Electrospun Poly(Ethylene Oxide) Fibers Reinforced with Poly (Vinylpyrrolidone) Polymer and Cellulose Nanocrystals

Green poly(ethylene oxide) (PEO)/cellulose nanocrystals (CNCs)/poly(vinylpyrrolidone) (PVP) composites were prepared via electrospinning technique. The use of PVP and/or CNCs improved the overall thermal stability and mechanical properties of the PEO fibers. A strong synergistic reinforcing effect was achieved when PVP polymer and CNCs were combined in the composite. This synergistic reinforcement was accompanied with the formation of unique fiber-bead-fiber morphology. The beads were elongated and orientated along the applied force direction during tensile testing, providing an energy dissipation mechanism and a positive reinforcement effect. The combination of CNCs with PVP induced special chemical interactions, and distracted the interactions between PVP and PEO. As a result, the crystallinity of PEO was increased in the system, which also helped enhance fiber properties. The approach developed in this work offers a new way for reinforcing electrospun PEO-based composite fibers for sustainable green composite development

The Effect of Chemical and High-Pressure Homogenization Treatment Conditions on the Morphology of Cellulose Nanoparticles

Cellulose nanoparticles were fabricated from microcrystalline cellulose (MCC) through combined acid hydrolysis with sulfuric and hydrochloric acids and high-pressure homogenization. The effect of acid type, acid-to-MCC ratio, reaction time, and numbers of high-pressure homogenization passes on morphology and thermal stability of the nanoparticles was studied. An aggressive acid hydrolysis was shown to lead to rod-like cellulose nanocrystals with diameter about 10 nm and lengths in the range of 50–200 nm. Increased acid-to-MCC ratio and number of homogenization treatments reduced the dimension of the nanocrystals produced. Weak acid hydrolysis treatment led to a network of cellulose nanofiber bundles having diameters in the range of 20–100 nm and lengths of a few thousands of nanometers. The high-pressure homogenization treatment helped separate the nanofiber bundles. The thermal degradation behaviors characterized by thermogravimetric analysis at nitrogen atmosphere indicated that the degradation of cellulose nanocrystals from sulfuric acid hydrolysis started at a lower temperature and had two remarkable pyrolysis processes. The thermal stability of cellulose nanofibers produced from hydrochloric acid hydrolysis improved significantly

Synthesis of renewable monomer 2, 5-bishydroxymethylfuran from highly concentrated 5-hydroxymethylfurfural in deep eutectic solvents

Abstract(#br)2, 5-Bishydroxymethylfuran (BHMF) has been currently emerged as a promising biomass-derived monomer. It is highly desirable to proceed a chemical process at a high substrate concentration, by which a facile and cost-effective separation of products can be expected. Herein, we report for the first time on the hydrogenation of highly concentrated 5-hydroxymethylfurfural (HMF) in deep eutectic solvents (DESs), giving a near quantitative selectivity towards BHMF in ChCl-glycerol DES at 25°C in 3h using NaBH 4 as the H-donor. DES is hailed as a new class of green solvent, in which HMF/BHMF could be stabilized by the strong hydrogen-bond interaction, and allowed the selective hydrogenation of HMF at high concentration up to 40wt%. Notably, the resulting BHMF could be facilely separated by extraction with ethyl acetate, and then high purity of BHMF with a desirable isolated yield around 80% was obtained after removing of ethyl acetate. Additionally, the reaction efficiency of HMF hydrogenation in DESs was verified to be strongly associated with the viscosity of DESs and the p K a value of hydrogen-bonding donor

Cascade conversion of furfural to fuel bioadditive ethyl levulinate over bifunctional zirconium-based catalysts

Abstract(#br)Biomass-derived ethyl levulinate (EL) is currently deemed as a promising fuel bioadditive to improve (bio)diesel combustion performance without the sacrifice of its octane number. In this contribution, a range of Zr–Al bimetallic catalysts were prepared for the cascade conversion of furfural to EL by the integration of transfer hydrogenation and ethanolysis in ethanol. The ratio of Lewis to Brønsted acid sites (L/B) could be tuned by the ratio of Al 2 O 3 to ZrO 2 over SBA-15 support. Among these catalysts, Zr–Al/SBA-15(30:10) with appropriate L/B ratio of 2.25 exhibited an outstanding catalytic performance to give a furfural (FF) conversion up to 92.8% with a EL selectivity as high as 71.4% at 453 K in 3 h

Performance and emission characteristics of a diesel engine running on optimized ethyl levulinate–biodiesel–diesel blends

Copyright © 2015 Elsevier Ltd. All rights reserved.In this study, biomass-based EL (ethyl levulinate) was evaluated as an additional fuel to biodiesel and diesel. Physical and chemical properties, including intersolubility, cold flow properties, spray evaporation, oxidation stability, anti-corrosive property, cleanliness, fire reliability and heating value of twelve different EL–biodiesel–diesel blends were analyzed. The results show that the fuel blends that were in line with China's national standard for biodiesel blend fuel (B5) have similar physical and chemical properties to pure diesel with improved cold flow properties. Optimized fuel blends based on grey relational analysis and analytic hierarchy process were selected to evaluate engine performance and emissions using an unmodified diesel engine test bench. The results show that engine power and torque with the fuel blends were in general similar to those with diesel (less than 3% differences). Both brake specific fuel and energy consumption were lower with the fuel blends than with diesel, suggesting higher fuel conversion efficiencies for the fuel blends. HC (Hydrocarbon) and CO (carbon monoxide) emissions and smoke opacity reduced significantly with the fuel blends compared with diesel while NOx (nitrogen oxides) and CO2 (carbon dioxide) emissions increased. Our study suggests that EL produced from lignocellulosic biomass could be used as a blending component with biodiesel and diesel for use in unmodified diesel engines and could potentially be a promising environment-friendly fuel

Insights into the active sites and catalytic mechanism of oxidative esterification of 5-hydroxymethylfurfural by metal-organic frameworks-derived N-doped carbon

Abstract(#br)Directly oxidative esterification of Biomass-derived 5-hydroxymethylfurfural (HMF) into dimethyl furan dicarboxylate (DMFDCA) is a promising route for the replacement of petroleum-derived commodity chemical terephthalic acid (TPA) extensively employed in polyester synthesis. Co-based N-doped carbon materials are one of the most promising applied catalysts for oxidative esterification reaction, however, the active sites and reaction pathway of these catalysts have not been clearly clarified, which is crucial to the practical application. Herein, we report that ZIF-67 (a zeolitic imidazolate framework (ZIF)-type cobalt-containing MOF) derived Co@C-N material is a highly effective catalyst for the selective conversion of HMF into DMFDCA in 95% yield. The high activity of the ZIF-67 derived nanocarbon composites Co@C-N can be attributed to the electron transfer between nitrogen-doped carbon shells and Co nanoparticles. The appropriate graphitic N and pyridinic N doping increases the electronic mobility and active sites. Density functional theory (DFT) simulations indicated that oxygen, HMF and methanol molecules are adsorbed and activated on C-N materials. Furthermore, no 2, 5-diformylfuran (DFF) was captured as an intermediate because the oxidative esterification of aldehyde preferentially occurred than the oxidation of hydroxyl group in HMF. We anticipate that these results can drive progress in the bio-based polymers sector and oxidative esterification reaction

A flexible Cu-based catalyst system for the transformation of fructose to furanyl ethers as potential bio-fuels

Abstract(#br)Biomass-derived furanyl ethers, such as 5-alkoxymethylfurfurals (AMFs) and 2,5-bis(alkoxymethyl)furans (BAMFs), can be employed as promising biofuels or additives. The development of multifunctional catalysts for the efficient production of furanyl ethers from sugars through 5-hydroxymethylfurfural (HMF) as an intermediate is highly desirable but challenging, because multiple reactions including dehydration, etherification and hydrogenation get involved and the side reaction of sugars and HMF to form humins is inevitable. In this contribution, we found that the introduction of CuO resulted in the generation of Lewis acid sites at the cost of Bronsted acid sites over CuO-USY catalysts through the formation of Al-O-Cu(II) species. The dispersity of CuO particles and the amount of Lewis acid sites could be manipulated by adjusting the loading of CuO. If 5 wt% CuO was supported on USY zeolite to give a CuO(5)-USY catalyst, CuO particles with a high dispersity (36.4%) afforded abundant Lewis acid sites (457.1 μ mol/g). Lewis acid over CuO(5)-USY greatly promoted the acid-catalyzed dehydration of fructose to HMF and HMF etherification to AMFs, resulting in a HMF yield up to 86.2% from fructose and AMFs yields greater than 90% from HMF. Interestingly, a combination of CuO(5)-USY and a small amount of metallic Cu powder was able to offer desirable BAMFs yields by the reductive etherification of HMF under hydrogen atmosphere. As a result, 5-methoxymethylfurfural (MMF) of 79.6% and 2,5-bis(methoxymethyl)furan (BMMF) yield of 74.5% were achieved from fructose through HMF as an intermediate in the presence of CuO(5)-USY alone or with metallic Cu as a co-catalyst. Therefore, the above Cu-based catalyst system holds the promise to flexibly produce a family of AMFs or BAMFs from fructose via a facile two-step approach

Common characteristics of feedstock stage in life cycle assessments of agricultural residue-based biofuels

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordIn this study, we conducted life cycle assessments (LCAs) for fuels based on different types of agricultural residues and determined the characteristics common to all LCAs. Each fuel type required specific conversion technology during the feedstock stage, particularly during the production and collection processes. We divided the field-to-fuel life cycle into five high-level and relatively independent sub-stages: production of agricultural residues, collection of agricultural residues, conversion of agricultural residues to biofuels, biofuel distribution, and biofuel utilization. We then illustrated the common characteristics during the feedstock stage for the first two field-to-fuel life cycle sub-stages: production and collection of agricultural residues. Agricultural residues-to-grain weight and price ratios and multifactorial LCA allocations were summarized for the production stage. In addition, the energy use availability coefficient, collection radius, and emissions were determined for each fuel type during the collection stage. System boundaries and benefits of direct emissions reduction during the feedstock stage were also discussed. Our results provide guidance for future LCA studies on agricultural residue-based biofuels.National Natural Science Foundation of ChinaChinese Academy of EngineeringHenan Province Talent ProjectHenan Academy of Sciences Research Project

Life cycle assessment of energy consumption and environmental emissions for cornstalk-based ethyl levulinate

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This study analysed the sustainability of fuel-ethyl levulinate (EL) production along with furfural, as a by-product, from cornstalk in China. A life cycle assessment (LCA) was conducted using the SimaPro software to evaluate the energy consumption (EC), greenhouse gas (GHG) and criteria emissions, from cornstalk growth to EL utilisation. The total life cycle EC was found to be 4.54MJ/MJ EL, of which 94.7% was biomass energy. EC in the EL production stage was the highest, accounting for 96.8% of total EC. Fossil EC in this stage was estimated to be 0.095 MJ/MJ, which also represents the highest fossil EC throughout the life cycle (39.5% of the total). The ratio of biomass to fossil EC over the life cycle was 17.9, indicating good utilisation of renewable energy in cornstalk-based EL production. The net life cycle GHG emissions were 96.6 g CO2-eq/MJ. The EL production stage demonstrated the highest GHG emissions, representing 53.4% of the total positive amount. Criteria emissions of carbon monoxide (CO) and particulates ≤ 10 um (PM10) showed negative values, of -3.15 and -0.72 g/MJ, respectively. Nitrogen oxides (NOx) and sulphur dioxide (SO2) emissions showed positive values of 0.33 and 0.28 g/MJ, respectively, mainly arising from the EL production stage. According to the sensitivity analysis, increasing or removing the cornstalk revenue in the LCA leads to an increase or decrease in the EC and environmental emissions while burning cornstalk directly in the field results in large increases in emissions of NMVOC, CO, NOx and PM10 but decreases in fossil EC, and SO2 and GHG emissions.This study was supported by the National Natural Science Foundation of China (51506049), the National High Technology Research and Development Program of China (863 Program) (2012AA051802) and the Henan Province Foundation and Advanced Technology Research Project (132300413218)