RESUMO
Residual lignocellulosic biomass (RLB) is a valuable resource that can help address environmental issues by serving as an alternative to fossil fuels and as a raw material for producing various value-added molecules. To gain a comprehensive understanding of the use of lignocellulosic waste in South America, a review was conducted over the last 4 years. The review focused on energy generation, biofuel production, obtaining platform molecules (such as ethanol, hydroxymethylfurfural, furfural, and levulinic acid), and other materials of interest. The review found that Brazil, Colombia, and Ecuador had the most RLB sources, with sugarcane, oil palm, and rice crop residues being the most prominent. In South America, RLB is used to produce biogas, syngas, hydrogen, bio-oil, biodiesel, torrefied biomass, pellets, and biomass briquettes. The most studied and produced value-added molecule was ethanol, followed by furfural, hydroxymethylfurfural, and levulinic acid. Other applications of interest that have been developed with RLB include obtaining activated carbon and nanomaterials. Significant progress has been made in South America in utilizing RLB, and some countries have been more proactive in regulating its use. However, there is still much to learn about the potential of RLB in each country. This review provides an updated perspective on the typification and valorization of residual biomass in South America and discusses the level of research and technology being applied in the region. This information can be helpful for future research on RLB in South America.
Assuntos
Biocombustíveis , Biomassa , Lignina , Lignina/química , América do SulRESUMO
The Editorial Office was made aware of an error in Figure S1 within the original publication [...].
RESUMO
Resumen Se sintetizaron catalizadores (SNX#WPA) basados en ácido tungstofosfórico, en soportes de nanoestructuras de sílice (SNX), con distribución de diámetros y tamaños de mesoporos variables. Las SNX se prepararon en medio de octano/agua, usando poliestireno y bromuro de cetiltrimetilamonio como plantillas. Los materiales se caracterizaron por DRX, TEM y adsorción/desorción de nitrógeno. La relación octano/agua influyó tanto en la morfología y el tamaño de las SNX como en la distribución del tamaño de poro. Las SNX obtenidas utilizando relaciones OCT/H2O en el rango de 0,07-0,35, presentan mesoporos pequeños (5-6 nm) y grandes (28-34 nm), generados principalmente por poliestireno. Los mesoporos grandes y su contribución de volumen fueron claramente más altos que en las muestras SN1, SN2 y SN3. La estructura y la morfología de SNX#WPA fueron similares a las de las SNX usadas como soporte. Además, la caracterización de todos los materiales SNX#WPA por FT-IR y 31P NMR indicó la presencia de especies [PW12O40]3- y [H3-XPW12O40](3-X)- sin degradar. Según los resultados de la valoración potenciométrica, los sólidos presentaron sitios ácidos muy fuertes. Se evaluó la actividad de SNX#WPA como catalizadores en la síntesis de quinoxalinas, a partir de lo cual se obtuvieron altos rendimientos, sin formación de subproductos. De ello resultó que los materiales preparados son catalizadores altamente selectivos y reutilizables.
Abstract Tungstophosphoric acid supported on silica nanostructures (SNX#WPA) with variable diameter and mesopore size distribution were synthetized. Silica nanostructures (SNX) were prepared in octane/aqueous media using polystyrene and CTAB as organic templates. The materials were characterized by XRD, SEM, TEM and dinitrogen adsorption/ desorption isotherm analysis. The octane/ water ratio influenced the morphology and size of SNX prepared, as well as its pore size distribution. The SNX samples obtained using OCT/H2O ratios in the range 0.07-0.35 (SN4, SN5, and SN6 samples). present small (5-6 nm) and large (28-34 nm) mesopores (mainly generated by polystyrene). Large mesopores and their volume contribution were clearly higher than in the SN1, SN2, and SN3 samples. The structure and morphology of SNX#WPA samples were similar to those of the SNX. Furthermore, the characterization of all the SNX#WPA materials by FT-IR and 31P NMR indicated the presence of undegraded [PW12O40]3- and [H3-XPW12O40](3-X)-species. According to the potentiometric titration results, the solids presented very strong acid sites. The performance of SNX#WPA materials as catalysts in the synthesis of quinoxalines was evaluated. The yields achieved were high, without formation of by-products resulting from competitive reactions or decomposition products, so the prepared materials are highly selective and reusable catalysts.
Resumo Catalisadores (SNX#WPA) baseados em ácido tungsofosfórico suportado em nanoestruturas de sílica (SNX) foram sintetizados com distribuição de tamanhos e diâmetros variados de mesoporos. Os SNX foram preparados em meio octano/aquoso usando poliestireno e brometo de cetiltrimetilamônio como modelos orgânicos. Os materiais foram caracterizados por DRX, TEM e adsorção/ dessorção de nitrogénio. A razão octano/ agua influenciou a morfologia e o tamanho do SNX, bem como a distribuição do tamanho dos poros. O SNX obtido usando razões OCT/ H2O na faixa de 0,07-0,35, possui mesoporos pequenos (5-6 nm) e grandes (28-34 nm) (gerados principalmente por poliestireno). Mesoporos grandes e sua contribuição em volume foram claramente maiores do que nas amostras SN1, SN2 e SN3. A estrutura e a morfologia do SNX#WPA foram semelhantes às do SNX usado como suporte. Além disso, a caracterização de todos os materiais SNX#WPA por FT-IR e 31P NMR indicou a presença das espécies [PW12O40]3- e [H3-XPW12O40](3-X)- sem degradar. De acordo com os resultados da titulação potenciométrica, os sólidos apresentaram locais ácidos muito fortes. A atividade do SNX#WPA como catalisadores na síntese de quinoxalinas foi avaliada, produzindo altos rendimentos, sem formação de subprodutos, resultando em materiais catalisadores altamente seletivos e reutilizáveis.