Ramón-Gonçalves, MarinaAlcaraz, LorenaPérez-Ferreras, SusanaLeón González, María Eugenia deRosales Conrado, NoeliaLópez, FélixNature Research2024-01-162024-01-162019Ramon-Goncalves, M; Alcaraz, L; Perez-Ferreras, ; Leon-Gonzalez, ME; Rosales-Conrado, N; Lopez, FA. Extraction of polyphenols and synthesis of new activated carbon from spent coffee grounds. 2019, 9:177062045-232210.1038/s41598-019-54205-yhttps://hdl.handle.net/20.500.14352/93251A valorization process of spent coffee grounds (SCG) was studied. Thus, a two-stage process, the first stage of polyphenols extraction and synthesis of a carbonaceous precursor and a subsequent stage of obtaining activated carbon (AC) by means of a carbonization process from the precursor of the previous stage, was performed. The extraction was carried out with a hydro-alcoholic solution in a pressure reactor, modifying time, temperature and different mixtures EtOH:H2O. To optimize the polyphenols extraction, a two-level factorial experimental design with three replicates at the central point was used. The best results were obtained by using a temperature of 80 °C during 30 min with a mixture of EtOH:H2O 50:50 (v/v). Caffeine and chlorogenic acid were the most abundant compounds in the analysed extracts, ranging from 0.09 to 4.8 mg∙g−1 and 0.06 to 9.7 mg∙g−1, respectively. Similarly, an experimental design was realized in order to analyze the influence of different variables in the AC obtained process (reaction time, temperature and KOH:precursor ratio). The best results were 1 h, 850 °C, and a mixture of 2.5:1. The obtained activated carbons exhibit a great specific surface (between 1600 m2∙g−1 and 2330 m2∙g−1) with a microporous surface. Finally, the adsorption capacity of the activated carbons was evaluated by methylene blue adsorption.engjournal articlehttps://doi.org/10.1038/s41598-019-54205-yopen access543Química2301 Química Analítica