a simple, rapid and sensitive spectrophotometric method has been proposed for the determinationof vanadium (iv). the method is based on the catalytic effect of v (iv) on the oxidation of alkali blue bypotassium bromate at ph 4. the rate of decrease in the absorbance of alkali blue (at 572 nm) wasproportional to the concentration of v (iv) in the range of 100-6000 ng ml-1. the detection limit wa...

the waste tyres represent a source of energy and valuable hydrocarbon products. waste tyres were pyrolysed catalytically in a batch reactor under atmospheric pressure. the effects of basic catalysts (mgo and caco3) were studied on the pyrolysis products. the distribution ratio of gas, liquid and char with mgo and caco3 were 24.4:39.8:35.8 wt % and 32.5:32.2:35.2 wt % respectively at 350°c for 2...

a kinetic-spectrophotometric procedure is reported for determination of trace amounts of ag(i). this method is based on catalytic effect of silver ion on the oxidation of congo red by potassium peroxodisulphate at ph=3.4 and 30 oc in the presence of 1,10-phenanthroline as an activator. the reaction was followed spectrophotometrically by measuring the rate of change in absorbance of congo red at...

a catalytic-kinetic method for the determination of selenium is proposed. alizarin navy blue is reduced by sodium sulfide to from a colorless product. the reaction is accelerated by trace amounts of se (iv), and can be followed by measuring the decrease in absorbance of the dye at 620nm and 30 °c by the fixed time method. selenium can be determined in the range of 0.004 — 0.12 1.1g.m1-1 . ...

Hierarchical two-dimensional (2D) lamellar zeolites represent a young emerging field and novel expression of the zeolite frameworks. Accompanied with synthesis catalytic performance investigation, assessment on local environment behavior acid sites in 2D are needed. Here, we described Lewis evaluated activities external (i.e. surface mesopores) titanium silicalite-1 (TS-1) zeolites. For compari...

Different functions were imparted to ramie fibers through treatment with noble metal nanoparticles including silver and gold nanoparticles. The in situ synthesis of silver and gold nanoparticles was achieved by heating in the presence of ramie fibers in the corresponding solutions of precursors. The unique optical property of synthesized noble metal nanoparticles, i.e., localized surface plasmo...

It is no surprise that the catalytic activity of electron-transport enzymes may be optimised at certain electrochemical potentials in ways that are analogous to observations of pH-rate optima. This property is observed clearly in experiments in which an enzyme is adsorbed on an electrode surface which can supply or receive electrons rapidly and in a highly controlled manner. In such a way, the ...

This paper presents an extension of stoichiometric analysis in systems where the catalytic compounds (enzymes) are also intermediates of the metabolic network (dual property), so they are produced and degraded by the reaction network itself. To take this property into account, we introduce the definition of enzyme-maintaining mode, a set of reactions that produces its own catalyst and can opera...