Aqueous zinc-ion batteries have gained significant interest, offering several distinct advantages over conventional lithium-ion batteries owing to their compelling low cost, enhanced battery safety, and excellent environmental friendliness. Nevertheless, the unfortunate growth of zinc dendrites during cycling leads to poor electrochemical performance of zinc batteries, primarily attributed to the diminished wet mechanical properties and limited electrolyte uptake of existing commercial separators. Herein, a bio-based separator was developed from sustainable resources using natural polymers derived from wood pulp to replace fossil-based polyolefin separators. The inherent hydrophilicity and swelling ability of cellulose fibers provide separators with superior electrolyte wettability and uptake. Notably, the structural reinforcement provided by lignin, especially after hot pressing, enhances the separator's wet mechanical integrity and performance during battery cycling. These improvements contribute to the separator's more stable electrochemical performance and improved ion transport properties. Separators composed of lignin-rich microfibrillated cellulose fibers showed superior dimensional stability under heat compared to Celgard, ensuring higher thermal safety and enhanced performance of aqueous zinc-ion batteries. Our results reveal the great potential of lignin-rich cellulose-based separators for future zincion batteries.

Capillary electrophoresis is a powerful separation technique for analysis of proteins and peptides, with benefits like low consumption of reagents, solvents and sample. The separation efficiency and resolution can be deteriorated by adsorption of analytes to the inner capillary wall, though. Many methods to circumvent this obstacle have been reported, including background electrolyte addition of surfactants that aggregate as protective coatings at the wall. In this work, anionic suberin surfactant was used together with the cationic surfactant cetyltrimethylammonium bromide (CTAB) for analysis of trypsin digested lysozyme as a model sample. Suberin fatty acids were extracted from birch bark, which is a side-stream product originating from pulp and paper waste streams. Different adjustments of the solvent extraction protocol, and the method to neutralize the suberin fatty acids to obtain surface active sodium salts were evaluated regarding number of peaks observed, separation repeatability, and analysis time. The influence of background electrolyte pH was also studied. The potential of the surface-active sodium salts of suberin fatty acids as an additive enhancer in combination with CTAB is illustrated by excellent repeatability, especially at lower pH values. The number of peaks observed was also higher at lower pH, while the analysis time was shorter.

Cellulose has inherent properties that are both hydrophilic and water-insoluble, which can create challenges in certain technical applications. One solution to these challenges is derivatization, however, the crystalline structure of cellulose limits its chemical reactivity. This study explores the reactivity of highly swollen cellulose produced by dissolving and reprecipitating microcrystalline cellulose. This extreme swelling of cellulose is expected to increase the accessibility and reactivity, however, upon drying the cellulose becomes hard and inflexible a phenomenon known as hornification. Different drying methods were used to overcome the problems of hornification, including freeze-drying, acetone-drying, and drying with glycerol as a spacer. The samples were carboxymethylated and the degree of substitution (DS) was used to assess reactivity, with freeze-dried samples showing the highest DS. The findings suggest that preserving the swollen structure through appropriate drying methods enhances cellulose reactivity, offering potential improvements in industrial cellulose ether production.

Future biorefineries should valorize all components of feedstock, and that includes bark, which constitutes at least 10 wt % of the biomass. Whereas the wood part of lignocellulosic biomass is mainly composed of cellulose, hemicellulose, and lignin, bark also contains suberin and tannin, as well as higher contents of ashes and extractives. Therefore, the valorization of bark shows unique opportunities, but its fractionation is more complicated than wood. However, given that it has only a heating value, bark can be a promising feedstock to turn future biorefineries more economically competitive and sustainable. After a brief discussion on bark's versatile composition, this perspective embraces a survey of different bark fractionation approaches to get useful products. State-of-the-art catalytic upgrading and valorization of bark to different fractions and products are presented. We hope that this perspective will inspire more researchers to consider bark and valorizing its fractions, preferably using catalysis, despite the challenges, disruptively advancing the field.

Tree bark is normally a side-stream product but by an integrated bark biorefinery approach, valuable compounds may be recovered and used to replace fossil-based products. Norway spruce bark was extracted to obtain cellulose, which was chemically treated to produce cellulose oxalate (COX) which was homogenized to yield nanocellulose. The nanocellulose was used to produce Pickering emulsions with almond oil and hexadecane as organic phases. COX from dissolving pulp was used to study the effect of various raw materials on the emulsifying properties. The COX samples of bark and dissolving pulp contained a significant amount of hemicelluloses, which affected the viscosity results. The emulsion properties were affected by the organic phases and the aspect ratio. Emulsions using hexadecane were more stable than the emulsions using almond oil. Since the aspect ratio of bark was lower than that of the dissolving pulp, the emulsifying properties of the COX dissolving pulp was better. It has been shown that nanocellulose from cellulose oxalate of both spruce bark and dissolving pulp is a promising substitute for petroleum-based emulsifiers and surfactants. By utilizing bark, value-added products can be produced which may be economically beneficial for various industries in the future and their aim for climate-neutral products.

Nanocelluloses and cellulose nanomaterials derived from natural resources are a group of ideal platform materials for advanced applications. However, their synthesis through sustainable and facile processes to achieve the required properties are still challenging. Here, we prepare the nanocellulose oxalate (n-COX) from cotton with outstanding physicochemical properties by defining the optimal oxalic acid pretreatment conditions. Thus-obtained n-COX with unique 1D nanofiber shape as a platform material is further processed to various high-performance multidimensional bio-nanomaterials through several simple yet effective strategies. First, 2D n-COX films prepared through a casting-drying method show comparable or even better transparency and tensile strength than those made from other types of nanocelluloses. Second, 3D n-COX hydrogels/aerogels fabricated by a molding-crosslinking approach demonstrate good shape stability, well-preserved nanoporous networks, and qualified mechanical properties. Third, n-COX-derived bioinks display improved printability and fidelity, resulting in better size-preserving and shape-control of the 3D-bioprinted scaffolds. We expect this work could offer new insights on engineering natural cellulose and using n-COX as a platform material for further advanced fabrication, and thus, open up application potentials of this new nanocellulose.

An ionization difference UV-Vis method (Delta epsilon-spectrum method) is the most potentially simple method for fast quantitation of phenolic hydroxyl groups (ph-OH) in lignin. However, the underestimated results were calculated from the conventional Delta epsilon-spectrum method using one- or two-point wavelengths measurement. In this study, a modified Delta epsilon-spectrum method using multi-point wavelengths measurement was developed and the negative absorbance was also considered. Four main typical lignin models, e.g. vanilla alcohol, 5-5 biphenyl, stilbenoid and vanillin, were applied as the guaiacyl-type (G-type) phenolic models for the determination of ph-OH by the modified Delta epsilon-spectrum method. The 2-methoxyethanol/water/acetic acid = 8/2/0.2 (V/V/V) was used as the acidic solvent system and the 2-methoxyethanol/0.2 M NaOH solution = 1/9 (V/V) was used as the alkaline solvent system. The ph-OH contents in the spruce milled wood lignin (SMWL) and the spruce Kraft lignin (SKL) were respectively quantified by the modified Delta epsilon-spectrum method as 1.078 and 4.348 mmol/g, which were comparable to the counterparts determined by P-31 Nuclear Magnetic Resonance Spectroscopy (P-31 NMR). The results revealed that the modified Delta epsilon-spectrum method can provide more accurate and reliable results compared to the conventional method.

Many of the amphiphilic molecules, or surfactants, are produced from fossil-based raw materials. With the increasing awareness of the climate situation, focus has shifted toward more environmentally friendly solutions to replace fossil-based products. This has led to more interest towards the forest. The circular bioeconomy is focused on making use of residues and waste and on optimizing the value of biomass over time via cascading. Nowadays, bark is seen as a waste product by industries and mainly incinerated as solid fuel. The bark contains interesting compounds but some of these are only available in low amounts, less than 1 % in the bark, while other components are present in several percentages. However, some of these components are potential candidates for the manufacture of amphiphiles and there seems to be a strong match between bark availability and surfactant demand. The global amount of bark available is approximately 359 million m3 and more than 10 million m3 of industrial bark are generated annually in Sweden and Finland. The bark of Norway spruce, Scots pine and silver birch contains approximately 25-32 % of extractives and part of these extractives has a potential as a surfactant backbone. This matches the global surfactant demand of about 15.6 million tons. Therefore, industrial bark has a significant potential value as a raw material source for amphiphilic molecules and polymers. This review focuses on betulin, condensed tannin and suberin. These compounds have been studied on individually and methods to extract them out from the bark are well investigated, but to utilize them as amphiphilic compounds has not been explored. With this review, we want to emphasis the potential of using bark, what today is seen as a waste product, as a raw material for production of amphiphiles. Moreover, a techno-economic analysis has been performed on betulin, tannins and suberin. 

In recent years, there has been extensive research into the development of cheaper and more sustainable carbon fiber (CF) precursors, and air-gap-spun cellulose-lignin precursors have gained considerable attention where ionic liquids have been used for the co-dissolution of cellulose and lignin. However, ionic liquids are expensive and difficult to recycle. In the present work, an aqueous solvent system, cold alkali, was used to prepare cellulose-lignin CF precursors by wet spinning solutions containing co-dissolved dissolving-grade kraft pulp and softwood kraft lignin. Precursors containing up to 30 wt% lignin were successfully spun using two different coagulation bath compositions, where one of them introduced a flame retardant into the precursor to increase the CF conversion yield. The precursors were converted to CFs via batchwise and continuous conversion. The precursor and conversion conditions had a significant effect on the conversion yield (12-44 wt%), the Young's modulus (33-77 GPa), and the tensile strength (0.48-1.17 GPa), while the precursor morphology was preserved. Structural characterization of the precursors and CFs showed that a more oriented and crystalline precursor gave a more ordered CF structure with higher tensile properties. The continuous conversion trials highlighted the importance of tension control to increase the mechanical properties of the CFs.

The interest in the bark and the attempt to add value to its utilization have increased over the last decade. By applying an integrated bark biorefinery approach, it is possible to investigate the recovery of compounds that can be used to develop green and sustainable alternatives to fossil-based materials. In this work, the focus is on extracting Norway spruce (Picea abies) bark lignin via organosolv extraction. Following the removal of the extractives and the subcritical water extraction to remove the polysaccharides, a novel cyclic organosolv extraction procedure was applied, which enabled the recovery of lignin with high quality and preserved structure. Main indicators for low degradation and preservation of the lignin structure were a high β-O-4' content and low amounts of condensed structures. Furthermore, high purity and low polydispersity of the lignin were observed. Thus, the obtained lignin exhibits high potential for use in the direct development of polymer precursors and other bio-based materials. During the extraction sequence, around 70% of the bark was extracted. Besides the lignin, the extractives as well as pectic polysaccharides and hemicelluloses were recovered with only minor degradation, which could potentially be used for the production of biofuel or other high-value products such as emulsifiers or adhesives.