The reduction of sulphur in transportation fuel has gained significant importance as the regulatory agencies worldwide react to air quality concerns and the impact of sulphur oxides on the environment. The overall objective of this research was to identify, develop and characterize, based on underlying scientific principles, sorbents that are effective in removal of refractory sulphur compounds from fuel through the process of selective adsorption. It was determined that impregnation of powdered activated carbon with a transition metal (TM) significantly boosted the adsorption performance of the activated carbon. It is hypothesized that the impregnation resulted in the formation of new adsorptive sites that strongly interacted with the lone pairs of electrons on sulphur and nitrogen while having minor impact on the existing oxygen functional groups on the surface of the activated carbon. The percent loading of the TM was determined through wet adsorption study. The best performing sorbent was shown to have maximum adsorption capacities of approximately 1.77 and 0.76 mmol-S/g-sorbent for DBT and 4,6 DMDBT, respectively, with approximately 100% regenerability through solvent wash and thermal treatment. On average, the PTM impregnation showed approximately 137% increase in adsorption capacity of the activated carbon. The sorbent also has good adsorption capacities for organo-nitrogen compounds (i.e., quinoline and carbazole) and a low selectivity towards aromatics, which is desired in adsorptive desulphurization. The surface morphology of the activated carbon, the oxygen functional groups on the surface of the activated carbon, as well as strong (chemisorption) interaction between the TM???s partly vacant and far reaching ???d??? orbital and lone pair electrons on sulphur and nitrogen are considered to be the main contributing factors to the observed enhancement. It was established in this study that the adsorption isotherms of the impregnated activated carbons best fit Sips isotherm equation, which is a combination of the Langmuir and Freundlich equations. This finding fits well with our initial hypothesis regarding the introduction of new adsorptive sites as a result of TM impregnation and that the sites did not fit well with Langmuir???s monolayer and uniform adsorption mechanism. A kinetic study of the sulphur adsorption using a flow reactor showed a good fit with pseudo second order kinetic model, indicative of an adsorption that is highly dependent on the concentration of available sites on the surface of the sorbent. On average, as expected, the TM impregnated ACC exhibited a higher initial rate of adsorption. The adsorption onto TM sites tends to be more exothermic than adsorption (mainly physisorption) on activated carbon. Therefore, more thermodynamically favoured chemisorption is expected to occur more rapidly than physisorption. It was determined that on average, the initial adsorption rate does not change significantly with temperature while the sulphur adsorption capacity decreases with increase in temperature. It is postulated that the increase in temperature increases surface diffusivity but impedes diffusion flux. The impediment of the diffusion flux will result in reduction in adsorbed quantity. It was also shown that the intra-particle diffusion exists in the adsorption of DBT on TM impregnated activated carbon, however, it is not likely that the overall adsorption is controlled or noticeable impacted by it. As the temperature of the reactor increases the Weber-Morris intra-particle diffusion plot moves away from the origin, and thus intra-particle diffusion becomes less of a controlling mechanism. This further confirms the fact that the boundary layer (i.e., surface diffusion) and potentially adsorptive interactions at the surface are the dominating mechanisms in the sulphur adsorption onto TM impregnated activated carbon. It was determined that the distribution of TM species on the surface of the activated carbon is relatively inhomogeneous, with some areas showing well dispersed TM species while other areas showing large clusters. Different impregnation method that can improve dispersion on the surface may significantly enhance adsorption performance of the sorbent. Furthermore, in this study impregnation of activated carbon using several other transition metals were examined. It was determined that other less expensive transition metals can also improve the adsorption performance of the activated carbon. Further study on less expensive options for impregnating the activated carbon may be beneficial.

Sample preparation is the most error-prone step in chemical analysis. A great deal of efforts has been made to develop efficient techniques and protocols for sample preparation to accomplish important goals such as miniaturization and implementation of green analytical methodologies. Solid-phase microextraction (SPME) has successfully eliminated the use of hazardous organic solvents in extraction sampling, sample preparation, preconcentration and sample introduction to the analytical instrument in an effective manner. Ensuring thermal- and solvent-instability of traditional SPME extraction phases represented one of their main drawbacks. This was solved by the introduction of sol-gel SPME phases characterized by enhanced thermal-, solvent-, and stability over a wide pH range. Sol-gel SPME phases (sorbents) facilitated excellent preconcentration effects for a wide range of analytes. In this dissertation, hydrolytic and nonhydrolytic sol-gel routes were explored for the creation of zirconia-, titania-, and niobia-based novel hybrid organic-inorganic sorbents using sol-gel active polymeric ligands. These sorbents were prepared in the form of surface coatings for capillary microextraction and preconcentration of biologically important molecules such as catecholamine neurotransmitters and phosphopeptides. In comparison with other sorbents made only of inorganic transition metal oxides, the presented sol-gel sorbents facilitated efficient desorption of the extracted analytes by LC-MS compatible mobile phases. The sol-gel zirconia- and titania-based hybrid sorbents provided pH-stable (pH range: 0 - 14) and derivatization-free extraction media that effectively overcame the major drawbacks of traditional sorbents for the analysis of catecholamines (silica-based sorbents suffer from narrow operational pH window while polymer-based sorbents require additional sample derivatization steps). The modification of the terminal hydroxy groups in PPO with ZrCl4 or TiCl4 provided an enhanced sol-gel reactivity of the polymer modified-terminals. Such a modification procedure allowed for an efficient incorporation of the polymeric ligand into the evolving sol-gel network. The effectiveness of the PPO modification was also evaluated by a systematic thermogravimetric investigation exploring the loading of the ligand in sol-gel hybrid sorbents, which revealed an enhanced ligand-loading achieved via the nonhydrolytic sol-gel route used with modified-PPO. Sol-gel hybrid sorbents prepared by the nonhydrolytic sol-gel (NHSG) pathway provided excellent microextraction performance for catecholamines: low detection limits (5.6 – 9.6 pM), enhanced run-to-run reproducibility (RSD 0.6 – 5.1 %), excellent desorption efficiency (95.0 – 99.5 %) and high enrichment factors (EF) for epinephrine (EF ~ 1480) and for dopamine (EF ~ 2650) extracted from aqueous and synthetic urine samples at pH 10.5. Run-to-run and capillary-to-capillary reproducibility remained below 5 % when the peak area or the sorbent-mass was used as the reproducibility criterion. Niobia-based sol-gel sorbents prepared with and without organic ligand (polyethylenimine) were utilized as microextraction media for the enrichment of phosphorylated and nonphosphorylated tetrapeptide VYKA. Sol-gel niobia-based sorbents with covalently anchored polyethylenimine showed excellent selectivity toward the phosphopeptide compared to analogous titania-based sorbents. Specific extraction (SE) values were higher by 97.0 % when obtained by niobia-based sorbents. Excellent run-to-run peak area reproducibility (RSD < 5.1 %) and high EF of ~ 4000 were achieved. The sol-gel niobia-based coating facilitated excellent desorption efficiency (97.5 %), which suggests that the surface of the niobia sorbent possesses moderate-strength Lewis acid sites that avoided the need for special elution solvents that are conventionally used for the desorption of phosphorylated molecules from titania-based sorbents. The sol-gel pathway for the creation of microextraction phases is versatile and capable to provide unique control on the characteristics of the sorbents that are critically important for many sample preparation applications.

Aim of this thesis is to design a technology of a flue gas desulphurization of fluidized bed boiler. Currently, the state of technology is not able to provide flue gas desulphurisation to required level. For this reason it is necessary to build additional device for the desulphurisation. Theoretical part of the thesis deals with the emission limits of sulphur dioxide, available methods of desulphurization and sorbents suitable for the desulfurization. In practical part conditioned dry sorption method is chosen for the specified source, technological and structural design for suggested desulphurization technology including design of all device is proposed. The thesis also includes a technology design and a 3D model.

No description available.

Целью ВКР является разработка процесса извлечения цветных металлов из гальванического шлама. Предложен вариант аммиачного растворения гальванического шлама, обеспечивающий селективный перевод в раствор никеля. Изучено сорбционное поведение никеля в сернокислых и аммиачных растворах. / The object of this work is to develop the process of extraction of non-ferrous metals from galvanic sludge. The variant of electroplating sludge leaching by ammonium solution, providing selective transfer of nickel in solution is proposed. Sorption behavior of nickel in sulfuric acid and ammonia solutions was studied.

No description available.

Segundo a Organização Mundial da Saúde (OMS), a esquizofrenia é reconhecida como um transtorno neuropsiquiátrico grave que afeta mais de 21 milhões de pessoas em todo o mundo. Para diminuir os sintomas associados a esta doença, a maioria dos pacientes esquizofrênicos fazem uso concomitantemente de antipsicóticos, antidepressivos, ansiolíticos e anticonvulsivantes. O desenvolvimento de métodos analíticos para a determinação desses fármacos em fluidos biológicos é importante para ajustar as doses administradas, minimizar os efeitos adversos e verificar a anuência do paciente à terapia. A química analítica moderna tem se direcionado para a simplificação, através da miniaturização dos sistemas analíticos. Neste contexto, pode-se destacar a técnica de microextração em sorvente empacotado (MEPS). O desenvolvimento de novas fases extratoras para MEPS, como, os monolitos de sílica híbrida permitem pré-concentração seletiva dos analitos. Neste projeto monolitos de sílica híbrida funcionalizados com grupos aminopropil ou cianopropil foram sintetizados pelo processo sol-gel. Estes monolitos apresentaram estrutura contínua, uniforme e porosa, como evidenciado pelas imagens de microscopia eletrônica de varredura (MEV). As análises de espectroscopia vibracional na região do infravermelho por transformada de Fourier (FTIR) dos monolitos de sílica híbrida exibiram picos facilmente identificáveis, característicos dos grupos cianopropil e aminopropil. Estes monolitos foram avaliados como fase estacionária para a MEPS para a determinação de fármacos em amostras de plasma por cromatografia líquida acoplada a espectrometria de massa em Tandem (LC-MS/MS). As variáveis MEPS (influência do pH na sorção dos analitos, número de ciclos aspirar/dispensar, etapa de limpeza do sorvente e solvente de eluição) foram otimizadas para aumentar a eficiência da extração. Em comparação com a fase de sílica híbrida aminopropil, a fase de sílica híbrida cianopropil apresentou maior capacidade de sorção para os fármacos em estudo. O método desenvolvido, MEPS/LC-MS/MS, empregando a fase extratora de sílica híbrida cianopropil, apresentou linearidade adequada com concentrações que variaram desde o limite inferior de quantificação (0,05-1,00 ng.mL-1) até o limite superior de quantificação (40-10.500 ng.mL-1) com coeficientes de determinação (R2) maiores do que 0,9955. Este método apresentou precisão com coeficientes de variação (CV) inferiores a 14% e exatidão com erro padrão relativo (EPR) de -12 a 14%. O método MEPS/LC-MS/MS foi aplicado com êxito para análise simultânea de cinco antipsicóticos (olanzapina, quetiapina, clozapina, haloperidol e clorpromazina), em combinação com sete antidepressivos (mirtazapina, paroxetina, citalopram, sertralina, imipramina, clomipramina e fluoxetina), dois anticonvulsivantes (carbamazepina e lamotrigina) e dois ansiolíticos (diazepam e clonazepam) em amostras de plasma de pacientes esquizofrênicos para fins de monitorização terapêutica. / According to World Health Organization (WHO), schizophrenia is recognizably a devastating neuropsychiatric disorder that affects more than 21 million people worldwide. To lessen the symptoms associated with the disease, most schizophrenic patients use other classes of drugs such as antidepressants, anxiolytics, and anticonvulsants concomitantly with antipsychotics. Developing analytical methods to quantify these drugs in biological fluids is important in therapeutic drug monitoring (TDM) to adjust doses, minimize adverse effects, and check patient adherence to the therapy. Regarding miniaturization and automation, microextraction by packed sorbent (MEPS) is a promising sample preparation technique. Sample preparation of biological matrixes is an important step in analytical processes: it removes endogenous components from the sample and pre-concentrates trace-level analytes. The development of new phases for MEPS such as the hybrid silica monoliths allows selective pre-concentration of the analytes. The present study reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the solgel process; evaluates these monoliths as selective stationary phase for MEPS to determine drugs in plasma samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS); and discusses important factors (influence of pH on the sorption of analytes, number of draw/eject cycles, washing step, and elution solvent) related to the optimization of MEPS efficiency. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network, as shown by scanning electron microscopy (MEV) images. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method, MEPS/LC-MS/MS, afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05 to 1.00 ng.mL-1) to the upper limit of quantification (40 to 10500 ng.mL-1); the coefficients of determination (R2) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12 to 14%. The developed MEPS/LC-MS/MS method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for TDM purposes.

SESMR (Sorption Enhanced Steam Methane Reforming), SMR (Steam Methane Reforming) avec capture de CO2 in situ par un adsorbant solide, peut amener à une exploitation durable du gaz naturel pour la production de H2. La thèse, partie du projet de recherche ASCENT (Advanced Solid Cycles with Efficient Novel Technologies), concerne le développement de matériaux combinés adsorbants catalyseurs Ni-CaO-mayenite pour le SESMR, aux fins d’étudier les influences dues à la fraction de Ni, aux sels précurseurs du Ni (Ni acétate ou Ni nitrate), et à la fraction de CaO disponible. Les techniques ICP AES, XRD, BET/BJH, SEM/EDS, TEM/EDS, TPR et TGA ont été utilisés pour caractériser les matériaux synthétisés. La réactivité a été évaluée par des tests en lit fixe à l’échelle du microréacteur, qui ont aussi permis une sélection des matériaux les plus prometteurs pour une étude de l’applicabilité industrielle par tests multi cycliques SESMR/régénération de solides par un réacteur automatisé à lit fixe. / Sorption enhanced steam methane reforming (SESMR), steam methane reforming (SMR) with in situ CO2 sorption by a solid sorbent, can lead to a sustainable exploitation of natural gas to produce H2. (CSCM). This thesis, as a part of ASCENT (Advanced Solid Cycles with Efficient Novel Technologies) project, deals with Ni-CaO-mayenite combined sorbent-catalyst material for SESMR, to study the effect of Ni fraction, its precursor salt (Ni nitrate or Ni acetate), and free CaO fraction. ICP AES, XRD, BET and BJH methods, SEM EDS, TEM EDS, TPR and TGA were used to characterize synthesized materials. Their reactivity was evaluated by tests in a packed bed microreactor, which served also as a screening tool to choose the most promising materials. Their industrial applicability was assessed by multicycle SESMR/regeneration tests in an automated packed bed bench scale rig.

A wide range of organic compounds are released from building and furnishing products and these have the potential to adversely affect indoor air quality. There are growing international requirements for testing and controlling these emissions for the protection of public health. The test methods require specialist analytical chemistry facilities based on thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). This project has addressed the need for better performance and greater automation of the analysis, as well as development of simpler screening tests. A variety of products were tested using screening techniques, with an emission cell method being used as a reference test. Short duration tests, using a micro-scale chamber at slightly elevated temperature, were shown to have the potential to predict emissions occurring during longer term reference tests. Multi-sorbent air sampling tubes, that have the potential to extend the volatility range of compounds determined by a single TD/GC/MS analysis, were compared with Tenax TA tubes specified by current standard methods. This showed no difference in performance for the range of compounds for which Tenax is optimal, with improved performance for a number of more volatile compounds. The determination of formaldehyde was investigated using 2-hydroxymethylpiperidine as a derivatising agent, followed by TD/GC/MS. The results showed the possibility of this method being developed as an alternative to the current standard method that involves solvent elution and liquid chromatography. The performance of a newly developed time-of-flight mass spectrometer was compared with a standard quadrupole instrument. This showed its potential, with the use of re-collection, to extend the concentration range of compounds quantified from a single air sample, of particular benefit for the determination of carcinogens. New compound identification software was applied to increase automation of analysis of the TD/GC/MS data. Good correlation with manual processing was achieved, demonstrating the possibility of routine application to material emissions testing.

abstract: Amine-modified solid sorbents and membrane separation are promising technologies for separation and capture of carbon dioxide (CO2) from combustion flue gas. Amine absorption processes are mature, but still have room for improvement. This work focused on the synthesis of amine-modified aerogels and metal-organic framework-5 (MOF-5) membranes for CO2 separation. A series of solid sorbents were synthesized by functionalizing amines on the surface of silica aerogels. This was done by three coating methods: physical adsorption, magnetically assisted impact coating (MAIC) and atomic layer deposition (ALD). CO2 adsorption capacity of the sorbents was measured at room temperature in a Cahn microbalance. The sorbents synthesized by physical adsorption show the largest CO2 adsorption capacity (1.43-1.63 mmol CO2/g). An additional sorbent synthesized by ALD on hydrophilic aerogels at atmospheric pressures shows an adsorption capacity of 1.23 mmol CO2/g. Studies on one amine-modified sorbent show that the powder is of agglomerate bubbling fluidization (ABF) type. The powder is difficult to fluidize and has limited bed expansion. The ultimate goal is to configure the amine-modified sorbents in a micro-jet assisted gas fluidized bed to conduct adsorption studies. MOF-5 membranes were synthesized on &alpha;-alumina supports by two methods: in situ synthesis and secondary growth synthesis. Characterization by scanning electron microscope (SEM) imaging and X-ray diffraction (XRD) show that the membranes prepared by both methods have a thickness of 14-16 &mu;m, and a MOF-5 crystal size of 15-25 &#956;m with no apparent orientation. Single gas permeation results indicate that the gas transport through both membranes is determined by a combination of Knudsen diffusion and viscous flow. The contribution of viscous flow indicates that the membranes have defects. / Dissertation/Thesis / M.S. Chemical Engineering 2010