Química Nova

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13323

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    Preparação de carvão ativado em baixas temperaturas de carbonização a partir de rejeitos de café: utilização de FeCl3 como agente ativante
    (Sociedade Brasileira de Química, 2008) Pereira, Elaine; Oliveira, Luiz C. A.; Vallone, Andréa; Sapag, Karim; Pereira, Márcio
    Ferric chloride as a new activating agent was used to obtain activated carbons from agroindustrial waste. This material was prepared at three temperatures of pyrolysis, 200, 280 and 400 ºC. The carbonaceous materials obtained after the activation processes showed high specific surface areas (BET), with values higher than 900 m² g-1. The materials showed different behaviors in the adsorption of methylene blue dye and reactive red textile dye in water solutions. An important fact in the use of FeCl3 as an activating agent is that the activation temperature is at 280 ºC, well below of those commonly employed in chemical or physical activations described in the literature.
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    Preparação e caracterização de carvão ativado produzido a partir de resíduos do beneficiamento do café
    (Sociedade Brasileira de Química, 2008) Brum, Sarah Silva; Bianchi, Maria Lucia; Silva, Vanésia Liane da; Gonçalves, Maraísa; Guerreiro, Mário César; Oliveira, Luiz Carlos Alves de
    Coffee fruit processing is one of the most polluting activities in agriculture due to the large amount of waste generated in the process. In this work, coffee parchment was employed as precursor for the production of carbons activated with ZnCl2 (CAP). The material was characterized using N2 adsorption/desorption at 77 K, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The material showed a surface area of 521.6 m²g-1 and microporous structure. CAP was applied as adsorbent for the removal of methylene blue dye in aqueous medium. The adsorption capacity was found to be about 188.7 mg g-1.
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    Produção e caracterização de carvão ativado produzido a partir do defeito preto, verde, ardido (PVA) do café
    (Sociedade Brasileira de Química, 2009) Ramos, Paulize H.; Guerreiro, Mário C.; Resende, Eliane C. de; Gonçalves, Maraísa
    The black, green and sour coffee defect (PVA) contributes with 20% of the total coffee production. It should be separate from the normal coffee grains in order to improve the final quality of the beverage. In this way, the present work has the objective to use the PVA reject for the production of activated carbon. The activated carbon (CA) was prepared from PVA defect using zinc chloride as activating agent. The prepared material (CA PVA) was characterized and the adsorption tests were carried out using as organic models methylene blue (AM) and reactive red (VR). The CA PVA revealed to be more efficient in the removal of the organic contaminants compared to a commercial activated carbon.