Showing papers by "Vitaliy L. Budarin published in 2018"
TL;DR: Supercritical carbon dioxide extraction is an important technology for the cleaner production of waxes, it is a sustainable pre-treatment of biomass as part of an integrated holistic biorefinery and significantly it can improve the safety of products, e.g. less off gassing of wood pellets as mentioned in this paper.
51 citations
TL;DR: In this article, the authors proposed a mechanism of the promoting effect of NaCl on the cellulose hydrolysis process based on a systematic kinetic study involving variable temperature studies and the use of deuterated agents.
Abstract: Depolymerisation of cellulose is a critical step for biomass-based bio-refining processes to produce valuable chemicals. Herein, we propose the mechanism of the promoting effect of NaCl on the cellulose hydrolysis process based on a systematic kinetic study involving variable temperature studies and the use of deuterated agents. It has been found that the presence of NaCl simultaneously enhances the generation of acidic products from cellulose decomposition and pushes the generated protons to the surface of cellulose, dramatically increasing surface acidity and facilitating the autocatalytic hydrolysis of cellulose. Cl− disrupted the intermolecular hydrogen bonding of cellulose, especially in the first surface layer. Thus, the solid cellulose chains were peeled off layer-by-layer, leading to an accelerated hydrolysis of cellulose by the adsorbed protons. Without the need for traditional acidic catalysts, this autocatalytic depolymerisation of cellulose in water, assisted by salt provides a practically viable route to the enhanced conversion of biomass to chemicals.
46 citations
TL;DR: The process of NaCl promoted depolymerization of xylo-oligomers to xylose through use of seawater and NaCl, under microwave hydrolytic conditions, is investigated by systematic kinetic study assisted by deuterated agents.
Abstract: The depolymerization of hemicellulose is essential in the downstream processing of biomass within a biorefinery, with the search for energy efficient selective pathways for its conversion presenting a significant challenge. Herein, the process of NaCl promoted depolymerization of xylo-oligomers to xylose through use of seawater and NaCl, under microwave hydrolytic conditions, is investigated by systematic kinetic study assisted by deuterated agents. It was found that NaCl shortened the reaction time (10 min in NaCl–H2O vs 60 min in H2O at 180 °C) to obtain the maximum yield of xylose (about 90 wt %) without significant secondary reaction products formed. NaCl was observed to generate acidic products from residual xylose structure, rate limiting the process, but providing acids that simultaneously catalyzed the depolymerization of xylose-oligomers. It was also found that Cl– cleaved the hydrogen bonding in xylo-oligomers, releasing separated xylo-oligomer chains and enhancing the interaction of H+ with xyl...
42 citations
TL;DR: In this article, a microwave assisted, acid-catalysed, organosolv (EtOH/H2O) system was used for the selective fractionation of bamboo.
32 citations
TL;DR: In this article, a microwave heated, one-step depolymerization process with a yeast, Metschnikowia pulcherrima, was used to metabolise an array of oligo-and monosaccharides.
31 citations
TL;DR: In this paper, the influence of sample density on microwave induced pyrolysis of crystalline cellulose, with heating rate, biochar and bio-oil yields investigated, was demonstrated.
Abstract: Herein we present the influence of sample density on the microwave induced pyrolysis of crystalline cellulose, with heating rate, biochar and bio-oil yields investigated This Letter demonstrates that sample density is a fundamental parameter influencing microwave-assisted biomass pyrolysis, with a direct impact on heating rate, the speed of volatiles diffusion through the sample matrix and distribution of products Of significant interest was that the maximum heating rate and bio-oil yield corresponded to an optimum sample density as a result of heat and mass transfer effects Increase in density above this value stimulated a rise in biochar yield The increased understanding of the mechanisms influenced by sample density in a microwave field gives increased ability for users to produce bio-oil or biochar, giving rise to improved microwave-based biorefineries for future energy and chemical needs
15 citations
TL;DR: In this paper, the effects of temperature, reaction time and/or catalyst amount increased glycerol decomposition due to the positive kinetic effects that these variables have on the process and the pressure exerted two counteracting effects: a positive kinetic effect and a thermodynamic inhibitory influence.
15 citations
TL;DR: In this article, microwave hydrolysis and extraction were carried out using only water as the processing medium, thus ensuring all products (mainly saccharides) are suitable for food grade status applications.
Abstract: Bilberry presscake, a byproduct from juice production, contains abundant polysaccharides that can be recovered by thermal treatment. In this research, microwave hydrolysis and extraction were carried out using only water as the processing medium, thus ensuring all products (mainly saccharides) are suitable for food grade status applications. This research aims to propose an approach to fulfill multiple chemicals recovery, including anthocyanins, saccharides, proteins, and even inorganic salts. Statistical analysis suggested the conversion of bilberry presscake was accurately predictable (R2 of 0.986) from conditions. Of the variables temperature, holding time, and solid content, the solid content affects conversion most significantly. A 30 min microwave hydrolysis gives mono-/disaccharides with a high total yield of 24.9%, which is more than three times the yield of a 24 h Soxhlet extraction (7.1%). The yield of rhamnose is particularly high (10.8%), most likely as a result of pectin degradation on microw...
12 citations
TL;DR: In this article, the authors would like to thank the ICTP-CSIC Characterisation Service and the personnel of the National EPSRC XPS User's Service (NEXUS) for the XPS analysis.
Abstract: The authors would like to thank the ICTP-CSIC Characterisation
Service and the personnel of the National EPSRC XPS User's
Service (NEXUS) for the XPS analysis. P. S. S. gratefully
acknowledges financial support from the Spanish Ministry of
Economy and Competitively (MINECO) for the grants MAT2014-
59674-JIN and MAT2013-47898-C2-2-R, and for a ‘Ramon y
Cajal’ Senior Research Fellowship. The Spanish Scientific
Research Council, CSIC (i-LINK+0636) is also acknowledged.
A. M. G. gratefully acknowledges Financial support from the
Wild Fund Scholarship and an STMS grant awarded by the
EUBIS COST Action
11 citations
TL;DR: In this article, an innovative pre-treatment of rapeseed meal was demonstrated, involving a one-step process using microwave heating and no additional chemicals or enzymes, and 57% of the biomass was solubilised over just a few minutes.
10 citations
TL;DR: In this paper, the assistance of the alkaline delignification stage by microwave was studied, in order to study its influence on the lignin removal and the strong influence of the temperature on the chemical composition and crystallinity of the delignified solids.
Abstract: The limitation of the fossil-resources has led the research to focus on the production of biomass-based fuels from lignocellulosic agricultural residues, as it is the case of the bio-ethanol. Due to the complex and heterogeneous structure of these residues, a delignification stage is usually necessary prior to a simultaneous saccharification and fermentation treatment (SSF) for the production of bio-ethanol. In a previous work, an alkaline delignification of hydrothermally pretreated vine shoots using conventional heating was carried out in order to obtain a solid residue with low lignin and hemicellulosic content, which could be further subjected to a SSF treatment. However, when this biorefinery scheme was evaluated by a Life Cycle Assessment it was observed that the energy and chemical requirements of the delignification stage needed to be reduced. Therefore, in this work the assistance of the alkaline delignification stage by microwave was studied. The treatments were carried out at different temperatures, in order to study its influence on the lignin removal. It was observed that the microwave assistance could permit the improvement of the delignification treatments not only by increasing the delignification yield but also by reducing the temperature, time and NaOH concentration used in the treatments. The strong influence of the temperature on the chemical composition, structure and crystallinity of the delignified solids was also appreciated during this study. The solid residues obtained under the most severe conditions of the microwave-assisted alkaline delignification treatment (125 °C) could be a promising solid for the employment in a SSF treatment due to its low lignin and hemicellulosic content (16.68 % and 0.01 % respectively) and its high glucan content (50.75 %), although it presented a higher crystallinity index than the hydrothermally pretreated vine shoots.
TL;DR: A new method has been developed for the semiquantitative analysis of three main components in important large volume types of lignocellulosic biomass (pubescens, softwood and wheat straw) using confocal microscopy in the absence of stains of other additives.
Abstract: Lignocellulosic biomass is essentially composed of three components, cellulose, hemicellulose and lignin, with a highly complicated physical structure. The complex network provides significant challenges for the effective analysis of the components in actual biomass while attempted isolation of the individual components usually leads to cross contamination and hence the need to detect the contaminating components. A new method has been developed for the semiquantitative analysis of three main components in important large volume types of lignocellulosic biomass (pubescens, softwood and wheat straw) using confocal microscopy in the absence of stains of other additives. Standard titration and thermogravimetric methods have been used to confirm the confocal microscopy results. This breakthrough opens the door to quick and easy methods for measuring both the ratio of the three major components in biomass and the purity of the isolated components.
TL;DR: The bio-based mesoporous materials made from polysaccharides, Starbons® can be modified by two different routes to give high levels of N-content, unexpectedly including significant quantities of nitrile groups which can improve the materials performance in applications including metal capture.
01 Jan 2018
TL;DR: In this article, the effect of supercritical extraction on the soot nanostructure and gasification product yields was investigated in the context of soot nano-structures and supercritical gasification.
Abstract: Effect of supercritical extraction on the soot nanostructure and gasification product yields