Treesearch Insight 2023
Here you find the abstracts for the poster session at Treesearch Insight 2023.
To get a printable version of the abstract please click on the title of the poster.
Author: Anna Dávid
Co-author: Xianjie Liu
Perovskites are promising candidates for several optoelectronic and perhaps spintronic applications, however one of the biggest roadblocks of development is the lead content of current best performing crystals. In lead-free halide double perovskites (elpasolites) there are two different types of cations inside the halide octahedra alternating through the crystal lattice.
Their low/non-toxicity and tunability re-opened the in-depth studies of fully inorganic double perovskites, and it has been found there are promising candidates for photocatalysts, LEDs, photodetectors, X-ray detectors and maybe even photovoltaics. Several high-throughput density functional calculations predicted their structural stability, however extensive experimental observations are not reported. Our group is focusing on the synthesis and studies of some examples from this great branch of materials.
Among several characterization techniques we employ X-rays (XAFS, XPS, XRD) to study the composition and structure of double perovskites with the Cs2NaBCl6 (Cs2NaFeCl6[1,2,3], Cs2NaVCl6) stoichiometry, where B is theoretically a trivalent cation. Using these methods, we are searching for direct evidence on valences and their contribution to the magnetic and optical properties.
 Ji, F. (2021), Bandgap Engineering of Lead-Free Halide Double Perovskites [Doctoral Thesis]
 Li, W. et al. (2021) J. Semicond. 42 072202
 Zhang, B., Buyanova, I. et al. (2023) The Journal of Physical Chemistry C, 127(4), 1908-1916
 Cao, X. et al. (2019), ACS Applied Materials & Interfaces 11 (42), 38648-38653
Sodium sulfite is commonly used for impregnating wood chips prior to refining when producing high-yield pulps such as CTMP. The impregnation process should ideally result in evenly sulfonated lignin, i.e. similar concentrations of sulfite (SO3 ^2-) ions in all parts of each wood chip. Sulfonated lignin is known to swell the fiber wall, which is beneficial for developing higher joint-strength between fibers. In reality, even sulfonation is not easy to achieve considering variations in wood chip size, density, quality, etc. Being able to trace where the sulfite ions end up in the wood or fiber structure can therefore be a key to both process and product development in the future. Synchrotron measurements can provide an understanding of the sulfur distribution both inside single wood fibers and on a larger scale between wood fibers. There is little knowledge of wood fiber nanostructures in 3 dimensions, although some interesting research has been conducted recently . We have compared these measurements with 2D synchrotron XRF mappings . The 3D material mapping provide insight on a sub-fiber level, but the 2D mapping technique might be preferable when studying sulfur distributions due to the highly uneven sulfur content observed. We can probably learn more about the development of fiber-joint-strength and strength uniformity in products by characterizing the distribution of sulfur on sub-fiber level. This paper discusses feasible future measurement strategies.
 Fernando, D., et.al, Sci Rep 13, 2350 (2023). DOI: 101038/s41598-023-29113-x
 Norlin, B., et.al, JINST 18 C01012. DOI: 10.1088/1748-0221/18/01/C01012
Paula Israelsson 1, Clemens Knill 2, Michael Finell 1, Gunnar Kalén 1, David A. Agar 1*
1 Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden
2 Swero GmbH & CO. KG, Wangen im Allgäu, Germany
*Corresponding author: Tel.: +46 72 450 6968. E-mail: email@example.com
Wood is a natural carbon sink and EU policy supports its cascaded use to extend its lifetime in the bioeconomy. Thermally modified wood (TMW) building products (e.g. flooring, deck and façade planking etc.) are increasingly utilised in modern construction and have extended lifetimes due to their enhanced durability and resistance to weathering and degradation. TMW is manufactured using only heat and steam (i.e. no chemicals) and this simplifies its recycling and reuse potential for many applications.
In this study, sixteen-year-old end-of-life thermally modified pine planking was recycled, pre-processed and reused as a feedstock for pelleted in a pilot-scale ring-die press. Quality analysis of produced pellets showed that they had high durability (97-98%), high bulk density (685-715 kg m-3), low production fines (0.7-1.0%), low moisture content (4.8-7.6%) and low ash content (0.13-0.24%). Based on higher heating value determination the pellets exhibited a high volumetric energy density (13.4-14.0 GJ m-1) indicating that the sequestered carbon in the material was well conserved. These values demonstrate that, whether as a material carrier for subsequent biorefining processes or for thermal conversion, pelleted end-of-life TMW is a high-quality biomaterial. The results are evidence that the cascading principle for TMW has potential in an EU bioeconomy and offers a strategy for further extending the lifetime of wood and sequestering biogenic carbon.
Kitchen-Based Light Tomography (KBLT) is a DIY toolkit for advancing tomography developed by and for the tomography community. KBLT uses a Raspberry Pi (RPi) single-board computer to control stepper motors for both rotation and translation, a web camera, and LED flash lights via a Graphical User Interface (GUI), in combination with a thin sheet of paper, as a detector screen.
To demonstrate the capabilities of KBLT, both non-transparent and transparent objects were scanned under both static (3D) and dynamic (4D) acquisition modes, also in combination with sample environments, thus modifying the sample during scanning
– The KBLT can be used by tomography users – for education and training, prior to carrying out a real X-ray or neutron tomography experiment.
– The KBLT will be useful for beamline scientists – for testing and implementing new hardware and software solutions, in situations where the X-ray or neutron beam is not available.
– The KBLT will allow computational researchers working with algorithm development, e.g., image reconstruction, image processing and analysis to test their algorithms on easily-generated KBLT datasets, both in 3D and 4D.
– Building and collaborating on this open-source KBLT project is foreseen to aid, develop and strengthen the international tomography community.
Pulp and paper mills can be converted to lignocellulosic biorefineries that produce pulp, paper, electricity, and novel biochemicals. To achieve this, highly selective separation processes with low-energy demand are required. Membrane processes fulfill these requirements making them an ideal separation technology in a sustainable bioeconomy. However, the unwanted adsorption of compounds to the hierarchical structure of the membrane known as membrane fouling, remains the greatest challenge. Membrane fouling reduces not only the capacity of the filtration process and increases its energy demand, but also increases operational costs and creates a need for chemical cleaning. Conventional analysis techniques such as SEM or AFM can provide information on the foulants attached onto the membrane surface, but the spatial distribution of the foulants inside the membrane structure remains unknown.
This poster presents a study on the spatial distribution of membrane fouling in commercial microfiltration (MF) and ultrafiltration (UF) membranes using ptychographic X-ray computed tomography (PXCT). MF and UF membranes were fouled with process water from thermomechanical pulping, an industrial solution containing hemicelluloses, colloidal wood extractives, and lignin in dissolved and suspended form. PXCT images revealed the fouling layer and its impact on the inner structure of the membrane in 3D. Additionally, membrane cleaning was investigated to understand its impact on the fouling layer and membrane structure. Results from this study provide new insights into the underlying processes leading to adsorption and desorption of compounds onto and from the membrane, ultimately contributing to the development of more efficient and sustainable membrane processes
Defibration of wood chips in high yield pulping such as CTMP production involves sulfonation of wood chips using (Na2SO3). When aiming to improve product properties, one key issue to investigate is the evenness of the sulfonation, i.e., the distribution of the sulfite (SO32-) ions. The challenge is that the inner parts of the wood chips absorb much less sodium sulfite than the outer parts. As a result, less sulfonated wood fibers have different bonding properties. It is likely so that the efficiency and evenness of fiber separation in a chip refiner depend greatly on how evenly the chips have been sulfonated. Uneven sulfonation then results in higher shives (unseparated fibers) content which impairs product properties. We suggest a laboratory-scale miniaturized X-ray fluorescence (XRF) scanner for measuring sulfur distribution in the wood chips on-site. By minimizing the differences in sulfonate content between fibers, we can minimize the requirement for sulfite (SO32-) dosage to a certain degree of fiber separation, thereby reducing the total amount of electricity used in chip refining. There has been a significant improvement in commercial XRF microscopy scanners over the last few years, but the spatial resolutions achieved are insufficient. We have developed an XRF scanner optimized for sulfur fluorescence energies , and further continued this development by implementing frontier technology polycapillary X-ray optics. We present spatial resolution measurements and discuss the relevance and usability of the proposed measurement methodology to demonstrate its performance.
 Rahman, H., et.al, ACS Omega 2022, 7, 51, 48555–48563, DOI: 10.1021/acsomega.2c07086″
Lignin is a complex aromatic heteropolymer that composes plant cell walls providing rigidity and protection against pathogens. It is one of the most abundant polymers on earth after cellulose, with an average of 130 million tons of this polymer being produced only by the Kraft pulping industry per year. Therefore, lignin is a low-cost abundant source of aromatic compounds that can be applied in the food, textile, plastic, and chemical industry, opening possibilities for a circular bioeconomy. However, lignin is recalcitrant for chemical and enzymatic degradations and requires elaborated strategies for its conversion to added-value chemicals.
In this project, we investigate a framework for lignin bioconversion by the bacteria Pseudomonas putida to produce nitrogenous bulk chemicals as an alternative to fossil fuels-based compounds. To achieve this, we explore different enzymes to generate new-to-nature biochemical routes, enabling the bioconversion of lignin-derived compounds. NMR metabolomics is used to detect undesired side reactions or key steps for the metabolic engineering of P. putida. Design of Experiments (DoE) method will be applied to optimize gene expression and growth conditions parameters for achieving higher yields of the target compounds, providing new routes for producing nitrogenous bulk chemicals.
Facing the issues of environmental pollution by non-renewable fossil-based materials, research is demanded to find natural and renewable substitutions. For that wood can be a perfect candidate. Apart of its unique properties it has also a long history in research and material production. Use of a new type of high precision experimental techniques based on synchrotron radiation can bring new insights into wood structure and extraction processes.
Kraft cooking is a well-established method for extraction of lignin and hemicellulose from wood and is widely used in industry. Investigation of wood compositional and structural variations before and after experiment were studied by numerous techniques, and instrumentation limitations often do not permit in situ experiments. In this work we want to investigate how structure and composition of a single wood building block – wood cell, is changing during different steps of Kraft cooking by in situ WAXS measurements using a specially customized reactor. We will demonstrate experimental setup and some preliminary results for digestion of spruce in water at different temperature and pressure.
3D visualization of two connected wood cells at different steps of cooking is another challenge we addressed in this project. Usually, it is performed by 3D TEM tomography using resin embedding and fine sectioning of a wood chip to 100 nm thickness. To investigate the impact of sample preparation on visualized structure 3D nanotomogrpahy was performed on a single wood cell cut by cryo ultramicrotome.
Cellulose is the primary structural component in wood, creating a highly organized skeletal structure spanning from nano to macroscale in a matrix with hemicellulose and lignin. Understanding the organization of cellulose is essential for comprehending the mechanical properties of native wood and developing cellulose-based biomaterials.
In plants, cellulose forms a monoclinic Iβ crystal structure composed of closely packed glucan chains. This structure diffracts radiation, such as x-rays and electrons, with the strongest reflections being 200, 110, and 1-10, all with scattering angles perpendicular to the extended fiber direction.
In this study, we utilized Scanning Electron Diffraction (SED) to determine the hierarchical organization of cellulose nanofibers in a bio-composite material through diffraction pattern analysis. SED is an emerging electron microscopy technique that uses a highly parallel electron beam scanned in a raster motion across the sample. A pixelated camera records a diffraction pattern for every beam position, and data analysis is later performed post-acquisition by the precise positioning of virtual detectors in diffraction space. New sensitive cameras, combined with low-dose illumination conditions, have enabled characterization of highly beam-sensitive materials. The ability to shape the electron beam diameter to less than 10 nm allows highly localized information from the sample, such as strain, phase, and orientation, to be determined and visualized. The cellulose fibril orientation can be determined in each beam position by measuring the rotation angle of the 200-reflection in every diffraction pattern.
Nylon is currently produced primarily from fossil sources. The production relies on energy-demanding processes that release nitrous waste and the potent greenhouse gas nitrous oxide (N2O). The areas of application for nylon are numerous and include industries such as textile, automotive and robotics. The aim of this project is to develop a microbial process for the conversion of lignin into nylon with a smaller environmental footprint. Lignin is the major waste product from pulp and paper mills and has large potential to be used to produce important chemicals by microbial processes. To enable production of nylon precursors from lignin, it is depolymerised into monoaromatic compounds that can be catabolised by microorganisms. In our previous work, the soil bacterium Pseudomonas putida was engineered to produce muconic acid from depolymerised kraft lignin (Almqvist et al., 2021).
In this project, P. putida is metabolically engineered to produce polyamide precursors carrying the amine moiety. A significant aspect of the project is to improve our understanding of the bacterium’s ability to perform amine forming reactions. We will particularly investigate and develop methods for amination reactions in the organism and expand the toolbox in this area.
Nataliia Smyk and Olena Sevastyanova
Contamination by heavy metals and organic pollutants is a persistent environmental issue that requires efficient and sustainable solutions. This study presents the development of a new bio-based sorbent material produced by depositing hardwood kraft lignin onto porous silica gel particles. The obtained material was characterized using FTIR and SEM, revealing a well-defined surface morphology and chemical composition.
The new bio-based sorbent demonstrated high sorption capacity and fast kinetic towards metal ions Fe(III), Cu(II), and organic dyes Methyl orange. Due to its high adsorption efficiency, low cost, simplicity of disposal, and nontoxicity, the new sorbent is a promising material for removing inorganic and polar organic trace pollutants from water. This research contributes to the development of sustainable materials with potential environmental applications.
Efficient routes for controlled modification of the wood-pulp fibre cell wall structure are attractive for obtaining increased accessibility to the fibre interior and enabling functionalisation such as controlled drug delivery, interpenetrated networks, and selective removal of metal ions from aqueous mixtures to mention a few examples. By changing the physical state of water, it should be possible to significantly alter the structure of the wet fibre wall, providing the possibility to perform cell wall modifications under extreme conditions. To address this challenge, we have investigated the structural development of the wet softwood kraft pulp fibre wall under high pressure and high temperature (HPHT) conditions (up to 2 GPa and 100 °C). Characterisation has been performed to clarify the effects on the porosity and the accessibility of the fibre wall, before and after the HPHT treatment. Furthermore, changes in the crystalline structure have been identified, including in-situ X-ray diffraction measurements at high pressures performed at the P02.2 Extreme Conditions Beamline at the DESY/Petra III synchrotron in Hamburg. These measurements have been complemented with Electron microscopy, X-ray diffraction, Small and wide-angle X-ray scattering, and Cross-polarized/magic angle spinning 13C-NMR. Key findings from the experiments show that extreme conditions cause changes in crystallinity, specific surface area, bound water content and surface morphology.
Hemicellulose, such as softwood galactoglucomannan is promising renewable bioresource. Degradation is possible with a combination of Glycoside Hydrolases (GHs), e.g family GH27 ɑ-galactosidase and GH5 β-mannanase in cooperation. These enzymes can also synthesize new glycosidic bonds during the catalysis in the presence of other acceptor molecules besides water, referred to as transglycosylation. In our work, we have demonstrated synergy between α-galactosidase and β-mannanase in formation of transglycosylation products using galactomannan as donor substrate through covalent fusion of mannose or galactose units to allyl alcohol.
We have shown that using HPLC for product screening in conjunction with NMR for structural determination of novel glycosides is a powerful approach for monitoring this reaction. Coincubation of GHs with complimentary activities has potential to result in improved substrate conversion and increased synthesis yields of allyl glycosides. These reactive glycosides could be utilized for downstream applications such as production of biomaterials and for surface modification. Furthermore, an engineered subsite +1/+2 variant of Trichoderma reesei B-mannanase TrMan5A showed enhanced allyl mannoside synthesis capacity, when compared to the wild-type. This application allows for generation of numerous different novel glycosides such as using allyl- or propargyl alcohol as the acceptor, allowing for downstream application in thiol-ene or -yne click chemistry respectively.
Sritama Mukherjee* and Ulrica Edlund
Industrialization and population growth result in huge impacts on water, air, and soil. Mistra TerraClean research program aims to develop new, smarter materials for novel and existing technologies to achieve a smoother and more efficient purification of water and air. Under this program, we target to synthesize the materials from scratch, providing them with smart functionalities and testing them under real conditions in case studies together with industry partners. The contaminants addressed are of increasing concern to the environment and human health, such as PFAS substances, VOCs, pharma products, pathogens, heavy metals and so on that require significant materials for remediation and sensor technologies.
As a part of this program, we focus on synthesizing novel materials for scavenging heavy metals from the contaminated water around mining sites. Another case study package motivates us to develop antifouling coatings for water-carrying crosslinked polyethylene pipes. And lastly, we also develop materials or membranes that can trap microplastics contaminated water from laundry emissions. All aforementioned materials are the results of biopolymer (lignin, cellulose, chitosan, cyclodextrin, etc.) functionalization and their composite formation. Various field water samples are analyzed and the synthesized materials are characterized and tested against each type of contaminant.
- D Georgouvelas, et al., Carbohydrate Polymers 2021, 264, 118044.
- S Mukherjee, et al., ACS Sustainable Chemistry & Engineering 2019, 7 (3), 3222-3233.
Suraya Kazi, Akchheta Karki, Shangzhi Chen, Magnus Jonsson*
Our group recently introduced conducting polymers as a new category of materials for dynamically tuneable nanooptics.[1,2,3] In brief, we showed that conducting polymer nanostructures can strongly interact with light at specific wavelengths through plasmonic resonances, acting as optical nanoantennas. The plasmons originate from mobile polaronic charge carriers in the polymer network, which leads to negative permittivity as for conventional metals. The plasmonic resonance nanostructures could then be reversibly turned on/off by varying the redox state of the material, which modulates the density and mobility of the charge carriers and thereby switches the permittivity between negative (metallic) to positive (dielectric). Such dynamic character, in addition to biocompatibility and flexibility, inherent to conducting polymers cannot be achieved in conventional metallic plasmonic nanostructures due to fixed permittivity. We typically fabricate the nanoantennas by deposition of a thin film of the conducting polymer using vapor phase polymerization, which is then structured into arrays of nanodisks using colloidal lithography. As examples of characterization techniques, we use ellipsometry, UV-vis spectroscopy, four-point probe measurements, and atomic force microscopy to determine permittivity, extinction spectra, conductivity, and geometry of the materials and nanostructures, respectively. Redox-tunable conducting polymer nano-antennas have potential for applications such as smart windows, reflective displays and not least dynamic metaoptics including flat lenses, holograms etc.[1,2]
- Chen, S. et al.Conductive polymer nanoantennas for dynamic organic plasmonics. Nanotechnol. 15, 35–40 (2020).
- Karki, A. et al.Electrical tuning of plasmonic conducting polymer nanoantennas. Mater. 34, 2107172 (2022).
- Karki, A. et al.Doped semiconducting polymer nanoantennas for tunable organic plasmonics. Commun Mater 3, 48 (2022).
New technology is required to produce bio-based materials solely from green sources and which can replace plastic in waterproof packaging. It is also important to maximize the use of the tree to increase resource efficiency. This could be possible with high yield pulp (HYP) in a hot-pressing process that utilizes the rheology and thermoplastic behaviour of all wood components. Pilot scale trials showed that when a moist paper web or molded pulp passes a press nip at temperatures above Tg, the density, tensile strength and stiffness increase significantly due to compressed fibre network. In addition, lignin-rich pulps showed remarkably high wet strength when pressed at high temperature up to 270°C. Wet strength of 50% of dry strength has been achieved.
To create hydrophobic surfaces, these were treated with betulin from birch bark. This was done by producing a water suspension with betulin which was sprayed on the surface, whereafter a hardening took place in the hot-pressing machine at a temperature up to 260°C, i.e. in the range of the melting point of betulin. Very hydrophobic paper surfaces are obtained with a contact angle of around 115°.
The process we developed was based on the synergy effect of hot-pressing of HYP and surface treatment with betulin without any additives and strengthening agents. Achieved properties such as high dry strength, high wet strength and water repellency are at the level of requirements for plastic replacement materials for several applications.
Kamani Sudhir K. Reddy, Nitin G. Valsange, Baozhong Zhang, and Patric Jannasch
Plastics are inarguably inseparable from our daily life, one of the few ways to get rid of end-of-life plastics that are polluting nature is to produce them such that it is easy to recycle them. One such way is to build monomers with degradable bonds that are responsive to certain chemical stimuli so that the feedstock can be recovered. In this approach, functional groups such as imine, ester, carbonate, ketal, and acetal were well explored. Our group previously studied several rigid spirocyclic monomers and their polymers with enhanced thermal properties, particularly glass-transition temperatures. The rigidity of the spirocyclic structure is responsible for enhanced thermal properties, this poster presentation discuss some of these monomers and thermal, degradation properties of their polyesters.
1.Subramaniyan, S. et al. ACS Sustain. Chem. Eng. 2023, 11, 3451–3465.
2.Manker, L. P. et al. Nat. Chem. 2022, 14, 976–984.
3.Abe, T., Kamiya, T., Otsuka, H. & Aoki, D. Polym. Chem. 2023, doi:10.1039/D3PY00079F.
4.Zhou, T., Meng, X. Bin, Du, F. S. & Li, Z. C. Chem. – An Asian J. 2023, doi:10.1002/asia.202201238.
5.Warlin, N. et al. Green Chem. 2019, 21, 6667–6684.”
A double flow-focusing channel technique has been developed as a proficient device for aligning cellulose nanofibrils (CNFs) and producing bio-based filaments. Utilising the outstanding mechanical properties of CNF fibrils themselves, these filaments are recognised as one of the strongest natural-based filaments. However, the coupling between the performance of the macro-scale fibres and properties of CNF dispersions remains incomplete. This study aims to identify the spinnability conditions for CNFs and identify the coupling between processes pre- and post-spinning to enhance the filaments’ mechanical properties.
CNF dispersions must be characterised before spinning using well-established techniques. To address the effects of remaining agglomerates and aggregates after storage, ultrasonication and centrifugation are employed to purify CNF dispersions and achieve more homogenous distributions. AFM analysis reveals that the cleaning process shortens CNFs, requiring higher concentrations to maintain suitable crowding factor that allows robust spinning. Rheological data corroborate this finding, indicating a favourable viscosity range for optimal dispersion consistency. A flow-stop technique utilising polarised optical microscopy (POM) allows for tracing the CNF network during flow. Fast and slow rotary diffusion coefficients, Dr,fast and Dr,slow, can be obtained through this method, reflecting CNF entanglement and the effects of Brownian motion. Spun filaments were dried at varying temperatures below the thermal degradation temperature. Results indicate that water molecules act as plasticisers, with increased drying temperature leading to faster removal and lower strain at break, but higher modulus due to the reduction of variability and less of weak filaments by high capillary forces.
1Mu-Rong Wang, 1Korneliya T. Gordeyeva, 1Tomas Rosén, 1L. Daniel SöderbergKTH, Royal Institute of Technology, Sweden
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