Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T19:31:22Z No. of bitstreams: 1 JoseAdolfoOliveiraDasChagas_DISSERT.pdf: 1637416 bytes, checksum: 6d7cf0aab8f26409a17019f936ed1d97 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-21T23:16:41Z (GMT) No. of bitstreams: 1 JoseAdolfoOliveiraDasChagas_DISSERT.pdf: 1637416 bytes, checksum: 6d7cf0aab8f26409a17019f936ed1d97 (MD5) / Made available in DSpace on 2017-03-21T23:16:41Z (GMT). No. of bitstreams: 1 JoseAdolfoOliveiraDasChagas_DISSERT.pdf: 1637416 bytes, checksum: 6d7cf0aab8f26409a17019f936ed1d97 (MD5) Previous issue date: 2017-01-25 / Ao longo dos ?ltimos 20 anos, a quantidade e composi??o da ?gua residual proveniente das atividades de explora??o e processamento do petr?leo tem causado preocupa??o quanto aos riscos ambientais. M?todos, tais como filtra??o, osmose reversa, adsor??o e oxida??o qu?mica s?o comumente aplicados no tratamento destas ?guas. Entretanto, esses m?todos podem apresentar limita??es, como custo energ?tico, espa?o para instala??o, gera??o de subprodutos, entre outras. Diante disso, surge como um material alternativo e de baixo custo, as membranas ? base de biopol?meros. Dentro dessa classe, a quitosana, um polissacar?deo policati?nico obtido da quitina, vem sendo investigada. O presente trabalho teve como objetivo investigar os efeitos da adi??o do glicerol nas propriedades das membranas de quitosana e avaliar a sua aplicabilidade no tratamento de ?guas residuais. O glicerol foi adicionado ao p? de quitosana em duas propor??es (m/m) 10 % e 25 % e as membranas foram obtidas por casting. As membranas com glicerol foram denominadas CS10 e CS25, respectivamente. As membranas CS, CS10 e CS25 foram caracterizadas pelas t?cnicas de espectroscopia de absor??o na regi?o do infravermelho (FTIR), difra??o de raios-X (DRX), microscopia de for?a at?mica (AFM) e an?lises t?rmicas (TG/DSC). Tamb?m foram realizadas medidas de ?ndice de intumescimento, propriedades mec?nicas e adsor??o de ?ons cobre. Pelas an?lises comparativas dos espectros de infravermelho foi poss?vel confirmar a incorpora??o do glicerol. Fato tamb?m confirmado pelas t?cnicas de DRX e AFM. A partir do DRX, observou-se um aumento do percentual de cristalinidade para a CS10, enquanto que, na CS25 ocorre uma redu??o. Os estudos de topologia atrav?s de AFM corroboram esses efeitos. A presen?a do glicerol tamb?m afetou diretamente as propriedades mec?nicas da quitosana: enquanto a CS25 possui maior ductilidade, a CS10 ? mais r?gida. Os valores de ?ndice de intumescimento para as membranas CS10 e CS25 em pH 6 mostram que a presen?a de glicerol conferiu maior car?ter hidrof?lico ?s membranas. A membrana CS25, apresentou redu??o nos ?ndices de intumescimento em pH 4 e pH 10, enquanto a CS10 teve os ?ndices de intumescimento favorecidos nestes meios. Nos estudos de adsor??o foram verificadas excelentes propriedades de adsor??o, alcan?ando valores entre 0,17-0,22 g.m-2, sendo a membrana CS25 mais eficiente para a remo??o de cobre. A partir deste estudo foi poss?vel considerar que o material tem potencialidades para a aplica??o no tratamento de ?guas residuais da ind?stria do petr?leo. / Over the past 20 years, the amount and composition of wastewater from oil exploration and processing activities has raised concerns about environmental risks. Methods, such as filtration, reverse osmosis, adsorption and chemical oxidation are commonly applied in the treatment of these waters. However, these methods may present limitations, such as, energy cost, space for installation, by-products generation, among others. Considering that, biopolymer based membranes appear as an alternative and low cost material. Within this class, chitosan, a polycationic polysaccharide obtained from chitin, has been investigated. The present work aimed to investigate the effects of the addition of glycerol on the properties of chitosan membranes and to evaluate its applicability on wastewater treatment. The glycerol was added to the chitosan powder in two ratios (w / w) 10% and 25% and the membranes were obtained by casting. Glycerol membranes were named CS10 and CS25, respectively. The membranes CS, CS10 and CS25 were characterized by infrared absorption spectroscopy (FTIR), X-ray diffraction (XRD), Atomic Force Microscopy (AFM), thermal analysis (TG / DSC). Swelling index, mechanical properties, and copper adsorption capacity were also analyzed. Comparing the infrared spectra it was possible to confirm the glycerol incorporation. This fact was also confirmed by XRD and AFM. From the XRD, an increase in the percentage of crystallinity for CS10 was observed, while in CS25 a reduction occurred. AFM topology studies also corroborate these effects. The presence of glycerol also affects the mechanical properties of chitosan. While CS25 has higher ductility, CS10 is more rigid. The swelling index values for the membranes CS10 and CS25 at pH 6 showed that the presence of glycerol gives a higher hydrophilic character to the membranes. CS25 membrane showed a reduction in swelling indexes at pH 4 and pH 10, while CS10 had the swelling indexes favored in these media. In the adsorption studies, excellent adsorption properties were found, reaching values between 0.17-0.22 g.m-2, and the CS25 membrane was more efficient for the removal of copper. Therefore, from this study it was possible to consider that the material has potentiality for the application in the wastewater treatment of the petroleum industry.

Made available in DSpace on 2014-12-17T15:42:26Z (GMT). No. of bitstreams: 1 WaldeniceAM.pdf: 1082421 bytes, checksum: bd7f6b4a35f59108d7807a3a68e163a3 (MD5) Previous issue date: 2007-03-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Textile activity results in effluents with a variety of dyes. Among the several processes for dye-uptaking from these wastewaters, sorption is one of the most effective methods, chitosan being a very promising alternative for this end. The sorption of Methyl Orange by chitosan crosslinked particles was approached using equilibrium and kinetic analyses at different pH s. Besides the standard pseudo-order analysis normally effectuated (i.e. pseudo-first-order and pseudo-second-order), a novel approach involving a pseudo-nth-order kinetics was used, nbeing determined via non-linear regression, using the Levenberg-Marquardt method. Zeta potential measurements indicated that electrostatic interactions were important for the sorption process. Regarding equilibrium experiments, data were well fitted to a hybrid Langmuir-Freundlich isotherm, and estimated Gibbs free energy of adsorption as a function of mass of dye per area of chitosan showed that the process of adsorption becomes more homogeneous as the pH of the continuous phase decreased. Considering the kinetics of sorption, although a pseudo-nth-order description yielded good fits, a kinetic equation involving diffusion adsorption phenomena was found to be more consistent in terms of a physicochemical description of the sorption process / A atividade t?xtil resulta em efluentes com uma variedade de corantes. Dentre os v?rios processos para a remo??o de corantes destes efluentes, o de sor??o constitui um dos m?todos mais efetivos, sendo a quitosana um sorvente alternativo bastante promissor para este fim. A sor??o do corante alaranjado de metila em part?culas de quitosana reticulada foi avaliada atrav?s de estudos de equil?brio e cin?tica de sor??o em diferentes pHs. Al?m da an?lise com o modelo de pseudo-ordem normalmente adotado na literatura (por exemplo, pseudo-primeira-ordem e pseudo-segunda-ordem), um novo modelo envolvendo uma cin?tica de pseudo-n-ordem foi usada, sendo ndeterminado via regress?o n?o-linear, usando o m?todo de Levenberg-Marquardt. Medidas de potencial zeta indicaram intera??es eletrost?ticas importantes no processo de sor??o. Com rela??o aos estudos de equil?brio, os dados foram bem representados pela isoterma h?brida Langmuir-Freundlich, e a energia livre de Gibbs de sor??o como uma fun??o da massa de corante por ?rea de part?cula mostrou que este processo torna-se mais homog?neo ? medida que o pH da fase cont?nua diminui. Considerando a cin?tica de sor??o, apesar do modelo de pseudo-n-ordem descrever bem os dados experimentais, a equa??o cin?tica envolvendo difus?o-adsor??o foi mais consistente em termos de descri??o f?sico-qu?mica do processo de sor??o

Made available in DSpace on 2014-12-17T15:41:57Z (GMT). No. of bitstreams: 1 RobertoRCL_DISSERT.pdf: 1216220 bytes, checksum: 291b5b64177a1fbc1bc254c50866a9c9 (MD5) Previous issue date: 2012-05-23 / The phenomenon of adsorption is of fundamental importance for the treatment of textile effluents and removal of dyes. Chitosan is characterized as an excellent adsorbent material, not only for its adsorption capacity but also the low cost production. Equilibrium and kinetic studies were developed in this study to describe the mechanism of adsorption of the anionic azo dye Orange G in chitosan, with the isotherms obtained from the variation of the concentration of dye in the continuous phase. The kinetics of the process was analyzed based on models involving the adsorption of molecules of the dye in nonpolar and polar sites. Adsorption experiments were carried out in water and in saline media with different NaCl concentrations, both for the determination of the equilibrium time as isotherms for making kinetic curves in which the amount of dye adsorbed measured indirectly varied with time. The experiments revealed the opening of the biopolymer structure with increasing concentration of Orange G, accompanied by high pH values and change on the type of interaction between the dye and the adsorbent surface, suggesting behavior advocated by the Langmuir equation in a certain range of concentration of the adsorbate and following the Henry's Law at higher concentrations, from the increased number of sites available for adsorption. The studies conducted showed that the saline medium reduces the chitosan s adsorption capacity according to a certain concentration, the occurrence of the cooperative adsorption process steps kinetic mechanism suggested as a new alternative for the interpretation of the phenomenon / O fen?meno da adsor??o ? de fundamental import?ncia no tratamento de efluentes t?xteis e remo??o de corantes. A quitosana caracteriza-se como excelente material adsorvente, n?o s? pela sua capacidade de adsor??o mas tamb?m pelo baixo custo de obten??o. Estudos cin?ticos e de equil?brio foram desenvolvidos neste trabalho para descrever o mecanismo de adsor??o do azo-corante ani?nico Alaranjado G em quitosana, com a obten??o de isotermas a partir da varia??o da concentra??o de corante na fase cont?nua. A cin?tica do processo foi analisada a partir de modelos envolvendo a adsor??o de mol?culas do corante em dois tipos de s?tios: polares e apolares. Experimentos de adsor??o foram desenvolvidos em ?gua e em meios salinos com diferentes concentra??es de NaCl, tanto para a determina??o do tempo de equil?brio como para a confec??o de isotermas e curvas cin?ticas nas quais a quantidade de corante adsorvido, medida de forma indireta, variou em fun??o do tempo. Os experimentos revelaram abertura da estrutura do biopol?mero com a eleva??o da concentra??o do Alaranjado G, acompanhada pela eleva??o do pH e modifica??o no tipo de intera??o entre o corante e a superf?cie do adsorvente, sugerindo comportamento preconizado pela equa??o de Langmuir em certa faixa de concentra??o do adsorvato e obedecendo ? lei de Henry em concentra??es mais elevadas, a partir do aumento do n?mero de s?tios dispon?veis para a adsor??o. Os estudos desenvolvidos mostraram que o meio salino reduz a capacidade de adsor??o do Alaranjado G em quitosana e pode impedir, em certa concentra??o, a ocorr?ncia de processo cooperativo de adsor??o conforme mecanismo cin?tico em etapas sugerido como uma nova alternativa para a interpreta??o do fen?meno

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-09T22:44:46Z No. of bitstreams: 1 JessicaSouzaMarques_TESE.pdf: 2267676 bytes, checksum: f71e2156c17464c73f99c0aec00ef206 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-10T22:44:23Z (GMT) No. of bitstreams: 1 JessicaSouzaMarques_TESE.pdf: 2267676 bytes, checksum: f71e2156c17464c73f99c0aec00ef206 (MD5) / Made available in DSpace on 2016-08-10T22:44:23Z (GMT). No. of bitstreams: 1 JessicaSouzaMarques_TESE.pdf: 2267676 bytes, checksum: f71e2156c17464c73f99c0aec00ef206 (MD5) Previous issue date: 2015-12-14 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Neste trabalho foram produzidas membranas de quitosana reticuladas ionicamente, utilizando o ?cido sulf?rico como agente de reticula??o para serem aplicadas no tratamento de ?guas residuais da ind?stria do petr?leo. Duas metodologias de reticula??o das membranas foram desenvolvidas: homog?nea e heterog?nea. No processo homog?neo a vari?vel analisada foi a raz?o molar de SO42-/ NH3+ (1:6 e 1:4), enquanto, no processo heterog?neo o tempo de imers?o das membranas em ?cido sulf?rico foi a vari?vel em estudo, sendo utilizado tempos de 5 e 30 minutos. Os resultados de FTIR-ATR evidenciaram a forma??o de liga??es i?nicas entre os grupos NH3+protonados da quitosana e os ?ons sulfato do agente reticulante. Apenasnas membranas heterog?neas indicando um grau de reticula??o bastante pequeno para as homog?neas.As an?lises de TG/DTG e DRX confirmaram a forma??o dessas intera??es, como tamb?m demonstraram que houve a forma??o de uma nova estrutura na regi?o superficial das membranas CS5 e CS30 em rela??o ?s membranas de CS, CS16 e CS14. Os ensaios de intumescimento em meio aquoso evidenciaram que os processos de reticula??o reduziram a capacidade de sor??o das membranas. Enquanto que em meio ?cido as membranas de CS16 e CS14 aumentaram a capacidade de sor??o at? um percentual m?ximo de aproximadamente 140%, e as de CS5 e CS30 atingiram um m?ximo de 60%. As propriedades mec?nicas indicaram o comportamento r?gido e d?ctil das membranas reticuladas. Atrav?s dos experimentos de sor??o de solu??o de CuCl2, foi determinado que o m?ximo de efici?ncia foi obtido para as membranas CS16 com 73% de remo??o de cobre em pH 5,0 e 87% em pH 4,0. Os experimentos realizados com CuSO4 tamb?m resultaram em 80% de remo??o de ?ons de Cu2+ para as membranas de CS16. Tamb?m foi verificado que o aumento da concentra??o e da temperatura refletiram na diminui??o da capacidade de adsor??o para todas as membranas. Os resultados de cin?tica evidenciaram que as membranas foram melhor caracterizadas pela equa??o de pseudo-segunda-ordem. E, osEstudos de equil?brio demonstraram que as membranas de CS, CS16 e CS14 seguem o modelo de Langmuir, enquanto que as membranas de CS5 e CS30 seguem o modelo de Freundlich. Os experimentos de filtra??o resultaram em m?ximo de reten??o de ?ons de Cu2+ para as membranas de CS16 e CS5, atingindo 92 e 98% respectivamente. / In this work a chitosan (CS) ionically crosslinked were manufactured by treatment with sulfuric acid solution for application in the treatment of wastewater from oil industry. Two crosslinking process were developed: homogeneous and heterogeneous. In the homogeneous process the ratio molar of SO42-/ NH3+ (1:6 and 1:4) were the variable analyzed, denominated CS16 and CS14 respectively. In the heterogeneous process the soaking time of the membranes in sulfuric acid solution were the variable studied, being used times of 5 (CS5) and 30 (CS30) minutes. FTIR-ATR results indicated no changes in the characteristics of chitosan after homogeneous crosslinking process, while heterogeneous crosslinking showed formation of ionic bonds between protonated groups from chitosan and the crosslinking agent sulfate ions. TG/DTG and XRD analysis confirmed the formation of these interactions, as also shown the new structure on the surface region of CS5 and CS30 membranes compared to CS, CS16 e CS14. Swelling test in aqueous medium have shown that crosslinking process reduced the membrane sorption capacity. Swelling test in acid medium demonstrated that CS16 and CS14 membranes increasing the adsorption capacity up to a maximum percentage of 140% approximately, whereas the CS5 e CS30 reached a maximum of 60%. The mechanical properties indicated the stiff and ductile behavior of crosslinked membrane. Adsorption experiments of CuCl2 results that CS16 membranes reached the efficiency maximum with 73% of copper removal at pH 5.0 and 87% at pH 4.0. The experiments with CuSO4 also obtained efficiency maximum to the CS16 membrane and 80% to the removal of Cu2+ ions. Also was verified that the increase of concentration and temperature cause a decrease in the adsorption capacity for all membranes. Kinetics study indicated that pseudo-second-order obtained characterized better the membranes. Equilibrium studies demonstrated that the CS, CS16 and CS14 follow the Langmuir model, whereas CS5 and CS30 follows Freundlich model. Filtration experiments results with rejection maximum to the CS16 and CS5 membranes, reaching 92 and 98% respectively.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-06-22T11:26:06Z No. of bitstreams: 1 2016 - B?rbara Magalh?es Neto.pdf: 3282939 bytes, checksum: a4ead0ff5e7307971c24940b1bea36a3 (MD5) / Made available in DSpace on 2017-06-22T11:26:06Z (GMT). No. of bitstreams: 1 2016 - B?rbara Magalh?es Neto.pdf: 3282939 bytes, checksum: a4ead0ff5e7307971c24940b1bea36a3 (MD5) Previous issue date: 2016-07-19 / Among the many existing methods for removing heavy metals off the effluents, the adsorption process stands out for being considered most effective, at lower cost. The phenomenon of adsorption consists in a process of the transfer of one or more constituents of a fluid phase to a surface of a solid phase. The adsorption process depends on physical and chemical characteristics, as: structural properties of the adsorbent (porosity, functional groups), adsorbate (ionic radius and coordination number), interaction between adsorbent and adsorbed. New technologies have emerged with focus returned to the use of biological materials with adsorbing properties for the treatment of effluents, in particular, removal and recovery of heavy metals, showing good performance. The main advantages of using natural adsorbents (biosorbents) in the process of sorption are: low waste generation, easy recovery of metals, the possibility of reuse of the adsorbent and lower operating costs, depending on the adsorbent material used in the process. From the foregoing this research used tablets of composite material, formed of recycled low density polyethylene (LDPErec) as polymer matrix and adsorbent materials (coconut fibber FC, chitosan Qui or clay B) and a comparative study using such tablets as adsorbents, to removal of the chromium (III), in order to determine which tablet has a better adsorption of chromium (III).To this end, there were realized three experimental design, where they were evaluated the influence of the size of coconut fibber particles, the composition of LDPErec/Fc, LDPErec/B, LDPErec/Qui, LDPErec/FC/Qui and LDPErec/B/Qui, the concentration of chromium (III) adsorbate and the exposure time of the tablets in the chromium (III) solution. With the results can conclude that the models used in the experimental design were valid for the evaluation of significant variables of this work, as the best chromium (III) removal conditions. That happened to the composition values of 40/60% to the tablets of LDPErec/FC1, LDPErec/FC3 and LDPErec/B. The particle size range of coconut fibber that proved more favourable was smaller particle size (100-120 mesh) in the composition of 40/60 %. The conductivity has been used to predict a chromium (III) sorption model but it proved not to be good parameter / Entre os muitos m?todos existentes para a remo??o de metais pesados em efluentes, o processo de adsor??o destaca-se por ser considerado um dos mais efetivos, com menor custo. O fen?meno da adsor??o consiste em um processo de transfer?ncia de um ou mais constituintes de uma fase fluida para a superf?cie de uma fase s?lida. O processo de adsor??o depende de caracter?sticas f?sicas e qu?micas, como: propriedades estruturais do adsorvente (porosidade, grupos funcionais), do adsorvato (raio i?nico, n?mero de coordena??o) e intera??es entre o adsorvente e o adsorvato. Novas tecnologias t?m surgido com o foco voltado para a utiliza??o de materiais biol?gicos com propriedades adsorventes para tratamento de efluentes, e particularmente, na remo??o e recupera??o de metais pesados, apresentando bom desempenho. As principais vantagens de utiliza??o de adsorventes naturais (biossorventes) no processo de sor??o s?o: baixa gera??o de res?duos, f?cil recupera??o dos metais, a possibilidade de reutiliza??o do adsorvente e menor custo operacional, dependendo do material adsorvente que ? utilizado no processo. A partir do exposto essa pesquisa utilizou pastilhas de materiais comp?sitos, formadas por polietileno de baixa densidade reciclado (PEBDrec) como matriz polim?rica e materiais adsorventes (fibra de coco-FC, quitosana-Qui ou argila-B) e realizar um estudo comparativo utilizando essas pastilhas como adsorventes, na remo??o de cromo (III), a fim de determinar qual apresenta uma melhor adsor??o de cromo. Com esta finalidade, foram realizados tr?s planejamentos experimentais, onde foram avaliadas a influ?ncia da granulometria das part?culas de fibra de coco, a composi??o das pastilhas de PEBDrec/FC, PEBDrec/B, PEBDrec/Qui, PEBDrec/FC/Qui e PEBDrec/B/Qui, a concentra??o do adsorvato de cromo (III) e o tempo de exposi??o das pastilhas a solu??o de cromo (III). Com os resultados p?de-se concluir que os modelos usados nos planejamentos experimentais foram v?lidos para a avalia??o da signific?ncia dessas vari?veis, como para as melhores condi??es de remo??o do cromo (III), as quais aconteceram nos valores de composi??o de 40/60% das pastilhas de PEBDrec/FC1, PEBDrec/FC3 e PEBDrec/B. A faixa granulom?trica da fibra de coco que se mostrou mais favor?vel foi de menor granulometria (100-120 mesh) na composi??o de 40/60%. Utilizou-se a t?cnica de condutividade para predizer um modelo de sor??o de cromo (III), por?m nas condi??es do estudo, a condutividade n?o demonstrou ser um bom par?metro

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-06-20T20:25:30Z No. of bitstreams: 1 2014 - Izabella Bezerra Coutinho.pdf: 1340327 bytes, checksum: f1f665c57591a73de6229abeb35569f3 (MD5) / Made available in DSpace on 2017-06-20T20:25:30Z (GMT). No. of bitstreams: 1 2014 - Izabella Bezerra Coutinho.pdf: 1340327 bytes, checksum: f1f665c57591a73de6229abeb35569f3 (MD5) Previous issue date: 2014-09-11 / CNPq / Soils have the capacity to retain metals due to the occurrence of the phenomenon of sorption, which is the accumulation of ions or molecules on the surface of organic and mineral colloids. For their high organic matter content, therefore large amount of organic colloids, the Histosols have high adsorptive capacity. Sorption can be described by means of different models, which consist in equations that seek to describe the phenomenon with minimal loss of information. Because each model is based on different assumptions, it is essential to select the best suited to the conditions to be analyzed, thus avoiding possible contamination of the environment caused by errors in predicting the adsorption capacity of the soil. This study aimed to select the models that best describe the sorption of Zn, Cd, Cu and Pb on Histosols. The study was conducted by an adaptation of the Batch of Lab Batch, with increasing concentrations of ZnCl2, CdCl2, Pb(NO3)2 and CuCl2. After determination of the concentration of adsorbed metals, the metal levels involved in complex internal and external sphere were evalueted through by desorption studies. The parameters of the sorption isotherms were determined by the ISOFIT program. To compare the fit of the models, the correlation coefficient, determination coefficient, the Akaike Information Criterion Corrected (AICc), AICc Range (?AICc) and the Weighting of AICc (AICcw) were analyzed. It was observed that the linear model was the best to describe the sorption of Zn, while Langmuir was the best to describe the sorption of Cd and Pb and the Freundlich showed better adjustment to the sorption of Cu. In general, the concentrations of N and fulvic acids were the most important factors that influences the sorption of metals. Most of Zn, Cd and Pb is sorbed in electrostatics bonds, easily reversible. However, Cu in strong and almost irreversible bonds. / Os solos possuem a capacidade de reter metais devido ? ocorr?ncia do fen?meno da sor??o, que consiste no ac?mulo de ?ons ou mol?culas na superf?cie dos col?ides org?nicos e minerais. Por apresentarem alto teor de mat?ria org?nica, portanto grande quantidade de col?ides org?nicos, os Organossolos possuem elevada capacidade adsortiva. A sor??o pode ser descrita por meio de diferentes modelos, que s?o equa??es que buscam descrever o fen?meno com o m?nimo de perda de informa??es. Como cada modelo se baseia em diferentes pressupostos, ? fundamental selecionar o que melhor se adequa ?s condi??es que se pretende analisar, evitando, assim, poss?veis contamina??es do ambiente causadas por erros na previs?o da capacidade adsortiva do solo. Este estudo teve como objetivos selecionar os modelos que melhor descrevem a sor??o de Zn, Cd, Cu e Pb em Organossolos. O estudo foi conduzido atrav?s de uma adapta??o do M?todo Batch de Laborat?rio, com concentra??es crescentes de ZnCl2, CdCl2, Pb(NO3)2 e CuCl2. Ap?s a determina??o dos teores de metais adsorvidos, os teores de metais envolvidos em complexos de esfera interna e externa foram avaliados atrav?s de estudos de dessor??o. Os par?metros das isotermas de sor??o foram determinados pelo programa IsoFit. Para compara??o do ajuste dos modelos, foram analisados o Coeficiente de Correla??o, Coeficiente de Determina??o, o Crit?rio de Informa??o de Akaike Corrigido (AICc), Varia??o de AICc (?AICc) e a Pondera??o de AICc (AICcw). Observou-se que o modelo Linear foi o que melhor descreveu a sor??o de Zn, enquanto Langmuir foi o que melhor descreveu a sor??o de Cd e Pb e o de Freundlich apresentou melhor ajuste ? sor??o de Cu. Em geral, os teores de N e ?cidos f?lvicos foram os fatores que mais influenciaram a sor??o dos metais. A maior parte de Zn, Cd e Pb sorvidas encontra-se em liga??es eletrost?ticas, facilmente revers?veis. Entretanto, o Cu encontra-se em liga??es fortes e quase irrevers?veis.

Made available in DSpace on 2014-12-17T14:57:53Z (GMT). No. of bitstreams: 1 TatianaRF.pdf: 1487701 bytes, checksum: 47d699fbf340cd289779ddf019fff3ee (MD5) Previous issue date: 2009-03-16 / Nowadays, when accidents with oil tanker or shore tanks occur and there is oil spill, some arrangements are made in order to repress and to fix the situation. For the containment, barriers or detours are usually made of synthetic materials such as polyurethane foam. In order to clear water away, techniques like in loco burning, biodegradant agents, dispersant agents and sorbent materials application are used. The most of the sorbent materials are also synthetic and they are used because it is easy to store them and their availability in market. This dissertation introduces the study of vegetable fibers of pineapple leaf fibers (Ananas comosus (L.) Merr.), cotton fibers (Gossypium herbaceum L.), kapok fibers (Ceiba pentandra (L.) Gaertn.), curau? fibers (Ananas erectifolius L.B. Sm.) and sisal fibers (Agave sisalana Perrine) related to their capacity of sorption of oil in case of accidental spill in the ocean. This work evaluates the substitution possibility of synthetic materials by natural biodegradable materials with less cost / Atualmente, quando ocorrem acidentes com navios petroleiros ou com tanques de armazenamento e h? derramamento de petr?leo em ?gua, s?o tomadas algumas provid?ncias no sentido de conter e de remediar o derramamento. Para conter o derramamento, s?o utilizadas barreiras de conten??o ou de desvio que s?o feitas, geralmente, de materiais sint?ticos como espuma de poliuretano. Para retirar o petr?leo da ?gua, s?o utilizadas t?cnicas como queima in loco, agentes biodegradantes, agentes dispersantes e aplica??o de materiais que sorvem o petr?leo. Os materiais que sorvem petr?leo tamb?m s?o, em sua maioria, sint?ticos e s?o muito utilizados pela facilidade de armazenamento e disponibilidade no mercado. Esta disserta??o apresenta o estudo de fibras vegetais de algod?o (Gossypium herbaceum L.), de capoc (Ceiba pentandra (L.) Gaertn.), da folha do abacaxizeiro (Ananas comosus (L.) Merr.), de sisal (Agave sisalana Perrine) e de curau? (Ananas erectifolius L.B. Sm.) quanto ? capacidade de sor??o petr?leo em caso de derramamento acidental em mar. Este trabalho avalia a possibilidade de substituir os materiais sint?ticos utilizados atualmente por materiais naturais, biodegrad?veis e de menor custo