Costa, Marina A. J. L. daGois, Jefferson S. deToaldo, Isabela M.Bauerfeldt, Ana Clara FavillaBatista, Diego B.Bordignon-Luiz, Marilde T.Lago, Dalva C. B. doLuna, Aderval S.Senna, Lilian F. de2022-07-132022-07-132020COSTA, M. A. J. L. et al. 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. Materials Research, São Carlos, v. 23, n. 5, p. 1-12, 2020.1980-5373https://doi.org/10.1590/1980-5373-MR-2019-0591http://www.sbicafe.ufv.br/handle/123456789/13582This 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.pdfenOpen AccessSpent ground coffeeChemical characterization of foodWaste managementPearson correlationGreen chemistryCorrosion inhibitorCafeicultura::Resíduos e subprodutos do caféArtigo