Les biocarburants issus de la transformation de la biomasse de deuxième génération (2G), devraient remplacer les carburants fossiles dans le secteur des transports. Cependant, ces biocarburants peuvent contenir de 0.5 à 7.0 pds. % de composés oxygénés résiduels, en particulier des molécules phénoliques qui pendant la combustion dans le moteur peuvent se transformer en benzène qui est fortement cancérigène. Dans ce contexte, le défi qui se présente est de développer un processus d'adsorption sélectif pour éliminer les composés oxygénés de type phénolique des carburants liquides. Pour la première étape de notre travail, nous avons utilisé des calculs DFT pour sélectionner un matériau poreux approprié dans la famille des faujasites échangées aux cations monovalents (cation = H+, Li+, Na+, Cs+, Ag+ et Cu+) afin de trouver une formulation zéolitique avec une très forte affinité pour le phénol en présence d'eau et de toluène (molécule modèle de biocarburant). Nous avons trouvé que l’introduction de sites acides de Brønsted et de Lewis dans la structure de faujasite serait un moyen approprié de purifier sélectivement les biocarburants de deuxième génération en éliminant les molécules de phénol. La deuxième étape consiste à étudier en détail l'élimination du phénol dans une solution d'isooctane sur une faujasite contenant les protons qui ont été considérés comme de bons cations lors de la première étape. Au cours de cette étape, nous nous sommes concentrés sur l'effet du rapport Si/Al sur les capacités d'adsorption et de régénération des zéolithes étudiées. Nous avons utilisé une combinaison puissante de deux types de techniques de modélisation : i) la théorie de la fonctionnelle de la densité (DFT) qui a été utilisée pour déterminer les énergies de liaison du phénol avec plusieurs types de formulations de faujasite, ii) les simulations de type Grand Canonical Monte Carlo (GCMC) qui ont été utilisées pour trouver les capacités d’adsorption de chaque zéolite protonée utilisée. Les résultats obtenus sont comparés à ceux mesurés expérimentalement par la spectroscopie infrarouge, les courbes de percée et les expériences de désorption. Nous avons trouvé que le phénol était éliminé sélectivement de l'isooctane dans les zéolithes HY (Si/Al = 2.5) et USY (Si/Al = 47), avec une capacité maximale d'adsorption de 2.2 mmol·g-1, ce qui correspond à 3 − 4 molécules de phénol par supercage d'une structure de faujasite. La capacité maximale d'adsorption a été atteint plus rapidement dans la DAY (Si/Al = ∞), en raison de la présence de grands pores qui dépendent de la faible densité de sites acides. Nous avons également montré que les zéolithes USY ont une bonne capacité de régénération par rapport aux faujasites à forte concentration de sites protonés. En effet, après désorption à température programmée, il existe une très petite quantité de phénol résiduel dans la faujasite contenant une petite quantité de sites protonés, en accord avec la faible énergie d’adsorption du phénol théorique pour cette formulation. / Biofuels from the transformation of second-generation biomass (2G) are expected to replace fossil fuels in the transport sector. However, the biofuels obtained after the co-treatment (bio- oil refining) still contain 0.5 to 7.0 wt% oxygenated compounds, in particular phenolic molecules, which leads to form carcinogenic benzene during combustion in the engine. In this context, a new challenge is to use selective adsorption to remove phenolic compounds from liquid fuels. As a first step in our work, we used DFT calculations to design a suitable porous material in the family of faujasites exchanged with monovalent cations (cation = H+, Li+, Na+, Cs+, Ag+, and Cu+) in order to find a zeolitic formulation with a high affinity for phenol in the presence of water and toluene (biofuel model molecule). We have found that increasing the amount of the protonated and Lewis acid sites in the faujasite structure would be an appropriate mean of selectively purifying second-generation biofuels by removing phenol molecules. The second step is to study the removal of phenol from an isooctane solution over a faujasite containing protons that was considered as a good cation in the first step. Herein, we focused on the effect of the Si/Al ratio on the adsorption and regeneration capacities of the studied zeolites. For this deeper investigation, we have used a powerful combination of two types of modeling techniques: i) density functional theory (DFT) was used to determine the binding energies of phenol with several types of faujasite formulations, ii) the Grand Canonical Monte Carlo (GCMC) was used to find the adsorption capacities of each used protonated zeolite. The obtained results are compared with those measured by various experimental tools (infrared spectroscopy, breakthrough curves and desorption experiments). As results, we have found that phenol was selectively removed from isooctane into HY (Si/Al=2.5) and USY (Si/Al=47) zeolites with a maximal adsorption capacity of 2.2 mmol·g−1, which corresponds to 3−4 phenol molecules per supercage of a faujasite structure. The adsorption equilibrium was reached more rapidly in DAY (Si /Al = ∞) compared to faujasites with a large amount of protonated sites, due to the presence of large pores at the expense of micro porosity as well as a low density of acidic sites. We have also shown that USY zeolites have good regenerative capacity compared to faujasites with high amounts of protonated sites. Indeed, after temperature programmed desorption, there is a low amount of residual phenol in the faujasite containing a small amount of protonated sites, in agreement with our low adsorption energy of phenol computed for this formulation.

Zeolites have been widely used in many different fields including catalysis, adsorption and separation, ion exchange, or gas storage. Conventional zeolites have three- dimensional (3D) structures with microporous channel system; typical pore sizes are well below 1 nanometer, therefore, diffusion limitation plays important role in many process and bulkier reactants (or products) cannot enter (or leave) the zeolite channel system. Two-dimensional (2D) zeolites prepared in last years can lift all diffusion limitation and they thus offer a very attractive alternative to conventional 3D zeolites. 2D zeolites attracted considerable attention on the experimental side; however, understanding of 2D zeolites based on computational investigation or on a combination of experimental and computational investigation is limited. A motivation for the computational work presented here is to improve our understanding of properties of 2D zeolites based on computational investigation. The originality of the research presented herein is in the strategy: we carried out systematic investigation of properties of corresponding 2D and 3D zeolites and we focus on the identification of similarities and differences. The most important zeolite properties, i.e., presence of Brønsted and Lewis acid sites, are investigated. A number of...

O objetivo deste trabalho consistiu na caracterização das zeólitas Y e ZSM-5, usando a técnica de Espectroscopia de Alta resolução em sólidos por Ressonância Magnética Nuclear (RMN). Os espectros de alta resolução do 13C e 27Al foram obtidos usando, simultaneamente, as técnicas de desacoplamento em alta potência (DEC) e rotação da amostra em torno de ângulo mágico (MAS). Utilizamos os espectros de alta resolução dos núcleos de 27Al para analisarmos a coordenação e a quantificação dos alumínios estruturais e extra-estruturais em zeólitas Y e de 13C para analisarmos o posicionamento de moléculas direcionadas localizadas nos canais da ZSM-5 / The objective of this work consisted of the characterization of zeolites Y and ZSM-5, using Solid State High Resolution Nuclear Magnetic Resonance Spectrsocopy. The 13C and 27Al high resolution spectra were obtained using simultaneously, High Power Decoupling (DEC) and Magic Angle Spinning (MAS). The high resolution 27Al spectra were used to distinguish and quantify framework and non-framework aluminium in zeolites Y. The high resolution 13C spectra were used to probe the position and configuration of the guest organic molecules within the framework of the ZSM-5 zeolite

L’adsorption de l’hydrogène et du deutérium purs ou en mélanges a été étudiée sur une série de zéolithes en faisant varier différents paramètres (taille et géométrie des pores, rapport Si/Al, nature du cation compensateur de charge).Les sélectivités d’adsorption ont été déterminées dans un large domaine de pression (0,1 – 1000 hPa) et de température (45 – 100 K) à l’aide une technique originale basée sur le couplage de la manométrie et de la spectrométrie de masse conçue et mise au point au laboratoire. En accord avec les données de la littérature, pour tous les matériaux et toutes les conditions expérimentales étudiées, le processus de coadsorption est toujours en faveur du deutérium. En revanche, la sélectivité varie en fonction du taux de remplissage, des propriétés des matériaux et de la température. La cinétique de coadsorption joue un rôle très important sur la sélectivité d’adsorption et ce tout particulièrement dans le domaine de fort remplissage.Ces travaux ont permis d’identifier les paramètres de l’adsorbant et les conditions opératoires qui permettront le développement d’un procédé de séparation efficace des isotopes de l’hydrogène par adsorption sélective. / The adsorption of hydrogen and deuterium (single gases and mixtures) was studied on a series of zeolites with varied parameters (Si/Al ratio, nature of the charge-compensating cation, pore geometry and diameter of pore aperture). Thermodynamic adsorption selectivities towards deuterium with respect to hydrogen were measured in a large pressure range (0.1 – 1000 hPa) and for several temperatures (45 – 100 K). The adsorption selectivity was assessed using direct coadsorption measurements performed by manometry coupled with mass spectrometry. For all studied zeolites and experimental conditions, the coadsorption process is selective towards deuterium, in agreement with the literature. However, the adsorption selectivity depends on the loading, the sorbent’s properties and the temperature. We have found that the coadsorption kinetics strongly influences the adsorption selectivity, especially at high loading. This work gives the guidelines for the choice of the formulation of materials and the optimal operating conditions for having an efficient separation of hydrogen isotopes using zeolite-based adsorbents.

Alkaline industrial wastes are considered potential resources for the mitigation of CO2 emissions by simultaneously capturing and sequestering CO2 through mineralization. Mineralization safely and permanently stores CO2 through its reaction with alkaline earth metals. Apart from natural formations, these elements can also be found in a variety of abundantly available industrial wastes that have high reactivity with CO2, and that are generated close to the emission point-sources. Apparently, it is the applicability and marketability of the carbonated products that define to a great extent the efficiency and viability of the particular process as a point source CO2 mitigation measure. This project investigates the valorization of iron- and steel-making slags through methods incorporating the carbonation of the material, in order to achieve the sequestration of sufficient amounts of CO2 in parallel with the formation of valuable and marketable products. Iron- and steel-manufacturing slags were selected as the most suitable industrial byproducts for the purposes of this research, due to their high production amounts and notable carbonation capacities. The same criteria (production amount and carbonation capacity) were also used for the selection of the iron- and steel-making slag types that are more suitable to the scope of this work. Specifically for the determination of the slag types with the most promising carbonation capacities, the maximum carbonation conversions resulting from recent publications related to the influence of process parameters on the conversion extent of iron- and steel-manufacturing slags, were directly compared to each other using a new index, the Carbonation Weathering Rate, which normalizes the results based on particle size and reaction duration. Among the several iron- and steel-manufacturing slags, basic oxygen furnace (BOF) and blast furnace (BF) slags were found to combine both high production volumes and significant affinity to carbonation. In the context of this research, two different procedures aiming to the formation of value added materials with satisfactory CO2 uptakes were investigated as potential BF and BOF slags valorization methods. In them, carbonation was combined either with granulation and alkali activation (BOF slag), or with hydrothermal conversion (BF slag). Both treatments seemed to be effective and returned encouraging results by managing to store sufficient amounts of CO2 and generating materials with promising qualities. In particular, the performance of the granulation-carbonation of BOF slag as a method leading to the production of secondary aggregates and the sequestration of notable amounts of CO2 in a solid and stable form, was evaluated in this work. For comparison purposes, the material was also subjected to single granulation tests under ambient conditions. In an effort to improve the mechanical properties of the finally synthesized products, apart from water, a mixture of sodium hydroxide and sodium silicate was also tested as a binding agent in both of the employed processes. According to the results, the granules produced after the alkali activation of the material were characterized by remarkably greater particle sizes (from 1 to 5 mm) compared to that of the as received material (0.2 mm), and by enhanced mechanical properties, which in some cases appeared to be adequate for their use as aggregates in construction applications. The maximum CO2 uptake was 40 g CO2/kg of slag and it was achieved after 60 minutes of the combined treatment of alkali activated BOF slag. Regarding the environmental behavior of the synthesized granules, increased levels of Cr and V leaching were noticed from the granules generated by the combination of granulation-carbonation with alkali activation. Nevertheless, the combination of granulation with alkali activation or that of granulation with carbonation were found not to worsen, if not to improve, the leaching behaviour of the granules with regards to the untreated BOF slag. The formation of a zeolitic material with notable heavy metal adsorption capacity, through the hydrothermal conversion of the solid residues resulting from the calcium- extraction stage of the indirect carbonation of BF slag, was also investigated in this project. To this end, calcium was selectively extracted from the slag by leaching, using acetic acid of specific concentration (2 M) as the extraction agent. The residual solids resulting from the filtration of the generated slurry were subsequently subjected to hydrothermal conversion in caustic solution of two different compositions (NaOH of 0.5 M and 2 M). Due to the presence of calcium acetate in the composition of the solid residues, as a result of their inadequate washing, only the hydrothermal conversion attempted using the sodium hydroxide solution of higher concentration (2 M) managed to turn the amorphous slag into a crystalline material, mainly composed by a zeolitic mineral phase (detected by XRD), namely, analcime (NaAlSi2O6·H2O), and tobermorite (Ca5(OH)2Si6O16·4H2O). Finally, the heavy metal adsorption capacity of the particular material was assessed using Ni2+ as the metal for investigation. Three different adsorption models were used for the characterization of the adsorption process, namely Langmuir, Freundlich and Temkin models. Langmuir and Temkin isotherms were found to better describe the process, compared to Freundlich model. Based on the ability of the particular material to adsorb Ni2+ as reported from batch adsorption experiments and ICP-OES analysis, and the maximum monolayer adsorption capacity (Q0 = 11.51 mg/g) as determined by the Langmuir model, the finally synthesized product can potentially be used in wastewater treatment or environmental remediation applications.

Made available in DSpace on 2014-12-17T15:42:15Z (GMT). No. of bitstreams: 1 ChristianWL_DISSERT.pdf: 3506891 bytes, checksum: d575f05807a1548e862bbdb4ae0a6222 (MD5) Previous issue date: 2014-05-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work reports the synthesis of zeolites with different compositions (pure silica, Si/Ti and Si/Al), via hydroxide and fluoride medium using the cation 1-butyl-3- methylimidazolium as structure directing agent. Initially, the cation was synthesized in chloride form and used for the synthesis in hydroxide medium. An anion-exchange (Cl- for OH-) was required for the synthesis in fluoride medium. Different reactants were used for the formation of gels synthesis, resulting in the crystallization of MFI and TON phases, the latter predominant in many compositions. The cation and synthesized zeolites obtained were characterized by different techniques such as NMR, TG/DTG, XRD, SEM, N2 adsorption and desorption, DRS and EPMA. Besides characterizing the cation and zeolites, the mother liquor of hydroxide synthesis was characterized and it was possible to observe a modification of the cation in the synthesis conditions employed. The materials synthesized in this work can be applied in catalytic reactions and adsorption / Este trabalho relata a s?ntese de ze?litas de diferentes composi??es (puramente sil?cicas, Si/Ti e Si/Al), via meio b?sico e fluor?drico, utilizando o c?tion 1-butil-3- metilimidaz?lio como agente direcionador de estrutura. Inicialmente o c?tion foi sintetizado e utilizado na forma de cloreto para as s?nteses em meio b?sico e uma troca ani?nica (Cl- para OH-) foi necess?ria para as s?nteses em meio fluor?drico. Diferentes reagentes foram empregados para a forma??o dos g?is de s?ntese, resultando na cristaliza??o das fases MFI e TON, esta ?ltima predominante em muitas composi??es de gel testadas. O c?tion sintetizado e as ze?litas obtidas foram caracterizados por diferentes t?cnicas, como RMN, TG/DTG, DRX, MEV, adsor??o e dessor??o de N2, DRS e EPMA. Al?m de caracterizar o c?tion e as ze?litas, a ?gua-m?e das s?nteses em meio b?sico foi caracterizada e foi poss?vel verificar uma modifica??o do c?tion nas condi??es de s?ntese empregadas. Os materiais sintetizados neste trabalho podem ser aplicados em rea??es catal?ticas e de adsor??o

Du fait du coût élevé de certains matériaux adsorbants d’intérêt pour le traitement de la micropollution organique, l’étude a porté sur la régénération de matériaux adsorbants de type zéolithes hydrophobes et monolithe de carbone dans le cas de l’adsorption du bisphénol A et du diclofénac comme micropolluants réfractaires. Des procédés d’oxydation avancée impliquant des espèces radicalaires HO• (réaction de Fenton, électro-Fenton) et SO₄• – (activation de persulfate par voie thermique) ont été utilisés pour assurer la régénération des matériaux par désorption et dégradation oxydative des polluants fixés. La production de radicaux HO• au sein de la phase aqueuse circulant au niveau de l’adsorbant n’est pas suffisamment efficace pour sa régénération. Il a donc été envisagé de générer les radicaux au plus près des molécules adsorbées. Au cours de ce travail, une méthode sensible d’analyse par polarographie de H₂O₂ a été développée et validée pour le suivi des expériences avec les procédés mettant en jeu la réaction de Fenton. Pour différentes zéolithes, le catalyseur de la réaction de Fenton à base de fer a été incorporé préalablement dans la zéolithe. Pour le monolithe de carbone, les propriétés de conduction du matériau ont été mises à profit en l’utilisant comme cathode pour l’application du procédé électro-Fenton permettant de produire les radicaux HO• directement au sein du matériau. Cela a conduit à améliorer les performances de la régénération avec toutefois une diminution de son efficacité au cours de cycles successifs adsorption/régénération. / The elimination of organic micropollutants often requires the use of adsorption processes among the water treatments. The aim of our study is to regenerate two expensive materials (hydrophobic zeolites and carbon monoliths) to increase their life expectancy and decrease their investing cost. Two organic contaminants were targeted : diclofenac and bisphenol A, which are refractory pollutants. Advanced oxidation processes involve radical species, HO• (Fenton and electro-Fenton reactions) and SO₄• – (thermal activation of persulfate ion). These oxidants were used to decompose the adsorbed pollutants and thus regenerate the adsorbents. The HO• production, within the core of aqueous phase, did not reach satisfactory regeneration, and a loss of adsorption capacity was observed. Furthermore, during this study, a sensitive polarographic analytical method was developed and validated for the quantification of H₂O₂ in the aqueous phase. This method was used to follow in situ the Fenton reaction. The location of the catalyst in a closer vicinity of the adsorbed species was then optimized and the iron catalyst was impregnated in the host, prior to the adsorption, on different types of hydrophobic zeolites. Concerning carbon monolith, the electro-Fenton process was carried out using the material as the cathode thanks to its electrical conductivity. Consequently, HO• are produced in the porosity of monolith. This latter property enhanced the degradation of adsorbed solutes. The overall performances were increased compared to the homogeneous Fenton process. Nonetheless, a decrease of the adsorption capacities with adsorption-regeneration cycles was observed.

Dans le domaine spatial, la contamination moléculaire est un problème important pouvant affecter considérablement la performance des instruments embarqués. Selon l’environnement thermique, certaines molécules polluantes provenant du dégazage sous vide des matériaux constitutifs des satellites viennent en effet se déposer sur les surfaces sensibles tels que les optiques et les différents détecteurs. Grâce à leur structure microporeuse organisée qui leurs confèrent de remarquables capacités d’adsorption, les zéolithes sont des solides de choix pour minimiser les risques de pollution. Les films zéolithiques offrent plus précisément l’avantage d’être directement intégrés dans la structure interne des satellites, sont légers et non pulvérulents. C’est pourquoi l’objectif de cette thèse est d’étudier la synthèse de films zéolithiques sur deux types d’alliages d’aluminium, matériaux largement utilisés dans l’industrie spatiale pour leur résistance mécanique élevée. Face aux milieux de synthèse corrosifs de certaines zéolithes, la sensibilité des substrats en aluminium a été minimisée grâce à la formation d’un film microporeux de type MFI, tandis que la couche zéolithique aux propriétés d’adsorption recherchées de type FAU, EMT ou *BEA a été synthétisée à sa surface. Cette étude propose donc l’élaboration de films hybrides contenant deux couches de zéolithes de type structural différent. Divers caractéristiques telles que la cristallinité, l’homogénéité, l’épaisseur des films et l’adhésion des différentes couches entre elles et au support ont été particulièrement étudiés. Après calcination, les films zéolithiques hybrides présentent une porosité disponible et des capacités d’adsorption de molécules organiques équivalentes à celles d’une poudre. De plus, en optimisant le traitement thermique final, les propriétés mécaniques des alliages d’aluminium de départ ont pu être conservées. / In low earth orbit, global performances of satellites can be affected by contamination of critical surfaces as optical devices and detectors. On-orbit molecular contamination is due to outgassed organic pollutants emanating from spacecraft materials. One way to reduce and eliminate this phenomenon is the use of molecular adsorbents. Among them, zeolites appear to be relevant materials for contaminants retaining. Unlike common powder materials, zeolites films can also avoid the secondary dust contamination due to particles breeding and can be easily inserted in the satellite structure. As a consequence, this work deals with the synthesis of zeolite films on aluminium alloys widely used in aerospace industry for their attractive mechanical properties. When attempting to elaborate microporous films of FAU, EMT or *BEA-type zeolites selected for their relevant sorption capacities, their corrosive synthesis media dissolves the aluminium substrate. To solve this problem, a bottom layer composed of MFI-type zeolite is synthesized and acts as a protective barrier for aluminium alloys. This study is thus dedicated to the development of zeolite hybrid films composed by two different structure-type layers. Various parameters such as crystallinity, homogeneity, film thickness and adhesion between both zeolite layers and the substrates were particularly studied in order to elaborate space-qualified materials. Once calcined, the sorption capacities of these hybrid films were identical to corresponding powders. Moreover, by optimizing the calcination step, the mechanical properties of the starting aluminium alloys are kept.

La protection de l’environnement et de la santé humaine représente une préoccupation éthique et scientifique primordiale. Les dioxines/furanes, produits, entre autres, par les processus d’incinération de déchets, font partie des polluants les plus dangereux de par leur stabilité et leur faculté à être bio-accumulés. Les polychlorobenzènes sont souvent référencés comme molécules modèles de ces composés et seront utilisés en tant que tels dans ces travaux de thèse. Grâce à leurs structures microporeuses organisées qui leur confèrent de remarquables capacités d’adsorption, les zéolithes et les Metal-Organic Frameworks (MOFs) représentent des matériaux de choix pour piéger ces polluants organiques. Leur mise en forme sous forme de billes par exemple offre l’avantage de s’affranchir de problèmes tels que le colmatage ou les pertes de charges trop importantes pouvant apparaître pour une application à l’échelle industrielle. C’est pourquoi, cette thèse vise à élaborer et caractériser des adsorbants zéolithiques et de type MOF, de les mettre en forme et d’étudier leurs propriétés d’adsorption vis-à-vis de polychlorobenzènes/dioxines/furanes. L’ensemble des zéolithes et MOFs ont été sélectionnés et préparés de sorte à optimiser leurs caractéristiques structurales, texturales et morphologiques pour les applications ciblées. Une étude sur la mise en forme de la zéolithe de type FAU a conduit à l’élaboration de billes présentant de bonnes propriétés mécanique et d’adsorption. Les différentes mesures d’adsorption de polychlorobenzènes/dioxines/furanes en phases gaz et liquide ont permis de mettre en évidence les meilleurs matériaux pour l’adsorption sélective de ces polluants à l’émission d’usines d’incinération de déchets. / Environmental and human health protection is a scientific and ethical concern. Dioxin/furan compounds, produced from waste incineration process among other, are ones of the most dangerous pollutants due to their stability and ability to bio-accumulate. Polychlorobenzenes are often referred as model molecules of these compounds and will be used as it in this PhD work. Thanks to their microporous organized structures which confer to them remarkable adsorption capacities, zeolites and Metal-Organic Frameworks (MOFs) are interesting materials to trap these organic pollutants. Their shaping as beads for example offer the advantage to overcome problems such as clogging or excessive pressure losses that can appear for an industrial application. Therefore, the aim of this PhD is to prepare and characterize zeolite and MOF, to shape them and to study their adsorption properties for polychlorobenzenes/dioxins/furans. All zeolites and MOFs have been selected and prepared in order to optimize their structural, textural and morphological characteristics for the intended application. A study on the shaping of the FAU-type zeolite has allowed the development of beads with good mechanical and adsorption properties. The different polychlorobenzenes/dioxins/furans adsorption tests into gas and liquid phases allowed identifying the best solids for the selective adsorption of these pollutants in waste incineration plant emissions.

A 25% niobium substituted sitinakite was exchanged with strontium as time resolved X-ray diffraction data was collected. The structural modeling of this data by Rietveld method1 has lead to the determination of the atomic positions of the ions and unit cell parameters as strontium occupancy increases. The starting material of the exchange experiment is the protonated phase, H2Nb0.67Ti1.33SiO7·1.9 H2O, with space group P42/mcm2,3. Once strontium (Sr2+) enters the unit cell, extra-framework H2O molecules shift to provide the necessary hydration coordination. These new positions of H2O result in a lowering of symmetry to the P-42m space group, and it is thought that the new hydrogen bonding network serves to enhance strontium ion diffusion into the channels of sitinakite. Exchange of strontium into the microporous material reaches a maximum fractional occupancy of 21% when a 10.0 mM strontium ion solution is forced over the powdered material. Sequestration of strontium into this material has contributed valuable information to the study of microporous materials and ion exchange chemistries.