D. S. N. Prasad

The role of free fall atmospheric dust in catalysing autoxidation of aqueous sulphur dioxide

Abstract The results of atmospheric free fall dust catalysed S(IV) autoxidation in acetate buffered suspensions are in conformity with the rate law: − d[S(IV)] dt = k 6 [S(IV)] [H + ] 1.30 + k 7 [dust] 0.42 [S(IV)] 2 [H + ] 1.36 All available evidence favours the catalytic activity of dust suspensions being due to leached metal ions. Fe(III) is the main suspect, which is in agreemnt with the chemical analysis of dust.

Kinetics of surface-catalyzed oxidation of sulphur(IV) by dioxygen in aqueous suspensions of cobalt(II) oxide

Abstract A comparative rate analysis of autoxidation of sulphur(IV) in CoO suspension, leachate solution and blank reaction suggests the reaction to be surface catalyzed. In acetate buffers, the experimental rate law is: Robs=Run + (k3 + k 4 [H + ] )[CoO][S(IV)][O2] where Run is the rate of uncatalyzed reaction. The suggested mechanism requires the adsorption of both S(IV) and O2 on the particle surface. Subsequently, the adsorbed species are activated resulting in the oxidation of sulphur( IV), probably through intervention of multiple oxidation states of cobalt.

Role of surface and leached metal ion catalysis in autoxidation of sulphur(IV) in power plant flyash suspensions

Abstract The kinetics of the autoxidation of sulphur(IV) in acetate buffered and unbuffered aqueous suspensions of flyash have been studied. Sulphate is the only autoxidation product. The results in buffered suspensions, at a given pH, are in agreement with the rate law (A) Robs = k1 [S(IV)] + k3 [flyash]0.3 [S(IV)]2. In buffered suspensions, the rate profiles are autocatalytic and a different rate law (B) is observed Robs = kA [ash]0.5 [S(IV))]. In buffered suspensions, in the presence of EDTA (which suppresses the trace metal ion catalysis), the kinetics are in agreement with the rate law (C) Robs = kS [ash] [S(IV)]. A comparative rate analysis in buffered suspensions and in corresponding leachates has shown the trace leached metal ions to be the main cause of catalysis.

Kinetics of autoxidation of aqueous sulphur dioxide in suspensions of nickel(III) oxide

SummaryAutoxidation of SIV to SVI in acetate buffered aqueous suspensions of Ni2O3 obeys the rate law Robs=(k4+k5[H+]−1)[Ni2O3][SIV][O2] The suggested mechanism requires the adsorption of O2 on the Ni2O3 surface, followed by the reaction of HSO3− and SO32− with these oxygenated particles.

Kinetics and mechanism of the oxidation of 2-furancarbox-aldehyde by thallium(III) in perchloric acid solutions

AbstractThe kinetics of the oxidation of 2-furancarboxaldehyde by thallic perchlorate at 50°C obeys the rate law(1)

Dynamics of Autoxidation of Aqueous Sulfur Dioxide in Aqueous Suspensions of Cadmium Oxide.

- \frac{{d[T1 (III)]}}{{dt}} = k[T1 (III)] [Substrate]

Rates of autoxidation of sulphur (IV) in aqueous suspensions of limestone. powder: Implications for scrubber chemistry

k has a value of 4.5±0.2×10−3 dm3 mol−1s−1 at 50°C. The rate of the reaction does not depend on [H+] and the oxidation product is 2-furancarboxylic acid.AbstractКинетика окисления 2-фуранкарбоксиальдегида перхпоратом таллия при 50°C подчиняется следующему уравнению: где к равно (4,5±0,2)·10−3 дм3 моля−1 сек−1 при 50°C. Скорость реакции не зависит от [H+] и продуктом окисления является 2-фуранкарбоксильная кислота.