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Previous issue date: 2017-02-14 / Nas ?ltimas d?cadas, a contamina??o dos corpos de ?gua por metais pesados vem se tornando um s?rio problema ambiental. O descarte inadequado de efluentes contaminados por ?ons de metais, mesmo em pequenas concentra??es, podem causar s?rios danos aos seres humanos, a fauna, flora e a microbiota, comprometendo assim, a qualidade de vida do ecossistema presente. Diante deste contexto, ? necess?rio o tratamento destes efluentes a n?veis ambientalmente aceit?veis antes de lan??-los no meio ambiente. N?o obstante a isso, o uso de bioadsorventes para o tratamento de efluentes contaminados, como alternativa a m?todos convencionais, tem sido objeto de estudo de diversas pesquisas contempor?neas. Nessa perpectiva, este trabalho buscou analisar a viabilidade da utiliza??o do p? das folhas in natura do cajueiro vermelho (Anacardium occidentale L.) e da carna?ba (Copernicia prunifera) como adsorventes para remo??o de ?ons de cobre presentes em efluentes sint?ticos. Inicialmente, foram investigadas as propriedades f?sico-qu?micas de ambas as folhas, utilizado ensaios de microscopia eletr?nica de varredura (MEV), difra??o de raio-X (DRX), fluoresc?ncia de raio-X (FRX), analise termogravim?trica (TG), espectroscopia na regi?o do infravermelho (FTIR) e adsor??o f?sica de nitrog?nio (BET). Os estudos de adsor??o foram realizados em sistema de batelada, cujo os efeitos do pH (3,0 a 10,0), da concentra??o do adsorvente (2 a 20 gL-1), do tamanho de part?cula (0,6 a 0,075mm) e da concentra??o inicial do adsorbato (10 a 150 mgL-1) foram avaliados. Os resultados indicaram um aumento na capacidade de adsor??o para valores de pH entre 3 e 7. Ap?s atingir pH igual a 7, observa-se que a capacidade de adsor??o ? reduzida, para ambos os estudos. Com rela??o a avalia??o da varia??o da concentra??o do adsorvente, observou-se que para o p? das folhas do cajueiro o aumento da quantidade de massa n?o afetou o processo de remo??o, no entanto, para o p? das folhas da carna?ba observou-se que o percentual de remo??o ? diretamente proporcional ao aumento da massa. Para ambos os casos estudados, observou-se uma melhor efici?ncia quando se utilizou part?culas com tamanhos compreendidos entre 0,106 e 0,075 mm. O estudo da concentra??o inicial para os bioadsorventes apresentaram comportamento semelhantes. A quantidade de adsor??o aumenta com o aumento na concentra??o inicial dos ?ons em solu??o. Os dados experimentais das isotermas de adsor??o realizadas no p? da folha de cajueiro melhor se ajustaram ao modelo de Freundlich, todavia, para o p? da folha da carna?ba o modelo de Langmuir mostrou-se mais adequado. A cin?tica do processo de adsor??o, para ambos os adsorventes, atingiu o equil?brio logo nos primeiros minutos de rea??o, aproximadamente, 2 minutos. De modo geral, os dados experimentais melhor ajustaram-se ao modelo de pseudo-primeira ordem para ambos os adsorventes. Comparando os adsorventes em estudo, observa-se que o p? da folha da carna?ba apresentou um desempenho superior de remo??o dos ?ons de cobre, atingindo um percentual de cerca de 79 %, onde nas mesmas condi??es de temperatura, concentra??o inicial, massa de adsorvente e volume da solu??o, o p? da folha do cajueiro removeu cerca de 19 %. Os resultados mostraram que o p? das folhas do cajueiro e da carna?ba apresentam caracter?sticas apropriadas para o processo de adsor??o do cobre e que podem ser uma alternativa a processos cl?ssicos de tratamento de efluentes. / Lately, the contamination of water bodies caused by heavy metals has become a serious environmental issue. The discharge of effluents which contain heavy metal ions, even at small concentration, without an adequate treatment damages human beings, fauna, and flora thus this affects the wellness of the entire ecosystem. Therefore, these effluents require certain treatment to lower the ions level to an environmentally acceptable concentration before discharging them into the environment. Additionally, bioadsorbents have been used for the treatment of contaminated effluents as an alternative to conventional methods. They have also been largely studied in recent researches. Hence, this work aims to evaluate the usage of red cashew (anacardium occidentale L) leaves and carna?ba (copernicia prunifera) leaves, in powder form, as adsorbents for copper ions removal from synthetic effluents. The physicochemical properties of both leaves were investigated, using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (FRX), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR) and physical nitrogen adsorption (BET).The adsorption studies were carried out in a batch system, whose effects of pH (3.0 to 10.0), adsorbent concentration (2 to 20 gL-1), particle size (0.6 to 0.075 mm) And the initial concentration of the adsorbate (10 to 150 mgL-1) were evaluated. The results indicated an increase in adsorption capacity at pH values between 3 and 7. After reaching pH equal to 7, it is observed that the adsorption capacity is reduced for both studies. Regarding the evaluation of the variation of the adsorbent concentration, it was observed that for the powder of the cashew leaves the increase of the mass quantity did not affect the removal process, however, for the powder of the leaves of the carnauba it was observed that the Percentage of removal is directly proportional to the mass increase. For both cases studied, a better efficiency was observed when using particles with sizes between 0.106 and 0.075 mm. The initial concentration study for the bioadhesives presented similar behavior. The amount of adsorption increases with the increase in the initial concentration of the ions in solution. The experimental data of the adsorption isotherms performed on the cashew leaf powder best fit the Freundlich model, however, for the carnauba leaf powder the Langmuir model was more adequate. The kinetics of the adsorption process for both adsorbents reached equilibrium in the first few minutes of reaction, approximately, 2 minutes. In general, the experimental data better fit the pseudo-first order model for both adsorbents. Comparing the adsorbents performance, it was observed that the carnauba leaves powder removed a superior copper ion amount, reaching a removal percentage approximately equal to 79 %, whereas, under the same conditions of temperature, initial concentration, adsorbent mass and solution volume, the cashew leaves powder showed a removal percentage approximately equal to 19 %. The results showed that both the cashew and carnauba leaves powder present the appropriate features for copper adsorption and they both represent an alternative to traditional effluent treatment processes.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/23392 |
| Date | 14 February 2017 |
| Creators | Pereira, J?ssyca Emanuella Saraiva |
| Contributors | 59545844434, http://lattes.cnpq.br/2811639726261017, Santos, Damilson Ferreira dos, 80732313449, http://lattes.cnpq.br/6595215766847065, Oliveira, Humberto Neves Maia de, 22179763468, http://lattes.cnpq.br/7302633941782540, Barros Neto, Eduardo Lins de |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA 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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