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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Možnosti odstranění zápachu na stokové síti / Options eliminate odors in sewer network

Žíla, Radim January 2019 (has links)
The diploma thesis focuses on the possibility of removing odor on the sewer network. The first part of the research describes how the odor is generally perceived and what legislation regulates its quantity in the air. The second part of the research focuses on problems of formation of smelting sulfate on the sewer network. This section describes the formation of sulfane as a major component of odor. Further disclosed are methods for its removal, and the ways in which the odor is measured. The practical part deals with laboratory testing of pre-selected fillings in order to determine their ability to remove odorous sulfane. In the second part, on-line measurements are made to determine the causes of sulphan formation in a given location.
82

Procena remedijacionog potencijala sedimenta zagađenog prioritetnim organskim zagađujućim materijama / Investigation of remediation potential of sediment polluted with priority organic pollutants

Grgić Marko 16 August 2019 (has links)
<p>Predmet&nbsp; istraživanja&nbsp; ove&nbsp; doktorske&nbsp; disertacije&nbsp; je&nbsp; procena&nbsp; potencijalno&nbsp; biodostupne&nbsp; frakcije odabranih&nbsp; prioritetnih&nbsp; organskih&nbsp; polutanata&nbsp;&nbsp; (pentahlorbenzena,&nbsp; heksahlorbenzena,&nbsp; lindana, trifluralina, 4-oktilfenola i 4-nonilfenola) u sedimentu, ispitivanje biodegradacionog potencijala ovih&nbsp; jedinjenja&nbsp; u&nbsp; sedimentu&nbsp; u&nbsp; različitim&nbsp; uslovima,&nbsp; kao&nbsp; i&nbsp; procena&nbsp; potencijala&nbsp; stabilizacije<br />sedimenta&nbsp; dodatkom&nbsp; ugljeničnih&nbsp; sorpcionih&nbsp; agenasa.&nbsp; U&nbsp; cilju&nbsp; razvoja&nbsp; metoda&nbsp; za&nbsp; određivanje biodostupnosti odabranih organskih polutanata ispitivane su i&nbsp; optimizovane metode vi&scaron;estepene i jednostepene parcijalne ekstrakcije primenom sledećih hemijskih agenasa:&nbsp; Tenaks&nbsp; smole, XAD-4&nbsp; smole&nbsp; i&nbsp; rastvora&nbsp; ciklodekstrina&nbsp; (2-hidroksipropil-&beta;-ciklodekstrina,&nbsp; &beta;-ciklodekstrina&nbsp; i&nbsp; metil-&beta;-ciklodekstrina).&nbsp; Optimalni&nbsp; agens&nbsp; za&nbsp; procenu&nbsp; biodostupne&nbsp; frakcije&nbsp; odabranih&nbsp; organskih zagađujućih&nbsp; materija&nbsp; sa&nbsp; sedimenta&nbsp; XAD-4&nbsp; smola,&nbsp; a&nbsp; optimalno&nbsp; vreme&nbsp; ekstrakcije&nbsp; primenom jednostepenih&nbsp; ekstrakcija&nbsp; je&nbsp; oko&nbsp; 8&nbsp; h.&nbsp; Procena&nbsp; biodegradacionog&nbsp; potencijala&nbsp; odabranih prioritetnih&nbsp; organskih&nbsp; zagađujućih&nbsp; materija&nbsp; u&nbsp; sedimentu&nbsp; ispitana&nbsp; je&nbsp; u&nbsp; različitim&nbsp; aerobnim&nbsp; i anaerobnim uslovima uz optimizaciju uslova putem biostimulacije i bioaugmentacije. Pokazano je&nbsp; da&nbsp; svih&nbsp; &scaron;est&nbsp; odabranih&nbsp; jedinjenja&nbsp; poseduju&nbsp; značajan&nbsp; potencijal&nbsp; biodegradacije&nbsp; u&nbsp; anaerobnoj sredini&nbsp; pri&nbsp; čemu&nbsp; u&nbsp; slučaju&nbsp; lindana&nbsp; i&nbsp; trifluralina&nbsp; dolazi&nbsp; do&nbsp; potpunog&nbsp; uklanjanja&nbsp; biodostupne količine&nbsp; jedinjenja&nbsp; primenom&nbsp; sva&nbsp; četiri&nbsp; ispitana&nbsp; inokuluma.&nbsp; Aerobni&nbsp; potencijal&nbsp; u&nbsp; ispitanim uslovima&nbsp; pokazali&nbsp; su&nbsp; samo&nbsp; alkil&nbsp; fenoli,&nbsp; gde&nbsp; je&nbsp; takođe&nbsp; uklonjena&nbsp; skoro&nbsp; celokupna&nbsp; količinabiodostupne&nbsp; frakcije&nbsp; jedinjenja&nbsp; u&nbsp; sedimentu&nbsp; (78-85%).&nbsp; Potencijal&nbsp; remedijacije&nbsp; sedimenta dodatkom&nbsp; ugljeničnih&nbsp; materijala&nbsp; ispitan&nbsp; je&nbsp; sa&nbsp; aspekta&nbsp; odabira&nbsp; ugljeničnih&nbsp; sorpcionih&nbsp; agenasa (aktivni&nbsp; ugalj,&nbsp; biougalj&nbsp; i&nbsp; humus);&nbsp; određivanja&nbsp; optimalne&nbsp; količine&nbsp; materijala;&nbsp; isptivanja dugoročnih i kratkoročnih efekata dodatka ovih agenasa na biodostupnost organskih zagađujućih materija&nbsp; kako&nbsp; bi&nbsp; se&nbsp; ispitao&nbsp; efekat&nbsp; starenja &nbsp; i&nbsp; toksičnosti&nbsp; dobijenih&nbsp; sme&scaron;a.&nbsp; Rezultati&nbsp; stabilizacije zagađujućih&nbsp; supstanci&nbsp; u&nbsp; sedimentu&nbsp; pokazuju&nbsp; da:&nbsp; (1)&nbsp; povećanje&nbsp; doze&nbsp; sva&nbsp; tri&nbsp; sorpciona&nbsp; agensa dovodi&nbsp; do&nbsp; povećanja&nbsp; efikasnosti&nbsp; imobilizacije&nbsp; i&nbsp; smanjenja&nbsp; biodostupne&nbsp; frakcije&nbsp; odabranih organskih jedinjenja; (2) starenjem sme&scaron;a sedimenta i&nbsp; sorbenata u toku prvih 90 dana dolazi do daljeg smanjenja biodostupne frakcije svih jedinjenja, nakon čega se biodostupna koncentracija ispitivanih&nbsp; jedinjenja&nbsp; primenom&nbsp; aktivnog&nbsp; uglja&nbsp; ne&nbsp; menja,&nbsp; dok&nbsp; primenom&nbsp; biouglja&nbsp; i&nbsp; humusa&nbsp; dolazi&nbsp; do&nbsp; porasta&nbsp; biodostupne&nbsp; frakcije&nbsp; jedinjenja.&nbsp; Testovi&nbsp; fitotoksičnosti&nbsp; su&nbsp; pokazali&nbsp; da&nbsp; je&nbsp; <em>Zea mays&nbsp; </em>akumulirao&nbsp; značajno&nbsp; veće&nbsp; količine&nbsp; ispitivanih&nbsp; jedinjenja&nbsp; iz&nbsp; netretiranog&nbsp; sedimenta&nbsp; u poređenju sa&nbsp; <em>Cucurbita pepo</em>&nbsp; i&nbsp;<em> Lactuca sativa. </em>Toksičnost sme&scaron;a sedimenta sa aktivnim ugljom i humusom&nbsp; procenjena&nbsp; na&nbsp; osnovu&nbsp; inhibicije&nbsp; luminiscencije&nbsp; na&nbsp; <em>Vibrio&nbsp; fischeri</em>&nbsp; kao&nbsp; i&nbsp; ispitivanjem <em>Zea&nbsp; mays&nbsp; </em>germinacije&nbsp; i&nbsp; produkcije&nbsp; biomase&nbsp; je&nbsp; pokazala&nbsp; značajno&nbsp; smanjenje&nbsp; u&nbsp; odnosu&nbsp; na netretirani&nbsp; sediment.&nbsp; Akumulacija&nbsp; ispitivanih&nbsp; jedinjenja&nbsp; u&nbsp; biomasi&nbsp; <em>Zea&nbsp; mays&nbsp; </em>u&nbsp; netretiranom sedimentu je bila značajno veća u odnosu na sve sme&scaron;e sedimenta i aktivnog uglja i humusa. Sva tri&nbsp; sorbenta&nbsp; pokazala&nbsp; su&nbsp; veliki&nbsp; remedijacioni&nbsp; potencijal&nbsp; za&nbsp; sediment&nbsp; zagađen&nbsp; organskim zagađujućim supstancama, ali je aktivni ugalj pokazao najbolje performance.</p> / <p>The&nbsp; aim&nbsp; of&nbsp; the&nbsp; research&nbsp; in&nbsp; this&nbsp; PhD&nbsp; dissertation&nbsp; is&nbsp; the&nbsp; assessment&nbsp; of&nbsp; the&nbsp; potentially biodegradable&nbsp; fraction&nbsp; of&nbsp; selected&nbsp; organic&nbsp; pollutants&nbsp;&nbsp; (pentachlorbenzene,&nbsp; hexachlorobenzene, lindane,&nbsp; trifluraline,&nbsp; 4-octylphenol&nbsp; and&nbsp;&nbsp;&nbsp; 4-nonylphenol)&nbsp; in&nbsp; the&nbsp; sediment,&nbsp; estimation&nbsp; of&nbsp; the biodegradation potential of these compounds in sediment in different conditions, as well as the assessment&nbsp; of&nbsp; the&nbsp; stabilization&nbsp; potential&nbsp; sediment&nbsp; by&nbsp; the&nbsp; sediment&nbsp; amendment&nbsp; with&nbsp; of&nbsp; carbon rich sorption agents. In order to develop and optimise&nbsp; methods for the bioavailability assessment of&nbsp; the&nbsp; selected&nbsp; organic&nbsp; pollutants,&nbsp; methods&nbsp; of&nbsp; multistage&nbsp; and&nbsp; single-step&nbsp; non&nbsp; exhaustive extraction&nbsp; were&nbsp; studied&nbsp; using&nbsp; the&nbsp; following&nbsp; chemical&nbsp; agents:&nbsp; Tenax&nbsp; resin,&nbsp; XAD -4&nbsp; resin&nbsp; and&nbsp; a cyclodextrin&nbsp; solution&nbsp; (2-hydroxypropyl- &beta;-cyclodextrin,&nbsp; &beta;-cyclodextrin&nbsp; and&nbsp; methyl-&beta;-cyclodextrin).&nbsp; Results&nbsp; showed&nbsp; that&nbsp; optimal&nbsp; agent&nbsp; for&nbsp; estimating&nbsp; the&nbsp; bioavailable&nbsp; fraction&nbsp; of selected organic pollutants from the sediment is XAD-4 resins, and that the optimum extraction time using single-step extraction is about 8 h. The assessment of the biodegradation potential of selected&nbsp; priority&nbsp; organic&nbsp; pollutants&nbsp; in&nbsp; the&nbsp; sediment&nbsp; was&nbsp; examined&nbsp; in&nbsp;&nbsp; various&nbsp; aerobic&nbsp; and anaerobic&nbsp; conditions,&nbsp; with&nbsp; the&nbsp; optimization&nbsp; of&nbsp; conditions&nbsp; through&nbsp; biostimulation&nbsp; and bioaugmentation.&nbsp; It&nbsp; has&nbsp; been&nbsp; shown&nbsp; that&nbsp; all&nbsp; six&nbsp; selected&nbsp; compounds&nbsp; possess&nbsp; significant biodegradation&nbsp; potential&nbsp; in&nbsp; the&nbsp; anaerobic&nbsp; environment,&nbsp; where&nbsp; in&nbsp; the&nbsp; case&nbsp; of&nbsp; lindane&nbsp; and trifluraline there is complete removal of the bioavailable amount of the compound&nbsp;&nbsp; using all four inoculum tested. Aerobic potential under the applied conditions has been showen only for alkyl phenols,&nbsp; where&nbsp; almost&nbsp; all&nbsp; of&nbsp; the&nbsp; bioavailable&nbsp; fraction&nbsp; of&nbsp; the&nbsp; compound&nbsp; in&nbsp; the&nbsp; sediment&nbsp; was removed (78-85%). The potential of sediment remediation with the amendment of sediment withcarbon&nbsp; rich&nbsp; materials&nbsp; was&nbsp;&nbsp; examined&nbsp; from&nbsp; the&nbsp; aspect&nbsp; of&nbsp; selecting&nbsp; carbon&nbsp; sorption&nbsp; agents (activated carbon, biochar and humus); estimation the optimal material doses; the long -term and short-term effects of the addition&nbsp; of these agents on the bioavailability of organic pollutants&nbsp; in order to examine the effect of aging and the toxicity of the resulting mixtures. The results of the stabilization of pollutants in the sediment show that: (1)&nbsp; increasing the dose of all three&nbsp;&nbsp; sorption agents&nbsp; leads&nbsp; to&nbsp; an&nbsp; increase&nbsp; in&nbsp; the&nbsp; immobilization&nbsp; efficiency&nbsp; and&nbsp; reduction&nbsp; of&nbsp; the&nbsp; bioavailable fraction of the selected&nbsp; organic compounds; (2) aging of the amended sediment during the first 90 days results in a further reduction of the biodegradable fraction of all compounds, after which the&nbsp; biodegradable&nbsp; concentration&nbsp; of&nbsp; the&nbsp; selected&nbsp; compounds&nbsp; remain&nbsp; the&nbsp; same&nbsp; in&nbsp; the&nbsp; case&nbsp; of activated carbon amendment, while the bioavailable fraction of&nbsp; the compound increases with the use&nbsp; of&nbsp; biohar&nbsp; and&nbsp; humus.&nbsp; Phytotoxicity&nbsp; tests&nbsp; showed&nbsp; that&nbsp; <em>Zea&nbsp; mays&nbsp;</em> accumulated&nbsp; significantly higher amount of selected organic pollutants from unamended sediment, comparing to&nbsp; <em>Cucurbita pepo&nbsp;</em> and <em>Lactuca sativa</em>. Toxicity of activated carbon and humus amended sediment assessed by <em>Vibrio&nbsp; fischeri&nbsp;</em> luminescence&nbsp; inhibition&nbsp; test&nbsp; and&nbsp; by&nbsp; measuring&nbsp; <em>Zea&nbsp; mays&nbsp; </em>germination&nbsp; and biomass yield was significantly reduced in the amended sediment samples. Accumulation of the selected&nbsp; organic&nbsp; pollutants&nbsp; in&nbsp; the&nbsp; <em>Zea&nbsp; mays</em>&nbsp; biomass&nbsp; in&nbsp; the&nbsp; unamended&nbsp; sediment&nbsp; were&nbsp; a significantly&nbsp; higher&nbsp; than&nbsp; in&nbsp; the&nbsp; humus&nbsp; and&nbsp; activated&nbsp; carbon&nbsp; amended&nbsp; sediment.&nbsp; Both&nbsp; sorbents show&nbsp; potential&nbsp; to&nbsp; be&nbsp; used&nbsp; as&nbsp; remediation&nbsp; agents&nbsp; for&nbsp; organically&nbsp; contaminated&nbsp; sediment,&nbsp; but activated carbon exhibited the better performance.</p>
83

High temperature reactive separation process for combined carbon dioxide and sulfur dioxide capture from flue gas and enhanced hydrogen production with in-situ carbon dioxide capture using high reactivity calcium and biomineral sorbents

Iyer, Mahesh Venkataraman 06 January 2006 (has links)
No description available.
84

CALCIUM LOOPING PROCESSES FOR CARBON CAPTURE

Ramkumar, Shwetha 30 August 2010 (has links)
No description available.
85

Η ρόφηση ρύπων σε ανόργανα υλικά μεγάλης ειδικής επιφάνειας και διαφορετικού επιφανειακού φορτίου / Sorption of contaminants onto inorganic sorbents of large specific surface area and of different surface charge

Νικολακοπούλου, Μυρτώ - Γεωργία 16 May 2014 (has links)
Η απορρύπανση των υδάτων αποτελεί αναγκαία και καθιερωμένη από δεκαετίες πρακτική. Η απορρύπανση με τη μέθοδο της ρόφησης είναι μία από την πληθώρα των τεχνικών που εφαρμόζονται. Το περισσότερο διαδεδομένο ροφητικό υλικό είναι ο ενεργός άνθρακας, του οποίου όμως το υψηλό κόστος παραγωγής, οδήγησε την επιστημονική έρευνα στην αναζήτηση εναλλακτικών, υλικών χαμηλότερου κόστους. Για το σκοπό αυτό, το επιστημονικό ενδιαφέρον έχει στραφεί σε πολλά υλικά κυρίως οργανικής προέλευσης, αλλά και σε ανόργανα υλικά, όπως τα οξείδια των μετάλλων, τα οποία αφθονούν στη φύση. Στην παρουσα εργασία έγινε μελέτη της ροφητικής ικανότητας φυσικών οξειδίων, για τη ρόφηση αρωματικών οργανικών ενώσεων και βαρέων μετάλλων. Πιο συγκεκριμένα, μελετήθηκε ο μηχανισμός της ρόφησης του φαινανθρενίου, της 2-ναφθόλης και του υδραργύρου από οξείδια αργιλίου, τιτανίου, αργιλίου/πυριτίου και σιδήρου, με σκοπό την αξιολόγηση των υλικών αυτών ως ροφητικών υλικών και τη σύγκριση των αποτελεσμάτων με αυτά της ρόφησης των αντίστοιχων ρύπων από υλικά που παρασκευάζονται από την πυρόλυση πρώτης ύλης βιολογικής προέλευσης. Για τη μελέτη της κινητικής της ρόφησης του φαινανθρενίου και της 2-ναφθόλης πραγματοποιήθηκαν πειράματα σε θερμοκρασία περιβάλλοντος, σε θαλασσινό και γλυκό συνθετικό νερό, με διαφορετικές ποσότητες ροφητικού υλικού (χωρίς χημική επεξεργασία) και για διαφορετικό χρόνο επαφής. Από τα πειράματα αυτά μετρήθηκε η κινητική της ρόφησης καθώς και το ποσοστό απομάκρυνσης των ρύπων από το διάλυμα. Από τις μετρήσεις που έγιναν, προέκυψε ότι το ποσοστό απομάκρυνσης του φαινανθρενίου από το διάλυμα αυξάνεται αυξανομένης της ποσότητας του ροφητικού υλικού. Η σταθερά της ρόφησης Kd, κυμάνθηκε σε ένα εύρος τιμών από 1 έως 10 L/Kg, τιμές 2 έως 4 τάξεις μεγέθους μικρότερες από αυτές άλλων ροφητικών υλικών βιολογικής προέλευσης, ή προϊόντων πυρόλυσης. Τη μεγαλύτερη ικανότητα ρόφησης φαινανθρενίου επέδειξε η γ-αλούμινα με ειδική επιφάνεια 270 m2/g, με μέγιστη απομάκρυνση φαινανθρενίου το 55 % της αρχικής συγκέντρωσης έπειτα από 8 ημέρες, ενώ τη μικρότερη ικανότητα ρόφησης η γ-αλούμινα με ειδική επιφάνεια 120 m2/g, με μέγιστη απομάκρυνση το 14 % της αρχικής συγκέντρωσης, έπειτα από 10 ημέρες. Η τιτάνια, με ειδική επιφάνεια 120 m2/g, είχε ως αποτέλεσμα την απομάκρυνση του 52 % της αρχικής συγκέντρωσης φαινανθρενίου, σε 8 ημέρες. Από τα πειράματα ρόφησης της 2-ναφθόλης από την γ-αλούμινα, δεν προέκυψε μετρήσιμη ρόφηση. Η ρόφηση του υδραργύρου από την γ-αλούμινα (ειδική επιφάνεια 131 m2/g), και τα οξείδια σιδήρου μελετήθηκε με πειράματα στους 25 °C, σε pH 5 και με χρόνο εξισορρόπησης τις 24 h. Από τα πειράματα προέκυψε ισόθερμη καμπύλη και έγινε προσπάθεια προσαρμογής της σε μοντέλα ρόφησης. Παρατηρήθηκε αύξηση του ποσοστού απομάκρυνσης του υδραργύρου, με αύξηση της μάζας της γ-αλούμινας. Το μέγιστο ποσοστό απομάκρυνσης, ήταν το 93 % της αρχικής συγκέντρωσης και επιτεύχθηκε με μάζα γ-αλούμινας ίση και μεγαλύτερη από 1 g. Για τιμή Ce=15 mg/L, μετρήθηκε qe=0,91 mg/g, τιμή 1 έως 2 τάξεις μεγέθους μικρότερη από αυτές άλλων ροφητικών υλικών βιολογικής προέλευσης ή προϊόντων πυρόλυσης. Τα οξείδια σιδήρου, παρότι είχαν ειδική επιφάνεια 55 m²/g, δεν παρουσίασαν μετρήσιμη ροφητική ικανότητα για κανέναν από τους ρύπους, που μελετήθηκαν στην παρούσα εργασία. Συνοψίζοντας μπορούμε να πούμε ότι τα ανόργανα υλικά που μελετήθηκαν στην παρούσα εργασία, παρόλο που παρουσιάζουν μεγάλες τιμές ειδικής επιφάνειας, δεν μπορούν να χαρακτηρισθούν ως αξιόλογα ροφητικά υλικά, τόσο για τη ρόφηση των οργανικών ρύπων φαινανθρένιο και 2-ναφθόλη, όσο και για τη ρόφηση του υδραργύρου. / Water treatment is a necessary and standard practice since decades. Adsorption technology in water treatment is one of many techniques being used. Activated carbon is the most widely applied adsorbent in water treatment, however its high production cost has led scientific research to investigate alternative low cost sorbent materials. This need has developed scientific interest towards novel materials most of them derived from biomass, but also inorganic oxides that are abundant in nature. The present study focuses on the investigation of the capacity of natural oxides to adsorb aromatic organic compounds and heavy metals. Specifically, sorption of phenanthrene, 2-naphthol and mercury onto aluminum, titanium, silicon and ferric oxides was examined, for the evaluation of these materials as sorbents, compared to pyrolized biomaterials. For the study of sorption of phenanthrene and 2-naphthol, batch experiments were conducted at room temperature, using artificial seawater and fresh water, different mass of sorbent material at different contact time. Sorption kinetics and the pollutant removal percentages were determined. The proportion of phenanthrene removal increased with the increase of the mass of the sorbent material. Sorption distribution coefficient Kd ranged between 1 and 10 L/Kg. These values are 2 to 4 orders of magnitude lower than the respective values shown for biomaterials and for pyrolysis products, respectively. Maximum sorption capacity of phenanthrene (55 % proportion removal) was shown by γ-alumina, with a specific surface area equal to 270 m2/g, after 8 days. Minimum sorption capacity (14 % proportion removal) was shown by γ-alumina, with a specific surface area equal to 120 m2/g, after 10 days. Titania, with a specific surface area equal to 120 m2/g, adsorbed a proportion of 52 % of the initial concentration of phenanthrene, after 8 days. Sorption experiments of 2-naphthol from γ-alumina, did not show a measurable sorption. Sorption of mercury from γ-alumina and ferric oxides was studied, conducting batch experiments at 25 °C, pH 5, 24 h contact time. The experiments resulted to an isotherm curve that was evaluated using different sorption isotherm models. An increase of the proportion of mercury removal, with the increase of the mass of γ-alumina was observed. Maximum proportion of mercury removal (93% of the initial concentration) was observed with the addition of γ-alumina of 1 g or more. At Ce=15 mg/L, qe=0,91 mg/g was measured. This value is 1 to 2 orders of magnitude lower, than the respective values shown for biomaterials and for pyrolysis products, respectively. Even though ferric oxides’ specific surface area was estimated at 55 m²/g, they did not show a measurable sorption capacity for any of the pollutants tested in the present study. Even though the materials examined in the present study, were of large specific surface area, their sorptive properties shown, are not competitive with the respective properties of biomaterials. Thus, they cannot be considered as promising sorbents for the removal of phenanthrene, 2-naphthol, or mercury from water.
86

Synthesis, characterisation and application of organoclays

Xi, Yunfei January 2006 (has links)
This thesis focuses on the synthesis and characterisation of organoclays. X-ray diffraction has been used to study the changes in the basal spacings of montmorillonite clay and surfactant-intercalated organoclays. Variation in the d-spacing was found to be a step function of the surfactant concentration. Three different molecular environments for surfactant octadecyltrimethylammonium bromide (ODTMA) within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. High-resolution thermogravimetric analysis (HRTG) shows that the thermal decomposition of montmorillonite modified with ODTMA takes place in four steps attributing to dehydration of adsorbed water, dehydration of water hydrating metal cations, loss of surfactant and the loss of OH units respectively. In addition, it has shown that the decomposition procedure of DODMA and TOMA modified clays are very different from that of ODTMA modified ones. The surfactant decomposition takes place in several steps in the DODMA and TOMA modified clays while for ODTMA modified clays, it shows only one step for the decomposition of surfactant. Also TG was proved to be a useful tool to estimate the amount of surfactant within the organoclays. A model is proposed in which, up to 0.4 CEC, a surfactant monolayer is formed between the montmorillonite clay layers; up to 0.8 CEC, a lateral-bilayer arrangement is formed; and above 1.5 CEC, a pseudotrimolecular layer is formed, with excess surfactant adsorbed on the clay surface. While for dimethyldioctadecylammonium bromide (DODMA) and trioctadecylmethylammonium bromide (TOMA) modified clays, since the larger sizes of the surfactants, some layers of montmorillonite are kept unaltered because of steric effects. The configurations of surfactant within these organoclays usually take paraffin type layers. Thermal analysis also provides an indication of the thermal stability of the organoclay as shown by different starting decomposition temperatures. FTIR was used as a guide to determine the phase state of the organoclay interlayers as determined from the CH asymmetric stretching vibration of the surfactants to provide more information on surfactant configurations. It was used to study the changes in the spectra of the surfactant ODTMA upon intercalation into a sodium montmorillonite. Surfaces of montmorillonites were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant ODTMA. Changes in the surfaces and structure were characterized using electron microscopy. The ultrasonic preparation method results in a higher surfactant concentration within the montmorillonite interlayer when compared with that from the hydrothermal method. Both XRD patterns and TEM images demonstrate that SWy-2-Namontmorillonite contains superlayers. TEM images of organoclays prepared at high surfactant concentrations show alternate basal spacings between neighboring layers. SEM images show that modification with surfactant will reduce the clay particle aggregation. Organoclays prepared at low surfactant concentration display curved flakes, whereas they become flat with increasing intercalated surfactant. Fundamentally this thesis has increased the knowledge base of the structural and morphological properties of organo-montmorillonite clays. The configurations of surfactant in the organoclays have been further investigated and three different molecular environments for surfactant ODTMA within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. Changes in the spectra of the surfactant upon intercalation into clay have been investigated in details. Novel surfactant-modified montmorillonite results in the formation of new nanophases with the potential for the removal of organic contaminants from aqueous media and for the removal of hydrocarbon spills on roads.

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