Suo - Mires and peat vol. 29 no. 5 | 1978
Termogravimetrian käyttömahdollisuudet polttoainetutkimuksissa. Osa III. Kiinteiden polttoaineiden pyrolyysin kinetiikan vertailua.
English title: The usability of the termogravimetry in fuel research. Part III. Comparison of the kinetics of the pyrolysis of solid fuels.
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In this work we have investigated the possibilities of the thermogravimetry (TG) to be applied to the peat research as well as to the rapid quality control of the peat products. It is shown, that the moisture content, the volatile matter and the ash content of the peat can be easily determined from the TG curves. Further, the pyrolysis
of the peat in various atmospheres can be investigated. The effect of the temperature rate and the carbonization time to the coke yield was also a subject of this study. Further investigations involve the calculations of the rate constants and the activation energies. Also, the products during the pyrolysis are of interest.
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Tummavuori,
Sähköposti:
ei.tietoa@nn.oo
- Venäläinen, Sähköposti: ei.tietoa@nn.oo
- Nyrönen, Sähköposti: ei.tietoa@nn.oo
Suopursun ekologiasta, erityisesti hivenainetaloudesta.
English title: Trace metal distribution in Ledum palustre.
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Concentrations of five metals — Mn, Fe, Zn, Pb, Cu — were determined in samples of a common dwarf shrub, Ledum palustre, collected from seven S. Finnish raised bogs (between 60 and 61 °N) in September-October 1977. The analyses were made separately for the twigs (stems) of last four years and for the leaves of last two years. The material was dry-ashed at 450°C, dissolved in cone. HC1 on hot plate, filtered and diluted to 50 ml with deionized H2O which solution was finally analyzed with an atomic absorption spectrophotometer (Varian Techtron AA-1200).
Ash percentage and manganese showed identical distributions with maximum values on second-year leaves and a decrease of concentrations in stems with age (Figs. 2 and 3). Also the concentrations of Fe, Zn and Pb (but not Cu) increased from first- to second-year leaves. In stems, there was a fairly regular increase in Fe and Pb levels from first to fourth year, while Zn and Cu changed little or decreased with age (Fig. 3).
Average concentrations in Ledum (leaves + stems of last two years) were compared with those in the substrate (Sphagnum fuscum peat). The results (Table 1) showed that manganese was the most favoured metal and iron the least. The relative enrichment of metals from the peat substrate to Ledum followed the order Mn >Cu >Zn >Pb >Fe.
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Pakarinen,
Sähköposti:
ei.tietoa@nn.oo
- Mäkinen, Sähköposti: ei.tietoa@nn.oo
Fosforin määrityksestä turpeesta.
English title: On the determination of phosphorus in peat.
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According to the investigations of Kaila, the phosphorus content in Finnish peat-lands varies at the range from 190 ppm to over 2000 ppm. (Kaila 1955, 1956). The amount of organic phosphorus lies between 55 % and 95 %.
The determination of the phosphorus from the matrix of organic matter is a tedious process. (Haiman 1972, John 1970, Alexander and Robertson 1968, Kaila 1955).
The aim of our study was to develop a method for the phosphorus determination in which the metals also could be determined after the same sample treatment.
The most common digestion method for the organic matter is the Kjeldahl wet digestion. It cannot, however, directly be employed to the metal determination with the atomic absorption technique.
We used a small autoclave ( ~ 25 cm3) made from teflon in the sample digestion. The amount of the sample was 0.5—1.0 g and then 11.7 cm3 of perchloric acid
(70 %), 6.7 cm3 of nitric acid (65 %) and 10 cm3 of hydrogen fluoride (40 %) was added. The sample was heated for five hours at 140 °C. The phosphorus was determined according to the method by Lueck and Boltz with the difference, that the absorbance of the solution was measured exactly after one hour since the last reagent addition. The results are presented in Table 1 and Figs. 1 and 2.
The comparative determinations were made after the Kjeldahl digestion with the method by Kaila. The results were in agreement.
The advantage of the autoclave method is its suitability to the routine work in the phosphorus determinations of peat, peat coke and wet carbonized peat, for instance. The same solution can be used to the metal determinations and the use of the autoclave improves the analytical accuracy and reduces the amounts of poisonous gases in the laboratory air.
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Tummavuori,
Sähköposti:
ei.tietoa@nn.oo
- Nyrönen, Sähköposti: ei.tietoa@nn.oo
- Saastamoinen, Sähköposti: ei.tietoa@nn.oo
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