TIn the wet flue gas desulphurization (FGD) process with forced oxidation, very soluble oxidised mercury is retained in the scrubbing solution while Hg0 is not and is emitted to the atmosphere. We showed experimentally that the complex chemistry in FGD solution can be modified in so that dissolved Hg0 is oxidised by air introduced for the oxidation of S(IV) to S(VI) compounds. The most important chemical reactions were identified. Oxidation is enhanced by catalytic reactions with transition metals like Fe and Mn, which, when combined, show a synergistic positive effect. It seems that the radicals involved in the chain reactions of autoxidation of S(IV) are also responsible for the oxidation of Hg0. The reaction products of this system are sulphates and polythionates, which were also determined in the absorber solutions. Hg0 removal efficiency from the gaseous phase achieved in laboratory testing was from 70% to over 95%. The schematic chemical model which includes the conclusions derived from experimental results and from published chemical mechanisms is proposed.
COBISS.SI-ID: 26542887
Hg speciation in air is of fundamental importance for the understanding of chemistry and reactivity in water and air. Measuremnts currently ongoing are based on one single protocol, which is a indirect measure of the presence of reactive, elemental and particle bound Hg. The consequences of such limited measurements are outlined in the leading international journal EST. The need for improved methodologies and comparability at the global level is lacking.
COBISS.SI-ID: 27872551
The method for temperature fractionation was checked and validated. A number of parameters can influence the T at which Hg compounds decompose, among those the solid substract plays the major role. Critical assessment of the currently existing methods are discussed. We also concluded that method based on AAS detection are limited due to poor understanding of Hg breakdown processes at elevated temperatures.
COBISS.SI-ID: 28250407
The measurement of reactive mercury in water samples is a subject of errors that are difficult to controlč, resulting in non-comparable results, in most cases to low values. The protocols used so far employed the use of SnCl2. In this paper we suggest the use of ethylation, which provides consistent and precise measurement of Hg(II) in aqueous samples, aplicable for industrila water samples.
COBISS.SI-ID: 28093223
The work falls within the scope of validation of the use of radioactive isotopes to experimentally demonstrate the transformations of Hg in aqueous solution. Radioactive isotopes were prepared from enriched Hg isotope 196, its irradiated in a nuclear reactor at JSI. The resulting, highly active isotope Hg197, was used for the latter processes of reduction and methylation. The main achievement is to remove interferences of process measurements by the useofradiochemical separation procedures.
COBISS.SI-ID: 2410575