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This paper presents a method for the measurement of absolute molecular weight of cellulose using a multi-angle light scattering (MALS) detector in 99% dimethyl sulfoxide/1% 1-Ethyl-3-methylimidazolium acetate (DMSO/EmimOAc). The paper also delivers a suitable dn/dc value for cellulose in this solvent. It discusses the pros and cons of using absolute molecular weight measurements versus traditional column calibration in this solvent. The conclusion is that the dn/dc for cellulose in this solvent is 0.049 ± 0.003 mL/g. Absolute molecular weight measurements in this solvent are somewhat beneficial for celluloses with Mw > 250 kg/mol. However, for low-Mw celluloses (e.g., Avicel), it has severe limitations. Herein, it is confirmed that the DMSO/EmimOAc system can be used to replace the traditional DMAc/LiCl system for cellulose molecular weight analysis of some cellulose materials. However, the former is more costly and time-consuming than the latter.

Developing effective fractionation methods remains challenging in biorefining. γ-Valerolactone (GVL) is a promising green solvent, yet its application in softwood biorefineries is still underexplored. In this study, GVL pretreatment for softwood biorefining was assessed at laboratory and pilot scales. The effects of temperature (170–210 °C), time (20–60 min), and GVL-to-water ratios (20:80 – 80:20 %) on the biorefining of spruce sawdust were initially investigated through lab-scale experiments using a 1-L reactor. A GVL/water solution at a 40:60 ratio, assisted by 0.4 g of sulfuric acid per 100 g of biomass, enabled the solubilization of up to 81.4 % of lignin and nearly the entire hemicellulosic fraction, while effectively preserving cellulose, which was subsequently saccharified with over 90 % conversion. Lignin was regenerated from the liquors and characterized using pyrolysis-gas chromatography/mass spectrometry, high-performance size-exclusion chromatography, Fourier-transform infrared spectroscopy, and 1H-13C heteronuclear single-quantum coherence nuclear magnetic resonance spectroscopy. The biorefinery concept was successfully scaled up and validated at pilot scale in a 50-L reactor, where enzymatic saccharification of the resulting cellulosic pulp produced hydrolysates that, upon fermentation, yielded 231.4 g of ethanol per kilogram of pulp. Lignin regenerated from the pilot-scale pretreatment liquors (118.9 g per kilogram of raw sawdust) and the lignin-rich saccharification residue (182.7 g/kg) were subjected to hydrothermal liquefaction, and the resulting biocrudes were characterized to assess their potential for biofuel formulation. The study showed the suitability of GVL for spruce biorefining to achieve high recovery of digestible cellulose, lignin and hemicelluloses fractions, that are subsequently valuable for chemicals and fuels production.

A biobased anode material for sodium-ion batteries (SIBs) was prepared through the simple pyrolysis of Scotch pine cones (Pinus sylvestris, SPC), followed by a heteroatom doping modification. The resulting nitrogen-doped hard carbon exhibited a high reversible capacity of 273 mA·h·g-1 at a current density of 25 mA·g-1 compared to the undoped material (197 mA·h·g-1). X-ray diffraction analysis shows that the produced hard carbon from the biomass is highly amorphous in nature, and high-resolution transmission electron microscopy images reveal the presence of localized graphite-like structures that are found to be beneficial for the storage and transport of Na+ ions during charging/discharging. Experimental results demonstrated that the increased specific surface area (SBET = 424 m2·g-1), high micropore volume (0.177 cm3·g-1), and expanded interlayer spacing (>3.7 Å) and a high Na+-ion diffusion coefficient (3.08 × 10-16 cm2·s-1) facilitated the diffusion of sodium ions, leading to a high capacity retention of 80% after 250 cycles for the SPC-N material over the undoped one, SPC (71%). This study highlights the potential of low-cost, widely available biobased Scotch pine cones as an alternative anode material to enhance the sustainability of SIB production.

This study presents the fabrication of double-layer electrospun nanofibrous membranes (DL-ENMs) using polyvinylidene fluoride (PVDF) and polyether sulfone (PES) based polymers with different degrees of hydrophilicity (PES, sulfonated PES, and PES with hydroxyl terminals). A comparative analysis was carried out with single-layer electrospun nanofiber membranes (SL-ENM) with a total thickness of about 375 μm. Using feed solutions, including sodium chloride, sodium nitrate, and simulated nuclear wastewater (SNWW), the performance of DL-ENMs was evaluated for desalination and radionuclide decontamination by direct contact membrane distillation (DCMD) and air gap membrane distillation (AGMD) techniques. The results showed that DL-ENMs, especially those incorporating a sulfonated PES-based hydrophilic layer, exhibited superior permeate fluxes, reaching values of 72.72 kg/m²h and 73.27 kg/m²h in the DCMD using aqueous feed solutions of NaCl and NaNO₃, respectively, and 70.80 kg/m²h and 41.96 kg/m²h using aqueous feed solutions of SNWW in DCMD and AGMD, respectively. Both SL-ENMs and DL-ENMs exhibited high rejection efficiencies and decontamination factors for the feed solutions (>99.9%). In addition, the prepared ENMs were exposed to gamma radiation to evaluate their applicability in real-life applications. The result of irradiation revealed the negative impact of gamma radiation on the fluorine content of PVDF which could be a critical point in using PVDF as a hydrophobic material for decontaminating nuclear wastewater by membrane distillation.

Utilization of biomass and reuse of industrial by-products and their sustainable and resource-efficient development into products that are inherently non-toxic is important to reduce the use of hazardous substances in the design, manufacture and application of biomaterials. The hypothesis in this study is that spent mushroom substrate (SMS), a by-product from mushroom production, has already undergone a biological pretreatment and thus, can be used directly as a starting material for fibrillation into value-added and functional biomaterial, without the use of toxic substances. The study show that SMS can be effectively fibrillated at a very high concentration of 6.5 wt % into fibrils using an energy demand of only 1.7 kWh kg−1, compared to commercial and chemically pretreated wood pulp at 8 kWh kg−1, under same processing conditions. SMS is a promising resource for fibrillation with natural antioxidant activity and network formation ability, which are of interest to explore further in applications such as packaging. The study shows that biological pretreatment can offer lower environmental impact related to toxic substances emitted to the environment and thus contribute to reduced impacts on categories such as water organisms, human health, terrestrial organisms, and terrestrial plants compared to chemical pretreatments.

The global production of fossil-based plastics has reached critical levels, and their substitution with bio-based polymers is an urgent requirement. Poly(3-hydroxybutyrate) (PHB) is a biopolymer that can be produced via microbial cultivation, but efficient microorganisms and low-cost substrates are required. Halomonas boliviensis LC1, a moderately halophilic bacterium, is an effective PHB producer, and hydrolysates of the residual stalks of quinoa (Chenopodium quinoa Willd.) can be considered a cheap source of sugars for microbial fermentation processes in quinoa-producing countries. In this study, H. boliviensis LC1 was adapted to a cellulosic hydrolysate of quinoa stalks obtained via acid-catalyzed hydrothermal pretreatment and enzymatic saccharification. The adapted strain was cultivated in hydrolysates and synthetic media, each of them with two different initial concentrations of glucose. Cell growth, glucose consumption, and PHB formation during cultivation were assessed. The cultivation results showed an initial lag in microbial growth and glucose consumption in the quinoa hydrolysates compared to cultivation in synthetic medium, but after 33 h, the values were comparable for all media. Cultivation in hydrolysates with an initial glucose concentration of 15 g/L resulted in a higher glucose consumption rate (0.15 g/(L h) vs. 0.14 g/(L h)) and volumetric productivity of PHB (14.02 mg/(L h) vs. 10.89 mg/(L h)) than cultivation in hydrolysates with 20 g/L as the initial glucose concentration. During most of the cultivation time, the PHB yield on initial glucose was higher for cultivation in synthetic medium than in hydrolysates. The produced PHBs were characterized using advanced analytical techniques, such as high-performance size-exclusion chromatography (HPSEC), Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). HPSEC revealed that the molecular weight of PHB produced in the cellulosic hydrolysate was lower than that of PHB produced in synthetic medium. TGA showed higher thermal stability for PHB produced in synthetic medium than for that produced in the hydrolysate. The results of the other characterization techniques displayed comparable features for both PHB samples. The presented results show the feasibility of producing PHB from quinoa stalks with H. boliviensis.

A cellulose ether that is easier to melt than benzyl cellulose was produced from the lignin degradation product veratryl alcohol. Veratryl chloride and bromide were synthesized from the alcohol, and these two chemicals were used to react with Avicel® cellulose to form the novel cellulose ether veratryl cellulose (VC). Spectroscopic characterisation techniques (1H NMR, FTIR) indicated the successful conversion of Avicel® cellulose to the cellulose ether VC, by both routes, at a degree of substitution of 1.4 to 1.6. Melting measurements of the VC samples showed a gradual softening from approximately 110 °C; the VC was melted below 200 °C. XRD analysis confirmed that the chemical treatments affect the degree of crystallinity. Size exclusion chromatography results showed that the products differ remarkably in molecular weight. The VC synthesized with veratryl chloride degraded almost twice as much as when veratryl bromide were used. The cellulose ethers were soluble in DMSO, DMAc, and CHCl3.

The replacement of fossil-based plastics with biobased and biodegradable alternatives has become an important research challenge in recent years, aiming to eliminate the negative environmental impact of persistent plastics in nature. In this report, design of experiments was successfully exploited to develop an efficient and sustainable method for extracting intracellular PHA from Photobacterium ganghwense C2.2 using dihydrolevoglucosenone (Cyrene) and ethanol as biobased solvents obtainable from sustainable sources. The extraction conditions were studied and optimized against the yield and molecular weight. The temperature range for the extraction was scouted by using differential scanning calorimetry, while size exclusion chromatography coupled to refractive index and multiangle light scattering detectors was used to assess the molecular weights of the extracted polymers. The examined ranges in the model were, respectively, 1.6–8.4% (w/v) of lyophilized cells content per 10 mL of solvent, 3–17 min extraction time, and temperatures from 116 to 144 °C. Time and temperature strongly affected the extraction yields and molecular weights of the obtained polymers while the concentration of bacterial biomass only effected the molecular weight. Several quadratic and interaction coefficients were significant in the well-fit partial least-squares regression models (R² > 0.8, Q² > 0.6) indicating that nonlinear effects and interacting parameter contributed to the optimization targets. The optimized extraction should be performed at 130 °C for 15 min with 2% loading of bacterial biomass. The predicted yield and molecular weight of the polymer matched the values obtained from the real experiment under the optimized conditions. The method setup provided similar yield and higher molecular weight in much shorter time compared to overnight Soxhlet extraction with CHCl₃. The clean ¹H nuclear magnetic resonance spectra of polymers extracted from bacteria indicate that high purity materials can be obtained using an optimized extraction scheme. Additionally, the Cyrene solvent could be recycled at least five times and still performed the extraction equally well as the fresh solvent. Finally, the current method demonstrated a high potential for scalability using a HP4750 stirred filtration cell. Three different filtration conditions were tested, achieving up to 97.4% recovery at 80 °C using a 0.3 μm glass fiber membrane, with a flux of 312.5 LMH.

With a multivariate approach, we investigate and correlate the effect of mercerization conditions on the properties of a cellulose ether. We have chosen to work with carboxymethylcellulose (CMC) for analytical reasons. As expected, the DS was found to increase when the NaOH/AGU (anhydroglucose unit) stoichiometric ratio (r) was increased (range 1.0–1.3) and [NaOH] was decreased (range 50-30%). However, such changes also favoured the formation of unwanted side products. Decreased (r) and increased [NaOH] resulted in increased heterogeneity, and thus the quantities of insoluble particles and unreacted chemicals also increased. As another result, the prediction between mercerisation and synthesis weakens. Consequently, a DS of 0.18–0.7 was obtained; the measured solubility was much lower than expected. A non-statistical distribution of substituents was further found. Interestingly, the relative importance of substitution at increases with an increased [NaOH].

In this report, 1-ethyl-3-methylimidazolium acetate, [EMIM][AcO] ionic liquid (IL) and acetic acid (AA) comprised solvents were used for the thermal treatment of poly (vinylidene difluoride), PVDF. Here, besides the various combinations of IL and AA in solvents, the pure IL and AA were also applied as a solvent upon thermal treatments. The samples obtained after the treatment were analysed for structural and crystalline phase changes, porosity, and molecular weight distribution with various analytical techniques. The Kamlet-Taft parameters measurement of the IL and AA containing solvents with different solvatochromic dyes was also performed to examine their solvent properties and correlate with the properties of the treated PVDF materials. The treatment of PVDF with pure IL results in the formation of highly carbonaceous material due to extensive dehydroflurination (DHF) as well as possibly successive cross-linking in the polymer chains. Upon IL and AA combined solvent treatment, the neat PVDF which composed of both α- and β crystalline phases was transformed to porous and β-phase rich material whereas in case of pure AA the non-porous and pure α-phase polymeric entity was obtained. A combined mixture of IL and AA resulted in a limited the DHF process and subsequent cross-linking in the polymer chains of PVDF allowed the formation of a porous material. It was observed that the porosity of the thermally treated materials was steadily decreasing with increase in the amount of AA in solvents composition and solvent with an AA:IL mole ratio of 2:1 resulted in a PVDF material with the highest porosity amongst the applied solvents. A recovery method for the IL and AA combined solvent after the thermal treatment of PVDF was also established. Hence, with varying the type of solvents in terms of composition, the highly carbonaceous materials as well as materials with different porosities as well as crystalline phases can be obtained. Most importantly here, we introduced new IL and AA containing recoverable solvents for the synthesis of porous PVDF material with the electroactive β-phase.