Polymer dispersed liquid crystal (PDLC) films, consisting of micro-sized domains of a liquid crystal dispersing in a polymer matrix, serve as the basis of a variety of high-efficiency electro-optical effects. The thermo-optical properties of the PDLCs were investigated in this thesis. The thermal properties and the morphologies of four low molar mass mesogens were studied by DSC and polarized optical microscope (POM). There were significant super cooling/heating effects on the first order phase transitions but not on the mesophase transitions. The structural effects on the transition temperature were investigated. Between the two 4-alkoxybenzoic acids mesogens, the clearing temperature of 4-(octyloxy)benzoic acid was higher than 4-(decyloxy)benzoic acid because of the increasing chain length. Trans-4-methoxycinnamic acid had the highest melting temperature among the four mesogens despite the molar mass because the carboxylic acid termini of trans-4-methoxycinnamic acid gave rise to strong intermolecular attractions. The smectic phases of 4-(octyloxy)benzoic acid were classified as head-to-head bilayer orientational smectic structures, SmA2 and SmC2, respectively, by wide angle X-ray diffraction through measuring the d spacing of the liquid crystal. The total solubility parameter was used to evaluate matching a polymer-LC-solvent combination. PDLC films were prepared by the solvent induced phase separation method and suitable morphologies were achieved by thermal induced phase separation. The phase transition temperatures of PDLCs were shifted to a lower temperature due to the polymer dispersion effects. Different mesophases were observed in PDLC films when LC exhibited different mesophases. The LC fractions in the droplets were calculated from the nematic to isotropic enthalpies through the Smith equation. Two factors, thermal cooling rate and the LC concentration, which affect the size of the droplet dispersed in the polymer matrix, were investigated in the PVC dispersed 4,4'-azoxyanisole. The phase transitions of pHEMA dispersed 4-(octyloxy)benzoic acid and PVC dispersed 4,4'-azoxyanisole were investigated by TMDSC and quasi-isothermal TMDSC. The TMDSC results were analysed by the two approaches, reversing and non-reversing heat flow and complex heat capacity. The results of the phase transitions of the two PDLCs illustrated that in the PDLCs it involved both non-reversing, melting, and reversing, clearing and the transition between two mesophases. In the non-reversing transition, the transition temperature would be affected by super cooling/heating and the results obtained in the experiments were dependent on the experimental conditions, such as the heating or cooling rate, sample size and purge gas flow rate. However, in the reversing transition process, there were no super cooling/heating effects observed and it seemed that the experimental conditions were not so critical. Results could be monitored by Lissajous figures obtained from the quasi-isothermal TMDSC. The plots of modulated heat flow versus the derivative of modulated temperature can be used to alert to unfavorable experimental conditions where loss of system linearity could be seen.

In this study, annual variations in biochemical composition of seston and zooplankton community were investigated to characterize the nutritional environment of zooplankton in the Mersin Bay, NE Mediterranean Sea. For this goal, seawater and zooplankton samples were collected at monthly intervals from two stations / one representing coastal and other representing open waters characteristics from November 2004 to January 2006. Seawater samples were collected with Niskin bottles from the sea surface. Zooplankton samples were collected both in the horizontal and vertical plane by towing a Nansen net (70 cm mouth diameter with 112 &micro / m mesh). Surface seston chl-a, lipid, protein and carbohydrate concentrations were measured by fractionating seawater into three different size groups, 0.7-2.7, 2.7-18 and &gt / 18 &micro / m representing pico, nano and micro particulates in the seston. Zooplankton biomass and abundance were determined at four size fractions: 112-200, 200-500, 500-1000 and &gt / 1000 &micro / m / dry and organic weights were measured by gravimetric method and major taxonomic groups of zooplankton was identified under stereo-microscope. The nearshore station was always more productive than the offshore station in terms of chl-a, particulate organic matter (POM: protein+lipid+carbohydrate), zooplankton abundance and biomass. Chl-a maxima occured in spring and autumn at both stations. Very low chl-a concentrations at the offshore station (0.02-0.35 &micro / g L-1) confirmed oligotrophic character of the Northeastern Mediterranean. The highest chl-a concentration (2.4 &micro / g L-1) was observed in March 2005 at the nearshore station due to the input of Lamas River nearby. POM varied from 42.1 &micro / g L-1 (in January 2006) to 1082 &micro / g L-1 (in March 2005) and 53.7 &micro / g L-1 (in January 2006) to 246 &micro / g L-1 (in May 2005) at the nearshore and offshore stations, respectively. The oligotrophy of this system was indicated by the extremely low particulate lipid, protein and carbohydrate concentrations (1-3 times lower than in more productive systems). The most evident characteristic of this oligotrophic environment was the dominance of pico-POM throughout the study period, accounting for 31&ndash / 65 % of the total carbohydrates, proteins, lipids and chl-a. The prt:cho ratio was generally lower than 1 (low in organic nitrogen). Carbohydrate was the dominant biochemical component at both stations. Zooplankton varied during the sampling period, and they showed two peak abundances, in spring and autumn, with small increase in summer. The higher biomasses of zooplankton were observed in summer and autumn in the entire water column, but in spring and autumn periods in the surface water. Zooplankton data showed that 200-500 and 112-200 &micro / m size fractions were dominant in abundance at both stations. However, 200-500 &micro / m size fraction was dominant in zooplankton biomass at nearshore, whereas &gt / 1000 &micro / m size fraction was at offshore station. Copepods were the most abundant zooplankton group and dominated the distribution of total zooplankton, followed by crustace nauplii, appendicularia, cladocera and pteropoda.

Abstract Kaohsiung Harbor is one of the most important international sea ports in the world. Due to the long-standing lack of in-situ current data, the complex variations of the flow field in this basin still remain unclear. As a consequence, the related environmental problems such as oil spills, water quality management and ship maneuvering safety , have long been a great concern in this harbor. The present study is conducted to better understand the flow field in the Kaohsiung Harbor. A series of synoptic flow observations of the Kaohsiung Harbor were conducted by using towed-ADCP or EM current meters. From these observations it can be shown that the flow field of the Kaohsiung Harbor is¡GWater entering the harbor through the second entrance and exiting the harbor through the first entrance during ebbs. During floods the flows are reversed. A 3-D numerical model (from POM) is developed for the Kaohsiung Harbor. The flows are more complicated by the M2 tide driven than by the mixed tide driven. From the results by the M2 tide driven show the ocean current is variable, especially the south ocean current. Therefore, the flows are more complicated owing to the mixed tidal characteristics and shoreline geometry. The maximum current speeds amount to 30 - 40 cm/s in the narrow first entrance and 10 - 20 cm/s in the second entrance. It is clearly demonstrated from the model results that drainage from the Chien-Chen River affects greatly the salinity and circulation patterns of the Kaohsiung Harbor, causing the salinity of the first entrance to be lower than that of the second entrance, and the surface layers flowing outward toward the ocean while the lower layers displaying tidal oscillations. From the modeling results, the influence of the wind on the harbor flows is insignificant and the tide is main force in the harbor. Under the simultaneous forcing of river and wind, flood and ebb tidal streams leaving the two entrances are found to diverge in a flow stagnation area inside the harbor near Pier 45 and 61, respectively. Based on the modeling results, it can be concluded that the main factors affecting the flow patterns of the Kaohsiung Harbor are (1) mixed tidal nature, (2) shoreline geometry and (3) river runoff

This dissertation explores the reflexive and performative practices found in Mocha Jean Herrup's documentary work, POM, LESBIANFILM, and A FEW GOOD DYKES. By exploiting realism's failure to ever fully represent, reflexive and performative techniques enable a queer discourse. These techniques create 1) a parodic premise that calls attention to the disjunction between documentary's legitimizing conventions and queer as a viable subject, 2) a subjectification of the insider-outsider that troubles distinctions between the audience and the subject and the filmmaker and the subject, and 3) enables the embodied knowledge of queer subjectivity to emerge. / text

Avec les récents changements climatiques et la mutation de plusieurs secteurs industriels, une meilleure gestion des rejets de dioxyde de carbone (CO2) est fortement envisagée. De plus en plus d'intérêt est porté sur la valorisation de CO2 au lieu de son stockage simple. Ainsi, ce projet de thèse s'est focalisé sur l'utilisation de polyoxométallates (POMs) et plus particulièrement ceux substitués par des métaux de transition (TMS-POMs), pour la valorisation de CO2 via son électroréduction. Cette approche permet par la même occasion d'assurer une meilleure gestion de l'énergie électrique. Différentes structures de TMS-POMs ont été préparés, donnant des POM mono et polysubstitués aux métaux de transition simples, ainsi qu'un POM fonctionnalisé par un complexe organométallique actif pour l'électroréduction de CO2. Une approche synthétique originale a permis d'obtenir ce dernier complexe, ouvrant la voie à de nouveaux complexes actifs pour l'électroréduction de CO2. Les propriétés électrochimiques, ainsi que leurs aptitudes à catalyser l'électroréduction de CO2 ont été évaluées en différents milieux réactionnels. Une vue globale sur l'application potentielle de cette classe de complexe a ainsi été adopté, montrant notamment la capacité de ces complexes de mener la réduction à 4 électrons et 4 protons de CO2 en formaldéhyde. / With the recent climate change issues and the recent industrial evolutions, a better management of carbon dioxide (CO2) releases is highly demanded. More and more research is focused on CO2 industrial uses rather than its mere storage. Thus, this PhD project deals with the use of polyoxometalates (POMs), especially transition metals substituted ones (TMS-POMs), for CO2 conversion through its électroréduction. This approach allows both a better electrical power and CO2 release management. Different TMS-POMs structures were prepared, yielding mono and polysubstituted POM with simple transition metal and also functionalized ones with active organometallic complex for CO2 électroréduction. An original synthetic approach allowed us to achieve this late functionalization, opening the way for new catalysts for CO2 conversion. Theirs electrochemical properties, as well as their ability to catalyze CO2 électroréduction were investigated in different reaction media. An overview on the potential application of this complex class has been adopted. Noticeably, it highlighted the ability of these complexes to carry out the 4-electrons and 4-protons reduction of CO2 to formaldehyde.

Dissolved organic matter (DOM) is a complex mixture of organic compounds and represents the largest reservoirs of carbon (C) on earth. Particulate organic matter (POM) is another important carbon component in C cycling and controls a variety of biogeochemical processes. Estuaries, as important interfaces between land and ocean, play important roles in retaining and transforming such organic matter (OM) and serve as both sources and sinks of DOM and POM. There is a diverse array of both autochthonous and allochthonous OM sources in wetland/estuarine ecosystems. A comprehensive study on the sources, transformation and fate of OM in such ecosystems is essential in advancing our understanding of C cycling and better constraining the global C budget. In this work, DOM characteristics were investigated in different estuaries. Dissolved organic matter source strengths and dynamics were assessed in a seagrass-dominated subtropical estuarine lagoon. DOM dynamics controlled by hydrology and seagrass primary productivity were confirmed, and the primary source of DOM was quantified using the combination of excitation emission matrix fluorescence with parallel factor analysis (EEM-PARAFAC) and stable C isotope analysis. Seagrass can contribute up to 72% of the DOM in the study area. The spatial and temporal variation of DOM dynamics was also studied in a freshwated dominated estuary fringed with extensive salt marshes. The data showed that DOM was primarily derived from freshwater marshes and controlled by hydrology while salt marsh plants play a significant role in structuring the distribution patterns of DOM quality and quantity. The OM dynamics was also investigated in a mangrove-dominate estuary and a comparative study was conducted between the DOM and POM pools. The results revealed both similarity and dissimilarity in DOM and POM composition. The dynamics of both OM pools are largely uncoupled as a result of source differences. Fringe mangrove swamps are suggested to export similar amounts of DOM and POM and should be considered as an important source in coastal C budgets. Lastly, chemical characterizations were conducted on the featured fluorescence component in OM in an attempt to better understand the composition and origins of the specific PARAFAC component. The traditionally defined ‘protein-like’ fluorescence was found to contain both proteinaceous and phenolic compounds, suggesting that the application of this parameter as a proxy for amino acid content and bioavailability may be limited.

Long term management plans for restoration of natural flow conditions through the Everglades increase the importance of understanding potential nutrient impacts of increased freshwater delivery on coastal biogeochemistry. The present study sought to increase understanding of the coastal marine system of South Florida under modern conditions and through the anthropogenic changes in the last century, on scales ranging from individual nutrient cycle processes to seasonal patterns in organic material (OM) under varying hydrodynamic regime, to century scale analysis of sedimentary records. In all applications, carbon and nitrogen stable isotopic compositions of OM were examined as natural recorders of change and nutrient cycling in the coastal system. High spatial and temporal variability in stable isotopic compositions were observed on all time scales. During a transient phytoplankton bloom, ä15N values suggested nitrogen fixation as a nutrient source supporting enhanced productivity. Seasonally, particulate organic material (POM) from ten sites along the Florida Reef Tract and in Florida Bay demonstrated variable fluctuations dependent on hydrodynamic setting. Three separate intra-annual patterns were observed, yet statistical differences were observed between groupings of Florida Bay and Atlantic Ocean sites. The POM ä15N values ranged on a quarterly basis by 7‰, while ä13C varied by 22‰. From a sediment history perspective, four cores collected from Florida Bay further demonstrated the spatial and temporal variability of the system in isotopic composition of bulk OM over time. Source inputs of OM varied with location, with terrestrial inputs dominating proximal to Everglades freshwater discharge, seagrasses dominating in open estuary cores, and a marine mixture of phytoplankton and seagrass in a core from the boundary zone between Florida Bay and the Gulf of Mexico. Significant shifts in OM geochemistry were observed coincident with anthropogenic events of the 20th century, including railroad and road construction in the Florida Keys and Everglades, and also the extensive drainage changes in Everglades hydrology. The sediment record also preserved evidence of the major hurricanes of the last century, with excursions in geochemical composition coincident with Category 4-5 storms.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23149号 / 工博第4793号 / 新制||工||1750(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 平石 哲也, 准教授 馬場 康之, 教授 森 信人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p>Fokus ove doktorske disertacije je bilo izučavanje sorpcionog pona&scaron;anja tri herbicida koji se nalaze na listi prioritetnih supstanci prema Okvirnoj Direktivi o vodama EU (2000/60/EC) sa generalnim ciljem dobijanja podataka korisnih za prioritizaciju na osnovu novog fundamentalnog znanja o efikasnosti (ad)sorpcije za uklanjanje ovih<br />supstanci iz&nbsp; vode u lokalno specifičnim uslovima. Odabrani su ksenobiotici različite rastvorljivosti, hidrofobnosti i donorsko-akceptorskih osobina, koji&nbsp; pripadaju&nbsp; različitim klasama&nbsp; herbicida (dinitroanilinski-trifluralin, hloroacetamidni-alahlor i triazinski-&nbsp; atrazin). Prva faza je obuhvatala karakterizaciju sorbenata i vodenih matriksa .U sintetičkom matriksu, trifluralin pokazuje veći afinitet na ispitivanim sedimentima u odnosu na alahlor i atrazin. I u slučaju organoglina, sorpcija je najizraženija za trifluralin. Alahlor i atrazin pokazuju slične sorpcione kapacitete na TMA-K, dok je na TMA-B, sorpcija izraženija za alahlor u odnosu na atrazin. U&nbsp; zavisnosti od prirodnog matriksa, na oba sedimenta, najveće&nbsp; Kd vrednosti su dobijene za trifluralin, dok su Kd vrednosti za atrazin i alahlor&nbsp; bile veoma slične ili&nbsp;pak veće za atrazin. U slučaju organoglina, vrednosti&nbsp; K_d su rasle sa porastom log&nbsp; K_OW vrednosti herbicida na TMA-K u oba prirodna matriksa. Kada je u pitanju TMA-B, rast K_dvrednosti sa rastom log&nbsp; K_OW vrednosti uočava se u povr&scaron;inskom matriksu pri C_e&nbsp; = 0,05 mg/l i 0,5 mg/l, i podzemnom matriksu pri najvećoj ravnotežnoj koncentraciji C_e&nbsp; = 0,5 mg/l. Kao najefikasniji sorbenti su se pokazali&nbsp; TMA-B&nbsp;(Kd&nbsp; = 10,5 -&nbsp; 483 l/kg) i model sediment (Kd = 16,4 -&nbsp; 761 l/kg). Odsustvo jasne linearne korelacije izmeĎu&nbsp; Kd i&nbsp; % TOC upućuje na važnost interakcija mineralne faze i herbicida. U slučaju sedimenata nisu utvrđene korelacije K_d sa log&nbsp; K_OW&nbsp;vrednostima, dok kod organoglina one postoje. K<span id="cke_bm_184S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_184E" style="display: none;">&nbsp;</span> /K_OW odnosi su najveći kod atrazina na svim sorbenti<span id="cke_bm_185E" style="display: none;">&nbsp;</span>ma pa se pretpostavlja da on najvi&scaron;e učestvuje u&nbsp; uspostavljanju specifičnih interakcija zbog svojih donorsko-akceptorskih osobina. &Scaron;to se tiče uticaja DOC,&nbsp; zaključuje se da poreĎenje efikasnosti sorbenata treba sprovoditi u prirodnim matriksima jer sorpcioni koeficijenti variraju u zavisnosti od&nbsp;koncentracije polutanata, tipa i sadržaja DOC. Kolonskim eksperimentima je pokazano da atrazin i alahlor prolaze kroz kolonu sedimenta, dok je trifluralin skoro u potpunosti adsorbovan i u vrlo maloj koncentraciji detektovan u efluentu &scaron;to je u saglasnosti sa rezultatima &scaron;aržnih eksperimenata na ovom sorbentu. Procenjeni faktor retardacije pomoću modela TransMod za atrazin je veći u prirodnim matriksima (R <span id="cke_bm_190S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_190E" style="display: none;">&nbsp;</span> = 54 i R_d = 55 u podzemnoj i povr&scaron;inskoj vodi, redom) nego u sintetičkoj&nbsp;vodi (R_d = 40). Kod alahlora nisu uočene značajne promene faktora retardacije meĎu matriksima (R_d = 30-35). Ovi rezultati su suprotni očekivanjima na osnovu hidrofilnosti ksenobiotika i mogu biti&nbsp; rezultat upravo interakcija sa organskim materijama koje su bile izražene u kolonskim testovima, verovatno i vi&scaron;e nego u &scaron;aržnim testovima gde se nije pojavilo povećanje R_d vrednosti u prirodnim matriksima u odnosu na sintetički matriks.&nbsp; Bez obzira &scaron;to je&nbsp; alahlor hidrofobniji od atrazina, u uslovima datog matriksa i sorbenta ispoljava slične (&scaron;aržni testovi) ili<br />slabije sorpcione karakteristike&nbsp; (kolonski testovi)&nbsp; koje upućuju na mobilnost kroz prvi za&scaron;titini sloj.&nbsp; Treća faza je obuhvatala ispitivanje adsorpcije herbicida na aktivnim ugljevima u prahu. Ispitana je kinetika adsorpcionog procesa određivanjem koeficijenta za unutarčestični prenos mase herbicida u sirovim i ozoniranim prirodnim matriksima. Određena je efikasnost uklanjanja herbicida na razlilčitim ugljevima u prahu. Efikasnost uklanjanja se kretala u različitim opsezima u zavisnosti od odabranog uglja, vodenog matriksa i doze uglja. Na komercijalnim ugljevima najveća postignuta efikasnost (doza uglja od 15 mg/l) za&nbsp; alahlor iznosi u povr&scaron;inskoj vodi 95%, a u podzemnoj 76%. Za atrazin to je u povr&scaron;inskoj vodi 58% i u podzemoj vodi 56%, a za trifluralin u povr&scaron;inskoj vodi 87%, a u podzemnom matriksu 92%. Na uglju sitnih čestica koji se koristi u kombinaciji sa membranskom filtracijom ove<br />vrednosti su&nbsp; i veće. Stepen uklanjanja DOC na komercijalnim ugljevima (pri dozi od 15 mg/l) iznosi do 57% za povr&scaron;inski matriks i do&nbsp; 51% za podzemni matriks. Slična efikasnost u uklanjanju DOC je postignuta i na uglju sitnih čestica u oba matriksa. Ozonizacija je ispoljila očekivan negativan uticaj, vi&scaron;e ili manje izražen. U slučaju ksenobiotika, uticaji ozonizacije su bili različiti, u zavisnosti od primenjenog uglja, matriksa i supstance. Najizraženiji uticaj je kod alahlora,&nbsp; i to u negativnom smislu,<br />zbog pada efikasnosti uklanjanja, verovatno zbog kompeticije sa organskom materijom ili efekta solubilizacije. U nekim slučajevima, ali mnogo manje, taj efekat je primećen i kod trifluralina. Na oba komercijalna uglja primećen je pozitivan uticaj ozonizacije na uklanjanje atrazina, ali u različitim matriksima,&nbsp; pa se može spekulisati<br />pretpostavljanjem da dolazi do favorizovane raspodele u novim oblogama&nbsp; POM na uglju formiranim nakon ozonizacije koje su i dovoljno adsorbabilne, ali i sa dovoljno reaktivnim osobinama za asociranje sa polarnim supstancama, &scaron;to je delimično i potvrđeno rezultatima adsorpcione analize.&nbsp;&nbsp;</p> / <p>The focus of&nbsp; this doctoral thesis was the study of the sorption behavior of three herbicides which are on the list of priority substances according to Water Framework Directive (2000/60/EC). The aim&nbsp; was&nbsp; to obtain the&nbsp; data useful for prioritization on the basis of the&nbsp; new fundamental knowledge about (ad) sorption efficiency&nbsp; for the removal of these substances from the&nbsp; locally specific water matrices. Selected xenobiotics&nbsp; were&nbsp; differing&nbsp; in&nbsp; solubility, hydrophobicity, and donor-acceptor properties, which belong to different classes of compounds(trifluralin as herbicide, alachlor as chloracetamide herbicide and atrazine as triazine herbicide).&nbsp; In the first phase&nbsp; of the thesis&nbsp; characterization&nbsp; of sorbents and water matrices&nbsp; was performed. The aim of the second phase was the testing&nbsp; of&nbsp; the sorption and<br />desorption of organic xenobiotics in the sediments and organoclays. The equilibrium&nbsp; sorption parameters and removal efficiencies of herbicides were determined in different water matrices.&nbsp; In the synthetic matrix, trifluralin showed a higher sorption affinity onto tested sediments in comparison to the alachlor and atrazine. In the case of organoclays, sorption was mostly&nbsp; pronounced for trifluralin. Alachlor and atrazine have similar sorption capacities onto the TMA-K. For the TMA-B, the sorption was more pronounced for alachlor than atrazine. Depending on the natural water matrices,&nbsp; the highest&nbsp; K_d values were obtained for trifluralin onto both sediments. The&nbsp; K_d values for atrazine and alachlor were very similar or even greater for atrazine. In the case of organoclays, K_d values increased with increasing log&nbsp; K_OW values of herbicides onto TMA-K in both natural matrices. When it comes to TMA-B,&nbsp; K_d&nbsp; valuesincreased with increasing log&nbsp; K_OW values in&nbsp; the surface matrix for<br />C_e = 0,05 mg/l and 0,5 mg/l, and in groundwater at the highest equilibrium&nbsp; concentration&nbsp; C<span id="cke_bm_506S" style="display: none;">&nbsp;</span>_e<span id="cke_bm_506E" style="display: none;">&nbsp;</span>&nbsp; = 0,5 mg/l. TMA-B (K_d = 10,5&nbsp; -&nbsp; 483 l/kg) and model&nbsp; sediment&nbsp; (kd= 16,4 to 761 l/kg) were the most efficient s<span id="cke_bm_507E" style="display: none;">&nbsp;</span>orbents. The absence of&nbsp; the&nbsp; clear linear correlation between&nbsp; K_d and % TOC&nbsp; indicates the importance of the interaction of mineral phases and herbicides. Correlation between K<span id="cke_bm_513S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_513E" style="display: none;">&nbsp;</span> and K_OW values did not existed in the case of sediments,&nbsp; contrary to the organoclays.&nbsp; Since K<span id="cke_bm_519S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_519E" style="display: none;">&nbsp;</span> /K_oW ratios were the h<span id="cke_bm_520E" style="display: none;">&nbsp;</span><span id="cke_bm_514E" style="display: none;">&nbsp;</span>ighest for atrazine onto all sorbents, it&nbsp; was&nbsp; assumed that atrazine mostly participate in specific interactions due to its donor-acceptor properties. Regarding the&nbsp; influence of DOC on sorption, it was concluded that a comparison of sorbents efficiencies should be carried in&nbsp; native matrices as sorption coefficients vary depending on the concentration of pollutants, the type and content of DOC. Column&nbsp; experiments showed that atrazine and alachlor passed through the column of the sediment, while the trifluralin almost completely was adsorbed and in very low concentrations detected in the effluent which is in accordance with the results of the&nbsp; batch experiments.&nbsp; Estimated retardation factors of atrazine were higher in natural matrices (R<span id="cke_bm_525S" style="display: none;">&nbsp;</span>_d<span id="cke_bm_525E" style="display: none;">&nbsp;</span>= 54 and R_d = 55 in groundwater and surface water, respectively) than in&nbsp; the synthetic water (R_d= 40_{). I}n the case of alachlor, retardation factors were similar among water matrices (R_d = 30-35). These results are in the opposition&nbsp; based on the xenobiotic hydrophilicity, and they could be the consequence of interaction with the organic matter&nbsp; present&nbsp; in the column tests, probably more than in the batch tests. Estimations of&nbsp; R_d based on batch tests&nbsp; did not show an increase of R_d values in natural matrices, in comparison to the synthetic matrix. More hydrophobic alachlor, in the circumstances of the sorbent matrix exerts similar&nbsp; (batch&nbsp; tests) or lower sorption (column tests) characteristics that indicate mobility through the first protective layer.<span id="cke_bm_526E" style="display: none;">&nbsp;</span> The third phase&nbsp; included herbicide adsorption tests onto powdered activated carbons. The adsorption kinetics was examined by determining the intraparticle mass transfer coefficients for herbicides in raw and ozonated natural water matrices. The removal efficiencies of herbicides for different powdered activated carbons were determined. Removal efficiencies were in different ranges depending on the selected carbon, water matrix and carbon dose. The highest removal efficiencies&nbsp; for commercial carbons (for carbon dose of 15&nbsp; mg/l)&nbsp; for&nbsp; alachlor were 95% and 76% in surface and groundwater, respectively. The highest&nbsp; removal of atrazine was&nbsp; 58% in surface water and 56% in groundwater. In thecase of trifluralin, removal efficiencies were&nbsp; 87% in surface water and 92% in groundwater. The removal efficiencies for the carbon with fine particles&nbsp; (usually&nbsp; used in combination with a membrane filtration)&nbsp; were greater. The removal of DOC&nbsp; &nbsp; by&nbsp; commercial carbons (at the dose of 15 mg/l) was less than 57% in the surface water and 47% in groundwater. A similar efficiency in DOC removal was achieved for the carbon with fine particles in both water matrices. Ozonation showed the expected &nbsp; negative influence on&nbsp; DOC&nbsp; removal efficiencies, more or less pronounced. In the case of xenobiotics, ozonation influence was different, depending on the applied carbon and xenobiotic. The most important negative influence was&nbsp; in the case of alachlor probably due to competition with organic matter or solubilization effect. The&nbsp; same, but less pronounced effect was observed for trifluralin. The positive influence of ozonation was observed in removal of atrazine&nbsp; by&nbsp; both commercial carbons but in &nbsp; different water matrices.&nbsp; One can speculate that it comes to the favorable distribution in new NOM coatings on carbons formed upon ozonation, which are sufficiently adsorbable, but with enough reactive qualities for association with polar substances, which is partly confirmed by the results of adsorption analysis.</p>

No description available.