AUTHOR=Diogo Emilay Baessa Teixeira , Vieira Angelica Fonseca Pinto , Nascimento Mayra Aparecida , Pinto Paula Sevenini , de Paula Fabiano Gomes Ferreira , Moreira Renata Pereira Lopes , Teixeira Ana Paula de Carvalho TITLE=Carbon nanostructures supported on Co/serpentinite for sulfentrazone removal JOURNAL=Frontiers in Carbon VOLUME=3 YEAR=2024 URL=https://www.frontiersin.org/journals/carbon/articles/10.3389/frcrb.2024.1402105 DOI=10.3389/frcrb.2024.1402105 ISSN=2813-4192 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.