Centro UTN QUIMOBI - Difusión Científica - Trabajos Presentados en Congresos
Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/676
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Item Producción de “building blocks” a partir de residuos lignocelulósicos, enmarcado en la biorrefinería de los mismos(2022-09-09) Ruiz, Carlos Raúl; Sequeira, Alfredo Fabián; Dagnino, Eliana PaolaEl ácido levulínico (LA) es considerado como uno de los compuestos orgánicos con mayor potencial en la biorrefinería de residuos lignocelulósicos. La composición de la cascarilla de arroz hace que la obtención de LA a través de la biorrefinería sea muy prometedora. Este trabajo tuvo como objetivo definir los rangos de estudio de las variables que afectan a la obtención de LA por tratamiento ácido e identificar el ácido levulínico en el producto de reacción, para posteriormente definir un diseño de experimentos de optimización. Para ello, se realizaron pruebas con cascarilla sin tratar, y con cascarillas pretratadas, modificando la temperatura, el tiempo de reacción, la concentración de ácido sulfúrico y la carga de sólidos. Se identificó y cuantificó la concentración de ácido levulínico por medio de HPLC y, con los datos obtenidos se determinaron los rangos de estudios para cada variable para su posterior optimización. A partir de estos datos preliminares se concluye que es factible la obtención de ácido levulínico a partir de cascarilla de arroz tratada y original por medio de tratamientos ácidos. Se obtuvieron licores con concentraciones de LA superiores a 20 mg/L, con los cuales, haciendo los ajustes correspondientes a los parámetros estudiados se podría esperar mejoras en el rendimiento.Item Levulinic acid obtention from lignocellulosic waste of agroforestry-industrial of different origins(2023-08-04) Ruiz, Carlos Raúl; Sequeira, Alfredo Fabián; Dagnino, Eliana PaolaWorldwide, since last decade levulinic acid (LA) was one of the most sought-after chemical precursors. Lignocellulosic waste of agroforestry-industrial origin like rice hulk, sawdust, and cotton stubble are pointed as raw material for this work, at the same time those lignocellulosic wastes are abundant in Argentina´s northeastern. Report about the evaluation of LA obtention reaction using different raw materials obtained in different treatment steps and maintaining the same operation conditions is the main objective of this work. This objective aims to demonstrate the technical feasibility to obtain LA from a lignocellulosic waste biorefinery scheme. The reaction was running in a cylindrical steel reactor (AISI 316) provided with a manometer and a security valve to ensure the maximum pressure work. The reactor was heated indirectly in a heat-resistant silicone bath. The raw material used were rice hulk (pretreated to extract hemicellulose, lignin, and inorganic compounds), Prosopis nigra sawdust (pretreated to extract lignin and others), and cotton stubble (two fractions one rich in the ground cotton husk and other rich in cotton fiber). The cellulose content was evaluated in each one of these raw materials since this is the main substrate to obtain LA. All raw materials were treated with a sulfuric acid solution 5% w/V, using an 8% solid-liquid rate, and heated to 180°C for 40 minutes (the maximum reaction pressure was 11atm). LA identification and quantification were made in an HPLC, using a sugars and organic acids detection column, a UV detector, and IR to determine unconverted hydrolyzed sugars. The reaction yield was calculated from the LA/cellulose ratio for each of the raw materials. The LA obtained for each raw material was: fractions rich in ground cotton husk 23,38g/L with a reaction yield LA/cellulose 58.85%, fraction rich in cotton fiber 24,44g/L with a reaction yield LA/cellulose 39,67%, pretreated rice hulk 36,01g/L with a reaction yield LA/cellulose 47,88% and pretreated Prosopis nigra sawdust 21,24 g/L with a reaction yield LA/cellulose 47,41%. Based on the results obtained, it is possible to say the LA obtention reaction shows, for each raw material, high yields compared with other studies reported. This could be possible due to the lignocellulosic waste biorefinery scheme used and the application of pretreatments to the raw materials except for the fraction rich in cotton fiber that shows poorer results. These results demonstrate the technical feasibility to obtain LA from a lignocellulosic waste biorefinery scheme. In future works, the seeking of optimal reaction conditions and the possibility to use catalysts in order to improve the LA obtention reaction ratio will be accessed.Item Carboxymethylcellulose obtained from lignocellulosic waste and its use as a biopolymeric matrix(2023-06-04) Cáceres, Liliana Mariel; Tourn, Silvana; Ruiz, Carlos Raúl; Sequeira, Alfredo Fabián; Dagnino, Eliana PaolaThe increase in the rate of production and accumulation of solid waste and the search for sustainable environmental solutions imposes the need to introduce advanced technologies to manage it efficiently. In this context, this work aims to obtain carboxymethylcellulose (CMC) from lignocellulosic waste and later use it in the encapsulation of liquid smoke and essential oils. Thus, a product of higher value can be obtained from an abundant and readably available waste product of northeastern Argentina`s agroforestal industry. Rice husk samples for this research were provided by a local company. The rice husk was treated in a biorefinery scheme (Acid hydrolysis, 0.3% w/V, 150°C, 30 min; followed by organosolv treatment, NaOH-ethanol-water, 160°C, 60min, and alkaline treatment). Subsequently, CMC was obtained, esterifying the unbleached cellulose obtained from the mentioned raw material, using a modification of the Druvacell method. The unbleached cellulose is pretreated with isopropanol and sodium hydroxide to promote fiber swelling and ionization of hydroxyl groups, and subsequently esterification with monochloroacetic acid. On the other hand, bio-oil was obtained by pyrolysis, at 400 °C for 120 min, from exhausted Schinopsis balansae (quebracho colorado) sawdust and the water-soluble fraction produced was refined, representing 34.6% based on the residual biomass fed. Finally, the refined fraction was characterized, to identify the improvement and its quality as liquid smoke to be encapsulated. The CMC obtained was used as a component, together with sodium alginate, of a biopolymeric matrix to encapsulate the water-soluble liquid smoke and hydrophobic essential oil. The raw material was characterized by determining its structural components, the substituent groups in CMC were recognized by FTIR and the degree of substitution was determined. In the production of microcapsules, using standard methods the performance and efficiency of the process were determined. On the other hand, the post-treatment rice husk is composed of 94% cellulose, and the rest is lignin and remaining inorganics. From it, it was possible to obtain a crude CMC with a purity greater than 70% and a degree of substitution greater than 0.6. The microencapsulation results show average yields greater than 55% and efficiencies greater than 90% for both encapsulated substances. With this work carried out, a very abundant residue could be valorized by obtaining CMC and using it in the microencapsulation of two chemically different substances. Good yields and efficiencies were obtained with liquid smoke [1] and essential oil [2], with comparable results with other authors.