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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/22374 |
| Date | 25 January 2017 |
| Creators | Chagas, Jos? Adolfo Oliveira das |
| Contributors | 83115951787, http://lattes.cnpq.br/5623374421279476, Rabello, Marcelo Silveira, 41924371472, http://lattes.cnpq.br/0384726674523131, Balaban, Ros?ngela de Carvalho, 65946499734, http://lattes.cnpq.br/7711521318854102, Pereira, Marcia Rodrigues |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM QU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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