Through our innovation, the product from a process that converts biowaste into a biofuel/biochar (HTC carbon) can be further refined into a bio-based high-value activated carbon and thus give the market an alternative to today's fossil activated carbon. When the bio-based activated carbon reaches the end of its life cycle, it is burned as a biofuel. This creates a carbon sink, which grows the more cycles the activated carbon is regenerated. When bio-based activated carbon gains market share from fossil activated carbon, the CO2 footprint decreases by about 10 tonnes of CO2/tonne of activated carbon. If all market shares worldwide are taken from fossil activated carbon, the CO2 footprint can be reduced by about 28 million tons/year. Different production methods to produce activated carbon from HTC carbon have been investigated within this project. One suitable method for producing activated carbon for gas applications and one for activated carbons for liquid applications have been developed. The properties of the produced qualities of activated carbon are not as good as the ones on the market today. However, there is potential for optimization so that an activated carbon with competitive quality can be produced from this renewable resource.

Lignin nano/microparticles have recently attracted growing interest for various value-additive applications of lignin, especially encapsulation. In this study, in order to establish a highly efficient and highly productive preparation process to effectively utilize technical lignin, a brand-new, slow and exhaustive solution evaporation process following a simple, self-assembly principle was developed using industrial softwood kraft lignin (SKL) from a starting acetone-water (80/20, v/v) solution to recover 100% of the lignin as homogeneous and well-shaped microspheres. The prepared microspheres had a typical average diameter of 0.81 ± 0.15 μm and were hollow with very thin shells (of nanoscale thickness). Based on this developed technique, encapsulation of urea by these lignin microspheres was directly achieved using the same process as hollow lignin microspheres with urea attached to the outside and entrapped inside of the wall. Two distinct urea release rates were observed for the urea-encapsulated microspheres: a fast release of the urea outside the shell wall and a slow (controlled) release of the urea inside the shell wall. The encapsulation efficiency was as high as 46% of the trapped urea as encapsulated inside the lignin microspheres. The slow and exhaustive solution evaporation procedure reported here is a simple and straightforward method for the valorization of industrial kraft lignin as hollow microspheres with controllable, homogeneous and desired morphologies, and especially for the direct preparation of lignin-based encapsulating fertilizers for controlled release.

Quantum dots (QD)/polymer materials have wide applications in biological imaging, clinical diagnostics, anti-counterfeiting materials, light-emitting devices and solar cells. The development of QD/cellulose nanofibrils (CNF) hybrids with a more perfect structure and excellent properties is important for improving known applications. A unique tunicate CNF (TCNF) was homogeneously blended with outstanding CdSe/CdS core/shell QD to prepare a novel QD/TCNF hybrid. The QD were monodispersed on a single TCNF fibril surface as an evenly distributed monolayer with an extremely high packing density and no visible aggregation. The prepared hybrid is an excellent platform nanomaterial which was demonstrated by its good writing fidelity when applied as a 1D ink and by its good processability in the preparation of 2D films with acceptable transparency and flexibility. This one-step direct blending approach provides a facile shortcut to effectively fabricate cellulose-based high-performance functional QD nanomaterials at the single-fibril level.

Substitution of phenol in phenol-formaldehyde (PF) resin preparations by technical lignins is hindered by the inherently lower reactivity of lignin compared to phenol. Demethylation of an industrial softwood kraft lignin (SKL) to improve its reactivity is the focus of this paper. To this purpose, kraft lignin (KL) was treated with two commercial laccases, NS51002 (L1) and NS51003 (L2), for 24 h in combination with three mediators, 2,2′-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1-hydroxybenzotriazole (HBT) and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO). The characterizations of the reaction solution and the resultant KL showed that methanol was released as a result of the methoxy group splitting from the aromatic rings, while such demethylation was dependent on the laccase-mediator system (LMS). The catechol structures formed, which were further oxidized to a quinone structures prone to polymerization, led to molecular mass increment. Also this reaction was LMS dependent. The same is true to the cleavage of β-O-4′ linkages, which resulted in depolymerization. The L1-ABTS, L1-TEMPO and L2-HBT combinations are the most efficient and the resulting modified lignin would be suitable to phenol substitution. Challenging is the lignin polymerization following the demethylation, especially in case of L1-ABTS, which might inhibit the reactivity of the treated lignin. 

This work reveals the structural variations of cellulose nanofibers (CNF) prepared from different cellulose sources, including softwood (Picea abies), hardwood (Eucalyptus grandis × E. urophylla), and tunicate (Ciona intestinalis), using different preparation processes and their correlations to the formation and performance of the films prepared from the CNF. Here, the CNF are prepared from wood chemical pulps and tunicate isolated cellulose by an identical homogenization treatment subsequent to either an enzymatic hydrolysis or a 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation. They show a large structural diversity in terms of chemical, morphological, and crystalline structure. Among others, the tunicate CNF consist of purer cellulose and have a degree of polymerization higher than that of wood CNF. Introduction of surface charges via the TEMPO-mediated oxidation is found to have significant impacts on the structure, morphology, optical, mechanical, thermal, and hydrophobic properties of the prepared films. For example, the film density is closely related to the charge density of the used CNF, and the tensile stress of the films is correlated to the crystallinity index of the CNF. In turn, the CNF structure is determined by the cellulose sources and the preparation processes. This study provides useful information and knowledge for understanding the importance of the raw material for the quality of CNF for various types of applications.

An industrial softwood kraft lignin was treated by different laccase-mediator systems (LMS) followed by comprehensive structural analysis. Analysis revealed that demethylation was a common reaction for all the LMS combinations investigated. After reaction, methanol was always released into the solutions. A reduction in the methoxyl content of the lignins was observed in the obtained products. The treatment reduced the quantities of different types of phenolic aromatic rings, with G units being the most attacked structures. Decarboxylation was also detected in two of the LMS, namely L1-TEMPO andL2-HBT. The highest demethylation rate came from the L1-ABTS combination and the most severe overall structural modification. Lignin polymerisation was observed for all treatments, with the L1-ABTS combination demonstrating the highest Mp, Ma and Mw values. An increased polydispersity was also observed for all the treatments, with the highest increase in polydispersity found for the L1-ABTS treatment. In addition, lignin depolymerisation took place. It has been concluded that the most efficient demethylation was achieved by N51002-ABTS.

The influence of pH on the Mannich reaction (amino alkylation in the presence of formaldehyde) has been analyzed by liquid chromatography-mass spectrometry (LC-MS) with vanillin (VA) as a model compound and a purified softwood kraft lignin (SKL) as a substrate. The reaction products of VA were studied at pH 5, 7, and 9 at 60°C for 4 h. The Mannich adduct and side reaction products with methylene bridge were found at both pH 7 and 9, while only di-substituted by-products were observed at pH 5. Nitrogen contents determined from blank runs were substantial at pH 5 and negligible at pH 7. In VA or SKL, the resulting N-contents at pH 7 corresponded to a 76 or 62 mol% of the theory, respectively, i.e. based on the available C5 positions in phenolic guaiacyl units (G-units). In the case of SKL, 31P-NMR analysis confirmed a 77% conversion of all phenolic G-units into their C5 substituted derivatives. The Mannich reaction should be performed on lignin at pH 7 for 1 h to suppress unwanted side reactions, which could be observed by LC-MS under other pH conditions. The reaction is suitable for fast and reliable determination of reactive C5-positions in lignin by multiplication of the N-content of the reaction products with a factor of 1.6.

An industrial softwood kraft lignin (SKL) was blended with polylactic acid (PLA) and used for complex coating of urea as nitrogen fertiliser. The coating was perfumed using a simple and cheap dip-coating technique. The lignin was pre-functionalised via esterification or Mannich reaction. Esterification rendered a lignin derivative with higher hydrophobicity, while the Mannich reaction introduced organically bound nitrogen onto the lignin derivative structure. It was found that the coating resulted in good attachment of the coating layer on the surface of urea pellets. The coating layer was very compact and the wall layer was rather homogeneous and well distributed. The urea coating not only constructed a physical barrier to delay urea dissolution (controlled release), but also supplied chemically slow-release, organically bound nitrogen and biological stabilisation effects. It was found that the Mannich reaction product (ManSKL/PLA) slowed down the urea release more than the PLA coating reference, taking approximately 1m000s or 6.7 times as long

Urea coating was conducted using polylactic acid (PLA) blended with industrial softwood kraft lignin after applying a dip-coating technique. The lignin was pre-functionalized via esterification that increased coat layer hydrophobicity or via amination that created an organically bound nitrogen structure. The PLA film reference had many pores, while the film from the PLA-lignin derivative complex was highly homogeneous and had no pores. The coat thickness was generally adjustable by repeating the coating process reaching up to 81% weight against the urea core. After coating, urea release in water was largely delayed, 20–30 and 6–10 times as long as that of uncoated urea or PLA-coated urea respectively. The coated urea will be a highly effective nitrogen fertilizer due to the controlled release after coating, the slow release from the organically bound nitrogen structure, and the expectedly extra stability against urease hydrolysis and microorganism nitrification after using the lignin structure.

The industrial lignin used here is a byproduct from Kraft pulp mills, extracted from black liquor. Since lignin is inexpensive, abundant and renewable, its utilization has attracted more and more attention. In this work, lignin was used for the first time as binder material for LiFePO4 positive and graphite negative electrodes in Li-ion batteries. A procedure for pretreatment of lignin, where low-molecular fractions were removed by leaching, was necessary to obtain good battery performance. The lignin was analyzed for molecular mass distribution and thermal behavior prior to and after the pretreatment. Electrodes containing active material, conductive particles and lignin were cast on metal foils, acting as current collectors and characterized using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge cycles. Good reversible capacities were obtained, 148 mAh·g-1 for the positive electrode and 305 mAh·g-1 for the negative electrode. Fairly good rate capabilities were found for both the positive electrode with 117 mAh·g-1 and the negative electrode with 160 mAh·g-1 at 1C. Low ohmic resistance also indicated good binder functionality. The results show that lignin is a promising candidate as binder material for electrodes in eco-friendly Li-ion batteries.