Calcium bentonite deposits of the Glendon and Bucatunna formations of the Oligocene Vicksburg Group located in Smith County, Mississippi were examined to determine the depositional environment, diagenetic history and origin of the bentonite. Traditionally, calcium bentonite was considered to be the product of the weathering of volcanic ash deposits. The hypothesis tested is that the bentonite deposits are not a result of weathered volcanic ash, but are a result of weathered marl. Core samples were drilled from the Chisholm bentonite mine in Smith County and were studied using X-ray diffraction, scanning electron microscopy, and petrographic microscopy. Abundant bacteria along with nanometer-scale organic textures were found throughout and are consistently associated with bentonite, illite, and smectite. No evidence of volcanic ash was found. It appears that the calcium bentonite clays in the Glendon and Bucatunna formations of Smith County, Mississippi formed from weathering, including bacterial activity, of glauconite-bearing marl.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-11T13:13:10Z No. of bitstreams: 1 JOÃO FERNANDES DUARTE NETO - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 2295774 bytes, checksum: d73166400ea15685ca449c373a12dc20 (MD5) / Made available in DSpace on 2018-07-11T13:13:10Z (GMT). No. of bitstreams: 1 JOÃO FERNANDES DUARTE NETO - DISSERTAÇÃO (PPGCEMat) 2015.pdf: 2295774 bytes, checksum: d73166400ea15685ca449c373a12dc20 (MD5) Previous issue date: 2015-02-24 / Este trabalho investigou o processo de adsorção, equilibrio e cinética de argilas esmectíticas da cidade de Boa Vista (Paraíba), usadas como adsorventes de corantes com comportamentos químicos distintos - rodamina B (RB), catiônico, e alaranjado de metila (AL), aniônico - em meio aquoso. Essas argilas foram escolhidas devido às suas propriedades características do argilomineral esmectítico, que possui sítios quimicamente ativos, provocado pela substituição isomórfica e interação das arestas, tornando-o atrativo sua aplicação para fins adsortivos. As argilas utilizadas são conhecidas como bentonita chocolate e bentonita chocobofe. Esses materiais foram utilizados na forma natural e após tratamento com carbonato de sódio, ácido clorídrico e organofilização (sal quaternário de amônio PRAEPAGEN). Todos os adsorventes foram caracterizados por fluorescência de raios X, difração de raios X, análises térmicas (TG, DTG e DTA) e determinação de tamanho de partícula. Os ensaios de adsorção dos corantes foram examinados por sistema de bateladas, alterando tempo de contato, quantidade de adsorvente, concentração dos corantes e pH inicial. Para a análise do comportamento de adsorção foi utilizado espectrofotometria UV-VIS. O modelo de isoterma de Freundlich foi o que melhor se ajustou aos dados experimentais das argilas naturais e modificadas. Porém nos processos adsortivos envolvendo as argilas organofilizadas, na interação com RB, tanto o modelo de Langmuir como o de Freundlich apresentaram um bom ajuste aos dados experimentais. Os dados cinéticos de adsorção foram ajustados ao modelo de pseudo-segunda ordem (R2>0,9). Os testes de capacidades de adsorção permitiram concluir que a maior eficiência em remover a RB ocorre quando as argilas são tratadas com ácido clorídrico. A maior eficiência na remoção do AL ocorre quando as argilas estudadas foram as organofilizadas. De modo geral, as argilas esmectíticas estudadas se mostraram adsorventes adequados para a remoção do corante RB, sendo, no entanto, necessário tratamentos específicos para maximizar ou melhorar a capacidade de adsorção dos corantes RB e AL. / This study investigated the process of adsorption, equilibrium and kinetics, of smectite clays from Boa Vista of Paraíba used as chemical adsorbents of dyes with different ionic behavior in aqueous media. Smectite clays known as chocolate and chocobofe and the dyes Rhodamine B (RB) (cationic) and Methyl Orange (AL), (anionic) were used in this study. The adsorbents were characterized by X-ray fluorescence, X-ray diffraction, thermal analysis (TG, DTA and DTG) and determination of particle size. Clays have been used in natural form and after treatment with sodium carbonate, acid and organophilization (quaternary ammonium salt – PRAEPAGEN). The dye adsorption was examined by a batch system, changing: contact time, amount of adsorbent, dye concentration and initial pH. UVVIS spectrophotometry was used for the analysis of the adsorption behavior. The clays were characterized as smectite clays and the efficiency of the treatments was confirmed by X-ray fluorescence and X-ray diffraction. The model of Freundlich isotherm presented the best fit to the experimental data of natural clays. However, in the adsorptive processes involving clays organophilizated both the Langmuir model and the Freundlich model showed good fitting to the experimental data. The kinetic adsorption data were fitted to the model of pseudo-second order (R2> 0.9). The adsorption capacities test showed that the highest efficiency in removing RB occurs when the clays are treated with hydrochloric acid. The highest efficiency of the removal of AL occurs when the clays are organophilizated. In general, the smectite clays were suitable adsorbent for the removal of the dye RB. However, special treatment is necessary to maximize or improve the adsorption ability of the dyes AL and RB.

Made available in DSpace on 2014-12-17T15:01:30Z (GMT). No. of bitstreams: 1 GeraldoMRF_TESE.pdf: 3870711 bytes, checksum: 6a5339896637d234e88f58bd692fe8cf (MD5) Previous issue date: 2012-09-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This study aimed to evaluate the potential use of smectite clays for color removal of textile effluents. The experiments were performed by testing exploratory/planning method factorial and fractional factorial where the factors and levels are predetermined. The smectite clays were used originating from gypsum hub of the region Araripe-PE, and the dye used was Reactive Yellow BF-4G 200%. The smectite clay was collected and transported to the Laboratory of Soil Physics of UFRPE, where it held its preparation through air drying, lump breaking and classification in sieve to then submit it to the adsorption process. Upon completion of 22 complete factorial design it was concluded that the values of (96, 96,5 and 95,8%) corresponding to the percentage of of removal for "in-kind", chemically and thermally activated, respectively and adsorbed amounts of (4,80, 4,61 and 4,74 mg/g) for three clays. Showed that the activation processes used did not increase the adsorption capacity of smectite clay. The kinetic data were best fitted to the Freundlich isotherm, with an exponential distribution of active sites and that shows above the Langmuir equation for adsorption of cations and anions by clays. The kinetic model that best adapted to the results was the pseudosecond order model. In the factorial design study 24-1, at concentrations up to 500 mg/L obtains high percentage of color removal (92,37, 90,92 and 93,40%) and adsorbed amount (230,94, 227,31 and 233,50 mg/g) for three clays. The kinetic data fitted well to Langmuir and Freundlich isotherms. The kinetic model that best adapted to the results was the pseudosecond order model / Este trabalho teve como objetivo avaliar o potencial de utiliza??o das argilas esmectitas, para remo??o de cor de efluentes t?xteis. Os experimentos foram realizados atrav?s de ensaios explorat?rios/m?todo de planejamento fatorial e fatorial fracion?rio, em que os fatores e os n?veis s?o pr?-determinados. As argilas esmectitas usadas foram origin?rias do p?lo gesseiro da regi?o do Araripe-PE, e o corante utilizado foi o Amarelo Reativo BF-4G 200%. A argila esmectita foi coletada e transportada para o Laborat?rio de F?sica de Solos da UFRPE, onde se realizou a sua prepara??o atrav?s de secagem ao ar, destorroamento e classifica??o em peneiras para, em seguida, submet?-la ao processo de adsor??o. A partir da realiza??o do planejamento fatorial 22 concluiu-se que os valores de 96, 96,5 e 95,8%, correspondentes aos percentuais de remo??o para as argilas esmectitas innatura , quimicamente e termicamente ativadas, respectivamente, e com quantidades adsorvidas de 4,80, 4,61 e 4,74 mg/g, para as tr?s argilas, mostraram que os processos de ativa??o utilizados n?o aumentaram o poder de adsor??o da argila esmectita. Os dados cin?ticos ajustaram-se melhor ? isoterma de Freundlich, com uma distribui??o exponencial de s?tios ativos e que se mostra superior ? equa??o de Langmuir para adsor??o de c?tions e ?nions pelas argilas. O modelo cin?tico que melhor se adequou aos resultados foi o modelo pseudo-segunda ordem. No estudo do planejamento fatorial 24-1, em concentra??es de at? 500 mg/L se obt?m elevados percentuais de remo??o de cor (92,37, 90,92 e 93,40 %) e quantidade adsorvida (230,94, 227,31 e 233,50 mg/g) para as tr?s argilas. Os dados cin?ticos ajustaram-se bem ?s isotermas de Langmuir e Freundlich. O modelo cin?tico que melhor se adequou aos resultados foi o modelo pseudo-segunda ordem