Several chromatographic and spectroscopic techniques were applied to Suwanne River reference fulvic acids (FA) and their permethylated derivatives. Retention mechanisms, structural characteristics, and thermal stabilities of FA and its derivatives and fractions were evaluated.

Thesis (Ph. D.)--University of Washington, 1995. / Vita. Includes bibliographical references (leaves [186]-201).

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2005. / Michael Saunders, Committee Chair ; Paul Work, Committee Member ; Jaehong Kim, Committee Member. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xiv, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 128-133).

Submitted by ADNIVIA SANTOS COSTA MONTEIRO null (adniviacosta@hotmail.com) on 2017-05-02T16:46:03Z No. of bitstreams: 1 Tese Adnívia S. C. Monteiro.pdf: 2683414 bytes, checksum: 3838428f87bcd749eeed2b8e389be1f3 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-03T20:31:20Z (GMT) No. of bitstreams: 1 monteiro_asc_dr_araiq.pdf: 2683414 bytes, checksum: 3838428f87bcd749eeed2b8e389be1f3 (MD5) / Made available in DSpace on 2017-05-03T20:31:20Z (GMT). No. of bitstreams: 1 monteiro_asc_dr_araiq.pdf: 2683414 bytes, checksum: 3838428f87bcd749eeed2b8e389be1f3 (MD5) Previous issue date: 2017-04-07 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os estudos de especiação em águas naturais são a chave para a compreensão do comportamento e destino dos íons metálicos no ambiente, uma vez que estes elementos podem ser encontrados em diversas formas químicas (livres ou complexados). A mobilidade, biodisponibilidade e transporte desses íons podem ser influenciados pela presença da matéria orgânica natural (MON) e as substâncias húmicas aquáticas (SHA), principais ligantes presente no ambiente aquático. Nesse contexto, o objetivo desse trabalho foi desenvolver métodos eletroanalíticos utilizando a cronopotenciometria de redissolução anódica (SCP) e a técnica de redissolução nernstiana na ausência de gradientes (AGNES) capazes de determinar a concentração de cádmio total (CdT) e livre (CdL), respectivamente, diretamente em amostras de águas dos rios Itapanhaú (RI) e Sorocabinha (RS) localizados no estado de São Paulo, que possibilitem uma futura aplicação on-site. E avaliar a influência da MON e SHA extraídas desses rios nas interações com o Cd(II) e/ou Pb(II). Para investigar o efeito da sazonalidade foram coletadas amostras de água no março e novembro de 2014, as quais foram caracterizadas através de parâmetros de qualidade da água, carbono orgânico dissolvido (COD), espectroscopia UV/Vis e concentrações de metal total, dissolvido e “livre” (ultrafiltrado em 1kDa com fluxo tangencial - UFT). As SHA e suas frações (ácido húmico (AH) e fúlvico (AF) foram caracterizadas por meio da análise elementar, RMN 13C e fracionadas através da UFT com membranas de 100, 30,10, 3 e 1 kDa. Os métodos desenvolvidos de SCP (determinação do CdT) e de AGNES (determinação do CdL) aplicados nas amostras de águas in natura e ultrafiltradas em 1kDa, foram validados por comparação com a espectroscopia de absorção atômica com atomização em forno de grafite (GF-AAS). Os resultados encontrados revelaram que as principais diferenças entre as águas dos RI e RS estão associadas possivelmente à maior influência da água do mar e da sazonalidade no RS. A composição estrutural das SHA e AF apresentou maior predominância de compostos alifáticos. A distribuição do COD após o fracionamento molecular mostrou que as frações predominantes nas SHA e AF estiveram entre 10 e 1 kDa, enquanto que para os AH, 50% do COD é maior que 100kDa. Os resultados de SCP (LD de 1,6x10-9 mol L-1) e AGNES (LD de 1,9x10-9 mol L-1) revelaram o seu potencial na quantificação do Cd(II) total e livre, respectivamente, nas amostras estudadas. Os estudos da interação de Cd(II) e Pb(II) com os AF e AH revelaram que ambos os materiais dos RI e RS apresentaram maior complexação com Pb(II), e a complexação aumenta com o aumento do pH. / The study of speciation in natural waters are crucial to understand the behaviour and fate of metal ions in the environment, since these elements can be found in different chemical forms (complexed or free). The mobility, bioavailability and transport of these ions can be influenced by natural organic matter (NOM) and aquatic humic substances (AHS), which are the main ligands in aquatic environments. The objective of this thesis was to develop electroanalytical methods using the techniques stripping chronopotenciometry (SCP) and absence of gradients and nernstian stripping (AGNES), which are able to determine the concentration of total (TCd) and free (FCd) cadmium directly in water samples from the rivers Itapanhaú (RI) and Sorocabinha (RS), located in the state of São Paulo. It would make possible a future on-site measurement applications. This study also aimed to evaluate the influence of NOM and AHS extracted from these rivers in the interactions with Cd(II) and Pb(II). Water samples were taken in march and november/2014 in order to investigate the effect of seasonality. These samples were characterised using water quality parameters, dissolved organic carbon (DOC), UV/VIS spectroscopy and concentrations of total, dissolved and free metal (ultrafiltered through 1 kDa membrane with tangential flow- TUF). AHS and their fractions (humic, HA, and fluvic acid, FA) were characterised by elemental analysis, NMR 13C. They were fractionated through TUF through membranes 100, 30, 10, 3 and 1 kDa. The methods developed of SCP (TCd determination) and AGNES (CdL determination) applied in the in natura and ultrafiltered (1 kDa) samples were validated using graphite furnace atomic absorption spectrometry (GFAAS). The results showed that the main differences between the waters from RI and RS are related probably to the influence of seawater and seasonality. The structural composition of AHS and FA presented higher content of aliphatic compounds. The distribution of DOC after size fractionation showed that the predominant fractions in the AHS and FA were between 10 and 1 kDa. On the other hand, 50% of the material was higher than 100 kDa in the HA. The results of SCP (LoD: 1.6x10-9 mol L-1) and AGNES (LoD: 1.9x10-9 mol L-1) revealed their potential in quantification of total and free Cd(II), respectively, in the samples analysed. The study of interactions of Cd(II) and Pb(II) with FA and HA showed that both materials from RI and RS presented higher complexation with Pb(II). The complexation increases with the pH for both materials. / FAPESP: 13/14122-0

The Supercritical Fluid Extraction (SFE) technique was used to fractionate Suwannee River reference fulvic acid (FA). The fractions were characterized by gas chromatography (GC) and reversed-phase high performance liquid chromatography (RP-HPLC). A SFE fractionation method was developed using stepwise gradient of supercritical CO₂ and methanol. Three FA fractions were separated. The average mass recovery was 102% with the coefficient of variation of 2.8%. The fractionation dynamics and the difference in the ratios of UV absorption to fluorescence emission indicate the real fractionation of the FA. The HPLC chromatographic peak patterns and the spectra of the corresponding peaks were almost indistinguishable. The overall results of this research support the argument that FA exhibits polymer-like molecular structure.

Pyrolysis-capillary gas chromatography combined with FID, ECD and MS detection were used to characterize refuse-derived fuel and aquatic fulvic acids. Different pyrolysis methods and programs were evaluated. Pyrolysis temperatures of 700-800°C produced the strongest signal for organics present in RDF and fulvic acid. Cellulose and fatty acids pyrolyzates were identifiable by GC-MS following preparative pyrolysis fractionation. At organic chloride content of 0.023%, only three halogenated compounds were detected in the GC-MS of the fractions. None of the priority pollutants were detected at lower detection limit of 0.72 to 24 mg/ kg RDF. Selective solvent extraction improves the reproduciblities of the technique and allows the detection of polymeric structures. Pyrograms of polyvinyl chloride and regular typing paper showed some common peaks that are present in the RDF pyrogram. About 65% of the peaks in the RDF pyrogram might be of paper origin. The organic chloride content of the RDF was evaluated by ion chromatography of the trapped pyrolyzates in 2% NaOH trap and it was found to be 221 mg Cl/ kg dry RDF. Pyrolysis conditions and temperature programs for FA were systematically evaluated. Samples included purified FA, methylated FA and HPLC separated fractions. Characteristic pyrograms were developed. Profiles of benzene, toluene, phenol, m-cresol and biphenyl from FA were evaluated. The production of phenol was the largest at 800°C, at concentration of 1.61 mg per gram of FA pyrolyzed. The profiles of benzene and toluene followed the same pathways. Both pyrolyzates had at least two precursors. HPLC fractions of FA showed some regular retention patterns characteristic of polymeric material. DL-proline, seriene and vanillic acid pyrograms showed some peaks with the same retention times as those in FA pyrogram under the same conditions. A reproducibility of 6% relative standard deviation was achieved in the pyrolysis of RDF and 0.91% in the case of FA.

High Performance Liquid Chromatography (HPLC) was used to investigate the utility of this technique for the analytical and preparative separation of components of aquatic fulvic acids (FA). Three modes of HPLC namely adsorption, anion exchange and reversed phase were evaluated. Aquatic fulvic acids were either extracted from surface water and sediment samples collected from the Southwest of the U.S., or were provided in a high purity form from the USGS. On the adsorption mode, a major fraction of aquatic fulvic acid was isolated on a semipreparative scale and subjected to Carbon-13 NMR and FAB Mass Spectroscopy. Results indicated that (1) The analyzed fraction of fulvic acid contains more aliphatic than aromatic moieties; (2) Methoxy, carboxylic acids, and esters are well-defined moieties of the macromolecule; (3) Phenolic components of the macromolecules were not detected in the Carbon-13 NMR spectrum possibly because of the presence of stable free radicals. Results of the anion exchange mode have shown that at least three types of acidic functionalities in aquatic fulvic acid can be separated. Results also indicated that aquatic fulvic acid can be progressively fractionated by using subsequent modes of HPLC. Results of reversed phase mode have shown that (1) The fractionation of aquatic fulvic acid by RP-HPLC is essentially controlled by the polarity and/or pH of the carrier solvent system; (2) Under different RP-HPLC conditions aquatic fulvic acid from several locations are fractionated into the same major components; (3) Fulvic acid extracted from water and sediment from the same site are more similar than those extracted from different sites; (4) Cationic and anionic ion pair reagents indicated the presence of amphoteric compounds within the polymeric structure of fulvic acid. Each mode of HPLC provided a characteristic profile of fulvic acid. The results of this research provided basic information on the behavior of aquatic fulvic acids under three modes of HPLC. Such informations are prerequisite for further investigation by spectroscopic methods.

Graduation date: 1994

Disinfectants, such as chlorine, are widely used in water treatment plants to ensure the safety and quality of drinking water. However, these disinfectants easily react with some natural or man-made organic compounds in raw water and form disinfection by-products (DBPs). For example, halogenated acetic acid (HAAs) and trihalomethanes (THMs) are two main components of DBPs. These DBPs contained in drinking water will increase the risk of cancer in human body. Therefore, researches on halogenated acetic acid¡¦s potential of causing cancer have increased currently. Organic acids are usually the reactants which proceed in chlorination reaction into products of disinfection by-products in water treatment plant. The purpose of this study is to investigate adsorption characteristics in solution by using tests of kinetics and equilibrium adsorptions and kinetic model evaluations of selected fulvic acids (FA) extracted from raw water. Therefore, we use commercial single-walled carbon nanotube (SWCNT) for the adsorbents, and calculate thermodynamic parameters (£GG, £GS and £GH) in order to further understand the adsorption mechanism of CNTs. The maximum adsorbed amounts of FA onto SWCNTs was calculated by the Langmuir model at 25¢J, reaching 61.88mg / g which were much higher than that onto commercially available granular activated carbon (10.69 mg/g). The adsorption capacity of FA onto CNTs increased with decreasing outer diameter of CNTs (dp), molecular weight of FA, trmperature and pH value in all texts. In the condition of constant temperature 25¢J, we analyzed HAAFP after the test of equilibrium adsorption and that the removal efficiency of HAAFP could reach 40.76%. The best selection in kinetic models evaluation, fitting models such as Modified Freundlich equation, Pseudo-1st-order equation and Pesudo-2nd-oder equation, is Modified Freundlch equation model. In addition, intraparticle diffusion equation model was fitted well and showed adsorption process was controlled by pore diffusion. We calculated the activation energy of carbon nanotube adsorption of FA and found that film diffusion was the main factor for controlling reaction rate. According to results of thermodynamic parameters indicated that the adsorption was spontaneously and an exothermic reaction. It is obvious that the adsorption capacity as well as the reaction rate of CNTs are superior to that of granular activated carbon in raw water. These results suggest that CNTs possess highly potential applications in environmental protection. In the future, if we can combine nanotube technology with disinfection technology and apply such technique on the end of processing unit for design of either the domestic treatment facilities or small simple water treatment in drinking water. Thus it will enhance the new treatment technology of drinking water and the safety of the public health. Another possibility will be to promote the opportunity of marketing development in drinking water.