposition of hy

ISSN:0268-2575    

DOI:10.1002/jctb.280620404

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractBiological air treatment methods are an alternative to conventional treatment methods such as activated carbon adsorption and chemical scrubbing. An external loop airlift bioreactor has been utilized to treat phenol‐contaminated air usingPseudomonas putida. Saturated air was found to be cleansed of phenol below the detectable limit because of the high mass transfer rate of the pollutant from the air and the high growth rate ofPseudomonas putida. The bioreactor was found to degrade over 99% of the inlet phenol at rates from 21·5 to 194 mg h−1at concentrations between 650 and 850 mg m−3of air. A model of the system is developed based on an initial transient period followed by a pseudo‐steady state period. The simulations compared well with the experimen

ISSN:0268-2575    

DOI:10.1002/jctb.280620405

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractRecovery of vanadium and nickel from an oil fly ash is studied in a two‐step leaching process, carried out under ambient pressure without calcination. In the leaching, nickel is dissolved with NH4Cl in the first step, followed by vanadium leaching with Na2CO3in the second step. Both leachants depress the dissolution of iron and aluminium from the ash and hence the selective leachings are feasible. Nickel was recovered in 87% yield from the leach liquor by precipitation with Na2S, the purity of NiS being over 99% on the basis of the target metals (V, Ni, Fe, Al and Mg). For the recovery of vanadium, which has a relatively low concentration in the leach liquor, solvent extraction with TOA is preferable to concentration, prior to crystallization with NH4Cl. The experimental data showed that the vanadium concentration of the stripping solution is increased by about 15 times that of the leach liquor, which results in 78% yield as NH4VO3crystal

ISSN:0268-2575    

DOI:10.1002/jctb.280620406

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractTwo kinds of bioreactors, a bubble‐column and an air‐lift bioreactor, have been designed. The influence of operating conditions such as medium composition, light intensity, carbon dioxide concentration in the flushing gas, culture temperature, and gas flow rate, on photosynthesis ofDunaliella tertiolectawere studied using a chemometrics approach. The bubble‐column bioreactor system was shown to be advantageous over the air‐life because of a weaker intensity of hydrodynamic stress derived from gas bubble dispersion and culture broth mixing. Optimal conditions for carbon dioxide fixation or maximal growth rate were determined. The effect of hydrodynamic shear forces on the algal wall produced by gas bubbling was identified as one of the most significant factors for algal

ISSN:0268-2575    

DOI:10.1002/jctb.280620407

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe bound water content of original and frozen activated sludge and an inorganic sludge were measured via differential scanning calorimetry (DSC) and drying tests. Original sludge contained a significant level of bound water which was reduced by about 50% after freeze/thaw treatment. A simple thermodynamic interpretation showed that liquid–solid binding strength played an important role in depression of the freezing point of bound water in a sludge. The choice of a threshold temperature in a DSC test was equivalent to definition of a threshold binding strength dividing bound/non‐bound water content. The possible close relationship between the bound water content measured via DSC and the drying test is discussed. The importance for sample uniformity was also exami

ISSN:0268-2575    

DOI:10.1002/jctb.280620408

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

Abstract1‐Oxa‐4‐thiaspiro[4.4]nonan‐2‐one (1a) and/or 1‐oxa‐4‐thiaspiro[4.5] decan‐2‐one (1b) were reacted with aniline and/orp‐chloroaniline to afford the corresponding spirothiazolidinones (2a–d). Reaction of2a–dwith chalcones gave 2‐(α – paracylbenzyl)‐4‐aryl‐1‐thia‐4‐azaspiro[4.4]nonan‐3‐one and 2‐(α‐aracylbenzyl)‐4‐aryl‐1‐thia‐4‐azaspiro[4.5]decan‐3‐one (3a–p) respectively. Compounds3a–pwere reacted with acetic anhydride and perchloric acid to yield the spiropyrano[2,3‐d]thiazol[4]ium perchlorate derivatives4a–p. The structures of the synthesized compounds were elucidated by elemental and spectroscopic (IRand1H‐NMR) analysis. All the prepared compounds were tested for their an

ISSN:0268-2575    

DOI:10.1002/jctb.280620409

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe metal transport protein transferrin, when immobilized to Sepharose, can serve as an affinity media for the selective removal and subsequent release of heavy metal ions from aqueous solution. The material is stable over the pH range of 2–10, is self‐indicating for the binding of certain metal ions, and maintains its integrity towards metal‐binding capacity for long periods of time. In one step heavy metal ion concentrations can be reduced by at least five orders of magnitude to, at most, part per billion levels. The findings here presented suggest a novel practical method for the decontamination and/or recovery of metals ions from very dilute solutions and represent the first efforts to extend the concept of affinity chromatography to metal

ISSN:0268-2575    

DOI:10.1002/jctb.280620410

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY

摘要:

AbstractMixed RhSn complexes found in aqueous and organic solutions involved in the liquid–liquid extraction of Rh(III) from chloride solutions, also containing SnCl2, with 7‐(4‐ethyl‐1‐methyloctyl)‐8‐hydroxyquinoline (Kelex 100) were characterized through119Sn NMR and Raman spectroscopy. At Sn: Rh molar ratios of 3:1 and 12:1, it was found that [RhIIICl3(SnCl3)3]3−and [RhI(SnCl3)5]4−, respectively, are the dominant complexes in both the aqueous and organic solutions. These complexes can be quantitatively extracted from the aqueous solutions in less than 1 min contact time via ion‐pair formation with the protonated 7‐substituted 8‐hydroxyquinoline reagent such that for both Sn:Rh ratios, the same RhSn complex is found in the aqueous feed and in the fully loaded organic. In addition, it was found that [RhI(SnCl3)5]4−is preferentially extracted over excess free Sn(II). Preliminary characterization of the complex stripped from the 12:1 loaded organic using 1·7MH2SO4shows an RhSn com

ISSN:0268-2575    

DOI:10.1002/jctb.280620411

出版商:John Wiley&Sons, Ltd.    

年代:1995

数据来源: WILEY