0000000000056346
AUTHOR
Oskars Purmalis
Characterization of Humic Acids from Raised Bog Peat
Abstract Humic substances form most of the organic component of soil, peat and natural waters, but their structure and properties are very much dependent on the source. The aim of this study was to characterize humic acids from raised bog peat to evaluate the homogeneity of humic acids isolated from the bog bodies and to study peat humification impact on the properties of humic acids. Peat humic acids (HA) have an intermediate position between the living organic matter and coal organic matter, with their structure formed in a process where the relatively labile moieties (carbohydrates, amino acids, etc.) are destroyed, and thermodynamically more stable aromatic and polycyclic structures eme…
Kūdras resursi un to izmantošanas iespējas
Latvijā un pasaulē kūdra tiek izmantota un iegūta daudz mazākā apjomā nekā tas būtu ekonomiski pamatoti, neapdraudot dabas vērtības un to aizsardzībai paredzētās teritorijas. Rakstā novērtēti Latvijas purvi un kūdras resursi, kā arī to izmantosanas jomas. Tiek sniegts ieskats purvu un kūdras klasifikācijā, kūdras veidosanās procesā un to ietekmējosajos faktoros.
Quality of Lake Ecosystems and its Role in the Spread of Invasive Species
Abstract Lake ecosystems are important elements of hydrological regime, the quality of these ecosystems is affected by anthropogenic actions, and therefore, a variety of organisms, living in these habitats depend on the applied management solutions. Due to human activities freshwater ecosystems suffer from loss of biodiversity and increased eutrophication. Therefore, important aspects related to lake management include knowledge about the water quality, ecosystem response to climate change as well as increased risks of appearance and spreading of invasive species. Water quality, content of oxygen, nutrients, phytoplankton and distribution of macrophytes, including invasive species were anal…
Sapropeļa kūdras, sapropeļa kokskaidu siltumizolācijas plāksnes un to īpašības
Siltumizolācijas materiāli, kuros par pildvielu tiktu izmantoti vietējie biomasas produkti, bet par saistvielu kalpotu dabiskas izcelsmes saistvielas, piemēram, sapropelis, uzskatāmi par inovatīviem un to pielietošana sekmētu ekoloģiskās būvniecības nozares attīstību. Šādu risinājumu izstrāde ir aktuāla, jo Latvijā ir ievērojami sapropeļa resursi, kuru izmantošanu kavē to nepietiekama izpēte un ekoloģiskās būvniecības nozares intensīva attīstība. Pētījuma mērķis ir iegūt sapropeļa-koksnes, kūdras-koksnes siltumizolācijas plāksnes, noteikt optimālās plātnes sastāva attiecības un raksturot iegūto plātņu īpašības. Veikto pētījumu rezultātā tika noteiktas siltumizolācijas materiālu paraugu mehā…
Properties and structure of raised bog peat humic acids
Abstract Humic substances form most of the organic components of soil, peat and natural waters, and their structure and properties differ very much depending on their source. The aims of this study are to characterize humic acids (HAs) from raised bog peat, to evaluate the homogeneity of peat HAs within peat profiles, and to study peat humification impact on properties of HAs. A major impact on the structure of peat HAs have lignin-free raised bog biota (dominantly represented by bryophytes of different origin). On diagenesis scale, peat HAs have an intermediate position between the living organic matter and coal organic matter, and their structure is formed in a process in which more labil…
The Impact of Humic Substances as Remediation Agents to the Speciation Forms of Metals in Soil
Abstract Humic substances (HS) are the most widespread group of organic substances in natural environment and have high stability. The main terrestrial reserves are found in the form of naturally occurring ore, peat or lignite. The aim of this paper is to study possibilities to use HS as agents for remediation of contaminated with heavy metals soil and impacts of HS of metal speciation forms in it. It has been proved that HS are able to bind to metal ions and change their speciation forms in soils. The ability to form complexes with metal ions depends on the type of soil, type of metal, as well as concentrations of HS in soil. The study was carried out in experimental conditions and analyti…
Surface Activity of Humic Substances Within Peat Profile
Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in natural environment and possibly also for industrial applications. The ability to influence the surface tension of humic substance solutions depends on their origin. The objective of this study is a comparison of the ability of humic substances from peat profile to influence the surface tension of their solutions and identification of the structural characteristics of peat humic acids, determining their surfactant properties. Humic acids isolated from peat demonstrated significant impact of the surface tension of their solutions – they act as weak surfactants. The surf…
Peat humic acid properties and factors influencing their variability in a temperate bog ecosystem
Studies of the properties of soil organic matter are essential for understanding the humification reactions and soil diagenesis processes. The aim of this study is to analyse properties of peat and peat humic acids as well as factors influencing their variability. Humic acids isolated from an ombrotrophic bog peat profile were used as study objects. Relations among peat age, decomposition and humification degree, botanical composition, and properties of peat humic acids (elemental, functional composition, spectral characteristics) were studied. The variability of peat properties was found to be less significant than the differences in the properties of peat-forming living matter, which indi…
Characterization of interaction between tricyclic structures containing pharmaceuticals, their models and humic substances.
Their persistence and wide consumption identify pharmaceuticals as “emerging pollutants”. The complexation of pharmaceuticals containing adamantine ring structures and their model substances with humic acids (HA) of different origins was compared using fluorescence spectroscopy as a function of pH, humic acid concentration, ionic strength, and molecular mass of HA. Binding constants between the studied pharmaceuticals and humic acids were calculated. A combination of dynamic and static quenching processes as indicated by nonlinear Stern-Volmer plots and high Kd values were positively correlated with the concentration of carboxyl groups in the studied humic acids. For basic functional group-…
Formation and Changes of Humic Acid Properties during Peat Humification Process within Ombrotrophic Bogs
Studies of the living organic matter humification process are essential for understanding the carbon biogeochemical cycle. The aim of this study is to analyze relations between the properties of peat, peat humic acids and peat humification degree. The analysis has been done on samples of humic substances extracted from peat profiles in two ombrotrophic bogs and relations between peat age, decomposition and humification degree, botanical composition and properties of peat humic acids (elemental, functional composition) were studied. The found variability of peat properties is less significant than differences in the properties of peat-forming living matter, thus revealing the dominant impact…
A study of major and trace element accumulation in humic acids
It has been widely studied recent as well as historic accumulation of elements in peat profiles depending on intensity of anthropogenic pollution and thereby peat profiles serve as archives for research of environmental change. Peat ability to accumulate major and trace elements depends on the character of element supply, potency of metal ions to bind functionalities in the peat structure, pH reaction, oxygen presence, presence of complexing compounds, inorganic ions and many other factors. The aim of this study is to assign major and trace element distribution in humic acids (HA) for two well characterized ombrotrophic peat profiles of Eipurs and Dzelve Bog and analyse factors affecting el…
COMPOSITION AND QUALITY OF FRESHWATER LAKE SEDIMENTS (BALVU AND PĒRKONU LAKES)
Water quality, watershed basin and urbanization are key factors from the perspective of freshwater management; however, actual depth of waterbodies is often an overlooked element. Actual depth represents the overall depth of lake bed and depth of sediments. Some cases have been reported, where with increase of average depth of lake , it is possible to expect improvements of water quality when sediments are removed. If lakes are eutrophic, shallow, overgrown with macrophytes and contain high concentrations of biogenic elements water and lake ecosystem quality can be endangered. Removal of sediments can be an expensive procedure and also depends on the composition, structure, local conditions…
Kūdras humusvielas: to sastāvs un tā veidošanos ietekmējošie faktori
Elektroniskā versija nesatur pielikumus
Humusvielas kā virsmas aktīvās vielas
Darbā pētīta humusvielu (HV) spēja ietekmēt to ūdens šķīdumu virsmas spraigumu, kā arī apstākļus, kas to var izmainīt. Pētījuma veikšanai izmantotas no dažādiem avotiem izdalītas, kā arī ķīmiski modificētas un rūpnieciski ražotas humusvielas. Darba gaitā iegūta atziņa, ka HV piemīt spēja samzināt to ūdens šķīdumu virsmas spraigumu. Spēja izmainīt virsmas spraigumu ir atkarīga no šķīduma pH, temperatūras, kā arī metālu jonu un sāļu koncentrācijas. To, ka HV veido micellāru uzbūvi, nosaka to molekulu amfifīlā daba - molekulas virsmu veidojot hidrofīlām, savukārt, iekšpusi - hidrofobām funkcionālajām grupām. Darba apjoms: 80 lappuses, 50 attēli, 7 tabulas, kā arī atsauces uz 70 literatūras avo…
Genesis of Peat Humic Acid Structure and Properties Within Bog Profiles
Studies of living organic matter humification process are essential for understanding of carbon biogeochemical cycle, and considering this, the aim of this study is to analyse relations between properties of the peat, peat humic acids (HAs) and humification degree on example of analysis of two bog profiles in ombrotrophic bogs to identify the links between peat age, decomposition and humification degree, botanical composition and properties of peat humic acids (elemental, functional composition). The found variability of peat properties is much less than the significant differences in properties of peat-forming living matter, thus stressing the dominant impact of humification process on pea…
Structural characterization and chemical classification of some bryophytes found in Latvia.
Bryophytes are the second largest taxonomic group in the plant kingdom; yet, studies conducted to better understand their chemical composition are rare. The aim of this study was to characterize the chemical composition of bryophytes common in Northern Europe by using elemental, spectral, and non-destructive analytical methods, such as Fourier transform IR spectrometry (FT-IR), solid-phase (13) C-NMR spectrometry, and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), for the purpose of investigating their chemotaxonomic relationships on the basis of chemical-composition data. The results of all these analyses showed that bryophytes consist mainly of carbohydrates. Judging by FT-IR …