Lignocellulosic biomass fractionation with deep eutectic solvents
Autor(a) principal: | |
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Data de Publicação: | 2019 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/29460 |
Resumo: | This work focused on studying the efficiency of two types of deep eutectic solvents (DES) on the fractionation of Eucalyptus globulus wood main components, namely cellulose, hemicellulose and lignin. The hydrogen bond donors (HBD) used for DES preparation were the dicarboxylic acids oxalic (OxA) and malic (MA), or the aliphatic diols ethanediol (Eth), butanediol (But) and hexanediol (Hex). Choline chloride (ChCl) was used as a hydrogen bond acceptor (HBA) in all studied DES. In order to evaluate the DES fractionation ability, certain operation parameters were studied, such as water content (25, 50 and 75 wt%), temperature (100 and 120 °C ) and DES molar ratio (1:1 and 1:3). For the acidic DES systems, ChCl:OxA revealed to be more efficient than ChCl:MA in biomass delignification at all tested conditions. In general, the fractionation of biomass components was favored by the addition of water up to 25 wt% into DES, while higher water contents decreased the efficacy of DES. The increase of both acid molar ratio in DES from 1:1 to 1:3 and temperature from 100 to 120 °C favored delignification, although a more pronounced effect was observed for the latter. In this sense, ChCl:OxA (1:1) at 120 °C was the most efficient system in biomass delignification, obtaining an insoluble cellulose-rich fraction (CrF) and a lignin-rich fraction (LrF) as separated solid streams with recovery yields of 62.4 wt% (from the initial biomass) and 69.8 wt% (from the initial lignin content), respectively. FTIR-ATR and solid-state NMR analysis further confirmed this cellulose enrichment compared to the original biomass, although residual lignin was also present. Additionally, the increase of temperature and DES molar ratio enhanced unwanted side reactions, such as esterification between separated components and organic acids from DES. Regarding hemicelluloses extraction, the addition of water and increased acid molar ratio favored xylose production in the liquid fraction, reaching a maximum yield of 71.7 mol% with ChCl:OxA (1:3) at 50 wt% water content. This condition also allowed for low furfural production (5.4 mol%) revealing its selectivity towards xylose production. In regard to diol-based DES, ChCl:Hex (1:1) revealed the best performance on biomass fractionation among examined diol-based DES. The addition of water up to 25 wt% content to ChCl:Hex (1:1) disclosed a positive effect allowing for 49.9 wt% and 82.4 wt% CrF and LrF yields, respectively, at 120 °C for 4 h of treatment. Further FTIR-ATR and solid-state NMR analysis showed an absence of lignin content in CrF, demonstrating the efficient biomass delignification provided by ChCl:Hex (1:1). Once again, the addition of water favored xylose production, whereas diol-based DES at 50 wt% water content produced xylose yields nearby 50 mol% at 120 °C for 4 h. This condition also allowed for low furfural production (9.7 mol%). Moreover, a kinetic study comparing the biomass fractionation performance of ChCl:Hex with Hex demonstrated a faster biomass delignification and higher furfural yield when ChCl was present. This may indicate a key role of ChCl on both delignification and furfural production. |
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Lignocellulosic biomass fractionation with deep eutectic solventsDeep eutectic solventsEucalyptus globulusLignocellulosic biomassDelignificationCelluloseLigninHemicelluloseThis work focused on studying the efficiency of two types of deep eutectic solvents (DES) on the fractionation of Eucalyptus globulus wood main components, namely cellulose, hemicellulose and lignin. The hydrogen bond donors (HBD) used for DES preparation were the dicarboxylic acids oxalic (OxA) and malic (MA), or the aliphatic diols ethanediol (Eth), butanediol (But) and hexanediol (Hex). Choline chloride (ChCl) was used as a hydrogen bond acceptor (HBA) in all studied DES. In order to evaluate the DES fractionation ability, certain operation parameters were studied, such as water content (25, 50 and 75 wt%), temperature (100 and 120 °C ) and DES molar ratio (1:1 and 1:3). For the acidic DES systems, ChCl:OxA revealed to be more efficient than ChCl:MA in biomass delignification at all tested conditions. In general, the fractionation of biomass components was favored by the addition of water up to 25 wt% into DES, while higher water contents decreased the efficacy of DES. The increase of both acid molar ratio in DES from 1:1 to 1:3 and temperature from 100 to 120 °C favored delignification, although a more pronounced effect was observed for the latter. In this sense, ChCl:OxA (1:1) at 120 °C was the most efficient system in biomass delignification, obtaining an insoluble cellulose-rich fraction (CrF) and a lignin-rich fraction (LrF) as separated solid streams with recovery yields of 62.4 wt% (from the initial biomass) and 69.8 wt% (from the initial lignin content), respectively. FTIR-ATR and solid-state NMR analysis further confirmed this cellulose enrichment compared to the original biomass, although residual lignin was also present. Additionally, the increase of temperature and DES molar ratio enhanced unwanted side reactions, such as esterification between separated components and organic acids from DES. Regarding hemicelluloses extraction, the addition of water and increased acid molar ratio favored xylose production in the liquid fraction, reaching a maximum yield of 71.7 mol% with ChCl:OxA (1:3) at 50 wt% water content. This condition also allowed for low furfural production (5.4 mol%) revealing its selectivity towards xylose production. In regard to diol-based DES, ChCl:Hex (1:1) revealed the best performance on biomass fractionation among examined diol-based DES. The addition of water up to 25 wt% content to ChCl:Hex (1:1) disclosed a positive effect allowing for 49.9 wt% and 82.4 wt% CrF and LrF yields, respectively, at 120 °C for 4 h of treatment. Further FTIR-ATR and solid-state NMR analysis showed an absence of lignin content in CrF, demonstrating the efficient biomass delignification provided by ChCl:Hex (1:1). Once again, the addition of water favored xylose production, whereas diol-based DES at 50 wt% water content produced xylose yields nearby 50 mol% at 120 °C for 4 h. This condition also allowed for low furfural production (9.7 mol%). Moreover, a kinetic study comparing the biomass fractionation performance of ChCl:Hex with Hex demonstrated a faster biomass delignification and higher furfural yield when ChCl was present. This may indicate a key role of ChCl on both delignification and furfural production.Este trabalho focou-se no estudo da eficácia de dois tipos de solventes eutécticos profundos (DES) no fracionamento dos principais componentes de Eucalyptus Globulus, nomeadamente celulose, hemicelulose e lenhina. Os componentes utilizados na preparação dos DES como dadores de pontes de hidrogénio (HBD) foram ácidos dicarboxílicos, nomeadamente os ácidos oxálico (OxA) e málico (MA), ou diois alifáticos, incluindo etanodiol (Eth), butanodiol (But) e hexanodiol (Hex). O cloreto de colina (ChCl) foi utilizado como aceitador de pontes de hidrogénio (HBA) em todos os DES estudados. De modo a avaliar a eficiência de fracionamento do DES, foram avaliados parâmetros operacionais, tais como, temperatura (100 e 120 °C), composição molar dos DES (1:1 e 1:3) e teor de água no DES (25, 50 e 75 wt%). Para os sistemas de DES acídicos ChCl:OxA revelou-se o mais eficaz na deslenhificação do que o ChCl:MA em todas as condições testadas. A extração de componentes da biomassa foi favorecida pela adição de água até 25 wt%, sendo desfavorecida com teores superiores. O aumento molar de ácido no DES (1:1 para 1:3) e o aumento de temperatura (100 para 120 °C) beneficiaram a deslenhificação, tendo o último parâmetro um efeito mais pronunciado. Deste modo, ChCl:OxA (1:1) a 120 ℃ revelou ser o mais eficiente para deslenhificação, obtendo uma fração insolúvel rica em celulose (CrF) e uma fração rica em lenhina (LrF) de 62.4 wt% (da biomassa inicial) e 69.8 wt% (do conteúdo de lenhina inicial). A análise de FTIR e RMN confirmou o enriquecimento em celulose, e revelou a presença de lenhina residual. Adicionalmente, o aumento da temperatura e rácio molar proporcionou um aumento de reações de esterificação indesejadas entre os componentes separados da biomassa e os ácidos orgânicos no DES. Relativamente à extração de hemiceluloses, a adição de água e o aumento do rácio molar de ácido favoreceram a produção de xilose, atingindo o máximo de 71.7 mol% com ChCl:OxA (1:3) a 100 ºC e com 50 wt% de água. Esta condição permitiu uma baixa produção de furfural (5.4 mol%) revelando a sua seletividade para a produção de xilose. Relativamente a DES baseados em diois, o sistema ChCl:Hex revelou-se o mais eficaz na deslenhificação dentre todos os outros DES examinados. A adição de água até 25 wt% a ChCl:Hex (1:1) revelou um efeito positivo no sistema, tendo sido obtido rendimentos de 49.9 wt% e 82.4 wt% para CrF e LrF, respetivamente, a 120 ℃ durante 4h. Após análise por FTIR e RMN, foi possível confirmar a ausência de lenhina na CrF, mais uma vez demonstrando a eficiência de deslenhificação da biomass do sistema ChCl:Hex (1:1). Mais uma vez, a adição de água favoreceu a produção de xilose, dado que estes DES baseados em diois com 50 wt% de água, produziram rendimentos de xilose de aproximadamente 50 wt% a 120 ℃ durante 4 horas. Esta condição produziu também uma quantidade baixa de furfural (9.7 mol%). Um estudo cinético comparando a performance do fracionamento de biomassa de ChCl:Hex e Hex revelou uma deslenhificação mais rápida e uma maior produção de fufural na presença de ChCl. Isto pode indicar que ChCl desempenha um papel importante tanto na deslenhificação como na produção de fufural.2019-122019-12-01T00:00:00Z2022-01-07T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/29460engCarvalho, Ana Maltainfo:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T11:56:59Zoai:ria.ua.pt:10773/29460Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:01:47.822585Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Lignocellulosic biomass fractionation with deep eutectic solvents |
title |
Lignocellulosic biomass fractionation with deep eutectic solvents |
spellingShingle |
Lignocellulosic biomass fractionation with deep eutectic solvents Carvalho, Ana Malta Deep eutectic solvents Eucalyptus globulus Lignocellulosic biomass Delignification Cellulose Lignin Hemicellulose |
title_short |
Lignocellulosic biomass fractionation with deep eutectic solvents |
title_full |
Lignocellulosic biomass fractionation with deep eutectic solvents |
title_fullStr |
Lignocellulosic biomass fractionation with deep eutectic solvents |
title_full_unstemmed |
Lignocellulosic biomass fractionation with deep eutectic solvents |
title_sort |
Lignocellulosic biomass fractionation with deep eutectic solvents |
author |
Carvalho, Ana Malta |
author_facet |
Carvalho, Ana Malta |
author_role |
author |
dc.contributor.author.fl_str_mv |
Carvalho, Ana Malta |
dc.subject.por.fl_str_mv |
Deep eutectic solvents Eucalyptus globulus Lignocellulosic biomass Delignification Cellulose Lignin Hemicellulose |
topic |
Deep eutectic solvents Eucalyptus globulus Lignocellulosic biomass Delignification Cellulose Lignin Hemicellulose |
description |
This work focused on studying the efficiency of two types of deep eutectic solvents (DES) on the fractionation of Eucalyptus globulus wood main components, namely cellulose, hemicellulose and lignin. The hydrogen bond donors (HBD) used for DES preparation were the dicarboxylic acids oxalic (OxA) and malic (MA), or the aliphatic diols ethanediol (Eth), butanediol (But) and hexanediol (Hex). Choline chloride (ChCl) was used as a hydrogen bond acceptor (HBA) in all studied DES. In order to evaluate the DES fractionation ability, certain operation parameters were studied, such as water content (25, 50 and 75 wt%), temperature (100 and 120 °C ) and DES molar ratio (1:1 and 1:3). For the acidic DES systems, ChCl:OxA revealed to be more efficient than ChCl:MA in biomass delignification at all tested conditions. In general, the fractionation of biomass components was favored by the addition of water up to 25 wt% into DES, while higher water contents decreased the efficacy of DES. The increase of both acid molar ratio in DES from 1:1 to 1:3 and temperature from 100 to 120 °C favored delignification, although a more pronounced effect was observed for the latter. In this sense, ChCl:OxA (1:1) at 120 °C was the most efficient system in biomass delignification, obtaining an insoluble cellulose-rich fraction (CrF) and a lignin-rich fraction (LrF) as separated solid streams with recovery yields of 62.4 wt% (from the initial biomass) and 69.8 wt% (from the initial lignin content), respectively. FTIR-ATR and solid-state NMR analysis further confirmed this cellulose enrichment compared to the original biomass, although residual lignin was also present. Additionally, the increase of temperature and DES molar ratio enhanced unwanted side reactions, such as esterification between separated components and organic acids from DES. Regarding hemicelluloses extraction, the addition of water and increased acid molar ratio favored xylose production in the liquid fraction, reaching a maximum yield of 71.7 mol% with ChCl:OxA (1:3) at 50 wt% water content. This condition also allowed for low furfural production (5.4 mol%) revealing its selectivity towards xylose production. In regard to diol-based DES, ChCl:Hex (1:1) revealed the best performance on biomass fractionation among examined diol-based DES. The addition of water up to 25 wt% content to ChCl:Hex (1:1) disclosed a positive effect allowing for 49.9 wt% and 82.4 wt% CrF and LrF yields, respectively, at 120 °C for 4 h of treatment. Further FTIR-ATR and solid-state NMR analysis showed an absence of lignin content in CrF, demonstrating the efficient biomass delignification provided by ChCl:Hex (1:1). Once again, the addition of water favored xylose production, whereas diol-based DES at 50 wt% water content produced xylose yields nearby 50 mol% at 120 °C for 4 h. This condition also allowed for low furfural production (9.7 mol%). Moreover, a kinetic study comparing the biomass fractionation performance of ChCl:Hex with Hex demonstrated a faster biomass delignification and higher furfural yield when ChCl was present. This may indicate a key role of ChCl on both delignification and furfural production. |
publishDate |
2019 |
dc.date.none.fl_str_mv |
2019-12 2019-12-01T00:00:00Z 2022-01-07T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/masterThesis |
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masterThesis |
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publishedVersion |
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http://hdl.handle.net/10773/29460 |
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http://hdl.handle.net/10773/29460 |
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eng |
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eng |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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