In English. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.



Volume 52 No. 1 March 2003


Recent advances in bioethanol fuel research. 1. Bioethanol, methyl tert-butyl ether, and other oxygenates in petrol blends; 3–19

Heino Rang and Jüri Kann

Abstract. In this review recent advances in the research on bioethanol, methyl tert-butyl ether (MTBE), and other oxygenates in petrol blends are presented. MTBE is nowadays the most common additive of petrol in order to enhance its octane value and to reduce the concentration of toxic components in motor exhaust gases. The extensive use of MTBE has caused contamination of surface and groundwater. The carcinogenicity of MTBE has been demonstrated by animal tests. Replacing MTBE with ethanol is currently on the agenda in the USA; the problem should be taken into consideration in Europe as well.

Key words: bioethanol, methyl tert-butyl ether (MTBE), petrol blends, carcinogenicity, water contamination, greenhouse effect.

Research of algal polysaccharides and related natural compounds in Estonia; 20–37

Kalle Truus and Merike Vaher

Abstract. The results of the investigations of the structure and composition of real natural algal polysaccharides, their fractionation, and chemical modification are summarized against the general scientific background. Elucidation of a suitable agarose matrix from the red alga Ahnfeltia tobuchiensis and the synthesis of affinity carriers on this basis are shown. Elaboration of technological schemata of red algae processing, immunochemical investigations, and lectin research are covered as well.

Key words: algal polysaccharides, gelling galactans, alginates, agarose, affinity carriers, furcellaran.

Degradation of nitroaromatics with the Fenton reagent; 38–47

Marina Trapido, Ave Dello, Anna Goi, and Rein Munter

Abstract. The feasibility of the Fenton reagent treatment for the degradation and detoxification of nitroaromatic compounds (NAC) such as p-nitrotoluene, nitrobenzene, and m-dinitrobenzene was studied. The degradation rate of NAC with the Fenton treatment was strongly dependent on the molar ratio NAC/hydrogen peroxide/catalyst (Fe2+). The 90% conversion times of NAC in the Fenton treatment followed the order p-nitrotoluene ≈ nitrobenzene < m-dinitrobenzene. The degree of nitrogen conversion to nitrate with the Fenton treatment varied from 25% to 100%, depending on the treatment conditions. Total organic carbon removal of 45–47% was obtained when the Fenton reagent treatment with the concentration of hydrogen peroxide 10 mM and catalyst 1 mM was applied. According to the Daphnia magna toxicity test the Fenton reagent treatment enabled to reduce the toxicity of NAC.

Key words: nitroaromatic compounds, Fenton reagent, degradation, toxicity assay, by-products.

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