Eucalyptus bleached kraft pulp-ionic liquid inks for 3D printing of ionogels and hydrogels

3D printing has been recently recognized as one of the most promising technologies due to the multiple options to fabricate cost-effective and customizable objects. However, the necessity to substitute fossil fuels as raw materials is increasing the research on bio-based inks with recyclable and eco-friendly properties. In this work, we formulated inks for the 3D printing of ionogels and hydrogels with bleached kraft pulp dissolved in [Emim][DMP] at different concentrations (1-4 wt%). We explored each ink's rheological properties and printability and compared the printability parameters with a commercial ink. The rheological results showed that the 3 % and 4 % cellulose-ionic liquid inks exhibited the best properties. Both had values of damping factor between 0.4 and 0.7 and values of yield stress between 1900 and 2500 Pa. Analyzing the printability, the 4 wt% ink was selected as the most promising because the printed ionogels and the hydrogels had the best print resolution and fidelity, similar to the reference ink. After printing, ionogels and hydrogels had values of the elastic modulus (G') between 10³ and 10⁴ Pa, and the ionogels are recyclables. Altogether, these 3D printed cellulose ionogels and hydrogels may have an opportunity in the electrochemical and medical fields, respectively.

Effect of autohydrolysis and ionosolv treatments on eucalyptus fractionation and recovered lignin properties†

Wood fractionation is key for the integral valorization of its three main components. In this sense, recovering the hemicellulosic fraction after the ionosolv treatment of lignocellulosic materials is one of the main drawbacks of this process. Thus, the incorporation of a previous autohydrolyisis step to recover the hemicellulosic sugars before the ionosolv treatment is an interesting approach. The influence of both treatments, autohydrolysis and ionosolv, on the biomass fractions recovery yields was studied by a central composite design of experiments, varying the autohydrolysis temperature in a 175–195 °C range and ionosolv time between 1–5 h. Lignin recovery and cellulose purity were maximized at 184 °C and 3.5 h of autohydrolysis temperature and ionosolv time, respectively. In addition, lignin properties were incorporated to the statistical model, revealing lignin recondensation at severe conditions and a higher influence of the ionosolv treatment on lignin characteristics. These results remarked the importance of studying the effect of both treatments in the whole fractionation process and not each process separately and enhanced the understanding of the treatments combination in a complete fractionation biorefinery approach.

This work enhances the understanding of the effect of autohydrolysis and ionosolv treatments combination on fractionation yields and lignin properties.

Organosolv and ionosolv processes for autohydrolyzed poplar fractionation: Lignin recovery and characterization

Biomass fractionation plays a major role in the search for competitive biorefineries, where the isolation and recovery of the three woody fractions is key. In this sense, we have used autohydrolyzed hemicellulose-free poplar as feedstock to compare two fractionation processes, organosolv and ionosolv, oriented to lignin recovery. The recovered lignins were then characterize by different techniques (NMR, GPC, TGA). Both treatments were tested at different temperatures to analyze temperature influence on lignin recovery and properties. The highest lignin recovery was obtained with the ionosolv process at 135 °C, reaching a solid yield of ~70%. Lignin characterization showed differences between both treatments. Lignins enriched in C-O linkages and G units were recovered with the organosolv process, where increasing temperature led to highly depolymerized lignins. However, lignins with higher C-C linkages and S units contents were obtained with the ionosolv process, producing more thermically stable lignins. In addition, increasing temperature caused lignin repolymerization when employing ionic liquids as solvents. Therefore, this work outlines the most important differences between ionosolv and organosolv processes for biomass fractionation, focusing on lignin recovery and its properties, which is the first step in order to valorize all biomass fractions.

Cellulose ionogels, a perspective of the last decade: A review

Cellulose ionogels have been extensively studied due to the variability of their properties and applications. The capability of trapping an ionic liquid in a biodegradable solid matrix without losing its properties makes this type of material a promising substitute for fossil fuel-derived materials. The possibility to formulate ionogels chemically or physically, to choose between different ionic liquids, cellulose types, and the possibility to add a wide range of additives, make these ionogels an adaptable material that can be modified for each target application in many fields such as medicine, energy storage, electrochemistry, etc. The aim of this review is to show its versatility and to provide a summary picture of the advances in the field of cellulose ionogels formulation (chemical or physical methods), as well as their potential applications, so this review will serve as a stimulus for research on these materials in the future.

Thermal degradation kinetics of a lignin particle-reinforced phenolic foam

In the present work, the thermal degradation kinetics of a phenolic (PF) and lignin particle-reinforced phenolic (LRPF) foam and the lignin used as the reinforcement (LR) were studied. The activation energies of the degradation processes were obtained using a discrete distributed activation energy model (discrete DAEM) and the Vyazovkin model-free kinetic (MFK) method. The discrete DAEM was validated by comparing the predicted values with the data obtained at 8 °C min−1. Heating ramps of 6 and 12 °C min−1 were used to calculate the kinetic parameters through the model. The effect of the reinforcement on the kinetics of the LRPF was studied by comparison with the results obtained for the PF. For reactions with non-zero mass fractions, the activation energies of the PF were in the range between 79.9 and 177.6 kJ mol−1, and the activation energy for the LRPF ranged from 91 to 187 kJ mol−1. For the LR, the activation energy values were in a narrower range than for the foams: 150–187 kJ mol−1. The degradation process of the LRPF was modified due to the use of LR: the range of activation energy for LRPF was between the ranges for the PF and LR. The activation energy dependence on conversion was also calculated using the Vyazovkin method and compared with the DAEM results; no compensation effect for the kinetic parameters was found.

Combining autohydrolysis and ionic liquid microwave treatment to enhance enzymatic hydrolysis of Eucalyptus globulus wood

The combination of autohydrolysis and ionic liquid microwave treatments of eucalyptus wood have been studied to facilitate sugar production in a subsequent enzymatic hydrolysis step. Three autohydrolysis conditions (150 °C, 175 °C and 200 °C) in combination with two ionic liquid temperatures (80 °C and 120 °C) were compared in terms of chemical composition, enzymatic digestibility and sugar production. Morphology was measured (using SEM) and the biomass surface was visualized with confocal fluorescence microscopy. The synergistic cooperation of both treatments was demonstrated, enhancing cellulose accessibility. At intermediate autohydrolysis conditions (175 °C) and low ionic liquid temperature (80 °C), a glucan digestibility of 84.4% was obtained. Using SEM micrographs, fractal dimension (as a measure of biomass complexity) and lacunarity (as a measure of homogeneity) were calculated before and after pretreatment. High fractals dimensions and low lacunarities correspond to morphologically complex and homogeneous samples, that are better digested by enzyme cocktails.

[Blood fractionation based on the extraction of the buffy-coat layer. Analysis of our results]

PURPOSE

To compare a procedure of blood processing via a quadruple bag for the preparation of white-cell-poor blood components with the results obtained with triple-bag-system, in order to adopt it as routine in our blood centre.

MATERIAL AND METHODS

Blood was collected in 289 quadruple-bag-system containing 63 mL of CPD as anticoagulant and 100 mL of SAG M solution as additive for the red cells. We used 237 standard quadruple-bags supplied by Fenwal (195) and NPBI (42), and 52 of the top-and-bottom system supplied by Fenwal. Blood separation was made automatically by CompomatR (NPBI) and platelet concentrates were prepared from the buffy-coat fraction. Standard bags were processing as follows: After the first centrifugation of the whole blood (28,800 g), the plasma was transferred into the 300-mL bag until the interface of red cells and plasma was detected; then approximately 80 mL of plasma and buffy-coat (BC) were collected into the 100-mL satellite bag. Top-and-bottom bags were centrifuged at 43,500 g., the red-cells were transferred into the bottom-bag containing SAGM, and plasma was transferred into the top-bag. The buffy-coat fraction remains in the original bag. In both procedures, platelet concentrates were prepared from buffy-coat fraction. After the centrifugation of this fraction (1,400 g and 1,600 g), the supernatant (concentrated platelets in plasma) was transferred into a 300-mL bag and the bag with the residual buffy-coat was then discarded. 287 triple-bags were separated in the traditional way, using platelet-rich plasma (PRP) as a source for the preparation of platelet concentrate (PC). Volumes were measured by weigh and specificity gravity. Platelet, leukocytes and red-cells were counted in the Coulter-Counter (STKR.Izasa). T-Student test and Chi2 test were used for statistical analysis and p < 0.05 was taken as a significant difference between samples.

RESULTS

The three kinds of quadruple-bags showed results very homogeneous with little differences. For all brand of bags packed-red-cells showed a volume of 300 +/- 2.9 mL, EVF of 51.9 +/- 0.7%. The recovery of red cells into the packed red cells and of platelets into the platelet concentrate was 90 +/- 0.4 percent and 69 +/- 2 percent respectively, of the original value. White cells in the packed red cells were 9.7 +/- 03 x 10(9) with recovery of 30.1 +/- 1.4 percent of the original value; statistical difference was found in comparison with triple bags PRC (p < 0.001). The PC volumes averaged 71 +/- 1 mL and the overall mean platelet concentration was 77 +/- 2 x 10(9). Eighty three percent of PC contained more than 55 x 10(9). White cells contamination of platelet concentrates was 0.283 +/- 0.039 x 10(9), with a recovery of 9.5 +/- 1.5 percent of the leukocytes present in the whole blood. This value is below the threshold that prevents febrile reactions and microaggregate formation. The plasma yield in the quadruple-bag system was much greater than that in the triple-bag system (p < 0.001). With this process we removed about 77 +/- 0.5 percent of the plasma present in the original unit in comparison with 56 +/- 1 percent removed in that of the triple-bag system.

CONCLUSION

With this procedure leukocyte-poor blood components are obtained in which more of 90 percent original white cells have been removed, with a red-cell recovery of 90 percent. Moreover, the plasma yield is also excellent.

[Study of relations between the peripheral organ of olfaction and the olfactory bulb using anterograde and retrograde axon transport of horseradish peroxidase (HRP)]

Utilizing 26 Wistar albino rats, an anterograde and retrograde study has been performed on the connections between the first neuron of the olfactory pathway located in the olfactory epithelium and the second neuron in the glomeruli of the bulb. In the experiment we used horse radish peroxidase (HRP) in free form and combined with wheat lectin. In anterograde transport (epithelium-bulb), the HRP is deposited in preestablished sites in the olfactory epithelium of the nasal fossa. In retrograde transport (bulb-epithelium), HRP combined with wheat lectin is injected by means of a Hamilton microsyringe, glass micropipette and stereotaxic apparatus, in foreseen sites of the glomerular layer of the bulb.