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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Remo??o de nitratos em ?gua utilizando diferentes materiais e processos

Costa, Vilma Ara?jo da 27 February 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-29T21:36:02Z No. of bitstreams: 1 VilmaAraujoDaCosta_TESE.pdf: 5125277 bytes, checksum: f4fd05e4d3bc191db6541bc4486c01a5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-01T19:24:21Z (GMT) No. of bitstreams: 1 VilmaAraujoDaCosta_TESE.pdf: 5125277 bytes, checksum: f4fd05e4d3bc191db6541bc4486c01a5 (MD5) / Made available in DSpace on 2016-03-01T19:24:21Z (GMT). No. of bitstreams: 1 VilmaAraujoDaCosta_TESE.pdf: 5125277 bytes, checksum: f4fd05e4d3bc191db6541bc4486c01a5 (MD5) Previous issue date: 2015-02-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A necessidade de preservar o meio ambiente tem levado a busca de novos materiais para a elimina??o eficiente de compostos qu?micos que alteram a estabilidade dos nossos recursos naturais. Entre estes recursos, se destaca em primeiro lugar a ?gua, como um bem precioso e escasso, o que conduz ao uso adequado e seu reuso. Em virtude disso, a Organiza??o Mundial da Sa?de estabeleceu valores m?ximos admiss?veis em ?guas pot?veis, tais como: 50 mg/L, 0,1mg/L e 0,5mg/L para NO- 3, NO- 2, NH+ 4, respectivamente. Por estas raz?es, avalia-se a implementa??o de novos materiais e processos no tratamento de ?guas objetivando a remo??o desses compostos, a exemplo de aluminas, tanto em p? como suporte para um sistema catal?tico utilizando membranas inorg?nicas capazes de suportar condi??es mais severas de temperatura e press?o abrindo novas possibilidades de aplica??es dos reatores de membrana; como tamb?m, tratamentos eletroqu?micos com eletrodos de diamante dopado com bobo(DDB), como ?nodo e cobre como c?todo. Para tal intento, foi realizado o estudo da adsor??o de nitratos em diferentes tempos para avaliar o tempo necess?rio para alcan?ar o equil?brio empregando tr?s aluminas comerciais denominadas: aluminas ?cida, b?sica e neutra, com posterior tratamento na alumina ?cida impregnando-se metais (Pd-Cu/Al2O3) para a rea??o catal?tica. Os materiais foram previamente caracterizados pelas t?cnicas de DRX, MEV e ABET. As aluminas apresentaram uma capacidade adsortiva consider?vel de nitrato nos primeiros trinta minutos, equivalente a 50% de remo??o alcan?ando equil?brio nesse tempo. Ap?s tratamento, utilizando a alumina como catalisador para a rea??o no reator em batelada (Pd-Cu/Al2O3), os resultados foram mais favor?veis, totalizando 64% de redu??o do ?on NO3 - no final de tr?s horas. Em contrapartida, os resultados para a rea??o catal?tica utilizando o suporte catal?tico Pd-Cu/TiO2 no reator de membrana mostrou-se baixa, sendo dessa forma, necess?rio aprimorar as condi??es do sistema catal?tico. J?, para os testes eletroqu?micos usando eletrodos de DDB1, como ?nodo, e Cu, como c?todo, houve uma redu??o de nitrato bastante significativa, cerca de 80% de remo??o do ?on durante tr?s horas de tratamento com custos de aplica??es vi?veis. / The need to preserve the environment has led to the search for new materials for efficient disposal of chemical compounds that alter the stability of our natural resources. Among these resources, stands in first place the water, as a precious commodity and scarce, leading to the proper use and reuse. As a result, the World Health Organization has established maximum permissible values in drinking water, such as: 50 mg/L, 0, 1 mg/L and 0, 5 mg/L to at-3, at-2, NH 4, respectively. For these reasons, assesses the implementation of new materials and water treatment processes aiming at the removal of these compounds, such as alumina, in the form of powder or as a support for a catalytic system using inorganic membranes capable of supporting more severe conditions of temperature and pressure by opening new possibilities for applications of membrane reactors; and also for electrochemical treatments with doped diamond bobo electrodes (BDD) as anode and copper as cathode. For such purpose, was conducted the study of adsorption of nitrate in different times to assess the time required to achieve equilibrium by employing three commercial alumina called: acidic, basic and neutral alumina, with subsequent treatment only in the acidic alumina impregnating metals (PdCu/Al2O3) for the catalytic reaction. The materials were previously characterized by XRD, SEM techniques and ABET. Aluminas presented a considerable adsortive capacity of nitrate in the first thirty minutes, equivalent to 50% of removal reaching equilibrium in that time. After treatment, using alumina as catalyst for the reaction in batch reactor (Pd-Cu/Al2O3), the results were more favourable, totalling 64% reduction of ion NO3-at the end of three hours. On the other hand, the results for the catalytic reaction using the catalytic support Pd-Cu/TiO2 in membrane reactor proved to be low. -if, in this way, improve the conditions of catalytic system to optimize the process. Already, for the electrochemical tests using DDB1 electrodes as anode, and Cu, as cathode, there was a fairly significant nitrate reduction, approximately 80% of ion removal during three hours and cost viable applications.

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