Zeolithgranulate sind etablierte Materialien für die Speicherung von Wärme mittels Wassersorption. Eine Erhöhung der Wärmespeicherdichte des Granulats ist durch Kombination mit hygroskopischen Salzen wie Calciumchlorid, Magnesiumchlorid oder Magnesiumsulfat möglich. In der vorliegenden Dissertation wird gezeigt, dass die Wär-mespeichereigenschaften derartiger Komposite von der Deliqueszenzluftfeuchte des Salzes, von der Salzbeladung und von der Luftfeuchte bei der Wassersorption abhängen. Liegt die Luftfeuchte unterhalb der Deliqueszenzluftfeuchte des Salzes, so nehmen Was-serbeladungshub, Wärmespeicherdichte und thermische Leistung mit steigender Salz-beladung um bis zu 71 % ab. Dies wird darauf zurückgeführt, dass Salzionen in die Mik-roporen des Zeoliths inkludiert werden und das für die Wassersorption zur Verfügung stehende Volumen verringern. Unterhalb der Deliqueszenzluftfeuchte ist das einge-brachte Salz daher thermochemisch inaktiv. Oberhalb der Deliqueszenzluftfeuchte und oberhalb einer salz- und luftfeuchteabhängigen Mindestsalzbeladung kommt es zur Ausbildung einer Salzlösung im Sekundärporensystem des Granulats. Die Absorption von Wasserdampf in der Salzlösung führt gegenüber dem salzfreien Granulat zu einer Steigerung von Wasserbeladungshub und Wärmespeicherdichte um bis zu 53 %. Dies geht jedoch einher mit einer Verringerung der thermischen Leistung um bis zu 50 %. Die Hydratation von kristallinem Salz im Granulat spielt gegenüber Salzinklusion und Ausbildung der Salzlösung nur eine untergeordnete Rolle. Die aus den experimentellen Befunden abgeleiteten Erkenntnisse konnten in ein semiempirisches mathematisches Modell überführt werden, welches den Wasserbeladungshub der Komposite quantitativ beschreibt. / Zeolite beads are established materials for the storage of heat by water sorption. An increase of the heat storage density of the beads is possible via the combination with hygroscopic salts. In this thesis it is shown, that the heat storage properties of compo-sites of this kind depend in a complex manner on the deliquescence humidity of the salt, on the salt loading, and on the humidity during water sorption. When the humidity is below the deliquescence humidity of the salt, water loading lift, heat storage density, and thermal power are reduced by up to 71 % with increasing salt content. This is at-tributed to the inclusion of salt into the micropores of the zeolite and the reduction of the volume available for the sorption of water. Thus, below the deliquescence humidity, the salt is thermochemically inactive. Above the deliquescence humidity and above a salt- and humidity-dependend minimum salt loading, a salt solution is formed in the secondary pore system of the beads. The absorption of water vapor in the salt solution gives rise to an increase of the water loading lift and of the heat storage density by up to 53 %, compared to the salt-free zeolite beads. However, this is accompanied by a reduc-tion of the thermal power output by up to 50 %. The hydration of crystalline salt in the beads is only of minor importance for the composites. The findings from the experi-mental work were transferred into a semi-empirical mathematical model, which de-scribes the water loading lift of the composites.

The goal of this research was to identify and fabricate zeolitic membranes that can separate radioisotope krypton-85 (half-life 10.72 years) and xenon gas released during spent nuclear fuel reprocessing. In spent nuclear fuel reprocessing, fissionable plutonium and uranium are recovered from spent nuclear fuel and recycled. During the process, krypton-85 and xenon are released from the spent nuclear fuel as process off-gas. The off-gas also contains NO, NO2, 129I, 85Kr, 14CO2, tritium (as 3H2O), and air and is usually vented to the atmosphere as waste without removing many of the radioactive components, such as 85Kr. Currently, the US does not reprocess spent nuclear fuel. However, as a member of the International Framework for Nuclear Energy Cooperation (IFNEC, formerly the Global Nuclear Energy Partnership), the United States has partnered with the international nuclear community to develop a “closed” nuclear fuel cycle that efficiently recycles all used nuclear fuel and safely disposes all radioactive waste byproducts. This research supports this initiative through the development of zeolitic membranes that can separate 85Kr from nuclear reprocessing off-gas for capture and long-term storage as nuclear waste. The implementation of an 85Kr/Xe separation step in the nuclear fuel cycle yields two main advantages. The primary advantage is reducing the volume of 85Kr contaminated gas that must be stored as radioactive waste. A secondary advantage is possible revenue generated from the sale of purified Xe. This research proposed to use a zeolitic membrane-based separation because of their molecular sieving properties, resistance to radiation degradation, and lower energy requirements compared to distillation-based separations. Currently, the only commercial process used to separate Kr and Xe is cryogenic distillation. However, cryogenic distillation is very energy intensive because the boiling points of Kr and Xe are -153 °C and -108 °C, respectively. The 85Kr/Xe separation step was envisioned to run as a continuous cross-flow filtration process (at room temperature using a transmembrane pressure of about 1 bar) with a zeolite membrane separating krypton-85 into the filtrate stream and concentrating xenon into the retentate stream. To measure process feasibility, zeolite membranes were synthesized on porous α-alumina support discs and permeation tested in dead-end filtration mode to measure single-gas permeance and selectivity of CO2, CH4, N2, H2, He, Ar, Xe, Kr, and SF6. Since the kinetic diameter of krypton is 3.6 Å and xenon is 3.96 Å, zeolites SAPO-34 (pore size 3.8 Å) and DDR (pore size 3.6 Å) were studied because their pore sizes are between or equal to the kinetic diameters of krypton and xenon; therefore, Kr and Xe could be separated by size-exclusion. Also, zeolite MFI (average pore size 5.5 Å) permeance and selectivity were evaluated to produce a baseline for comparison, and amorphous carbon membranes (pore size < 5 Å) were evaluated for Kr/Xe separation as well. After permeation testing, MFI, DDR, and amorphous carbon membranes did not separate Kr and Xe with high selectivity and high Kr permeance. However, SAPO-34 zeolite membranes were able to separate Kr and Xe with an average Kr/Xe ideal selectivity of 11.8 and an average Kr permeance of 19.4 GPU at ambient temperature and a 1 atm feed pressure. Also, an analysis of the SAPO-34 membrane defect permeance determined that the average Kr/Xe selectivity decreased by 53% at room temperature due to unselective defect permeance by Knudsen diffusion. However, sealing the membrane defects with polydimethylsiloxane increased Kr/Xe selectivity by 32.8% to 16.2 and retained a high Kr membrane permeance of 10.2 GPU at ambient temperature. Overall, this research has shown that high quality SAPO-34 membranes can be consistently fabricated to achieve a Kr/Xe ideal selectivity >10 and Kr permeance >10 GPU at ambient temperature and 1 atm feed pressure. Furthermore, a scale-up analysis based on the experimental results determined that a cross-flow SAPO-34 membrane with a Kr/Xe selectivity of 11.8 and an area of 4.2 m2 would recover 99.5% of the Kr from a 1 L/min feed stream containing 0.09% Kr and 0.91% Xe at ambient temperature and 1 atm feed pressure. Also, the membrane would produce a retentate stream containing 99.9% Xe. Based on the SAPO-34 membrane analysis results, further research is warranted to develop SAPO-34 membranes for separating 85Kr and Xe.

Zeolites are crystalline aluminosilicates with diverse structures and uniform porosities. They are widely used as catalysts, adsorbents and ion-exchangers in industry. Direct or post modifications optimize the performance of zeolites for different applications. In this thesis, IZM-2 and TON-type zeolites were synthesized, modified and studied. In addition, FAU-type zeolite and silicoaluminophosphate (SAPO) molecular sieves were applied as templates for the preparation of microporous carbons. In the first part of this thesis, the IZM-2 zeolite with an unknown structure was synthesized. We focused on the increasing the secondary porosity and the varied framework compositions upon post modifications. The structure determination of this IZM-2 zeolite was hindered by the small size of crystals. In the second part of this thesis, the synthesis composition was directly modified in order to increase the crystal sizes. IZM-2 crystals were enlarged by excluding the aluminium atoms from the framework. The micropores of the obtained pure-silica polymorphs were activated by ion-exchanging alkali-metal ions with protons. Typically, TON-type zeolites that are synthesized at hydrothermal conditions under stirring have needle-shaped crystals. In the third part of this thesis, snowflake-shaped aggregates were produced by using static hydrothermal conditions for the synthesis of TON-type zeolites. The effects of synthesis parameters on the growth and morphology of crystals were discussed in detail. In the last part of this thesis, microporous carbons with a structural regularity were prepared by chemical vapour deposition (CVD) of propylene using a silicoaluminophosphate (SAPO-37) template. Compared to the conventional zeolite templates, the SAPO template could be removed under mild conditions, without using hydrofluoric acid, and the generated carbons had a large specific surface area and a high fraction of ultrasmall micropores. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>

M. Tech. (Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology / Acid mine drainage (AMD) is a serious problem associated with mining activities, and it has the potential to contaminate surface and ground water. The aim of this study was to evaluate the performance of constructed wetland and photocatalysis in treating AMD. Three identical unvegetated upflow constructed wetlands packed with natural zeolite (clinoptilolite) and coarse silica sand were made of a cylindrical plastic pipe, and the slurry photocatalyst was prepared using quartz material. A hydro-alcohol thermal method was used to prepare an anatase core-void-shell TiO2 photocatalyst. The results showed that the three unvegetated upflow constructed wetlands (CW) had relatively similar percentage removal of heavy metals despite their varying concentrations within the AMD. The removals were: Fe (86.54 - 90.4%); Cr (56.2 - 64.5%); Mg (56.2 - 67.88%); Ca (77.1 - 100%); and 100% removal was achieved for Be, Zn, Co, Ni, and Mn. The removal of sulphate was also 30%. Heavy metals concentration in CW packing material was significantly higher in the outlet of the constructed wetlands than in the inlet. The adsorption isotherms revealed that the experimental data fitted the Langmuir Isotherms better, which suggested a monolayer coverage of heavy metals on the surface of the adsorbents; thermodynamic studies showed that the nature of adsorption taking place was physical; the kinetics models showed that the adsorption was first order reaction. A higher photocatalytic reduction (62%) of Cr(VI) was obtained at pH 2, 30 mg/l Cr(VI) initial concentration, and three hours of irradiation time. It was also found that the presence of Fe(III) enhanced the reduction of Cr(VI). The core-void-shell TiO2 photocatalyst showed a better activity than the commercial P25 Degussa for the reduction of Cr(VI) to Cr(III). The kinetic studies showed that the reduction of Cr(VI) was first order reaction. Photocatalytic reduction of Cr(VI) in real AMD sample was achieved only for the Douglas North Discharge (DND) sample (68%), and the Fe(III) reduction was found to be 83%. Therefore it was concluded that the combination of constructed wetland and UV/ TiO2 photocatalysis employing anatase core-void-shell TiO2 as a photocatalyst has a potential to reduce the toxicity of Cr(VI)-laden acid mine drainage.

<p>Uklanjanje amonijaka iz podzemnih voda u cilju dobijanja<br />pijaće vode predstavlja značajan problem, koji se do sada<br />re&scaron;avao primenom različitih postupaka. Poznato je da zeoliti<br />kao prirodni jonoizmenjivači i adsorbenti kvalitetno vezuju<br />amonijum jone u svoju alumosilikatnu matricu. Njihova<br />efektivnost, u različitim tehnolo&scaron;kim procesima, zavisi od<br />fizičko-hemijskih osobina, koje su usko povezane sa njihovim<br />geolo&scaron;kim nalazi&scaron;tima, kada se govori o prirodnim zeolitima.<br />Pored prirodnih zeolita u praksi se koriste i sintetički zeoliti<br />dobijeni raznim postupcima. Danas, je komercijalna primena<br />sintetičkih zeolita rasprostranjenija u odnosu na primenu<br />prirodnih, zbog čistoće kristalnih proizvoda i uniformne<br />veličina čestica. Crystal-Right&trade; (CR-100) je zeolit koji spada u<br />grupu najizdržljivijih proizvedenih minerala. Ovaj zeolit<br />podiže pH vrednost tretiranih voda, dok istvremeno smanjuje<br />tvrdoću i uklanjanja gvožđe i mangan. Ovo pode&scaron;avanje pH i<br />uklanjanje nepoželjnih mineralnih materija postiže se izvrsnim<br />osobinama ovog zeolita u pogledu filtriranja, ali i ispiranja<br />nakon primene.<br />Maksimalna količina adsorbovanog amonijaka iznosi 2,31 mg<br />(98%) i 2 mg (87%), iz model rastvora i uzorka podzemne,<br />bunarske vode, redno. Prisustvo drugih komponenti u<br />bunarskoj vodi uzrokuje promene u količini adsorbovanog<br />amonijaka na zeolitu. Najbolje uklanjanje postignuto je za<br />jone kalijuma već sa najmanjim masama upotrebljenog<br />zeolita. Nasuprot tome, joni kalcijuma i magnezijuma se pri<br />nižim vrednostima doziranja zeolita slabije uklanjaju iz<br />bunarske vode, dok sa porastom doziranja raste i efikasnost<br />uklanjanja na svim posmatranim temperaturama.<br />Izbor adsorpcione izoterme je pokazao da najbolje rezultate<br />daje Freundlich-ova adsorpcione izoterme, a rezultati<br />aproksimacije ukazuju na fizičku adsorpciju na heterogenoj<br />povr&scaron;ini. Negativne vrednosti entropije aktivacije upućuju na<br />zaključak da se radi o asocijativnoj adsorpciji amonijaka na<br />povr&scaron;inu zeolita, odnosno da postoji interakcija između<br />adsorbovanih molekula. Vrednosti entalpije aktivacije od<br />15,096 kJ/mol i 28,978 kJ/mol, za model rastvor i realan<br />sistem, redno, upućuju da se radi o endotermnom procesu,<br />&scaron;to i potvrđuju podaci o ravnotežnim koncentracijama na<br />različitim temperaturama.<br />Tokom eksperimenata izvedenih sa poluindustrijskom<br />kolonom ispunjenom zeolitom Crystal Right&trade; (tip CR-100)<br />potvrđena je efikasnost u uklanjanju zeolita iz bunarske vode.<br />Između ispitanih modela za određivanje kinetike u kolonskom uređaju najboljim se pokazao model Yoon-Nelson-a.<br />Koeficijent linearne korelacije za model Yoon-Nelson-a iznosi -<br />0,975, dok je koeficijent determinacije imao vrednosti 0,950.<br />Iako je model razvijen jednokomponentne sisteme pokazao<br />se kao zadovoljovajući iako se radi o realnom sistemu<br />podzemne bunarske vode koja sadrži brojne rastvorene<br />supstance, katjone zemnoalkalnih i alkalnih metala, huminske<br />kiseline, anjone itd. Može se primetiti da je postignuto<br />zadovoljavaće slaganje eksperimentalnih podataka o<br />vremenu probaja sloja (50%) sa Yoon-Nelson-ovim modelom,<br />eksperimentalno određeno vreme proboja sloja iznosi oko 59<br />časova, dok je modelom dobijeno vreme 62 časa. Konstanta<br />brzine Yoon-Nelson-ovog modela iznosi 0,051 1/h.</p> / <p>Removing ammonia from groundwater to obtain drinking<br />water is an important issue, which is so far solved using<br />different methods. It is known that zeolites as natural ion<br />exchangers and adsorbents that bind ammonium ions in its<br />aluminosilicate matrix. Their effectiveness in various<br />technological processes depends on the physical and<br />chemical properties, which are closely related to their<br />geological sites, when it comes to natural zeolites. In addition<br />to the natural zeolites in practice synthetic zeolites are used.<br />Today, the commercial application of synthetic zeolites is<br />widespread in relation to the use of natural, due to the purity<br />of crystal products and uniform particle size. Crystal-Right &trade;<br />(CR-100) is a zeolite among the most durable minerals<br />produced. This zeolite raises the pH of the treated water, while<br />the same time it reduces the hardness and remove iron and<br />manganese. This pH adjustment and removal of undesirable<br />mineral substances is achieved by the excellent characteristics<br />of the zeolite in terms of filtering, and rinsing after application.<br />The maximum amount of adsorbed ammonia at 2.31 mg<br />(98%) and 2 mg (87%), from the model solution and the<br />sample of groundwater, well water, respectively. The presence<br />of other components in the well water causes changes in the<br />amount of ammonia adsorbed on zeolite. Selection of<br />adsorption isotherms showed that the best results are<br />achieved by Freundlich&#39;s adsorption isotherm, and the results<br />indicate physical adsorption on heterogeneous surfaces.<br />Negative values of entropy of activation lead to the<br />conclusion that it is associative adsorption of ammonia on the<br />surface of the zeolite, or that there is an interaction between<br />the adsorbed molecules. The values of enthalpy of activation<br />of 15,096 kJ / mol and 28,978 kJ / mol, for the model solution<br />and real system, respectively, indicating that it is an<br />endothermic process, which is confirmed by data on the<br />equilibrium concentrations at different temperatures.<br />Experiments conducted with the pilot plant column filled with<br />zeolite Crystal Right &trade; (type CR-100) confirmed the<br />effectiveness in removing zeolite from well water. Among the<br />surveyed models to determine the kinetics of the column<br />device Yoon-Nelson&#39;s model has proven to be the best. The<br />linear correlation coefficient for the model Yoon-Nelson&#39;s is -<br />0.975, and the value of the coefficient of determination was 0.950. Although the model developed for one-component<br />systems it is proved to be satisfactory for ground water<br />ammonia adsorption. The agreement between experimental<br />data on the breakthrough point at 50% concentration (59<br />hours) with Yoon-Nelson&#39;s model, is good (62 hours). Constant<br />of Yoon-Nelson&#39;s model is 0.051 1 / h.</p>

This thesis combines solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), chemical synthesis, isotopic enrichment and density-functional theory (DFT) calculations to provide insight into a number of microporous materials. The first class of materials studied is metal-organic frameworks (MOFs), where the presence of paramagnetic ions has a range of effects on the ¹³C NMR spectra, depending on the nature of the ligand-metal interactions. For the Cu²⁺-based MOFs, HKUST-1 and STAM-1, the assignment of the NMR spectra is non-intuitive, and unambiguous assignment requires specific ¹³C labelling of the organic linker species. It is shown that ¹³C NMR spectra of these two MOFs could act as a sensitive probe of the nature of “guest” molecules bound to the Cu²⁺. The second class of materials is aluminophosphates (AlPOs). It is shown that, using a series of relatively simple linear relationships with the crystal structure, the NMR parameters calculated by DFT (with calculation times of several hours) can be predicted, often with experimentally-useful accuracy, in a matter of seconds using the DIStortion analysis COde (DISCO), which is introduced here. The ambient hydration of the AlPO, JDF-2, to AlPO-53(A) is shown to occur slowly, with incomplete hydration after ~3 months. The resulting AlPO-53(A) is disordered and some possible models for this disorder are investigated by DFT. The final class of materials is gallophosphates (GaPOs), particularly GaPO-34 and related materials. The two as-prepared forms of GaPO-34 are characterised by solid-state NMR, and their calcination investigated by TGA and in-situ powder XRD. An unusual dehydrofluorinated intermediate phase is isolated and characterised for the first time by solid-state NMR. The fully calcined material is shown to be stable under anhydrous conditions, but hydrates rapidly in air. The hydrated material is stable under ambient conditions, but collapses upon heating. Partial dehydration without collapse is achieved by gentle heating or room-temperature evacuation. The impurity phases, GaPO₄ berlinite and GaPO-X are investigated by solid-state NMR and, while the structure of GaPO-X remains unknown, much structural information is obtained.

Le glycérol est valorisable par déshydratation en acroléine qui est un important intermédiaire chimique et peut être converti en une multitude de produits à valeur ajoutée dont l’acide acrylique qui est la base de nombreux polymères. Cette réaction est réalisée sur des catalyseurs acides comme les zéolithes protoniques qui donnent d’importants rendements initiaux en phase gazeuse (275-325°C) et à pression atmosphérique. Cependant, le principal inconvénient de ces matériaux est la désactivation rapide au cours du temps dû à la formation de dépôts carbonés appelés « coke ». L’ajout du fer sur les zéolithes H-BEA (larges pores) et H-MFI (pores moyens) a montré un effet fortement bénéfique sur cette réaction en présence d’air avec une formation supposée d’espèces actives qui permettraient de réduire de manière importante la désactivation du catalyseur et tout en favorisant la formation directe de l’acide acrylique sur la fonction métallique. Les zéolithes MFI au fer préparées par substitution isomorphe sont les plus performantes avec un rendement maximum en acide acrylique de 40% obtenu sur H-Fe3.8-Z-45 (préparé par synthèse hydrothermale). La zéolithe Np-Fe0.6-MFI-41 (préparé par traitement post-synthèse en milieu fluorure) permet d’obtenir un rendement en acroléine de plus de 80% après 24h de réaction, reproductible après régénération. Ce catalyseur est non seulement très actif, sélectif en acroléine, stable mais aussi régénérable, ce qui le place parmi les meilleurs pour ce procédé. / Glycerol is recoverable by dehydration into acrolein, which is an important chemical intermediate and can be converted into a variety of value-added products including acrylic acid that is the basis of many polymers. This reaction is carried out over acid catalysts, such as protonic zeolites which provide significant initial yields in the gas phase (275-325° C) and at atmospheric pressure. However, the main drawback of these materials is the rapid deactivation over time because of the formation of carbonaceous deposits known as "coke". The addition of iron over H-BEA (large pore) and H-MFI (mean pore) zeolites showed a highly beneficial effect on this reaction in the presence of air with an assumed formation of active species that would reduce significantly catalyst deactivation while promoting the direct formation of the acrylic acid on the metal function. H-MFI iron zeolites prepared by isomorphous substitution are the most efficient with a maximum acrylic acid yield of 40% obtained over H-Fe3.8-Z-45 (prepared by hydrothermal synthesis). Np-Fe0.6-MFI-41 zeolite (prepared by post-synthesis treatment in a fluoride medium) gives an acrolein yield of 80% after 24 hours of reaction, reproducible after regeneration. This catalyst is not only very active, selective to acrolein and stable but also regenerable, which places it among the best for this process.

Zeólitas sintetizadas a partir de cinzas leves e pesadas de carvão e modificadas com hexadeciltrimetilamônio (HDTMA) foram usadas como adsorvente para remoção dos corantes Solophenyl Navy (SN) e Solophenyl Turquesa (ST) e suas formas hidrolisadas, Solophenyl Navy hidrolisada (SNH) e Solophenyl Turquesa hidrolisada (STH), de efluente simulado de indústria têxtil. As zeólitas leve modificada (ZLM) e pesada modificada (ZPM) foram caracterizadas por diferentes técnicas, tais como, espectrometria de fluorescência de raios-X, difração de raios-X e microscopia eletrônica de varredura. As ZLM e ZPM apresentaram carga estrutural negativa devido à formação de uma bicamada parcial de HDTMA na superfície externa da zeólita. A concentração inicial dos corantes, o tempo de contato e o equilíbrio de adsorção foram avaliados. A cinética de adsorção de SN, ST, SNH e STH sobre as zeólitas seguiu o modelo de pseudo segunda- ordem. O tempo de equilíbrio foi de 20 min para SN e ST e 30 min para SNH e STH sobre ZLM, enquanto sobre ZPM foi de 60 min para SN e ST e 20 e 30 min para SNH e STH, respectivamente. Os modelos de Langmuir, Freundlich e Temkin foram aplicados para descrever as isotermas de adsorção. A adsorção dos corantes foi melhor descrita pelo modelo de Langmuir, com exceção dos sistemas SN/ZPM, SNH/ZPM e SNH/ZLM que seguiram modelo de Freundlich. As capacidades máximas de adsorção foram 3,64; 3,57; 2,91 e 4,93 mgL-1 para SN, ST, SNH e STH pela ZLM, respectivamente e 0,235; 0,492; 1,26 e 1,86 mgL-1 pela ZPM, nesta mesma ordem. O melhor desempenho dos corantes hidrolisados foi atribuído à redução do tamanho das moléculas dos corantes durante o processo de hidrólise. A toxicidade aguda dos corantes foi avaliada por diferentes organismos teste. O microcrustáceo C. dubia apresentou valores de EC50 de 1,25; 54,5; 0,78 e 2,56 mgL-1 para SN, ST, SNH e STH, respectivamente. A macrófita L. minor mostrou valores de EC50 de 18,9; 69,4; 10,9 e 70,9 mgL-1 para SN, ST, SNH e STH, respectivamente. As larvas de mosquitos C. tepperi mostraram valores de EC50 de 119 e 440 mgL-1 para a SN e ST, respectivamente. Com relação ao processo de adsorção, os efeitos agudos foram substancialmente reduzidos após o tratamento da solução aquosa de SN e ST com ZLM, assim como de suas formas hidrolisadas, apresentando nenhuma toxicidade após a remoção de 100% da cor. Após o tratamento dos corantes com ZPM houve um aumento da toxicidade, com exceção dos corantes SNH e STH que não apresentaram toxicidade após o tratamento. Testes de Avaliação e Identificação da Toxicidade foram realizados a fim de identificar quais substâncias estariam causando a toxicidade nos corantes SN, ST e no lixiviado de ZLM e ZPM. Os efeitos tóxicos foram reduzidos significativamente após a manipulação com Extração de Fase Sólida (SPE) e ácido etilenodiaminotetracético (EDTA) para o lixiviado de ZLM e ZPM. Os corantes mostraram redução na toxicidade após a manipulação com EDTA indicando que as substâncias tóxicas eram principalmente metais catiônicos. / Zeolites synthesized from fly and bottom ashes and modified with hexadecyltrimethylamonium (HDTMA) were used as adsorbent to remove dyes - Solophenyl Navy (SN) and Solophenyl Turquoise (ST) and their hydrolysed forms Solophenyl Navy Hydrolysed (SNH) and Solophenyl Turquoise Hydrolysed (STH), from simulated textile wastewater. The HDTMA-modified fly zeolite (ZMF) and HDTMA-modified bottom zeolite (ZMB) were characterized by different techniques, as X-ray fluorescence spectrometry, X-ray diffraction and scanning electron microscopy, etc. The ZMF and ZMB presented negative charge probably due to the formation of a partial bilayer of HDTMA on exchangeable active sites on the external surface of unmodified zeolite. Initial dye concentration, contact time and equilibrium adsorption were evaluated. The adsorption kinetic for SN, ST, SNH and STH onto the zeolites followed the pseudo second-order model. The equilibrium time was 20 min for SN and ST and 30 min for SNH and STH, respectively. Langmuir, Freundlich and Temkin models were applied to describe the adsorption isotherms. Adsorption of the dyes were best described by the Langmuir model, with exception to SN/ZPM, SNH/ZPM and SNH/ZLM systems that followed Freundlich model. The maximum adsorption capacities were 3,64; 3,57; 2,91 e 4,93 for SN, ST, SNH e STH by ZLM, respectively and 0,235; 0,492; 1,26 e 1,86 by ZPM, in this order. The best performance for hydrolyzed dyes has been attributed to reduction of the size of dyes molecules during the hydrolysis process. Acute toxicity of the dyes to a different organism were evaluated by different test-organisms. Waterflea, Ceriodaphnia dubia showed EC50 value of 1,25; 54,5; 0,78 and 2,56 mgL-1 for SN, ST, SNH and STH, respectively. The plant Lemna minor showed EC50 values of 18,9; 69,4; 10,9 and 70,9 mgL-1 for SN, ST, SNH and STH, respectively. Midges larvae of Chironomus tepperi showed EC50 values of 119 and 440 mgL-1 for SN and ST, respectively. Regarding the adsorption process, acute effects were substantially reduced after adsorption treatment of aqueous solution with SN and ST by ZMF, as well as their hydrolysed forms, showing no toxicity after removal of 100% of colour. After treatment with ZPM there was an increase of the toxicity, with exception of SHN and STH dyes that do not show toxicity after the treatment. Toxicity Identification Evaluation tests (TIE) were realized in order to identify what substances were causing the observed toxicity for the SN, ST and the leached of ZMF and ZMB. The acute effects were significantly reduced after manipulation with Solid-Phase Extraction (SPE) and Ethylenediaminetetraacetic acid (EDTA) for the leached of ZMB and ZMF. The dyes showed reduced in the toxicity after manipulation with EDTA indicating that the toxicants are mostly cationic metals.

[pt] A síntese direta de dimetil éter (DME) a partir de gás de síntese é catalisada a partir de catalisadores bifuncionais que possuem duas propriedades: uma hidrogenante que catalisa a formação de metanol a partir de gás de síntese e a outra desidratante que se encarrega da formação do dimetil éter a partir do metanol. Catalisadores bifuncionais com componente hidrogenante baseado em Cu, Zn e Al e componente desidratante baseado na zeólita H-ferrierita foram sintetizados, avaliando-se, o método de preparação, a influência do alumínio no componente hidrogenante e a razão componente desidratante versus componente hidrogenante. Dos diferentes métodos de preparação utilizados: precipitação-deposição, coprecipitação-impregnação e coprecipitação-sedimentação foram os dois últimos que apresentaram melhores resultados na conversão de gás de síntese além de apresentar a formação do precursor do catalisador de síntese de metanol. Os catalisadores foram caracterizados por: absorção atômica, análise térmica gravimétrica, adsorção de N2, difração de raios-x, redução com temperatura programada (RTP), dessorção com temperatura programada de amônia (DTPNH3), dessorção com temperatura programada de hidrogênio (DTP-H2) e microscopia eletrônica de transmissão. Verificou-se que o catalisador bifuncional apresenta um entupimento no volume de poros de aproximadamente 50 por cento. Os resultados dos raios-x identificaram a formação das fases auricalcita, hidrozincita, malaquita e rosacita nos catalisadores com componente hidrogenante baseado em Cu e Zn dos catalisadores com componente hidrogenante baseado em Cu, Zn e Al, e razão atômica Cu/Zn/Al:55/30/15, se observou somente a fase hidrotalcita. A inclusão de alumínio no componente hidrogenante favoreceu a formação de partículas de CuO muito pequenas, conforme observado na microscopia eletrônica de transmissão e difração de raios-x. A análise da DTP-H2 mostrou que os catalisadores preparados por coprecipitação-impregnação apresentam áreas de cobre um pouco maiores. A DTP-NH3 identificou a presença de sítios ácidos de Lewis e de Bronsted que ainda permanecem na H-ferrierita após a preparação do catalisador bifuncional. Sítios ácidos de Bronsted diminuem em maior proporção no catalisador bifuncional quando é preparado pelo método de coprecipitação-impregnação. Os testes catalíticos mostraram não existem grandes diferenças entre os catalisadores bifuncionais preparados por ambos os métodos e que o alumínio no componente hidrogenante não melhora a atividade catalítica destes catalisadores na síntese direta de DME. Concluiu-se que a etapa limitante do processo é a hidrogenação e que esta é dominada pelo cobre e que a H-ferrierita é um excelente componente desidratante pela sua elevada acidez. / [en] The direct synthesis of dimethyl ether from syngas is catalyzed by bifunctional catalysts: the hydrogenation function that catalyzes the methanol formation and the dehydration function to produce dimethyl ether from methanol. Bifunctional catalysts with Cu, Zn and Al as hydrogenation component and Hferrierite zeolite as dehydration component had been synthesized. It was evaluated the method of preparation, the influence of aluminum present in the hydrogenation component and dehydration/hydrogenation component ratio. The coprecipitating impregnation and coprecipitating sedimentation methods were used to form the precursor of hydrogenation component. The catalysts had been characterized by atomic absorption, thermal gravimetry analysis, N2 adsorption, xrays diffraction, TPR, ammonia TPD, hydrogen TPD and transmission electronic microscopy. It was verified that the bifunctional catalyst lost 50 percent of its pore volume. The results of x-rays identified the formation of aurichalcite, hydrozincite, malachite and rosacite phases in the catalyst based on Cu and Zn. However, in the catalyst based on Cu, Zn and Al (for an atomic ratio, Cu/Zn/Al:55/30/15) only the hidrotalcite phase was found. It was observed that the aluminum introduction in the hydrogenation component favors the formation of very small particles of CuO as verified in transmission electronic microscopy and x-rays diffraction. The NH3-TPD identified the presence of Lewis and Bronsted acid sites that still remain in the H-ferrierite after the preparation of the bifunctional catalysts. Bronsted acid sites had an importante decrease in the bifunctional catalysts when it is prepared by the method of coprecipitating impregnation. The catalytic tests showed that the catalysts prepared by the coprecipitating sedimentation method, present higher conversions and DME selectivitys than the prepared by coprecipitating impregnation. The presence of Al in the hydrogenation component doesn`t improve the catalytic activity. It can be concluded that the H-ferrierite is an excellent dehydration component for its high acidity and that the methanol synthesis can be limitant in the process of direct synthesis of DME from syngas.

Methoden der Dichtefunktionaltheorie (DFT) sind beliebte quantenmechanische (QM) Verfahren. Einige Größen, wie z.B. Dispersionsenergien oder Reaktionsbarrieren, werden mit Standardfunktionalen jedoch schlecht beschrieben. Solche Probleme sind für kleine Systeme mit Elektronenkorrelationsmethoden lösbar. In dieser Arbeit wird ein Hybridansatz vorgestellt, der Vorzüge von DFT und Elektronenkorrelationsmethoden vereint. Dazu erfolgen DFT-Rechnungen für das Gesamtsystem und ein darin eingebettetes Modell des aktiven Zentrums. Dieses wird außerdem mit Moller–Plesset Störungstheorie zweiter Ordnung (MP2) zur Korrektur entsprechender DFT-Werte beschrieben. Die Zuverlässigkeit so erzielter Ergebnisse wird durch Extrapolation auf den Grenzfall einer vollständigen Orbitalbasis und eines unverkleinerten Modells erhöht. MP2-Korrekturen werden für eine Reihe unterschiedlich großer Modelle ermittelt. Daran wird ein C6-Paarpotential angepasst, das auch für das (periodische) Gesamtsystem die Ableitung von Werten in MP2-Qualität erlaubt. Zur Anwendung der Hybridmethode in der Katalyseforschung werden Protonensprünge im Zeolith Chabasit und Protonierungsreaktionen von Isobuten im Zeolith Ferrierit untersucht. Die MP2/DFT-Ergebnisse bestätigen, dass Aktivierungsbarrieren mit einfachen Dichtefunktionalen unterschätzt werden. Geschwindigkeitskonstanten sind nach Korrektur um ein bis zwei Größenordnungen kleiner. DFT-Adsorptions- und -Chemisorptionsenergien für Kohlenwasserstoffe in Zeolithen sind nicht verlässlich. Unterschiedlich große MP2-Korrekturen für die untersuchten Produkte liegen in einem Bereich von –29 bis –70 kJ/mol. Gegenüber dem wasserstoffgebundenen tert-Butylcarbeniumion profitieren Oberflächenalkoxide energetisch am meisten von der Erfassung der Dispersion. Die berechnete MP2-Adsorptionswärme des Isobutens im Zeolith Ferrierit (–74+–10 kJ/mol) entspricht experimentellen Anhaltspunkten und zeigt die Zuverlässigkeit des in dieser Arbeit vorgestellten Hybridansatzes. / Density functional theory (DFT) belongs to the most popular computational approaches in quantum mechanics (QM). For certain terms, e.g., dispersion energies or reaction barriers, widely used functionals do not yield reliable results. For small systems these problems can be overcome by using electron correlation methods. In this work a hybrid approach is presented combining advantages of both DFT and electron correlation methods. DFT calculations are performed for the full system and an embedded model representing the active site. The embedded model is also described by second-order Moller–Plesset perturbation theory (MP2) to obtain corrections to corresponding DFT values. The reliability of the results obtained with this hybrid method is further improved by extrapolation to the limiting case of a complete orbital basis set and an unreduced model system. MP2 corrections are obtained for a series of models of increasing size to fit a C6 pair potential. The fitted potential is applied to the full (periodic) system yielding results of MP2 quality. The hybrid method is applied in the field of catalysis research to investigate proton jump reactions in the zeolite chabazite and protonation reactions of isobutene in the zeolite ferrierite. The MP2/DFT results obtained confirm that with purely gradient corrected density functionals reaction barriers are clearly underestimated. Rate constants are corrected by one to two orders of magnitude. DFT reaction energies for adsorption and chemisorption of hydrocarbons in zeolites are not reliable. MP2 corrections obtained range between –29 and –70 kJ/mol and are not the same for different products. Compared to the hydrogen-bonded tert-butyl carbenium ion the surface alkoxides benefit most from treating dispersion explicitly. The calculated MP2 heat of adsorption of isobutene in ferrierite (–74+–10 kJ/mol) corresponds to experimental clues and underlines the reliability of the hybrid MP2/DFT approach presented in this work.