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The main issue of this thesis was to obtain information ondiffusion and sorption behaviour on organic colloids incompacted bentonite through experimental studies. It was tostudy if bentonite is an efficient barrier for organic colloidsor not. If colloids diffuse into bentonite in sufficientconcentrations, the speciation and sorption characteristics ofdiffusing radionuclides will change. Colloids might facilitatetransport, especially of radionuclides immobilised by strongsorption on bentonite. Laboratory experiments were performed to determine thestability of humic substances (HS) and bentonite colloids insolutions of ionic strengths representative for deep graniticgroundwaters. The HS but not the bentonite colloids were foundto be stable in these conditions. The competition between complexation with HS and sorption onbentonite of the cations Sr(II) and Eu(III) were studied inbatch experiments. Eu(III) was foundto complex with HS to bigextent. If HS is present in sufficient concentrations andstable in compacted bentonite, the Eu(III)-HS will be a speciesthat has to be accounted for. Sr(II) sorption decreases in thepresence of HS at ionic strength 0.01 M, but not at 0.1 M.Sr(II) sorbs weakly on bentonite and forms weak complexes withHS. The diffusion of Sr(II) in bentonite compacted to 1.8 g/cm3dry density and equilibrated with 0.1 M NaClO4 solutions wasstudied with and without HS in the system. The HS concentrationwas varied between 0.1 and 0.2 g/l. The Sr(II) diffusion wasnot affected by the presence of HS, which is in agreement withthe competition data of complexation to HS and sorption onbentonite. Diffusion of Co(II) and Eu(III) was studied in bentonite ofcompaction 0.6-1.8 g/cm3in the presence of HS. Eu(III)diffusion without HS in the system was studied as well. Co(II)diffusivity was found to increase significantly in the presenceof HS and the Kd-values decreased drastically. The decrease inthe Kd-values was found to be ionic strength dependent. This isexplained by HS complexation capacity decreases with increasingionic strength. The results indicate that the strongly surfacecomplexed Co(II) is mobilised by HS, but the Co-HS is not theonly diffusing Co(II) species in the experimental conditions ofthis study. Considering that Eu(III) sorbs strongly on bentonite, thediffusivity of Eu(III) was found to be rather high at ionicstrength 0.01 M. The high diffusivity rates are explained bythat the cation-exchanged Eu(III) around 1 % of the totalsorption is in practise mobile. In the presence of HS, Eu(III)diffusivity increases and the sorption decrease drastically.The Eu(III)-HS seems to be the dominating Eu(III) species whenthe HS concentrations are sufficiently high, and the HSsorption and diffusivity govern the system. <b>Keywords:</b>Diffusion, sorption, complexation, stability,bentonite, humic substances, Sr(II), Co(II) and Eu(III).

Polycyclic aromatic hydrocarbons (PAHs) are in general characterized by high toxicity, persistance, and bio-accumulation in environment. It is important to understand the transport and fate of PAHs in environment. In aquatic environment, PAHs are easily bound with dissolved organic matter (DOM), such as humic substance, and KDOC is usually used in denoting the binding constant. Previously, many investigations focused on the binding of a single PAH to DOM. However, few researches considered the competition effect on the binding of multiple PAHs to DOM. This study therefore explored the competition between the binary PAHs, pyrene and phenanthrene, in binding with humic substances. No significant competition effect in KDOC could be observed between these two compounds with LHA (Leonardite Humic Acid) because of the relatively large variation in KDOC determination. Humic substances from different sources might have different properties. Several characteristic indicators of humic substances were used to interprete the variations of KDOC of pyrene and phenanthrene, such as elemental ratio, total acidity, functional group content, etc. Negative correlations of O/C and phenolic group content to the KDOC of pyrene and phenanthrene were observed (p<0.05). In contrast, positive correlation of aromaticity and £`280 of humic substance to the KDOC of pyrene and phenanthrene were observed (p<0.05). Therefore, the contents of phenolic and aromatic groups of humic substance are essential factors in determining their binding constants with PAHs.

<p>The main issue of this thesis was to obtain information ondiffusion and sorption behaviour on organic colloids incompacted bentonite through experimental studies. It was tostudy if bentonite is an efficient barrier for organic colloidsor not. If colloids diffuse into bentonite in sufficientconcentrations, the speciation and sorption characteristics ofdiffusing radionuclides will change. Colloids might facilitatetransport, especially of radionuclides immobilised by strongsorption on bentonite.</p><p>Laboratory experiments were performed to determine thestability of humic substances (HS) and bentonite colloids insolutions of ionic strengths representative for deep graniticgroundwaters. The HS but not the bentonite colloids were foundto be stable in these conditions.</p><p>The competition between complexation with HS and sorption onbentonite of the cations Sr(II) and Eu(III) were studied inbatch experiments. Eu(III) was foundto complex with HS to bigextent. If HS is present in sufficient concentrations andstable in compacted bentonite, the Eu(III)-HS will be a speciesthat has to be accounted for. Sr(II) sorption decreases in thepresence of HS at ionic strength 0.01 M, but not at 0.1 M.Sr(II) sorbs weakly on bentonite and forms weak complexes withHS.</p><p>The diffusion of Sr(II) in bentonite compacted to 1.8 g/cm3dry density and equilibrated with 0.1 M NaClO4 solutions wasstudied with and without HS in the system. The HS concentrationwas varied between 0.1 and 0.2 g/l. The Sr(II) diffusion wasnot affected by the presence of HS, which is in agreement withthe competition data of complexation to HS and sorption onbentonite.</p><p>Diffusion of Co(II) and Eu(III) was studied in bentonite ofcompaction 0.6-1.8 g/cm3in the presence of HS. Eu(III)diffusion without HS in the system was studied as well. Co(II)diffusivity was found to increase significantly in the presenceof HS and the Kd-values decreased drastically. The decrease inthe Kd-values was found to be ionic strength dependent. This isexplained by HS complexation capacity decreases with increasingionic strength. The results indicate that the strongly surfacecomplexed Co(II) is mobilised by HS, but the Co-HS is not theonly diffusing Co(II) species in the experimental conditions ofthis study.</p><p>Considering that Eu(III) sorbs strongly on bentonite, thediffusivity of Eu(III) was found to be rather high at ionicstrength 0.01 M. The high diffusivity rates are explained bythat the cation-exchanged Eu(III) around 1 % of the totalsorption is in practise mobile. In the presence of HS, Eu(III)diffusivity increases and the sorption decrease drastically.The Eu(III)-HS seems to be the dominating Eu(III) species whenthe HS concentrations are sufficiently high, and the HSsorption and diffusivity govern the system.</p><p><b>Keywords:</b>Diffusion, sorption, complexation, stability,bentonite, humic substances, Sr(II), Co(II) and Eu(III).</p>

Made available in DSpace on 2014-06-11T19:35:05Z (GMT). No. of bitstreams: 0 Previous issue date: 1999-02Bitstream added on 2014-06-13T18:46:14Z : No. of bitstreams: 1 toscano_ias_dr_araiq.pdf: 387630 bytes, checksum: 64cc6245511279744bb2dd4a814e3afb (MD5) / Substâncias húmicas aquáticas (SHA) foram obtidas por processo de adsorção em resinas macroporosas não-iônicas, XAD 7 e XAD 2, dispostas em série. Após eluição com solução de NaOH, o extrato alcalino de SHA foi acidificado a pH 1,0 para separação em ácidos húmico (AH) que precipita, e ácido fúlvico (AF) o qual permanece em solução. Para caracterização físicoquímica do material húmico (AH e AF), foram feitas análise elementar, determinação do teor de substâncias húmicas e acidez total. Os resultados obtidos por UV-VIS e FTIR indicaram que AH apresenta maior número de grupos aromáticos em relação a AF, que em geral possui mais cadeias alifáticas. A aplicação da técnica imunoquímica, enzyme-linked immunosorbent assay (ELISA), para a determinação do herbicida atrazina em águas foi avaliada em amostra de água contendo alto teor de matéria orgânica (~35 mg L-1) e baixo valor de pH (3,8). O efeito matriz devido a presença de SHA pode ser notado pela perda de sensibilidade da técnica, ou seja, os valores de IC50 variaram de 60 ng L-1, na ausência de SHA, para 112 ng L-1 em concentrações acima de 10,0 mg L-1 de material húmico e para 137 ng L-1 em pH < 5,0. Além disto, pode-se inferir que a luz solar aumentou a velocidade de degradação da atrazina na presença de SHA formando produtos, com partes de suas estruturas, semelhantes ao produto original levando a resultados falso-positivos. A quantidade de material húmico presente na amostra de água foi a principal fonte de erro na análise de atrazina, levando à interações não-específicas entre as SHA e os reagentes enzimáticos. O procedimento ELISA, aplicado neste estudo, pode ser utilizado para determinação de atrazina desde que se faça diluição da amostra até cerca de 2,5 mg L-1 de húmicos e em pH alcalino (7,0 – 9,0). / Aquatic humic substances (AHS) were isolated from water samples using Amberlite XAD 7 and XAD 2. After elution with NaOH solution, the XAD concentrated AHS was fractioned at pH 1.0 resulting in fulvic acid (FA - supernatant) and humic acid (HA - slurry). All humic materials were characterized with respect to elemental analysis, amount of AHS and total acidity. UV and FTIR spectra showed HA aromatic character greater than FA. Enzyme-linked immunosorbent assay (ELISA) was evaluated by analyzing atrazine in rich-humic matter water sample (~35 mg L-1) and acid water (pH 3.8). From all the conditions studied the low pH (pH < 5.0) and high humic substances concentrations (>10 mg L-1) showed the greatest influence. The IC50 values to control sample (no humic) decreased from 60 ng L-1 to 112 ng L-1 to humic solution at >10 mg L-1 and to 137 ng L-1 at pH < 5.0. The presence of AHS alters the photochemical behaviour of atrazine by accelerating its degradation forming metabolites which can be recognized by the antibodies. The assay performance showed a strong dependence on the pH values and amount of humic matter. However, analysis could be carried out directly in samples containing HA or FA that had been adjusted the pH in the range between 7.0 and 9.0, and humic concentration at 2.5 mg L-1.

Η εργασία έχει ως στόχο τη μελέτη των χαρακτηριστικών του λιγνίτη Κρυανής (Νομού Φθιώτιδας), προκειμένου να προσδιοριστούν οι συνθήκες απόθεσης του λιγνίτη στον παλαιοτυφώνα, αλλά και να εξεταστεί η καταλληλότητά του ως εδαφοβελτιωτικό και οργανοχουμικό λίπασμα. Η Νεογενής λεκάνη Ζελίου-Αγνάντης αποτελεί τμήμα της Υποπελαγονικής ζώνης. Τα περιθώρια και το υπόβαθρο της λεκάνης αποτελούνται από Ανω-Τριαδικούς δολομίτες και Ανω-Τριαδικούς και Ιουρασικούς ασβεστόλιθους, οι οποίοι υπόκεινται πυριτόλιθων και σχιστολίθων με εναλλαγές οφιολίθων. Τα πετρώματα του Παλαιογενούς απουσιάζουν, πιθανότατα λόγω διάβρωσης. Το λιγνιτικό κοίτασμα φιλοξενείται σε ιζήματα Μειοκαίνου έως κατωτέρου Πλειστοκαίνου και διακρίνεται σε τρεις σχηματισμούς: τον ανώτερο λιγνίτη, τον ενδιάμεσο και τον υποκείμενο. Ο υποκείμενος και ο ανώτερος λιγνιτικός σχηματισμός περιλαμβάνουν κυρίως χονδρόκοκκα κλαστικά υλικά, ενώ ο ενδιάμεσος ορίζοντας αποτελείται από στρώματα λιγνίτη που εναλλάσσονται με λεπτόκοκκα κλαστικά υλικά και ασβεστολιθικά πετρώματα. Στην περιοχή δειγματοληψίας παρατηρήθηκαν εκτός από το λιγνίτη, χουμώδεις άργιλοι, ιλυόλιθοι, άμμος και ψαμμίτες. Στη λεκάνη δραστηριοποιούνται μια σειρά από μικρά επιφανειακά ορυχεία, όπως αυτά της Κρυανής, Αγνάντης και Γολεμίου. Από τον ανώτερο ορίζοντα του επιφανειακού ορυχείου Κρυανής συλλέχθησαν συνολικά 20 δείγματα λιγνιτών μέσω δειγματοληψίας ανοικτής αύλακας. Η δειγματοληψία καλύπτει συνολικό πάχος στρωμάτων 20,93 m με πάχος λιγνίτη 11,54 m. Πραγματοποιήθηκαν προσεγγιστική και στοιχειακή ανάλυση, ανθρακοπετρογραφική εξέταση και ορυκτολογική ανάλυση. Επιπλέον προσδιορίστηκε η περιεκτικότητα σε χουμικά συστατικά, ώστε να διαπιστωθεί η καταλληλότητα του λιγνίτη Κρυανής ως εδαφόβελτιωτικού ή/και οργανοχουμικού λιπάσματος. Ο επικρατέστερος λιθότυπος είναι ο matrix, ενώ ακολουθούν ο ορυκτομιγής και σπανιότερα ο ξυλιτικός. Τα στρώματα που παρεμβάλλονται μεταξύ των λιγνιτών είναι κυρίως ιλυόλιθοι, άργιλοι, καθώς και φακοί ψαμμιτών. Η υγρασία, η τέφρα, η περιεκτικότητα σε πτητικά συστατικά είναι 25,37%, 34,37% και 48,69% (επί ξηρού) κατά μέσο όρο αντίστοιχα. Ο μόνιμος άνθρακας ανέρχεται κατά μέσο όρο σε 23,53%, ενώ η θερμαντική ικανότητα είναι κατά μέσο όρο 13,98 MJ/kg. Η ορυκτολογική ανάλυση έδειξε ότι τα κύρια ορυκτά είναι ο χαλαζίας, ο χλωρίτης και τα αργιλικά (ιλλίτης). Η περιεκτικότητα σε χουμικά συστατικά είναι σε αρκετά υψηλά επίπεδα: τα χουμικά οξέα κυμαίνονται από 47,0% έως 56,6% σε δείγματα επί ξηρού και τα φουλβικά συστατικά από 1,8% έως 10,8%. Mε βάση αυτά τα στοιχεία και σε σύγκριση με αποτελέσματα προηγούμενης μελέτης που πραγματοποιήθηκε σε αρκετές λεκάνες του Ελλαδικού χώρου ο λιγνίτης Κρυανής θεωρείται κατάλληλος για χρήση ως εδαφοβελτιωτικό και οργανοχουμικό λίπασμα. / This study aims to determine the features of the Kryani lignite deposit (Prefecture of Fthiotida, Central Greece) in order to assess the palaeoenvironmental conditions during peat deposition and to test the potential of certain lignite beds for soil improvement media. The Neogene Zeli-Agnanti Basin is part of the Sub-Pelagonian Ζone. The margins and the basement of the basin consist of Upper Triassic dolomites and Upper Triassic and Jurassic limestones, overlain by shale and chert strata alternating with ophiolites. Palaeogene rocks are lacking presumably due to erosion. The lignite deposit is hosted in sediments deposited from Miocene to Early Pleistocene and distinguished into lignite seams: the lower, the intermediate and the upper ones. The lower and the upper formations consist mainly of clastic, relatively coarse-grained rocks, whereas the intermediate one formation includes lignite beds alternating with fine-grained clastic and calcareous rocks. At the sampling site, except of lignite layers, Neogene sediments such as humic clay, siltstone, sandstone and sand were encountered. The basin includes several small deposits, namely these of Kryani, Agnanti, Golemi. Applying channel sampling, twenty lignite samples were collected from the upper seam exposed at the Kryani open pit mine. Inorganic intercalations were additionally sampled. The total thickness of the sampled profile is 20.93 m and the cumulative lignite thickness is 11.54 m. The matrix lithotype is dominant with the mineral-rich lithotype being less common. Xylite- and charcoal-rich lithotypes seldom. The intercalations consist mainly of siltstone, claystone, as well as of sandstone lenses or layers, sometimes including pebbles. Proximate and ultimate analyses, along with maceral and mineralogical analyses provide evidence for the depositional environment of the Kryani lignite deposit. Additionally, the extraction and the separation of humic substances (humic and fulvic acids, humins) constitute criteria for the adequacy of certain layers as soil-improvement media. The predominant lithotype is the matrix one, followed by the mineral-rich lithotype and rarely the xylite-rich lithotype. The intercalates between the main lignite is siltstone, claystone and sandstones lenses. The moisture, ash and the content of volatile components are 23.9%, 45.06% and 30.98% respectively. The carbon fix averages at 23.53% and the calorific value 13.98 MJ/kg. The mineralogical analysis proved that the main minerals are quartz, chlorite and the clay (illite). The humic substances content is quite high: the humic acids display values from 47.0% to 56.6% (on dry basis) and fulvic acids 1.8% to 10.8%. The results compared with these of previous studies conducted in several areas of Greece, prove that Kryanis lignite is suitable for application as soil-improvement media and organic fertilizer.

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