Pub Date : 2024-07-25DOI: 10.3389/frcrb.2024.1393077
Mayara G. Gonçalves, Vinícius O. Costa, André H. G. Martinez, Bernardo M. Régnier, Gabriel C. B. Gomes, Aldo Zarbin, Elisa S. Orth
Graphene oxide (GO) has attracted significant attention from the scientific community due to its mechanical, optical, electrical, and chemical properties. This review outlines synthetic methods for GO functionalization, including those involving covalent and noncovalent bonds with organic molecules. In a novel contribution to this field, particular emphasis is placed on functionalization via epoxy ring opening, a poorly studied and understood topic. We first provide an overview of the basic structure and properties of graphene oxide. We then explore the various methods employed to functionalize graphene oxide, noting the complexity of these reactions, which sometimes occur in a non-specific manner. However, there are some strategies for targeted functionalization. Furthermore, we present a critical analysis of the covalent functionalization through epoxy groups, demonstrating important aspects to be considered when choosing the reaction medium. An alkaline environment seems to favor this reaction, and there is no consensus regarding the advantages and disadvantages of using basic pH in functionalization reactions. We also demonstrate some challenges involving the characterization and confirmation of the functionalization, mainly in the basal plane, and we show advances in characterization techniques that can be explored in future studies. Finally, some current challenges and future research directions are presented to contribute to the advancement of the field.
氧化石墨烯（GO）因其机械、光学、电学和化学特性而备受科学界关注。本综述概述了 GO 功能化的合成方法，包括与有机分子共价键和非共价键的合成方法。作为对这一领域的新贡献，本综述特别强调了通过环氧树脂开环进行功能化的方法，这是一个研究和理解不多的课题。我们首先概述了氧化石墨烯的基本结构和特性。然后，我们探讨了对氧化石墨烯进行功能化的各种方法，并指出了这些反应的复杂性，这些反应有时会以非特异性的方式发生。不过，也有一些有针对性的功能化策略。此外，我们还对通过环氧基团进行共价官能化进行了批判性分析，展示了在选择反应介质时需要考虑的重要方面。碱性环境似乎更有利于这种反应，而在官能化反应中使用碱性 pH 值的利弊尚未达成共识。我们还展示了涉及表征和确认功能化的一些挑战，主要是在基底面上，我们还展示了表征技术的进步，这些都可以在未来的研究中进行探索。最后，我们提出了一些当前面临的挑战和未来的研究方向，以促进该领域的发展。
{"title":"Functionalization of graphene oxide via epoxide groups: a comprehensive review of synthetic routes and challenges","authors":"Mayara G. Gonçalves, Vinícius O. Costa, André H. G. Martinez, Bernardo M. Régnier, Gabriel C. B. Gomes, Aldo Zarbin, Elisa S. Orth","doi":"10.3389/frcrb.2024.1393077","DOIUrl":"https://doi.org/10.3389/frcrb.2024.1393077","url":null,"abstract":"Graphene oxide (GO) has attracted significant attention from the scientific community due to its mechanical, optical, electrical, and chemical properties. This review outlines synthetic methods for GO functionalization, including those involving covalent and noncovalent bonds with organic molecules. In a novel contribution to this field, particular emphasis is placed on functionalization via epoxy ring opening, a poorly studied and understood topic. We first provide an overview of the basic structure and properties of graphene oxide. We then explore the various methods employed to functionalize graphene oxide, noting the complexity of these reactions, which sometimes occur in a non-specific manner. However, there are some strategies for targeted functionalization. Furthermore, we present a critical analysis of the covalent functionalization through epoxy groups, demonstrating important aspects to be considered when choosing the reaction medium. An alkaline environment seems to favor this reaction, and there is no consensus regarding the advantages and disadvantages of using basic pH in functionalization reactions. We also demonstrate some challenges involving the characterization and confirmation of the functionalization, mainly in the basal plane, and we show advances in characterization techniques that can be explored in future studies. Finally, some current challenges and future research directions are presented to contribute to the advancement of the field.","PeriodicalId":502487,"journal":{"name":"Frontiers in Carbon","volume":"13 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141802883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-21DOI: 10.3389/frcrb.2024.1402105
Emilay B T Diogo, Angelica Fonseca Pinto Vieira, Mayra Aparecida Nascimento, P. S. Pinto, Fabiano Gomes Ferreira de Paula, Renata Pereira Lopes Moreira, Ana Paula de Carvalho Teixeira
The presence of environmental contaminants is a major problem today. In this context, it is necessary to develop new sustainable materials to be used to remediate these contaminants. In this work, the serpentinite rock was impregnated with cobalt, 5%, 10% and 20% and used as a support for the synthesis of carbon nanostructures by CVD (chemical vapour deposition) process, at 900°C. This temperature was chosen due to the high thermal stability of the carbon source. The materials were characterized by X-ray diffraction, Raman spectroscopy, thermal analysis, scanning and transmission microscopy. As expect the main phases formed were forsterite, Mg2SiO4, graphitic carbon and metallic cobalt. All the synthesis showed the formation of carbon structures as multiwalled carbon nanostructures over cobalt cores. The carbon structures showed good thermal stability, between 470 and 600°C. The higher the cobalt content, the higher the yield of the carbon structures synthesis, i.e. 14%, 23% and 37% for Serp5, Serp10 and Serp20, respectively. The produced materials were used to removal of the environmental contaminant sulfentrazone. After CVD process, the removal of sulfentrazone increase to 17.3%, 18.4% and 25.2% for Serp5, Serp10 and Serp20, respectively, showing an increase in sulfentrazone removal with the increase in carbon content. In addition, the percentage of sulfentrazone removal by Serp20 was greater at acidic pH values, decreasing from 41.7% to 12.7% with an increase from 2 to 10 in pH. The removal capacity obtained experimentally at a sulfentrazone concentration of 50 mg L−1 was equal to 14.9 mg g−1. According to literature and data obtained in this work, it was observed that the removal of contaminants from the aqueous medium occurred through two mechanisms: reduction of the organic compound by Co nanoparticles and adsorption carried out by carbon nanostructures.
{"title":"Carbon nanostructures supported on Co/serpentinite for sulfentrazone removal","authors":"Emilay B T Diogo, Angelica Fonseca Pinto Vieira, Mayra Aparecida Nascimento, P. S. Pinto, Fabiano Gomes Ferreira de Paula, Renata Pereira Lopes Moreira, Ana Paula de Carvalho Teixeira","doi":"10.3389/frcrb.2024.1402105","DOIUrl":"https://doi.org/10.3389/frcrb.2024.1402105","url":null,"abstract":"The presence of environmental contaminants is a major problem today. In this context, it is necessary to develop new sustainable materials to be used to remediate these contaminants. In this work, the serpentinite rock was impregnated with cobalt, 5%, 10% and 20% and used as a support for the synthesis of carbon nanostructures by CVD (chemical vapour deposition) process, at 900°C. This temperature was chosen due to the high thermal stability of the carbon source. The materials were characterized by X-ray diffraction, Raman spectroscopy, thermal analysis, scanning and transmission microscopy. As expect the main phases formed were forsterite, Mg2SiO4, graphitic carbon and metallic cobalt. All the synthesis showed the formation of carbon structures as multiwalled carbon nanostructures over cobalt cores. The carbon structures showed good thermal stability, between 470 and 600°C. The higher the cobalt content, the higher the yield of the carbon structures synthesis, i.e. 14%, 23% and 37% for Serp5, Serp10 and Serp20, respectively. The produced materials were used to removal of the environmental contaminant sulfentrazone. After CVD process, the removal of sulfentrazone increase to 17.3%, 18.4% and 25.2% for Serp5, Serp10 and Serp20, respectively, showing an increase in sulfentrazone removal with the increase in carbon content. In addition, the percentage of sulfentrazone removal by Serp20 was greater at acidic pH values, decreasing from 41.7% to 12.7% with an increase from 2 to 10 in pH. The removal capacity obtained experimentally at a sulfentrazone concentration of 50 mg L−1 was equal to 14.9 mg g−1. According to literature and data obtained in this work, it was observed that the removal of contaminants from the aqueous medium occurred through two mechanisms: reduction of the organic compound by Co nanoparticles and adsorption carried out by carbon nanostructures.","PeriodicalId":502487,"journal":{"name":"Frontiers in Carbon","volume":"34 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141118247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-08DOI: 10.3389/frcrb.2024.1339418
Nimita K. C, Jiji Abraham, Martin George Thomas, H. Vahabi, Hanna. J. Maria, Sabu Thomas
Rubber (elastomer) based polymer nanocomposites have attracted wide range of attention from industries and other fields due to its exceptionally good mechanical, thermal and electrical properties. One of the promising candidates of this category is CNT filled rubber nanocomposites. This review throws light on the historical trajectory of development of CNT filled rubber nanocomposites. Various fabrication methods, detailed explanation of reinforcement mechanism in CNT/rubber nanocomposites and the relationship between the structure and properties are reviewed. The next part of the review discusses about the morphological and interface characteristics. An attempt to investigate the versatile mechanical, thermal, and electrical properties also included in the review. The final part of the review includes the applications of CNT filled rubber nanocomposites. Major applications in fields like electronics, sustainable biomedical and EMI shielding are discussed in detail. The review also focuses on the key challenges that arises while incorporating CNTs into rubber matrices.
{"title":"Carbon nanotube filled rubber nanocomposites","authors":"Nimita K. C, Jiji Abraham, Martin George Thomas, H. Vahabi, Hanna. J. Maria, Sabu Thomas","doi":"10.3389/frcrb.2024.1339418","DOIUrl":"https://doi.org/10.3389/frcrb.2024.1339418","url":null,"abstract":"Rubber (elastomer) based polymer nanocomposites have attracted wide range of attention from industries and other fields due to its exceptionally good mechanical, thermal and electrical properties. One of the promising candidates of this category is CNT filled rubber nanocomposites. This review throws light on the historical trajectory of development of CNT filled rubber nanocomposites. Various fabrication methods, detailed explanation of reinforcement mechanism in CNT/rubber nanocomposites and the relationship between the structure and properties are reviewed. The next part of the review discusses about the morphological and interface characteristics. An attempt to investigate the versatile mechanical, thermal, and electrical properties also included in the review. The final part of the review includes the applications of CNT filled rubber nanocomposites. Major applications in fields like electronics, sustainable biomedical and EMI shielding are discussed in detail. The review also focuses on the key challenges that arises while incorporating CNTs into rubber matrices.","PeriodicalId":502487,"journal":{"name":"Frontiers in Carbon","volume":" 30","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141000472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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