Materials Research
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13556
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Item Ecotoxicological Effects of Biochar Obtained from Spent Coffee Grounds(ABM, ABC, ABPol, 2022-11-21) Souza, Lorrana Zélia Martins de; Pinto, Bruna Cristina; Alves, Adriana Barboza; Ribeiro, Amanda Vanessa de Oliveira; Feliciano, Débora Cristina Teodoro; Silva, Luisa Heringer da; Dias, Thiago Tales Moraes; Yılmaz, Murat; Oliveira, Magno André de; Bezerra, Augusto Cesar da Silva; Ferreira, Osania Emerenciano; Lima, Robson Pereira de; Pimenta, Lúcia Pinheiro do Santos; Machado, Alan Rodrigues TeixeiraThe objective of this work is to investigate the conversion of spent coffee grounds (SCG) into biochar (BSC) and the ecotoxicological effects of the product obtained. The SCG and BSC were characterized by characterized by different techniques (TGA/DTG, FTIR, XRD, SEM, EDS, and EDXRF). Proton Nuclear Magnetic Resonance (1H NMR) was used to characterize the aqueous extract of BSC. The inhibitory effect on lettuce (Lactuca sativa) germination was investigated. Besides, antimicrobial activity evaluation trials were conducted with Azospirillum brasilense and Trichoderma spp. The results showed that in the BSC production process, the extractives and lignocellulosic components in the SCG were partly decomposed. Tests conducted with microorganisms did not reveal any toxic effect of BSC. However, high phytotoxicity against lettuce was recorded for rate 100 t/ha of BSC. This effect was associated with the presence of carboxylic acids identified by 1H NMR in the BSC extract aqueous.Item Kinetic study of a bacterial cellulose production by Komagataeibacter rhaeticus using coffee grounds and sugarcane molasses(ABM, ABC, ABPol, 2021) Souza, Karina Carvalho de; Trindade, Nicolas Mattos; Amorim, Júlia Didier Pedrosa de; Nascimento, Helenise Almeida do; Costa, Andréa Fernanda Santana; Henrique, Mariana Alves; Caetano, Viviane Fonseca; Sarubbo, Leonie Asfora; Vinhas, Glória MariaBiotechnology can be used to convert waste into valuable products. In this context, there is bacterial cellulose (BC), a natural biopolymer that can be transformed into several useful materials, but its production is limited due to the high cost of the culture media used for its industrialization. In this work, BC was produced from the bacteria Komagataeibacter rhaeticus, using coffee grounds, sugarcane molasses and ethanol. The experiments were carried out under static conditions. The products were collected every 48 h, with a total period of 240 h. The maximum BC production (11.08 g.L-1) was obtained in a culture medium supplemented with coffee powder, hydrolyzed cane molasses and the addition of 1% (v/v) ethanol. The results show that the use of different carbon sources of the evaluated by-products are viable alternatives in reducing costs in BC production.Item Optimization of espresso spent ground coffee waste extract preparation and the influence of its chemical composition as an eco-friendly corrosion inhibitor for carbon steel in acid medium(ABM, ABC, ABPol, 2020) Costa, Marina A. J. L. da; Gois, Jefferson S. de; Toaldo, Isabela M.; Bauerfeldt, Ana Clara Favilla; Batista, Diego B.; Bordignon-Luiz, Marilde T.; Lago, Dalva C. B. do; Luna, Aderval S.; Senna, Lilian F. deThis work proposes the reuse of spent ground coffee waste (SCG) extracts as eco-friendly corrosion inhibitors for carbon steel in acid medium, and the correlation between their anticorrosive efficiency and chemical composition. The extraction method was optimized using a central composite design, and the chemical composition of the extracts was accessed using UV-Vis spectrometry, HPLC, and ICP-OES. EIS and Potentiodynamic Polarization (PP) tests evaluated the anticorrosive properties of the extracts. Total phenol content ranged from 93 mg L-1 to 219 mg L-1 Gallic Acid Equivalent. The highest concentration of phenolic compounds was observed for syringic acid (78.67 mg L-1), while the lowest concentration was verified for (-)-epigallocatechin-3-O-gallate (0.01 mg L-1). The Pearson correlation coefficient showed no correlation between the Rct and the total phenol content, although, positive correlations with the Rct was observed for caffeic acid, (+)-catechin, ferulic acid, and protocatechuic acid. EIS analysis revealed that all of the extracts could act as corrosion inhibitors. The best performance was verified for C3 extract (IE % = 94.83%). PP tests showed that this extract acted as a mixed inhibitor, with a predominant cathodic effect. Therefore, the valorization of the extracts as corrosion inhibitors was successfully achieved.