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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

Estudo da participa??o das esp?cies fortemente oxidantes produzidas durante a oxida??o eletroqu?mica de corantes usando eletrodo de diamante dopado com boro: fun??o das propriedades eletroqu?micas do eletrodo e condi??es experimentais / Study of the involvement of strong oxidizing species produced during the electrochemical oxidation of dye using boron-doped diamond electrode: role of the electrochemical properties of the electrode and experimental conditions

Ara?jo, Danyelle Medeiros de 07 August 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-02T22:01:12Z No. of bitstreams: 1 DanyelleMedeirosDeAraujo_TESE.pdf: 2493847 bytes, checksum: 8fe977d6cde2a451ebdc6de841d6373c (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T00:38:23Z (GMT) No. of bitstreams: 1 DanyelleMedeirosDeAraujo_TESE.pdf: 2493847 bytes, checksum: 8fe977d6cde2a451ebdc6de841d6373c (MD5) / Made available in DSpace on 2015-12-09T00:38:23Z (GMT). No. of bitstreams: 1 DanyelleMedeirosDeAraujo_TESE.pdf: 2493847 bytes, checksum: 8fe977d6cde2a451ebdc6de841d6373c (MD5) Previous issue date: 2014-08-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A Rodamina B, RhB, ? um corante xanteno, amplamente utilizada na ind?stria t?xtil para tingir seda, l? e algod?o. O descarte incorreto deste corante no meio ambiente pode causar efeitos carcinog?nicos e teratog?nicos sobre a sa?de p?blica. Este trabalho tem como objetivo utilizar t?cnica eletroqu?mica com ?nodo de diamante dopado com boro, DDB, como uma op??o r?pida e limpa para o tratamento desse corante, bem como, avaliar a influ?ncia das caracter?sticas sp3/sp2 em diferentes ?nodos de DDB para a degrada??o da RhB. Com o intuito de alcan?ar o primeiro objetivo, realizou-se eletro-oxida??o da RhB em quatro densidades de correntes (1,2; 4,8; 7,6 e 9,8 A) e em quatro eletr?litos (HClO4, H3PO4, NaCl e Na2SO4) a temperatura ambiente. Amostras foram coletadas durante todo o processo. Para observar a degrada??o da RhB an?lises de pH, condutividade, UV-vis?vel, COT, HPLC e CG-MS foram desenvolvidas. Observou-se que em todos os casos estudados (densidade de corrente e eletr?litos) a RhB se degradou por completo, obtendo zero como resultado final na an?lise de carbono org?nico total. A melhor densidade de corrente estudada foi a de 1,2 A para este processo. J? em rela??o ao estudo dos diferentes DDB utilizou-se a densidade de corrente de 7,6 A e o eletr?lito estudado foi o Na2SO4. As an?lises desenvolvidas foram ?s mesmas citadas acima. Atrav?s dos resultados pode-se concluir que a configura??o do ?nodo sp3/sp2 influencia no processo de degrada??o da RhB, onde o que apresentou o melhor resultado foi o ?nodo com maior configura??o sp3/sp2. / The textile industry is one of the most polluting in the world (AHMEDCHEKKAT et al. 2011), generating wastewater with high organic loading. Among the pollutants present in these effluents are dyes, substances with complex structures, toxic and carcinogenic characteristics, besides having a strong staining. Improper disposal of these substances to the environment, without performing a pre-treatment can cause major environmental impacts. The objective this thesis to use a technique of electrochemical oxidation of boron doped diamond anode, BDD, for the treatment of a synthetic dye and a textile real effluent. In addition to studying the behavior of different electrolytes (HClO4, H3PO4, NaCl and Na2SO4) and current densities (15, 60, 90 and 120 mA.cm-2 ), and compare the methods with Rhodamine B (RhB) photolysis, electrolysis and photoelectrocatalytic using H3PO4 and Na2SO4. Electrochemical oxidation studies were performed in different ratio sp3 /sp2 of BDD with solution of RhB. To achieve these objectives, analysis of pH, conductivity, UV-visible, TOC, HPLC and GC-MS were developed. Based on the results with the Rhodamine B, it was observed that in all cases occurred at mineralization, independent of electrolyte and current density, but these parameters affect the speed and efficiency of mineralization. The radiation of light was favorable during the electrolysis of RhB with phosphate and sulfate. Regarding the oxidation in BDD anode with different ratio sp3 /sp2 (165, 176, 206, 220, 262 e 329), with lower carbon-sp3 had a longer favoring the electrochemical conversion of RhB, instead of combustion. The greater the carbon content on the anodes BDD took the biggest favor of direct electrochemical oxidation

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