Biobased adsorbents and membranes offer advantages related to resource efficiency, safety, and fast kinetics but have challenges related to their reusability and water flux. Nanocellulose/alginate composite hydrogel beads were successfully prepared with a diameter of about 3–4 mm and porosity as high as 99%. The beads were further modified with in situ TEMPO-mediated oxidation to functionalize the hydroxyl groups of cellulose and facilitate the removal of cationic pollutants from aqueous samples at low pressure, driven by electrostatic interactions. The increased number of carboxyl groups in the bead matrix improved the removal efficiency of the adsorbent without compromising the water throughput rate; being as high as 17 000 L h⁻¹ m⁻² bar⁻¹. The absorptivity of the beads was evaluated with UV-vis for the removal of the dye Methylene Blue (91% removal) from spiked water and energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) elemental analyses for the removal of Cd²⁺ from industrial mining effluents. The modified beads showed a 3-fold increase in ion adsorption and pose as excellent candidates for the manufacturing of three-dimensional (3-D) column filters for large-volume, high flux water treatment under atmospheric pressure.

The processing of hierarchical porous zeolitic imidazolate frameworks (ZIF-8) into a cellulose paper using sheet former Rapid-Köthen (R.K.) is reported. The procedure is a promising route to overcome a significant bottleneck towards applying metal-organic frameworks (MOFs) in commercial products. ZIF-8 crystals were integrated into cellulose pulp (CP) or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-oxidized cellulose nanofibrils (TOCNF) following an in-situ or ex-situ process; the materials were denoted as CelloZIFPaper_In Situ and CelloZIFPaper_Ex Situ, respectively. The materials were applied as adsorbents to remove heavy metals from water, with adsorption capacities of 66.2–354.0 mg/g. CelloZIFPaper can also be used as a stand-alone working electrode for the selective sensing of toxic heavy metals, for instance, lead ions (Pb²⁺), using electrochemical-based methods with a limit of detection (LOD) of 8 µM. The electrochemical measurements may advance 'Lab-on-CelloZIFPaper' technologies for label-free detection of heavy metal ions.

The need for clean water has led to the development of several different water treatment methods as well as to a large number of organic, inorganic, hybrid and/or composite materials that are used in these methods. Cellulose, being a highly abundant biopolymer with meritorious properties, such as high mechanical strength, tunable surface chemistry, high aspect ratio and surface area, to mention a few, is exploited in the current thesis for water treatment applications. Cellulose and its nanoscaled derivatives (i.e. cellulose nanocrystals and cellulose nanofibers) are modified or hybridized to achieve multiple functionalities.

Cellulose and lignocellulose nanocrystals were successfully prepared by mechanical treatment from the residue of bioethanol production and were decorated with zwitterionic polymer grafts through controlled radical polymerization reactions. The presence of residual lignin and polymer grafts was investigated which showed that especially the polymer grafting can significantly improve the antibacterial and antifouling performance of nanocellulose.

Functional cellulose-based membranes were prepared in a one-step water-based process. The membranes were evaluated as adsorbents for the removal of dyes and metal ions as well as metal-free catalysts for the decolorization of dyes Methylene Blue (MB) and Rhodamine B (RhB). The membranes exhibited maximum adsorption capacity of 78.6 mg/g for Co2+, up to 100 % of MB removal efficiency and up to 3-fold increase in the decolorization of MB.

Both in-situ and ex-situ growth of ZIF-8 crystals was performed on the surface of cellulose and nanocellulose and cellulose/ZIF hybrid membranes were manufactured. The adsorption capacity of the membranes was tested with Cd2+, Cu2+, Fe3+, and Pb2+, exhibiting a maximum adsorption capacity of 354 mg/g for Cu2+. Furthermore, the membranes showed potential for use as self-standing electrode for the detection of Pb2+.

Processing of cellulose/alginate composite hydrogels in the form of highly porous beads was successful. The surface of the beads was modified via in-situ TEMPO oxidation for the introduction of carboxyl groups. Adsorption of cationic contaminants as dyes and metal ions (MB and Cd2+ were used as models, respectively) was enhanced with in-situ modification. Removal of metal ions from the mining industry wastewater using modified cellulose/alginate hydrogel beads confirmed the potential of the adsorbent in complex water sources.

All-cellulose flat sheets (100 × 20 cm) were produced via a water-based process using a Formette dynamic sheet former. The sheets exhibited excellent mechanical properties attributed to the alignment of the micro and nanofibers that this process offers. The adsorption performance of the sheets was evaluated both with Irgalite Blue RL and Irgalite Violet H dyes, which are highly used in paper and pulp industries as dyes models, and Fe3+, Mg2+, Cd2+, Co2+, Cr3+, and Mn2+ as metal ion models. A maximum removal efficiency of 83% for IB RL and maximum adsorption capacity of 737 mg/g for Mg2+.

The work shows the potential of cellulose as a sustainable and scalable platform for the tailoring of multifunctional materials for water treatment with cationic pollutants removal, antifouling, antibacterial and sensing capabilities.

Polymeric composite membranes have shown great potential in removing pollutants from water. In the current study, flat sheet functional membranes of microfibrillated cellulose (MFC) with mixed and layered architectures are produced using the up-scaled Dynamic Sheet Former (Formette) in a fully water-based-system, and their potential for the removal of charged impurities is evaluated. The processing of composite membranes is unique in terms of their size (1 m × 20 cm), assembled MFC architectures, controlled/tunable porosity, functional groups densities, and free-standing at high water pressure. Such properties could be difficult to achieve with a lab-scale processing setup. It is shown that the MFC assembly has a direct influence on the pollutant removal efficiency, and again the layered architecture turns out to be a more efficient scavenger of the charged pollutants due to the combined actions of electrostatic interactions, hydrogen bonding, and size exclusion, which are responsible for an ultrafast separation of the impurities through the flat sheets membranes. These experimental results are supported by reactive molecular dynamics simulations of representative model systems that provided possible realistic scenarios at the atomic/molecular scale. All the data confirm the scalability and tunability of the produced MFC-based water cleaning membranes, which show high adsorption capacity, flexibility, hydrolytic stability, and mechanical robustness.

In this study, we present a facile, one-step method for the manufacturing of all-cellulose, layered membranes containing cellulose nanocrystals (CNC), TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidized cellulose nanofibers (TO-CNF), or zwitterionic polymer grafted cellulose nanocrystals (CNC-g-PCysMA) as functional entities in combination with cellulose fibers and commercial grade microfibrillated cellulose. The presence of active sites such as hydroxyl, carbonyl, thioethers, and amines, gave the membranes high adsorption capacities for the metal ions Au (III), Co (II), and Fe (III), as well as the cationic organic dye methylene blue (MB). Furthermore, the membranes served as excellent metal-free catalysts for the decolorization of dyes via hydrogenation. A 3-fold increase of the hydrogenation efficiency for cationic dyes such as rhodamine B (RhB) and methylene blue was obtained in the presence of membranes compared to NaBH₄ alone. Water-based processing, the abundance of the component materials, and the multifunctional characteristics of the membranes ensure their potential as excellent candidates for water purification systems.

This article proposes a process to prepare fully bio-based elastomer nanocomposites based on polyfarnesene and cellulose nanocrystals (CNC). To improve the compatibility of cellulose with the hydrophobic matrix of polyfarnesene, the surface of CNC was modified via plasma-induced polymerization, at different powers of the plasma generator, using a trans-beta-farnesene monomer in the plasma reactor. The characteristic features of plasma surface-modified CNC have been corroborated by spectroscopic (XPS) and microscopic (AFM) analyses. Moreover, the cellulose nanocrystals modified at 150 W have been selected to reinforce polyfarnesene-based nanocomposites, synthesized via an in-situ coordination polymerization using a neodymium-based catalytic system. The effect of the different loading content of nanocrystals on the polymerization behavior, as well as on the rheological aspects, was evaluated. The increase in the storage modulus with the incorporation of superficially modified nanocrystals was demonstrated by rheological measurements and these materials exhibited better properties than those containing pristine cellulose nanocrystals. Moreover, we elucidate that the viscoelastic moduli of the elastomer nanocomposites are aligned with power-law model systems with characteristic relaxation time scales similar to commercial nanocomposites, also implying tunable mechanical properties. In this foreground, our findings have important implications in the development of fully bio-based nanocomposites in close competition with the commercial stock, thereby producing alternatives in favor of sustainable materials.

Despite the increased use of hemp fiber, negligible attention has been given to upgrade the hemp hurd, which constitutes up to 70 wt % of the hemp stalk and is currently considered a low-value byproduct. In this work, valorization of hemp hurd was performed by reductive catalytic fractionation (RCF) in the presence of a metal catalyst. We found an unexpectedly high yield of monophenolic compounds (38.3 wt %) corresponding to above 95% of the theoretical maximum yield. The high yield is explained by both a thin cell wall and high S-lignin content. In addition, organosolv pulping was performed to generate a pulp that was bleached to produce dissolving-grade pulp suitable for textile fiber production (viscosity, 898 mL/g; ISO-brightness, 90.2%) and nanocellulose. Thus, we have demonstrated a novel value chain from a low-value side stream of hemp fiber manufacture that has the potential to increase textile fiber production with 100% yield and also give bio-oil for green chemicals.

In this work, we explore the statistical copolymerization of 1,3-butadiene with the terpenic monomers myrcene and farnesene, carried out via coordination polymerization using a neodymium-based ternary catalytic system. The resultant copolymers, poly(butadiene-co-myrcene) and poly(butadiene-co-farnesene), were synthesized at different monomer ratios, elucidating the influence of the bio-based monomer content over the kinetic variables, molecular and thermal properties, and the reactivity constants (Fineman-Ross and Kelen-Tudos methods) of the resultant copolymers. The results indicate that through the herein employed conditions, it is possible to obtain more sustainable high-cis (approximate to 95%) polybutadiene elastomers with random and tunable content of bio-based monomer. Moreover, the polymers exhibit fairly high molecular weights and a rather low dispersity index. Upon copolymerization, the T-g of high-cis PB can be shifted from -106 to -75 degrees C (farnesene) or -107 to -64 degrees C (myrcene), without altering the microstructure control. This work contributes to the development of more environmentally friendly elastomers, to form green rubber materials.

Hybrid materials from nanocellulose, lignin, and surface- grafted zwitterionic poly(sulfobetaine methacrylate) (PSBMA) chains are prepared to attain antifouling bio-based nanomaterials with enhanced antibacterial performance. The grafting of PSBMA from both cellulose and lignocellulose nanocrystals (CNC and LCNC, respectively) is attempted; however, the materials' analysis with FTIR, XPS, and solid-state C-13 NMR reveals that the grafting on LCNC is negligible. Antifouling and antibacterial performances of CNC and LCNC, as well as PSBMA-grafted CNC, are evaluated by using quartz crystal microbalance with dissipation monitoring, confocal microscopy, and the agar diffusion method using bovine serum albumin and E. coli ACTT 8937 as protein model and bacterial model, respectively. The results demonstrate that the grafting of CNC with PSBMA improves the antifouling and antibacterial activity of the material compared to pristine CNC and LCNC.