a simple, rapid and sensitive method has been developed for determination of trances of tellurium (vi) (0.096-1.250 mg/ml) based on its catalytic effect on the reduction reaction of toluidine blue by sulfide ion at ph 4. the reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 628 nm by the fixed time method. the detection limit is 80 ng/ml and...

a series of copper and cobalt substituted nanospinel ferrites have been synthesized by the hydrothermal method. these compounds were characterized by ft-ir, xrd, edx, sem and vsm techniques. all of the synthesized nanospinel ferrites were found to be highly efficient and magnetically recoverable in the solvent-free synthesis of substituted 2,6-(2-hydroxybenzyl)-phenols (trisphenols). a wide ran...

this research evaluates the efficiency of nanosized zno in the catalytic ozonation of 4-chloro-2-nitrophenol and determines the effect of ph on heterogeneous catalytic ozonation. the combined use of ozone and zno catalyst leads to conversion of 98% 4-chloro-2-nitrophenol during 5 min. in addition, it was found that in zno catalytic ozonation, the degradation efficiency of 4-chloro-2-nitrophenol...

This research evaluates the efficiency of nanosized ZnO in the catalytic ozonation of 4-chloro-2-nitrophenol and determines the effect of pH on heterogeneous catalytic ozonation. The combined use of ozone and ZnO catalyst leads to conversion of 98% 4-chloro-2-nitrophenol during 5 min. In addition, it was found that in ZnO catalytic ozonation, the degradation efficiency of 4-chloro-2-nitrophenol...

In the Boudouard reaction, where CO2 is reacted with carbon (char) to produce CO, very high temperatures are required to shift the equilibrium towards CO production. This endothermic reaction is inherently slow and catalytic species are effective to speed up the reaction rate at temperatures below 900 °C. In this study, the catalytic effect of some alkali (K, Na), alkaline earth (Ca) and transi...

the effect of physiological concentrations of caffeine (purified from persian tea) on adenosine deaminase (ada) activity at physiological and pathological concentrations of adenosine (as substrate) in 50 mm tris-hcl buffer (ph 7.3) at 37°c was investigated, using uv-vis spectroscopy. ada exhibited a bi-phasic activity behavior and both phases showed positive cooperativities indicating adenosine...