Perturbed and Unperturbed: Analyzing the Conservatively Perturbed Equilibrium (Linear Case).

The "conservatively perturbed equilibrium" (CPE) technique for a complex chemical system is computationally analyzed in a batch reactor considering different linear mechanisms with three and four species. Contrary to traditional chemical relaxation procedures, in CPE experiments only some initial concentrations are modified; other conditions, including the total amount of chemical elements and temperature are kept unchanged. Generally, for "unperturbed" species with initial concentrations equal to their corresponding equilibrium concentrations, unavoidable extreme values are observed during relaxation to the equilibrium.

New Invariant Expressions in Chemical Kinetics.

This paper presents a review of our original results obtained during the last decade. These results have been found theoretically for classical mass-action-law models of chemical kinetics and justified experimentally. In contrast with the traditional invariances, they relate to a special battery of kinetic experiments, not a single experiment.

Dual kinetic curves in reversible electrochemical systems.

We introduce dual kinetic chronoamperometry, in which reciprocal relations are established between the kinetic curves of electrochemical reactions that start from symmetrical initial conditions. We have performed numerical and experimental studies in which the kinetic curves of the electron-transfer processes are analyzed for a reversible first order reaction. Experimental tests were done with the ferrocyanide/ferricyanide system in which the concentrations of each component could be measured separately using the platinum disk/gold ring electrode.

Frequency of negative differential resistance electrochemical oscillators: theory and experiments.

An approximate formula for the frequency of oscillations is theoretically derived for skeleton models for electrochemical systems exhibiting negative differential resistance (NDR) under conditions close to supercritical Hopf bifurcation points. The theoretically predicted omega infinity (k/R)1/2 relationship (where R is the series resistance of the cell and k is the rate constant of the charge transfer process) was confirmed in experiments with copper and nickel electrodissolution. The experimentally observed Arrhenius-type dependence of frequency on temperature can also be explained with the frequency equation.

Macro kinetic studies for photocatalytic degradation of benzoic acid in immobilized systems.

Semiconductor photocatalytic process has been studied extensively in recent years due to its intriguing advantages in environmental remediation. In this study, a two-phase swirl-flow monolithic-type reactor is used to study the kinetics of photocatalytic degradation of benzoic acid in immobilized systems. Transport contributions into the observed degradation rates were determined when catalyst is immobilized.