Many parts of the world are facing water crises due to the lack of clean drinking water. Growing industrialization in many areas and extensive use of chemicals for various concerns has increased the burden of deleterious contaminants in drinking water especially in developing countries. It is reported that nearly half of the population in developing countries suffers from health problems associated with lack of potable drinking water as well as the presence of microbiologically contaminated water [1] . Synthetic and natural organic contaminants are considered among the most undesirable contaminants found in water. Various treatment processes are applied for the removal of organic contaminants from water including reverse osmosis membranes, ion exchange, oxidation, nanofiltration, and adsorption. The adsorption process is a widely-used technology for the removal of organic compounds from water. In this work, the adsorption of chloroform and methyl tertiary butyl ether (MTBE) onto granular zeolites was investigated. Zeolites were specifically chosen because they have shown higher efficiency in removing certain organics from water than granular activated carbon (GAC). Batch adsorption experiments to evaluate the effectiveness of several granular zeolites for the removal of MTBE and chloroform from water were conducted and the results compared with GAC performance. Results of these batch equilibrium experiments showed that ZSM-5 was the granular zeolite adsorbent with the greatest removal capacity for MTBE and chloroform from water, and outperformed GAC. Fixed-bed adsorption experiments with MTBE and chloroform were performed using granular ZSM-5. Breakthrough curves obtained from these column experiments were used to understand and predict the dynamic behavior of fixed bed adsorbers with granular ZSM-5. The ii film pore and surface diffusion model (FPSDM) was fit to the breakthrough curve data obtained from the fixed bed adsorption experiments. The FPSDM model takes into account the effects of axial dispersion, film diffusion, and intraparticle diffusion mechanisms during fixed bed adsorption. Generally, good agreement was obtained between the FPSDM simulated results and experimental breakthrough profiles. This study demonstrated that film diffusion is the primary controlling mass transfer mechanism and therefore must be accurately determined for good breakthrough predictions.

published_or_final_version / Physiology / Master / Master of Philosophy

abstract: Chloroform (CHCl3) is an important atmospheric pollutant by its direct health effects as well as by its contribution to photochemical smog formation. Chloroform outgassing from swimming pools is not typically considered a source of atmospheric CHCl3 because swimming pools are scarce compared to other sources. However, large urban areas in hot climates such as Phoenix, AZ contain a substantial amount of swimming pools, potentially resulting in significant atmospheric fluxes. In this study, CHCl3 formation potential (FP) from disinfection of swimming pools in Phoenix was investigated through laboratory experiments and annual CHCl3 emission fluxes from swimming pools were estimated based on the experimental data. Swimming pool water (collected in June 2014 in Phoenix) and model contaminants (Pharmaceuticals and Personal Care Products (PPCPs), Endocrine Disrupting Compounds (EDCs), artificial sweeteners, and artificial human waste products) were chlorinated in controlled laboratory experiments. The CHCl3 production during chlorination was determined using Gas Chromatography-Mass Spectrometry (GC-MS) following solid-phase microextraction (SPME). Upon chlorination, all swimming pool water samples and contaminants produced measureable amounts of chloroform. Chlorination of swimming pool water produced 0.005-0.134 mol CHCl3/mol C and 0.004-0.062 mol CHCl3/mol Cl2 consumed. Chlorination of model contaminants produced 0.004-0.323 mol CHCl3/mol C and 0.001-0.247 mol CHCl3/mol Cl2 consumed. These numbers are comparable and indicate that the model contaminants react similarly to swimming pool water during chlorination. The CHCl3 flux from swimming pools in Phoenix was estimated at approximately 3.9-4.3 Gg/yr and was found to be largely dependent on water temperature and wind speed while air temperature had little effect. This preliminary estimate is orders of magnitude larger than previous estimates of anthropogenic emissions in Phoenix suggesting that swimming pools might be a significant source of atmospheric CHCl3 locally. / Dissertation/Thesis / Masters Thesis Chemistry 2014

A novel, portable, filter fluorometer was developed for the determination of chloroform and TCE at environmentally-relevant levels when coupled with improved sampling techniques and reagents. Reagents selective for the TCE or chloroform convert these toxic species into fluorescent species that can be monitored. The fluorometer is based on LED excitation light sources, a battery-operated photomultiplier tube as a radiation detector, and appropriate excitation and emission filters. A unique low-power, miniature heater inside the cell holder of the fluorometer provides control of the temperature of the reagent solution above ambient temperature. The fluorometer and the sampling systems, including a miniature air pump, are portable and can be operated from a small lead battery over an entire day. Sparging, passive transfer, and membrane sampling techniques were used to transfer TCE or chloroform from the sample solution as a vapor into the appropriate reagent and to provide preconcentration. The apparatus for membrane sampling was improved to be applicable for continuous sampling of water in the field situations with minimal sample manipulation. Each of the three sampling techniques provides a transfer rate of the analyte of ~1 ng/min per ng/mL of analyte in the sample. The optimized reagent based on 1-(3-pyridylmethyl)urea provides high selectivity to chloroform and the reagent based on isonicotinamide has excellent selectivity to TCE. These two reagents serve as an alternative to the more common pyridine reagent for the determination of chloroform or TCE in water and eliminate the exposure of the user to toxic pyridine vapor. The developed filter fluorometer, the optimized reagents, and the membrane sampling technique provide a detection limit for chloroform of 0.2 and 10 ng/mL, respectively, with the pyridine and 1-(3-pyridylmethyl)urea reagent. The detection limit for TCE is 0.3 ng/mL with the isonicotinamide reagent. For TCE, the detection limit is almost two orders of magnitude better than obtained previously with a fluorometric technique. Analysis times vary from 15 to 30 min. / Graduation date: 2003

Doctor Pharmaceuticae - DPharm / Natural products have been an important source of drugs and novel lead compounds in drug discovery. Their unique scaffolds have led to the synthesis of derivatives that continue to give rise to medicinally relevant agents. Thus, natural product-inspired drugs represent a significant proportion of drugs in the market and with several more in development. Cancer is among the leading public health problems and a prominent cause of death globally. Chemotherapy has been important in the management of this disease even though side effects that arise due to lack of selectivity is still an issue.

<p> A detailed experimental and theoretical study has been performed on several different photochemical systems. Lead-salt tunable diode lasers operating in the infrared region have been used as diagnostic tools to probe the molecules in these gaseous systems. Knowledge of these systems is expected to be useful in evaluating future schemes of laser isotope separation.</p> <p> In the course of this work a computerized digital technique has been developed that allows molecular parameters such as linestrength and linewidth to be obtained by measuring the infrared absorption on vibrational-rotational transitions of the molecule. Molecular concentrations can then be determined enabling one to gain valuable insight into the chemical processes occurring in the system.</p> <p> The digital technique was first tested on CO2 gas in a multi-pass White cell to verify the validity of the measurements. Subsequently, measurements were performed on mixtures of NH3/N2, NH3/Ar, HTO/H2O, and HTO/air. Those NH3 measurements that could be compared to previous measurements were found to be very accurate. For the HTO system, no previous measurements on linestrength and linewidth for the transitions examined have been performed.</p> <p> Described next is the application of the tunable diode laser diagnostic system to the investigation of infrared multiphoton dissociation of deuterated chloroform immersed in a chloroform bath. The sensitivity of the technique allowed for the measurement of the few parts per million of DCl formed by the photolysis of natural abundance CDCl3 in CHCl3.</p><p> In addition, the feasibility of transient detection with tunable diode lasers was examined. High fluence CO2 laser pulses were used to dissociate C3F6 or C2F3Cl and create CF2 radicals. Current-modulation of the tunable diode laser made it possible to monitor the transient CF2 radicals as they were formed, and as they subsequently decayed. The sensitivity of the transient detection technique was found to be limited by detector noise.</p> / Thesis / Master of Science (MSc)

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-08-25T16:15:33Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_karine_laste_macagnan.pdf: 989328 bytes, checksum: a2029037b34e4625051db4296d4fad83 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-08-28T20:59:34Z (GMT) No. of bitstreams: 2 dissertacao_karine_laste_macagnan.pdf: 989328 bytes, checksum: a2029037b34e4625051db4296d4fad83 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-08-28T20:59:41Z (GMT) No. of bitstreams: 2 dissertacao_karine_laste_macagnan.pdf: 989328 bytes, checksum: a2029037b34e4625051db4296d4fad83 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-28T20:59:48Z (GMT). No. of bitstreams: 2 dissertacao_karine_laste_macagnan.pdf: 989328 bytes, checksum: a2029037b34e4625051db4296d4fad83 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-12-04 / Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS / O poli(3-hidroxibutirato) [P(3HB)] é o biopolímero mais estudado e caracterizado dentre a família dos polihidroxialcanoatos (PHAs), termoplásticos que têm como principais características a rápida biodegradabilidade e a biocompatibilidade. O processo de recuperação do bioplástico consiste em uma etapa importante no processo de produção. O desenvolvimento de metodologias mais seguras, econômicas e ambientalmente corretas, e que permitam um alto rendimento desse biopolímero, torna-se necessário para uma produção de P(3HB) economicamente e ecologicamente atrativa. Portanto, o objetivo do trabalho foi otimizar a metodologia clássica de recuperação de poli(3-hidroxibutirato) utilizando clorofórmio como solvente. O bioprocesso foi realizado em duas etapas, utilizando linhagem de Ralstonia solanacearum. O inoculo foi produzido em Erlenmeyers aletados de 500 mL, contendo 160 mL de meio YM e 40 mL de suspensão bacteriana, mantidos em incubador agitador orbital por 24 h, 150 rpm e 28 °C. A segunda etapa, produção de P(3HB), foi realizada utilizando Erlenmeyers aletados de 500 mL, contendo 160 mL de meio F4 e 20 % de inóculo, mantidos em 28 °C, 200 rpm e 72 h em incubador agitador orbital. Após a fermentação, as células foram separadas por centrifugação a 10.000 x g, lavadas com solução salina 0,89 % e secas a 56 °C. O acúmulo de P(3HB) na célula foi quantificado por cromatografia gasosa. A metodologia de extração foi otimizada em relação aos parâmetros: tempo de extração (2 h a 15 min), separação da biomassa/solução extrativa (papel filtro ou funil de separação), estado de célula (seca ou fresca) e proporção de solvente (10:1, 20:1 e 40:1 v/m). Por evaporação da solução extrativa foram obtidos filmes poliméricos. Os filmes recuperados foram analisados física e quimicamente por Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Calorimetria Diferencial de Varredura (DSC), Análise Termogravimétrica (TGA) e Cromatografia de Permeação em Gel (GPC). O acúmulo de P(3HB) foi de 51,15 %. Os maiores rendimentos de filme foram obtidos após 30 min de aquecimento, utilizando funil de decantação para separar a solução extrativa da biomassa, célula seca, e proporção de solvente 40:1 v/m, alcançando-se recuperação de 98 % do polímero acumulado. A análise dos filmes através de FTIR resultou em bandas características de P(3HB). Os filmes oriundos de células secas tiveram temperaturas inicial e final de degradação e grau de cristalinidade superiores aos filmes de célula fresca. Todavia, os últimos apresentaram massa molar maior do que os primeiros. A metodologia clássica de extração química de poli(3-hidroxibutirato) por clorofórmio com aquecimento pode ser otimizada, resultando em redução de 75 % do tempo de aquecimento e separação da biomassa/solução extrativa mais rápida e econômica. Porém, não foi possível substituir a utilização de massa celular seca por fresca nem reduzir a proporção inicial de solvente de 40:1 (v/m). / Poly (3-hydroxybutyrate) [P(3HB)] is the most important biopolymer from the polyhydroalcanoates (PHAs) families, and they are thermoplastics with rapid biodegradability and biocompatibility. The recovery process of bioplastics is an important stage in the production process. Development of safe, economic and environmentally friendly methodologies, that result in high yield biopolymer, is necessary for the attractive P(3HB) production. Therefore, the objective was to optimize the classical methodology for poly (3-hydroxybutyrate) recovery using chloroform as solvent. The bioprocess was performed in two phases, with Ralstonia solanacearum strain. In the first phase, inoculum production, was performed in Erlenmeyer 500 mL flasks, containing 160 mL medium YM and 40 mL bacterial suspension. The flasks were incubated in shaker for 24 h, 150 rpm and 28 °C. The second phase, P(3HB) production, was performed using Erlenmeyer 500 mL flask, containing 160 mL medium F4 and 20 % (v/v) inoculum, maintained in 28 °C, 200 rpm and 72 h. After fermentation cells were separated by centrifugation at 10,000 x g, washed with saline (0,89 % w/v) and dried at 56 °C. P(3HB), accumulation was quantified by gas chromatography. The extraction methodology was optimized according to: extraction time (2 h - 15 min), extractive solution/biomass separation (paper filter or separation funnel), state of cell (dry or fresh), and solvent ratio (10:1, 20:1 and 40:1 v/m). Polymeric films were obtained by evaporation from extractive solutions and they were analysed by Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Gel Permeation Chromatography (GPC). The P(3HB) accumulation was 51,15 %. Highest yields of film were obtained after 30 min heating, by funnel for extractive solution recovery, dry cell and solvent ratio 40:1 v/m; and highest recovery was 98 % of cumulated polymer in the cell. Characteristic bands of P(3HB) were obtained to produced films by FTIR analysis. Films from dried cells showed initial and final degradation temperature and crystallinity degree higher than and films these from fresh cell, however, they showed higher molar weight than the first ones. The classical chemical extraction of P(3HB) by chloroform with heating can be optimized, resulting in a 75 % reduction as well heating time extraction solution most fastest and economical. However, wasn’t possible replace the dry cell mass use by fresh cell mass or reduce the initial solvent proportion [40:1 (v/m)].

Solvents have been used in endodontic retreatment for a long time and the dissolving effect is well proven. Latterly chloroform has come in a bad light due to its possible carcinogenicity. Despite the negative health effect it is still used in dental environment. Other more biocompatible solvents have now reached the market and tests should be performed to evaluate the softening efficacy. The purpose of this in-vitro study was to evaluate the softening efficacy of four different solvents used in endodontics; chloroform, eucalyptol, tetrachloroethylene, orange-oil and a control group. 100 simulated canals filled with gutta-percha, epoxy amine resin based sealer, zinc oxide eugenol based sealer and non eugenolcalcium hydroxide based sealer were tested with hardness measurement before and after two minutes exposure time of medicament. Non-eugenol calcium hydroxide failed to set and was excluded from the test. A Shore A durometer was used to evaluate the hardness of the materials and all data was first analyzed with Kruskal-Wallis test and then Mann-Whitney test to compare with control group. With a digital camera connected to a microscope we also took pictures to compare the impressions with the different medicaments. The result showed that chloroform and tetrachloroethylene is significant better to soften gutta-percha than control group (p &lt; 0.05) but only chloroform significant better than control group to soften epoxy amine resin based sealer and zinc oxide eugenol based sealer (p &lt; 0.05). Even if the result was significant, we cannot draw any conclusions due to small sample size.

Little is known about the enzyme-substrate interactions occurring during the dechlorination of chloroform (CF) and 1,1,1-trichloroethane (1,1,1-TCA) by the enrichment culture containing Dehalobacters, hereafter called DHB-CF/MEL. Compound specific isotope analysis (CSIA) is used to investigate the factors which may affect the isotope fractionation observed for CF and 1,1,1-TCA dechlorination. This thesis reports the first isotope enrichment factors observed for CF biodegradation at -27.5‰ ± 0.9‰, thus providing fundamental information for comparing isotope enrichment factors observed during trichlorinated alkane degradation by DHB-CF/MEL. The thesis also reports how the presence of CF and 1,1,1-TCA influences isotope fractionation and explores the possible influence of substrate inhibition on isotope fractionation during 1,1,1-TCA dechlorination. The data suggests that substrate inhibition during 1,1,1-TCA dechlorination by DHB-CF/MEL may not affect carbon isotope fractionation. The results suggest that CSIA is a promising monitoring tool even for the simultaneous biodegradation of CF and 1,1,1-TCA at different 1,1,1-TCA starting concentration.

Little is known about the enzyme-substrate interactions occurring during the dechlorination of chloroform (CF) and 1,1,1-trichloroethane (1,1,1-TCA) by the enrichment culture containing Dehalobacters, hereafter called DHB-CF/MEL. Compound specific isotope analysis (CSIA) is used to investigate the factors which may affect the isotope fractionation observed for CF and 1,1,1-TCA dechlorination. This thesis reports the first isotope enrichment factors observed for CF biodegradation at -27.5‰ ± 0.9‰, thus providing fundamental information for comparing isotope enrichment factors observed during trichlorinated alkane degradation by DHB-CF/MEL. The thesis also reports how the presence of CF and 1,1,1-TCA influences isotope fractionation and explores the possible influence of substrate inhibition on isotope fractionation during 1,1,1-TCA dechlorination. The data suggests that substrate inhibition during 1,1,1-TCA dechlorination by DHB-CF/MEL may not affect carbon isotope fractionation. The results suggest that CSIA is a promising monitoring tool even for the simultaneous biodegradation of CF and 1,1,1-TCA at different 1,1,1-TCA starting concentration.