CONTENTS & ABSTRACTS

In English. Summaries in Estonian

Proceedings of the Estonian Academy of Sciences.

Chemistry

Volume 51 No. 2 June 2002

Advances in biodiesel fuel research; 75–117

Jüri Kann, Heino Rang, and Jüri Kriis

Abstract. The paper gives a thorough review of research on biodiesel fuel sources, properties, preparation methods, production, exhaust gases emitted by using biodiesel fuel, analytical methods, and economic aspects. The main advantage of biodiesel fuel is lower concentration of greenhouse gases (especially CO₂) and other pollutants in motor exhaust gases compared to petroleum diesel fuel. The main concerns with biodiesel fuel are its relatively high price, instability, and low-temperature properties. The future aims in biodiesel fuel research are improvement of production technology and reduction of the costs of production of plant oil by plant breeding, selection, and gene technology. The low-temperature properties and stability of biodiesel fuel can be improved by additives and genetic engineering of oil plants. The paper includes 250 references.

Key words: biodiesel fuel, diesel fuel, plant oils, pollutants, fuel additives.

Treatment of landfill leachates: aerobic bio-oxidation and post-ozonation; 118–125

Inna Kamenev, Lui Pikkov, and Juha Kallas

Abstract. The purpose of the study was to improve the purification process of landfill leachate. Aerobic bio-oxidation of landfill leachate and post-ozonation of biologically treated leachate were studied. The results of experiments indicate that aerobic bio-oxidation is efficient for purifying young landfill leachate only under stable operating conditions with a long retention time. Subsequent ozonation results in significantly improved biodegradability of the wastewater.

Key words: landfill leachate, aerobic bio-oxidation, post-ozonation.

Determination of manganese in thermoluminescent materials by inductively coupled plasma atomic emission spectrometry and spectrophotometry; 126–133

Aime Lust, Lilli Paama, Mihkel Kerikmäe, Mare Must, and Paavo Perämäki

Abstract. The content of manganese in the mixed fluorides CaF₂: MnF₂ and CaF₂: Mn thermoluminophors was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and spectrophotometry. The various Mn emission lines were compared and the manganese emission line at 257.610 nm was used for ICP-AES analysis. For the spectrophotometric determination the manganese(II) ions were oxidized to intensively coloured permanganate ions using potassium periodate. No statistically significant differences were found between the results of ICP-AES and spectrophotometric methods of analysis. The thermoluminophors were synthesized by coprecipitation of manganese with CaF₂, varying the concentration of manganese in the initial solutions in the range of 0.01–2.0% (m/m). The coprecipitated mixed fluorides CaF₂: MnF₂ were heated at 1423 K. The glow curves of synthesized CaF₂: Mn thermoluminophors were measured.

Key words: manganese determination, ICP-AES spectrophotometry, thermoluminophors CaF₂ : Mn, glow curves.

Instructions to authors; 134–136