[pt] Os hidrocarbonetos policíclicos aromáticos (HPA) são compostos orgânicos de origem petrogênica e pirogênica, ubíquos, persistentes, bioacumuláveis em tecidos adiposos e comprovadamente carcinogênicos. O Monumento Natural do Arquipélago das Ilhas Cagarras (MONA) é uma unidade de conservação de proteção integral localizada a 4,5 km da cidade do Rio de Janeiro, cujas potenciais fontes de HPA para o local incluem o Emissário Ipanema, a Baía de Guanabara, o trânsito de grandes e pequenas embarcações, e a deposição atmosférica proveniente do alto trânsito de veículos e emissões industriais. Considerando que moluscos bivalves são biomonitores efetivos da exposição aos HPA, em fev/22 (C1) e jul/22 (C2) coletou-se cerca de 240 mexilhões da espécie Perna perna em três ilhas do MONA para avaliar o aporte de HPA oriundos de atividades antrópicas. Amostras compostas (3-5 animais) foram extraídas em triplicata utilizando extração acelerada por solvente (ASE) com purificação na célula, e purificação adicional por cromatografia em coluna. A fração de HPA foi determinada por cromatógrafo a gás acoplado a um espectrômetro de massas (GC-MS). As concentrações de (Somatório)39HPA variaram de 236 a 1378 ng g-1 , com os maiores valores encontrados em C1, níveis semelhantes aos de estudos anteriores com P. perna na região da Baía de Guanabara e algumas das ilhas do MONA (68-6271 ng g-1), sendo caracterizado, no entanto, aumento no aporte ao longo dos últimos 10 anos. O perfil geral dos contaminantes demonstra uma mistura de fontes pirolíticas e petrogênicas na região do MONA, sendo fontes prováveis a queima de combustíveis fósseis na região metropolitana e o aporte crônico de óleo, incluindo vazamentos irregulares, pelo trânsito constante de embarcações e fundeios próximos ao MONA. As concentrações de benzo[a]pireno, o (Somatório)4HPA – benz[a]antraceno, benzo[a]pireno, criseno e benzo[b]fluoranteno – e o Quociente de Equivalência Tóxica de Benz[a]pireno (TEQ BaPy) ficaram abaixo dos limiares de 5 ng g-1, 30 ng g-1 e 18 ng g-1, respectivamente, porém mais altos na amostragem realizada no verão, sugerindo um risco potencial para a qualidade de frutos do mar (moluscos) e da população humana. O cenário fornecido por um conjunto de dados limitado (apenas duas amostragens) reforça a necessidade de um programa de biomonitoramento no MONA Cagarras que inclua HPA e outras classes de contaminantes orgânicos, como as bifenilas policloradas (PCB) e pesticidas. / [en] Polycyclic aromatic hydrocarbons (PAH) are organic compounds of petrogenic and pyrogenic origin that are ubiquitous, persistent, bioaccumulative in adipose tissue, and proven to be carcinogenic. The Cagarras Islands Natural Monument (MONA) is a protected area located 4,5 km from the city of Rio de Janeiro, whose potential sources of PAH to the site include the Ipanema Outfall, Guanabara Bay, the transit of large and small vessels, and atmospheric deposition from high traffic of vehicles and industrial emissions. Considering that bivalve mollusks are effective biomonitoring organisms of exposure to PAH, in Feb/22 (C1) and Jul/22 (C2), approximately 240 mussels of the species Perna perna were collected from three MONA islands to assess the input of PAHs from anthropogenic activities. Composite samples (3-5 animals) were extracted in triplicate using accelerated solvent extraction (ASE) with purification in the cell, and additional purification by column chromatography. The PAH fraction was determined by gas chromatography-mass spectrometry (GC-MS). The concentrations of (summation)39PAH ranged from 236 to 1378 ng g-1, with the highest values found in C1, similar to previous studies with P. perna in the region of Guanabara Bay and some of the MONA islands (68-6271 ng g-1), but characterized by an increase in input over the last 10 years. The general profile of contaminants demonstrates a mixture of pyrolytic and petrogenic sources in the MONA region, with probable sources being fossil fuel combustion in the metropolitan region and chronic oil input, including irregular leaks, from the constant traffic of vessels and anchoring near the MONA. The concentrations of Benzo[a]pyrene, the (summation)4PAH – benzo[a]anthracene, chrysene, benz[b]fluoranthene, and benzo[a]pyrene – and the Toxic Equivalent Quotient of Benzo[a]pyrene (TEQ BaPy) were below the thresholds of 5 ng g-1, 30 ng g-1, and 18 ng g-1, respectively, but higher in the sampling performed in summer, suggesting a potential risk to the quality of seafood (mollusks) and the human population. The scenario provided by a limited data set (only two samplings) reinforces the need for a biomonitoring program in the Cagarras Islands Natural Monument that includes PAHs and other classes of organic contaminants, such as polychlorinated biphenyls (PCBs) and pesticides.

Priority organic and emerging contaminants are a growing concern for drinking water treatment due to their increasing presence in the environment. This study developed a predictive model for the sorption of anionic organic contaminants from drinking water on three anion exchange resins: a strong polystyrenic (IRA-910), weak polystyrenic (IRA-96), and a strong polacrylic (A860). The model quantifies the individual mechanisms of sorption using poly-parameter linear free energy relationships (pp-LFERs) and the feasibility of phase conversion (e.g., an ideal gas phase as the reference state) for ionic species was examined. To develop the model, a training set of isotherms was obtained using aliphatic and aromatic carboxylates, phenols, anilines, nitrobenzene, and ibuprofen. These compounds were chosen as model organic contaminants in the environment. The training set and 1-3 test compounds (3-methyl-2-nitrobenzoate, phenol, and 4-nitroaniline) were accurately predicted using the created model for each resin. An understanding of the effects of resin structure on sorption interactions was also developed that focused on ionic functional groups, resin matrix, and hydrophilicity (i.e. water content). It was shown that greater sorption efficiency was achieved when electrostatic (ion exchange) and nonelectrostatic (adsorption) interactions were present together to create a synergistic addition. However, sorption on ion exchangers was poor if the pH of the system approached levels lower than the sorbate pKa. Additionally, weak base exchanges lose exchange capacity as pH levels approach resin pKa (IRA-96 pKa = 6.0). Additional contributions to the sorption mechanisms were observed by studying various electron donating/withdrawing functional groups on the contaminants. It was concluded that π-π and H-bonding interactions contributed a greater amount to the nonelectrostatic mechanisms than cavity formation forces and nonspecific forces. A comparison between the three resins showed that IRA-96 (weak base polystyrenic) had a greater removal capacity than IRA-910 (strong base polystyrenic), followed far behind by A860 (strong base polyacrylate). This is due to differences between the resins, such as the hydrophilicity, the density of the ion exchange group, and the presence of aromatic rings within the matrix structure. Although the modeling method accurately predicted the phase change from aqueous to sorbent phases, it was shown that the SPARC calculated aqueous-gas ion transfer energies were poor estimations of the transfer energy to the ideal gas phase and further study is necessary to accurately determine this value. This modeling methodology is believed to be applicable to emerging contaminants such as pharmaceuticals in water systems and helps further new water treatment technologies while developing a mechanistic understanding of electrostatic and nonelectrostatic interactions in general. This can be applied to additional separation processes such as chemical purification and chromatographic separation. / Civil Engineering

Passive sampling, as opposed to the conventional spot or bottle water sampling technique, has shown to be reliable and efficient in monitoring the toxicologically relevant, freely dissolved (e.g. bioavaialable) concentrations of a wide range of organic contaminants in water. At the same time, partitioning controlled delivery (passive dosing; PD) techniques promise to overcome many of the challenges associated with toxicity testing of hydrophobic substances that may bias the interpretation of toxicity data. The present study investigated the feasibility of coupling silicone rubber passive sampling devices (SR-PSDs) with bioassay techniques for both chemical and ecotoxicological assessment of complex mixtures of organic contaminants in the aquatic environment. SR-PSDs were deployed in water at various locations within the Ythan catchment (north east, Scotland, UK), Forth estuary and the Firth of Forth (east coast of central Scotland, UK) for 7 to 9 weeks. Following retrieval, extracts from the SR-PSDs were analysed for dissolved concentrations of a variety of organic contaminants including PAHs and PCBs using GC-MS and GC-ECD respectively and were screened for a wide range of pesticides using GC-MS/MS and LC-MS/MS. The extracts were further evaluated for acute cytotoxicity (i.e. neutral red uptake assay) and EROD induction potential using rainbow trout liver cell line (Oncorhynchus mykiss; RTL-W1) and for phytotoxicity and developmental toxicity potential using algal growth inhibition test (with a marine phytoplankton, Diacronema lutheri) and fish embryo toxicity test (with embryos from zebrafish Danio rerio) respectively. Overall, the individual and total dissolved concentrations of PAHs (ΣPAH40; parent and branched) and PCBs (ΣPCB32; ortho and mono-ortho) measured in water from the Ythan, Forth estuary and Firth of Forth were relatively low compared with other studies using PSDs. A number and level of pesticides, including insecticides, herbicides and fungicides of varying hydrophobicity (log KOWs ~2.25 to ~5.31) were detected in the silicone rubber (SR) extracts from the Ythan catchment, the Forth estuary and the Firth of Forth, suggesting input mainly from agricultural run-off and possibly from direct discharges. No statistically significant (p<0.05) acute cytotoxicity was observed following 48 h exposure of RTL-W1 cells to SR extracts from the Ythan catchment. But, on a sublethal level, for every site, statistically significant EROD activity was observed to some degree following 72 h exposure. In addition, developmental and algal toxicities on embryos of D. rerio and D. lutheri respectively, were measured in all the deployed samples compared with the procedural controls (undeployed samples). Interestingly, extracts of SR-PSDs from the Forth estuary and the Firth of Forth exhibited growth inhibitions on D. lutheri that were similar to those of extracts from the Ythan, even though, fewer numbers of pesticides were detected in the Forth estuary and Firth of Forth than the Ythan. This suggests that pesticides were not solely responsible for the observed effects in the Ythan catchment. To further improve data from toxicity testing of hydrophobic substances, the study identified the use of SR O-rings as a suitable passive dosing format in in vitro toxicity tests and was partially validated through their use in dosing RTL-W1 cells with two individual PAHs and subsequently determining cytotoxicity and EROD-activity.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology / Water pollution caused by organic and inorganic contaminants represents an important ecological and health hazard. Simultaneous treatment of organic and inorganic contaminants had gradually gained great scientific interest. Advanced oxidation processes such as photocatalysis, using TiO2 as a photocatalyst, have been shown to be very robust in the removal of biorecalcitrant pollutants. These methods offer the advantage of removing the pollutants, in contrast to conventional techniques. At present, the main technical challenge that hinder its commercialization remained on the post-recovery of the photocatalyst particles after water treatment. Supporting of the photocatalyst on the adsorbent surface is important as it assists during the filtration step, reducing losses of the materials and yielding better results in degrading pollutants. To overcome this challenge, in this study composite photocatalysts of TiO2/zeolite and TiO2/silica were prepared and investigated to explore the possible application in the simultaneous removal of organic and inorganic compounds from contaminated water. The main objective of this study was to investigate the heterogeneous photocatalytic degradation of organic compounds in the presence of metal ions using composite photocatalysts. The Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy (RS) and zeta potential (ZP) analyses were used to characterize the prepared composite photocatalysts. The successive composite photocatalysts were used in a semi-batch reactor under an irradiation intensity of 5.5 mW/m2 (protected by a quartz sleeve) at 25 ± 3°C for the photocatalytic degradation of synthetic textile (methyl orange) and agricultural (atrazine) wastewater in the presence of ions. The effect of operating parameters such as TiO2 composition on supporting material, particle size, composite photocatalyst loading, initial pollutant concentration and pH were optimized. The effects of inorganic salts and humic acid on dye and pesticides degradation were also studied, respectively. The performance of the photocatalyst reactor was evaluated on the basis of color removal, metal ion reduction, total organic carbon (TOC) reduction, intermediates product analysis and modeling of kinetics and isotherms. Different kinetic and isotherm models were introduced and applied in this work. Important aspects such as error functions with the optimal magnitude were used for the selection of the best suitable model. / European Union. City of Mikkeli, Finland. Water Research Commission (RSA)

Η ορυκτολογική σύσταση του αργιλικού υλικού που χρησιμοποιείται σε ένα χώρο υγειονομικής ταφής απορριμμάτων είναι καθοριστικής σημασίας όσον αφορά την πιθανή διαφυγή και μετανάστευση ρύπων στο περιβάλλον. Ο προσδιορισμός των αργιλικών ορυκτών που συμμετέχουν στο αργιλικό υλικό, θεωρείται βασική παράμετρος όσον αφορά την εκτίμηση της ικανότητας τους για συγκράτηση οργανικών και ανόργανων ρύπων. Για το σκοπό αυτό η αναγνώριση των ορυκτολογικών συστατικών του αργιλικού υλικού που χρησιμοποιήθηκε στο χώρο υγειονομικής ταφής της Ν. Ζακύνθου κρίθηκε απαραίτητη. Από τα αποτελέσματα της περιθλασιμετρίας ακτίνων Χ προέκυψε ότι στο αργιλικό υλικό που χρησιμοποιήθηκε μέσα στο χώρο υγειονομικής ταφής, διακρίθηκε μία ομάδα δειγμάτων πλούσια σε σμεκτίτη (μοντμοριλλονίτη) και μία δεύτερη πλούσια σε χλωρίτη και βερμικουλίτη. Παράλληλα, η χρήση της περιθλασιμετρίας ακτίνων Χ σε συνδυασμό με την ηλεκτρονική μικροσκοπία και τις γεωχημικές αναλύσεις έδωσαν πληροφορίες για την προέλευση των ιζημάτων, καθώς και για τη παρουσία ρύπων και τον τρόπο συγκράτησης τους στις ορυκτές φάσεις που τα απαρτίζουν. Η μελέτη των φασμάτων NMR στα εκχυλίσματα των δειγμάτων έδειξε την ύπαρξη κορυφών απορροφήσεως από πρωτόνια που σχετίζονται με ομάδες πολυσακχαριτών, πεπτιδίων/πρωτεϊνών, αλκοολών, αμινοξέων, ομάδων που περιέχουν –Cl, σουλφιδίων και μεθυλενίων –CH2– παρακείμενων σε ομάδες αιθέρων ή και εστέρων τα οποία παράγονται ως αποτέλεσμα υδρόλυσης και αναερόβιας ζύμωσης στα διαλύματα στραγγισμάτων. Επιπλέον, οι μικροαναλύσεις έδειξαν την παρουσία χλωρίου και θείου σε κρυστάλλους απατίτη, καθώς και χλωρίου, θείου και φωσφόρου σε αργιλικά ορυκτά στα δείγματα που βρίσκονταν σε επαφή με στραγγίσματα, ενισχύοντας την άποψη ότι οι παραπάνω ομάδες προέρχονται από την αλληλεπίδραση με τα στραγγίσματα. Η διαφορετική ορυκτολογική σύσταση του αργιλικού υλικού που χρησιμοποιήθηκε στο χώρο απόθεσης απορριμμάτων (χλωρίτης-μοντμοριλλονίτης) φαίνεται να ευνοεί την εκλεκτική προσρόφηση των διαφορετικών οργανικών ρύπων που συμμετέχουν στα στραγγίσματα και κατά συνέπεια θεωρείται επιθυμητή. Προς την κατεύθυνση αυτή εστιάστηκε το ενδιαφέρον της διατριβής οπότε και προέκυψε ότι ο χλωρίτης παρουσιάζει εκλεκτική προσρόφηση για τις αρωματικές ενώσεις σε αντίθεση με τον μοντμοριλλονίτη, ο οποίος επιδεικνύει εκλεκτική προσρόφηση εκείνων των αλειφατικών ομάδων που εκχυλίζονται από υδατικά διαλύματα. Επιπλέον, οι αρωματικές ενώσεις δεν εκχυλίζονται από υδατικά διαλύματα και κατά συνέπεια από ύδατα επιφανειακών απορροών με αποτέλεσμα να επιδεικνύουν περιορισμένη κινητικότητα. Αντίθετα, οι αλειφατικές ομάδες εκχυλίζονται από υδατικά διαλύματα ενώ η παρουσία τους ευνοεί το σχηματισμό ευδιάλυτων συμπλόκων με μέταλλα, γεγονός που οδηγεί τελικά σε κινητοποίηση τους μέσω των επιφανειακών απορροών. Τέλος, η προσρόφηση αμινομάδων από τα αργιλικά ορυκτά φαίνεται ότι οδηγεί μέσω μιας διαδικασίας φυσικής οργανοφιλίωσης στην μετατροπή των υδρόφιλων επιφανειών των αργιλικών ορυκτών σε υδρόφοβες και κατά συνέπεια την προσρόφηση των υδρόφοβων οργανικών συστατικών που περιέχονται στα διαλύματα στραγγισμάτων. Το γεγονός αυτό είναι ιδιαίτερα σημαντικό εφόσον δείχνει την δυνατότητα για in situ μετατροπή των αργίλων σε οργανόφιλες αργίλους δημιουργώντας νέες προοπτικές στην διαχείριση των μη πολικών οργανικών ρύπων. / The mineralogy of a clay liner used in a landfill may influence the mobility of contaminants. Therefore, the determination of the types of clay minerals that are present in the landfill is of great importance for the assessment of their efficiency in the retention of organic and inorganic pollutants. In the present work, clay materials from an operating waste disposal facility in Zakynthos Island, Western Greece were collected in order to determine the different clay minerals present and their pollutant retention potential. Mineralogical analyses by XRD of the clay material collected from the landfill revealed a smectite (montmorillonite) rich and a chlorite/vermiculite rich material. The information obtained from X-ray Diffraction and SEM-EDS combined with chemical analyses provided valuable information concerning the provenance of the sediments and their retention potential. 1H NMR revealed that some of the organic components which are present in the samples are aliphatics, polysaccharides, alcohols, esters, Cl halogens, sulphides, amines, peptide/protein groups, amide and aromatics which are produced in the landfill as a result of several complex phenomena involving solubilization, hydrolyzation and anaerobic biological processes. SEM-EDS analyses showed the presence of chlorine and sulphur in apatite crystals, and of chlorine, sulphur and phosphorus in clay minerals suggesting the interaction of these minerals with leachate. The different clay mineralogy of the material used in the landfill, smectite (montmorillonite) rich and chlorite/vermiculite rich material facilitated the adsorption of different organic compounds, which is significant for the retention of pollutants. NMR analyses showed that aromatic moieties are preferentially adsorbed on chlorite than on montmorillonite, while those aliphatic moieties that are water soluble are preferentially adsorbed on montmorillonite. Aromatics are not accessible to rainwater and therefore hardly migrate. The aliphatic chains that are water accessible can be released to the environment through natural leaching by rainwater and since they are known to form soluble metal-organic complexes, supervision of the landfill is considered essential. Moreover, the interaction of amine groups with clay minerals in an aqueous system is favoured by the formation of an "insoluble" hydrophobic product leading to the formation of naturally organically modified clays. Thus clays become organophilic and capable of removing non ionic organic contaminants. This is of great importance for environmental applications since it demonstrates the in situ formation of organophilc clays in landfills, hence enabling effective containment and immobilisation of toxic organic compounds.

Suite à une anthropisation généralisée des ressources aquatiques et des écosystèmes associés, on retrouve de nombreux contaminants chimiques organiques à l’état de traces dans l’environnement aquatique. En parallèle de ces contaminants, dans les milieux aquatiques on retrouve également des molécules rassemblées sous la dénomination « matière organique dissoute (MOD) », qui sont des mélanges complexes de molécules et macromolécules, qui peuvent s’associer à ces contaminants et influencer leur comportement et leur distribution. Les interactions entre MOD et contaminants peuvent s’avérer difficiles à étudier étant donné qu’elles sont dépendantes de nombreux facteurs tels que la nature des contaminants et de la MOD, ainsi que des paramètres physico-chimiques du milieu. L’objectif de ces travaux était donc d’étudier ces interactions. Les contaminants organiques choisis ont été les Hydrocarbures Aromatiques Polycycliques (HAP) et les substances pharmaceutiques. D’autre part, plusieurs types de MOD d’origine naturelle ou commerciale ont été utilisés. Pour étudier les interactions, plusieurs techniques analytiques ont été développées dont la micro-extraction sur phase solide couplée à la chromatographie en phase gazeuse et à la spectrométrie de masse et l’extinction de fluorescence. / In relation with a widespread human impact on aquatic resources and ecosystems, many organic chemical contaminants are present at trace levels in aquatic environments. In parallel to these contaminants, dissolved organic matter (DOM), which is composed of complex mixtures of molecules and macromolecules, is also found and could be associated with these contaminants and influence their behavior and distribution. Interactions between DOM and contaminants can be very difficult to understand because they depend on many factors such as the nature of contaminants and DOM, as well as on environmental physico-chemical parameters. The aim of this work was thus to study these interactions. Organic contaminants studied were Polycyclic Aromatic Hydrocarbons (PAHs) and pharmaceuticals. On the other hand, several types of natural and commercial DOM have been used. To study the interactions, several analytical techniques have been developed like solid phase microextraction coupled to gas chromatography and mass spectrometry and fluorescence quenching.

Une étude approfondie a été menée dans deux zones distinctes (Estarreja au Portugal, noté EST, et Casier Peyraud 6 en France, noté PEY) pour évaluer les niveaux de contamination, ainsi que leurs comportements dans des anthroposols et les risques potentiels de ces contaminants pour des organismes vivants du sol. L’objectif principal étant d’évaluer la mobilité environnementale des retardateurs de flamme bromés (RFBs) dans un écosystème terrestre, notamment vers les vers de terre (Eisenia fetida) et les plants (luzerne (Medicago sativa), cresson (Nasturtium officinale), moutarde blanche (Sinapsis alba), dans une prospective d’évaluation du risque de transferts de ces molécules.Le facteur de bioaccumulation (BAF) ainsi que les indices SET et ERITME ont été calculés. Le BAF permet de déterminer si une substance est accumulée dans un organisme donné et s’il existe un risque d’entrée et de diffusion tout au long de la chaine alimentaire. Les indices SET et ERITME permettent de classer les sites testés en fonction du transfert efficace des COs par les anthroposols aux organismes testés, et d’avoir une idée du risque potentiel pour l’écosystème. L’indice SET donne une idée globale de l’excès de transfert pour tous les contaminants dans les matrices étudiées. L’indice ERITME permet d’évaluer le risque environnemental global inhérent associé à l’excès de transfert des contaminants considérés. Compte tenu des valeurs ERITME, les matrices étudiées peuvent être classées dans un ordre de toxicité qui est aussi conforme pour l’ensemble des organismes testés (E. fetida, luzerne, cresson et moutarde). / A comprehensive study was conducted in two distinct areas (Estarreja in Portugal, noted EST, and Casier Peyraud 6 in France, noted PEY) to assess the contamination levels as well as their behavior in soils and the potential risks posed by these contaminants to soil organisms. The principal aim was to evaluate the environmental mobility of brominated flame retardants (BFRs) in a terrestrial ecosystem, namely to earthworms (Eisenia fetida) and plants (alfalfa (Medicago sativa), watercress (Nasturtium officinale) and white mustard (Sinapis alba)), concerning the BFRs transfer risk evaluation. The Bioaccumulation factor (BAF) as well as the SET and ERITME indexes were calculated. The BAF allow to determine if a substance is accumulated in a certain organism and if there exists the risk of entry and diffusion along the food chain. SET and ERITME indexes allow to rank the tested sites according to the effective OCs transfer from anthroposoils to the tested organisms and have an idea of the potential risk to the ec system. The SET index gives a global idea of the excess of transfer for all the contaminants in the studied matrices. The ERITME index allows to evaluate the possible inherent global environmental risk associated with the excess of transfer on the considered contaminants. Considering the ERITME values, the studied matrices can be classified in an apparent increasing order of toxicity that it is also in accordance with the levels of OCs found in the all the tested organisms (E. fetida, alfalfa, cress and mustard).

Condensed phase membrane introduction mass spectrometry (CP-MIMS) is a direct, in situ analysis technique that is well suited to persistent organic pollutants, pesticides, and other small molecules. In CP-MIMS, neutral analytes permeate a hollow fibre membrane, typically polydimethylsiloxane (PDMS), driven by a concentration gradient. Analytes are subsequently dissolved by a liquid (condensed) solvent acceptor phase that is continuously flowed through the membrane lumen, which finally entrains the analytes to a mass spectrometer for detection. The membrane rejects charged and particulate matrix components, therefore eliminating sample cleanup that is otherwise necessary for conventional (i.e., chromatographic) techniques. However, larger analytes may suffer from relatively lengthy response times and lower sensitivity. A heptane cosolvent was therefore doped into the PDMS membrane, resulting in a polymer inclusion membrane (PIM). Through a system coupling CP-MIMS to electrospray ionization (ESI), the use of a PIM for model compounds resulted in faster response (~3×) and improved sensitivity (~3.5×, parts per trillion level detection limits). While effective for the demonstration of the PIM, pairing ESI with CP-MIMS represents an inherent incongruity: ESI is effective for polar, hydrophilic analytes, whereas CP-MIMS (i.e., PDMS membranes) is effective for hydrophobic analytes. CP-MIMS was therefore coupled with liquid electron ionization (LEI) as a more suitable ionization strategy. In LEI, the post-membrane solvent flow is entrained at nanolitre per minute flowrates to a LEI source, where the liquid is sequentially nebulized, vaporized, and ionized. The CP-MIMS-LEI coupling was optimized for the measurements of polycyclic aromatic hydrocarbon (PAH) isomer classes from aqueous samples, demonstrating low ng/L detection limits and response times (≤1.6 min). CP-MIMS-LEI was also applied to PAH isomer classes from soil samples, demonstrating rapid sample throughput (15 samples/hr) and low μg/kg detection limits, and additionally was quantitatively comparable to conventional techniques. A similar CP-MIMS-LEI system was applied to online monitoring of catalytic oxidation and alkylation reactions, demonstrating quantitative, real-time results for harsh, complex organic reaction mixtures. A significant analytical improvement was conducted by intentionally exploiting the already present liquid acceptor phase as an in situ means of providing liquid chemical ionization (CI) reagents for improved analyte sensitivity and selectivity (i.e., CP-MIMS-LEI/CI). Acetonitrile and diethyl ether were used as a combination acceptor phase/CI reagent system (i.e., proton transfer reagents) for the direct analysis of bis(2-ethylhexyl)phthalate from house dust (6 mg/kg detection limit). CP-MIMS-LEI/CI was then applied to PAHs from soils. Using methanol and dichloromethane combination acceptor phase/CI reagents, CP-MIMS-LEI/CI was shown to quantify and resolve PAH isomers from direct soil analyses via diagnostic PAH adduct ions: [M+CH2Cl+CH3OH-HCl]+ or [M+CHCl2-HCl]+. Using these selective ions, CP-MIMS-LEI/CI was again shown to be rapid (15 soils/hr), sensitive (ng/g detection limits) and quantitatively comparable to gas chromatography-MS for PAH measurements (average percent difference of -9% across 9 PAHs in 8 soil samples). The results across this thesis present a compelling argument for direct, quantitative screening from complex samples using CP-MIMS-LEI/CI, particularly given the simple workflow and short analytical duty cycle. / Graduate

Ph. D. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Aromatic organic contaminants are difficult to biodegrade, and thus effective green technologies are required to remove these pollutants from the ecosystem. Tetracycline antibiotic, an organic water pollutant, can be degraded by heterogeneous photocatalysis using an appropriate catalyst, with capability in converting the visible light energy into active species. The thesis focused on silver nanoparticles anchored on silver bromide (Ag/AgBr) as a plasmonic catalyst dispersed on activated carbon (ACK), were used as a photocatalyst (AABR-ACK) in tetracycline removal. The aim is to develop a catalyst that is active in low intensity visible light, whilst the addition of activated carbon will increase the light absorption and separate the charge pairs, after the photocatalyst has been excited by the visible light. The activated carbons were derived from pinecone pyrolyzed in a microwave. The pinecone mass to potassium hydroxide impregnation ratio and microwave pyrolysis time influenced the activated carbon properties. An impregnation ratio of 2.24 and microwave pyrolysis time of 16 minutes at constant microwave power of 400 W yielded the activated carbon with the best-developed porous structure and electrochemical properties. This activated carbon was used during the optimisation of the Ag/AgBr activated carbon (AABR-ACK) catalysts preparation using a thermal polyol precipitation method and response surface methodology. The most active catalyst was the AABR-ACK 11 obtained by a preparation temperature of 140 ºC, time (17.50 minutes), mass of surfactant and activated carbon (0.26 g and 0.03 g) respectively. This catalyst had an ordered nanospheres morphology, reduced electron-hole recombination rate, better electrochemical properties and exhibited enhanced activity on the tetracycline antibiotic removal in comparison to other Ag/AgBr activated carbon catalysts. A percentage degradation of 92% was obtained in 180 minutes were obtained with the AABR-ACK 11 catalyst. The photocatalyst prepared using the best activated carbon derived from pinecone developed in this study was compared to photocatalysts prepared using commercial activated carbon and biochar. The Ag/AgBr activated carbon catalysts using pinecone-derived activated carbon degraded the tetracycline to 92%, which is significantly higher than the percentage degradations (80% and 74%) for the catalyst prepared using commercial activated carbon and biochar catalysts respectively. The higher activity of the Ag/AgBr activated carbon catalysts using pinecone-derived activated carbon was due to the conductive attributes of the catalyst support for accelerated transfer of photo-induced electrons. The Ag/AgBr activated carbon catalysts using pinecone- derived activated carbon also exhibited better performance on tetracycline removal when compared to photocatalysts reported in literature. Two catalyst preparation methods, thermal polyol and deposition precipitation, were compared. The thermal polyol method yielded a more active catalyst for the degradation of the tetracycline in comparison to the deposition precipitation method. The degradation reaction conditions such as pH, light intensity and degradation temperature influenced the rate of the reaction. The highest rate of degradation was obtained at a pH of seven, white light and 40 ºC temperature. The intermediate products formed because of hydroxylation, deamination, demethylation and dehydration during the photocatalytic degradation of tetracycline antibiotics were identified using liquid chromatography mass spectrometer. Quenching experiments with hydroxyl, hole, and superoxide anion species showed that the most important radical responsible for the tetracycline degradation was the superoxide anion radical.

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.