{"id":{"repo_id":"brazil-ufrn","oai_identifier":"oai:repositorio.ufrn.br:123456789/51297"},"canonical_url":"https://search.dev.ndltd.org/etd/brazil-ufrn/oai:repositorio.ufrn.br:123456789/51297","repository":{"repo_id":"brazil-ufrn","name":"Brazil UFRN","base_url":"https://repositorio.ufrn.br/server/oai/request"},"display":{"title":"Desenvolvimento de heterojunções constituídas de ZnO/g-C3N4 e ZnFe2O4/g-C3N4 para fotodegradação de contaminantes orgânicos emergentes","abstract":"In recent years there has been growing concern about the contamination of water by emerging contaminants - substances that are not completely degraded by conventional processes of water and wastewater treatments and are not biodegradable. For this reason, several techniques have been developed to efficiently treat such compounds. In this work, different heterojunctions of ZnO/g-C3N4 and ZnFe2O4/g-C3N4 in different mass proportions of g-C3N4 (10, 50, and 80 %) were synthesized through a simple method of mixing, sonication and heat treatment. The influence of the amount of g-C3N4 in the heterojunctions as well as the influence of the type of zinc-based catalyst on the structural, morphological, optical, and photocatalytic properties of the materials were investigated. The XRD, FTIR, and SEM/EDS results confirmed the achievement of the desired heterojunctions. The incorporation of g-C3N4 was relevant in modifying the textural and optical properties of the heterojunctions produced. The 50-Zn/gCN heterojunction showed better photocatalytic degradation of the antibiotic cefazolin (78 %) and the dye RB5 (95 %) in 120 min of the experiment, when compared with the pure materials and with the other heterojunctions. In addition, it exhibited faster reaction kinetics and good photostability. The best photocatalytic performance presented by this material can be attributed to the real synergistic effect between ZnO and g-C3N4, which promoted relevant interaction in a possible mechanism of Z scheme type, as verified in the PL analysis. The results of the experimental design showed that the catalyst concentration and the pH are the variables that most influence the cefazolin photodegradation, whereas for RB5, all the evaluated variables were significant for 95% confidence. 50-Zn/gCN exhibited 100% degradation for both contaminants evaluated in 90 min of reaction for cefazolin and in 10 min for RB5, under the following conditions: catalyst concentration 0.5 g L-1 , contaminant concentration 5 mg L-1 and pH 2.5. Adsorption played a key role in the photodegradation of RB5. However, the degradation of the dye (adsorbed and remaining in the solution) and the regeneration of the catalyst surface were due to photocatalysis. The Z-scheme mechanisms for the photocatalytic reactions of cefazolin and RB5 have been adequately proposed, in which the photogenerated holes in the valence band of ZnO and the electrons in the conduction band of g-C3N4 were the main degradation pathways of cefazolin and RB5, respectively. The evaluated heterojunction showed good photostability for both contaminants. Finally, the promising character of 50-Zn/gCN synthesized for application in photocatalytic reactions mediated by sunlight for the degradation of contaminants of different classes, as well as the possibility of its use as an efficient alternative to minimize water pollution caused by overuse of medication during the COVID-19 pandemic.","abstract_html":"In recent years there has been growing concern about the contamination of water by emerging contaminants - substances that are not completely degraded by conventional processes of water and wastewater treatments and are not biodegradable. For this reason, several techniques have been developed to efficiently treat such compounds. In this work, different heterojunctions of ZnO/g-C3N4 and ZnFe2O4/g-C3N4 in different mass proportions of g-C3N4 (10, 50, and 80 %) were synthesized through a simple method of mixing, sonication and heat treatment. The influence of the amount of g-C3N4 in the heterojunctions as well as the influence of the type of zinc-based catalyst on the structural, morphological, optical, and photocatalytic properties of the materials were investigated. The XRD, FTIR, and SEM/EDS results confirmed the achievement of the desired heterojunctions. The incorporation of g-C3N4 was relevant in modifying the textural and optical properties of the heterojunctions produced. The 50-Zn/gCN heterojunction showed better photocatalytic degradation of the antibiotic cefazolin (78 %) and the dye RB5 (95 %) in 120 min of the experiment, when compared with the pure materials and with the other heterojunctions. In addition, it exhibited faster reaction kinetics and good photostability. The best photocatalytic performance presented by this material can be attributed to the real synergistic effect between ZnO and g-C3N4, which promoted relevant interaction in a possible mechanism of Z scheme type, as verified in the PL analysis. The results of the experimental design showed that the catalyst concentration and the pH are the variables that most influence the cefazolin photodegradation, whereas for RB5, all the evaluated variables were significant for 95% confidence. 50-Zn/gCN exhibited 100% degradation for both contaminants evaluated in 90 min of reaction for cefazolin and in 10 min for RB5, under the following conditions: catalyst concentration 0.5 g L-1 , contaminant concentration 5 mg L-1 and pH 2.5. Adsorption played a key role in the photodegradation of RB5. However, the degradation of the dye (adsorbed and remaining in the solution) and the regeneration of the catalyst surface were due to photocatalysis. The Z-scheme mechanisms for the photocatalytic reactions of cefazolin and RB5 have been adequately proposed, in which the photogenerated holes in the valence band of ZnO and the electrons in the conduction band of g-C3N4 were the main degradation pathways of cefazolin and RB5, respectively. The evaluated heterojunction showed good photostability for both contaminants. Finally, the promising character of 50-Zn/gCN synthesized for application in photocatalytic reactions mediated by sunlight for the degradation of contaminants of different classes, as well as the possibility of its use as an efficient alternative to minimize water pollution caused by overuse of medication during the COVID-19 pandemic.","abstract_has_math":false,"creators":["Brasileiro, Islanny Larissa Ouriques"],"institution":"Universidade Federal do Rio Grande do Norte","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Moriyama, André Luís Lopes"],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-12-16","date_published":"2022-12-16","updated_at":"2026-07-24T01:20:46Z","subjects":["Heterojunção","Cefazolina","Preto Reativo 5","Fotocatálise heterogênea","Esquema Z","Estudo cinético"],"languages":["pt_BR"],"rights":["Acesso Aberto"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://repositorio.ufrn.br/handle/123456789/51297","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Moriyama, André Luís Lopes"]},{"key":"dc:creator","label":"Author","values":["Brasileiro, Islanny Larissa Ouriques"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2023-02-15T18:00:31Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2023-02-15T18:00:31Z"]},{"key":"dc:date.issued","label":"Date","values":["2022-12-16"]},{"key":"dc:publisher","label":"Institution","values":["Universidade Federal do Rio Grande do Norte"]},{"key":"dc:type","label":"Dc Type","values":["doctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Heterojunção","Cefazolina","Preto Reativo 5","Fotocatálise heterogênea","Esquema Z","Estudo cinético"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["pt_BR"]},{"key":"dc:rights","label":"Dc Rights","values":["Acesso Aberto"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://repositorio.ufrn.br/handle/123456789/51297"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In recent years there has been growing concern about the contamination of water by emerging contaminants - substances that are not completely degraded by conventional processes of water and wastewater treatments and are not biodegradable. For this reason, several techniques have been developed to efficiently treat such compounds. In this work, different heterojunctions of ZnO/g-C3N4 and ZnFe2O4/g-C3N4 in different mass proportions of g-C3N4 (10, 50, and 80 %) were synthesized through a simple method of mixing, sonication and heat treatment. The influence of the amount of g-C3N4 in the heterojunctions as well as the influence of the type of zinc-based catalyst on the structural, morphological, optical, and photocatalytic properties of the materials were investigated. The XRD, FTIR, and SEM/EDS results confirmed the achievement of the desired heterojunctions. The incorporation of g-C3N4 was relevant in modifying the textural and optical properties of the heterojunctions produced. The 50-Zn/gCN heterojunction showed better photocatalytic degradation of the antibiotic cefazolin (78 %) and the dye RB5 (95 %) in 120 min of the experiment, when compared with the pure materials and with the other heterojunctions. In addition, it exhibited faster reaction kinetics and good photostability. The best photocatalytic performance presented by this material can be attributed to the real synergistic effect between ZnO and g-C3N4, which promoted relevant interaction in a possible mechanism of Z scheme type, as verified in the PL analysis. The results of the experimental design showed that the catalyst concentration and the pH are the variables that most influence the cefazolin photodegradation, whereas for RB5, all the evaluated variables were significant for 95% confidence. 50-Zn/gCN exhibited 100% degradation for both contaminants evaluated in 90 min of reaction for cefazolin and in 10 min for RB5, under the following conditions: catalyst concentration 0.5 g L-1 , contaminant concentration 5 mg L-1 and pH 2.5. Adsorption played a key role in the photodegradation of RB5. However, the degradation of the dye (adsorbed and remaining in the solution) and the regeneration of the catalyst surface were due to photocatalysis. The Z-scheme mechanisms for the photocatalytic reactions of cefazolin and RB5 have been adequately proposed, in which the photogenerated holes in the valence band of ZnO and the electrons in the conduction band of g-C3N4 were the main degradation pathways of cefazolin and RB5, respectively. The evaluated heterojunction showed good photostability for both contaminants. Finally, the promising character of 50-Zn/gCN synthesized for application in photocatalytic reactions mediated by sunlight for the degradation of contaminants of different classes, as well as the possibility of its use as an efficient alternative to minimize water pollution caused by overuse of medication during the COVID-19 pandemic."]},{"key":"dc:title","label":"Title","values":["Desenvolvimento de heterojunções constituídas de ZnO/g-C3N4 e ZnFe2O4/g-C3N4 para fotodegradação de contaminantes orgânicos emergentes"]}]}],"canonical_facts":{"dc:contributor.advisor":["Moriyama, André Luís Lopes"],"dc:creator":["Brasileiro, Islanny Larissa Ouriques"],"dc:date.accessioned":["2023-02-15T18:00:31Z"],"dc:date.available":["2023-02-15T18:00:31Z"],"dc:date.issued":["2022-12-16"],"dc:description.abstract":["In recent years there has been growing concern about the contamination of water by emerging contaminants - substances that are not completely degraded by conventional processes of water and wastewater treatments and are not biodegradable. For this reason, several techniques have been developed to efficiently treat such compounds. In this work, different heterojunctions of ZnO/g-C3N4 and ZnFe2O4/g-C3N4 in different mass proportions of g-C3N4 (10, 50, and 80 %) were synthesized through a simple method of mixing, sonication and heat treatment. The influence of the amount of g-C3N4 in the heterojunctions as well as the influence of the type of zinc-based catalyst on the structural, morphological, optical, and photocatalytic properties of the materials were investigated. The XRD, FTIR, and SEM/EDS results confirmed the achievement of the desired heterojunctions. The incorporation of g-C3N4 was relevant in modifying the textural and optical properties of the heterojunctions produced. The 50-Zn/gCN heterojunction showed better photocatalytic degradation of the antibiotic cefazolin (78 %) and the dye RB5 (95 %) in 120 min of the experiment, when compared with the pure materials and with the other heterojunctions. In addition, it exhibited faster reaction kinetics and good photostability. The best photocatalytic performance presented by this material can be attributed to the real synergistic effect between ZnO and g-C3N4, which promoted relevant interaction in a possible mechanism of Z scheme type, as verified in the PL analysis. The results of the experimental design showed that the catalyst concentration and the pH are the variables that most influence the cefazolin photodegradation, whereas for RB5, all the evaluated variables were significant for 95% confidence. 50-Zn/gCN exhibited 100% degradation for both contaminants evaluated in 90 min of reaction for cefazolin and in 10 min for RB5, under the following conditions: catalyst concentration 0.5 g L-1 , contaminant concentration 5 mg L-1 and pH 2.5. Adsorption played a key role in the photodegradation of RB5. However, the degradation of the dye (adsorbed and remaining in the solution) and the regeneration of the catalyst surface were due to photocatalysis. The Z-scheme mechanisms for the photocatalytic reactions of cefazolin and RB5 have been adequately proposed, in which the photogenerated holes in the valence band of ZnO and the electrons in the conduction band of g-C3N4 were the main degradation pathways of cefazolin and RB5, respectively. The evaluated heterojunction showed good photostability for both contaminants. Finally, the promising character of 50-Zn/gCN synthesized for application in photocatalytic reactions mediated by sunlight for the degradation of contaminants of different classes, as well as the possibility of its use as an efficient alternative to minimize water pollution caused by overuse of medication during the COVID-19 pandemic."],"dc:identifier.uri":["https://repositorio.ufrn.br/handle/123456789/51297"],"dc:language":["pt_BR"],"dc:publisher":["Universidade Federal do Rio Grande do Norte"],"dc:rights":["Acesso Aberto"],"dc:subject":["Heterojunção","Cefazolina","Preto Reativo 5","Fotocatálise heterogênea","Esquema Z","Estudo cinético"],"dc:title":["Desenvolvimento de heterojunções constituídas de ZnO/g-C3N4 e ZnFe2O4/g-C3N4 para fotodegradação de contaminantes orgânicos emergentes"],"dc:type":["doctoralThesis"]},"updated_at":"2026-07-24T01:20:46Z"}