Given the declining demand for newsprint and the rising demand for packaging materials, new applications for high-yield pulps (HYPs), such as sustainable packaging, are being developed. While the traditional use of HYPs as a major component in paperboard is growing alongside this demand, their use in other packaging types with different property demands requires quality modifications or improvements to enhance mechanical strength and/or barrier properties. The research presented here explores the role of lignin and lignin-rich fine content, combined with hot-press technology, in improving the paper produced with chemithermomechanical pulp (CTMP). Critical properties for some packaging materials, as tensile strength (dry and wet) and air permeability were evaluated. Results indicate that moderate delignification (15%) or increased fines content together with hot-pressing improves the evaluated properties. The highest dry tensile strength was achieved through soft delignification, tripling the resistance (from 27 to 83 kN m/kg). Maximum wet strength (28 kN m/kg) was obtained with 35% fines content and 260 °C hot-pressing, which also resulted in the densest sheets. Air permeability was significantly reduced, either through partial delignification or by increasing the fines content, resulting in values decreasing from approximately 2000–20 mL/min. This approach aims to develop more sustainable packaging materials without relying on wet strength additives typically derived from fossil raw materials.

Nanocellulose is a promising raw material due to its distinctive properties, including renewable origin, biodegradability, lightweight, and high mechanical strength. It has a very high potential to enhance products in a broad spectrum of applications. However, the production of highly fibrillated cellulose nanofibrils (CNFs) remains costly due to the high energy and chemical consumption. TEMPO-mediated oxidation (TMO) is the most widely accepted pretreatment for CNF production due to its high efficiency and selectivity. However, challenges associated with scaling up this process are limiting their implementation, as high catalysts and oxidant doses, extended reaction times, and large reaction volumes. Several strategies have been developed with the aim of enhancing the CNF production and optimizing the overall process. These strategies include real-time monitoring of the reaction parameters, optimizing pulp concentration, reusing the reaction medium, and using different reactor configurations such as kneaders and twin-screw extruders. These advancements are reviewed to show the significant and critical progress carried out in the last decade toward achieving more efficient and sustainable nanocellulose production.

Improving the mechanical properties of wood and paper is crucial for enhancing their performance in structural and packaging applications. A particularly effective method for increasing strength is hot-pressing, where lignin softening has been proposed as a key mechanism underlying improved fiber bonding. In this study, we investigated the deformation behavior of Norway spruce lignin across temperatures of approximately 25-300 °C and moisture contents of 0-25 wt % using molecular dynamics simulations and paper hot-pressing experiments. We simulated key mechanical paper properties, including Young's modulus, glass transition temperature, and the diffusivity of water and lignin chains. Experimental results showed a pronounced increase in wet strength above 175 °C, which correlated with lignin softening and enhanced fiber-fiber bonding in the simulations. Our findings highlight the ability of molecular simulations to elucidate the mechanisms of lignin-driven bonding and provide a foundation for optimizing the use of lignin-rich materials in various applications.

Emerging contaminants (ECs) include a wide range of substances whose presence may pose a risk to the environment and human health. Research on cytostatic pollutants is increasing because the exponential growth of cancer treatments leads to higher discharge of cytostatic contaminants with wastewater treatment plant effluents. This systematic bibliometric review shows 4166 publications within the topic of ECs and cytostatic drugs in water bodies since 1996, mainly in the category of Environmental Science. China, Spain and USA are the most productive countries nowadays and Europe has 41,6% of the publications. Research topics have shifted from identifying the presence of ECs, in the period 1996-2012, to understanding their fate, distribution, and long-term impacts as well as on developing removal technologies, in the period 2012-2023. 29 main keywords have been identified and classified into four thematic groups: contaminants, analytical techniques, water bodies and treatments. Principal component analysis has integrated them into two principal components (PC). PC1 includes keywords within the groups of water bodies and treatments, and it reflects 70% of the original data variance; while PC2 represents the analytical topic, and it represents 20% of the variance. The co-occurrence networks of keywords, analysed by VOSviewer, show four clusters in both periods, with “emerging contaminants”, “pharmaceuticals”, and “personal care products” as the most important. “Contaminants” that appear in the first period have been substituted by “treatment plants” in the last decade. The keyword “personal care products” shows the highest increase (14-fold), higher than “emerging contaminants” (13 times) and “cytostatic drugs” (10 times). In recent years, the research interest on the formation of transformation products during water treatments and their risks has increased as shown by the higher importance of keywords such as "transformation products", "risk assessment" and "toxicity”, as consequence of the development of advanced oxidation treatments.

The examination of primary risk assessment methodologies reveals a significant expansion in recent years, particularly toward encompassing ecosystem preservation and predictive models for environmental contaminant behavior. However, alongside this progress, new challenges have surfaced, such as engineered nanoparticles, cumulative impacts, and the risks associated with emerging contaminants of concern. This research aims to uncover fresh perspectives within the realm of global environmental risk assessment concerning the stress on water resources. Based on the results, the directions for studying water pollution’s environmental risks are highlighted. Special attention is given to water multi-stressor challenges with significant impact and therefore to multi-risk assessment of aquatic ecosystem components and human health. The foundational framework for the primary phases of risk assessment was delineated, taking into account the existing body of prior research. Drawing from the current state of knowledge, the notion of evaluating cumulative ecological risks (termed multi-risk) stemming from pollutant exposure, encompassing emerging contaminants among other factors, is introduced. This encompasses the phases of contaminant migration, transformation, and accumulation within the various components of the hydrosphere, specifically in surface water bodies, groundwater, and their eventual discharge into the sea and ocean, within a unified global water system. Furthermore, alternative approaches for incorporating additional factors, such as climate change, into the overarching risk assessment framework have been pinpointed, offering novel perspectives for future research endeavors in this domain.

This paper studies the effect of three swelling pretreatment processes (glycerol, alkaline, and molten salt hydrate) to improve the efficiency of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO)-mediated oxidation (TMO) to produce cellulose nanofibrils (CNFs). The novelty of this research lies in the presentation of a new approach that increases the process`s sustainability. The new pretreatment results in the reduction of both chemical reagents and energy consumption. Results demonstrate that pulps pretreated with molten salt hydrate exhibit a crystallinity index up to 50% lower than the original fibers, while the carboxyl groups obtained during oxidation increase up to 30%. The increase in oxidation efficiency allows us to obtain a highly fibrillated CNF with a 50% dose reduction of TEMPO and NaBr at the same time that the energy consumption (kWh/kg) is reduced by 15%.

The recovery of Co(II), Mn(II), Ni(II), and Cu(II) from black mass e-waste solutions through cellulose nanofibers (CNFs) and nanocrystals (CNCs) was investigated. These materials were synthetized by TEMPO-oxidation followed by high-pressure homogenization, and acid hydrolysis, respectively. The NC characterization included the measurement of consistency, cationic demand, carboxylic content, dissolved amorphous cellulose, and transmittance at λ = 600 nm. These parameters revealed a high transmittance of the NC solutions and a large presence of anionic groups on the surface. The high surface area and charge of the NC justify their high interaction with the cationic metals. Results indicate that short contact times (even 1 min) and low sorbent doses (10 mg/L) at acidic pHs (2 to 4) implied remarkable sorption capacities in most cases with more than 1 g/g of sorption capacity of Co(II), Mn(II), and Cu(II) in single-step sorption tests. Such levels of sorption capacities exceed by at least one order of magnitude most of the literature values of metal recovery applying cellulosic materials. Isotherm modeling through a combination of Langmuir and Freundlich models suggested that both sorption and surface precipitation occurred. A novel procedure following multiple-step batch operation was applied for Mn(II) sorption. This new method was applied as a five-step process, leading to a fourfold and 18-fold increase of sorption capacity onto CNCs and CNFs, respectively, compared to the single-step process. Therefore, this process shows an innovative way to implement the multiple-step batch sorption with NC as an efficient and environmentally friendly solution for critical metal recovery from e-waste leachates.

The industrial use of TEMPO-mediated oxidation (TMO) reaction to produce highly fibrillated cellulose nanofibrils has been hindered by high catalyst costs, long reaction times and high reaction volumes. The hypothesis that cellulose concentration during TMO process is key to increase the process of efficiency has been confirmed. The novelty of this research is the proof-of-concept for a significant enhancement of the TMO reaction by kneading the cellulose to work in concentrations above 120 g/L. Results show that the increase of the cellulose concentration in the TMO reaction, from the traditional 10 g/L to 120 g/L, increase not only the production for the same reaction volume (1200 %) but also the pulp recovery (up to 94 %). Moreover, the oxidation time can be reduced from 42 min to only 4 min while properties of both the oxidized pulps and the final nanocellulose are similar. On the other hand, the use of buffers in the TMO reaction allows us to keep the pH constant without using NaOH, and to improve the selectivity of the carboxyl groups production. The proposed process also minimizes the final environmental impact.

Circular bioeconomy is one of the major socio-economic objectives for the twenty-first century, which includes the use of biomass waste and its transformation through environmentally friendly processes into biorefinery building blocks. Among these compounds, succinic acid (SA) obtained by fermentation stands out. This work demonstrates the feasibility of using beer bagasse and spent brewer’s yeast as carbon and nitrogen sources for the bioproduction of SA with Actinobacillus succinogenes. The use of a progressive enzymatic treatment liberated simple monosaccharides and peptides that were used by the microorganism, in a subsequent fermentation. Compared to the use of commercial xylose and yeast extract, the used of beer wastes obtained better yields (0.77 g g −1) and selectivity (76

Cellulose regeneration is a critical step in the production of textiles, cellulose derivates, edible films for packaging or biomedical products because the regeneration process alters the cellulose properties. Cellulose regeneration involves complex intermolecular interactions and kinetics that determine the structure and properties of the regenerated cellulose products. Homogeneous quality is crucial for meeting market demands, but it is challenging due to variations in raw materials, process conditions, and other factors. On-line real-time monitoring of the cellulose regeneration process will allow researchers to optimize the process and producers to assess and control the key parameters involved during the regeneration process, ensuring both optimal product quality and process efficiency. This paper describes for the first time the potential of using focused beam reflectance measurements (FBRM) to monitor the evolution of cellulose regeneration under different conditions. The analysis of the evolution of the cellulose particle growth under different conditions allow us to confirm that the mechanism of cellulose aggregation is initiated by hydrophobic interactions and to understand the contribution of the different processes involved during the regeneration such as nucleation, particle growing, cellulose flocculation and floc break down. The results indicate that hydrolysis of urea in alkaline conditions, accelerated by elevated temperatures, has a major impact on the regeneration process confirming the idea that urea prevents hydrophobic interactions. The effects of temperature, initial cellulose concentration, seeding and aging have been quantified. FBRM analysis offers crucial insights that enhance understanding of the regeneration process, enabling its optimization and facilitates the creation of customized cellulose-based materials tailored for specific applications.

Accumulation of Cr(VI) in industrial fiber cement process water may compromise the product quality and cause health issues. Furthermore, it must be removed from process waters to avoid environmental risks. For this purpose, this work evaluates the potential of advanced nanocelluloses and compare it with the efficiency of conventional adsorbents. The analysis of the industrial process allowed to perform a techno-economic assessment on the long-scale implementation. Among the studied adsorbents, granular (GAC) and powdered activated carbons (PAC) and cationic cellulose nanocrystals (CCNCs) removed >99 % of Cr(VI) from real waters. CCNCs efficiency is linked to their large number of cationic groups. The CCNCs reached adsorption capacities up to 90 times higher than GAC in just 5 min by applying an order of magnitude lower dosages. The cost analysis of GAC adsorption revealed that the ultrafiltration and reverse osmosis treatment of backwashing water costed up to 9.5 US$m(-3). To minimize the generated hazardous wastes, the application of evaporation or a second UF and RO treatments reduced costs in 66 % and 71 %, respectively. The use of high-performance membranes and achieving discounts on GAC purchase, 1.6 US$m(-3) would be reached. This suggests that the CCNCs competitive price would be below 22 US$kg(-1).

A promising alternative to extend the limits of chemithermomechanical pulps (CTMPs) has been proposed to produce extremely resistant waterproof paper for use in sustainable packaging products, replacing plastics. The synergies between the incorporation of lignin microparticles (LMPs) in a pulp furnish (mass), with retention agents and hot-pressing technology, have been successfully tested in CTMP paper sheets. The addition of LMPs as a wet-strength agent, combined with the high temperature produced in hot-pressing, allows the softening of the LMPs to enhance mechanical properties. Two retention agents, cationic starch (CS) and chitosan (CH), have been studied to ensure the retention of the LMPs. Results show that both CS and CH remarkably improve the wet tensile index while maintaining or slightly increasing the dry tensile index. Regarding hot-pressing, three seconds of pressing is enough to achieve these properties, and some moisture (20

The replacement of fossil resources by biomass is one of the key strategies for the development of bioeconomy. Here we have focused on the bioproduction of succinic acid, a biorefinery platform of great versatility and importance. In this study, the anaerobic bacterium Actinobacillus succinogenes was selected as the biocatalyst, choosing discarded potatoes and spent brewer's yeast hydrolysates served as carbon and nitrogen sources, respectively. The use of food residues is critical to reduce operating expenses in this type of processes. Furthermore, to analyze and improve the process performance, repeated batch fermentations were carried out in several conditions: with potato waste hydrolysate or 40 g L-1 of pure glucose as carbon sources and spent brewer's yeast hydrolysate or commercial yeast extract as nitrogen sources. Very promising results were obtained with the residue preparations: 35.8 g L-1 of succinic acid were produced, with a yield of 0.84 g g-1 and an average productivity of 1.19 g L-1 h -1, increasing the selectivity towards the target acid in comparison to pure glucose and yeast extract. Finally, a previously developed unstructured non-segregated global kinetic model is successfully applied, obtaining the parameters values in all conditions.

Selective critical metal recovery from black mass leachates (BML) is a great challenge for the Li-ion batteries recycling sector. This paper shows the potential of nanocellulose products as green adsorbents for a selective recovery of critical metals through multibatch sorption processes. Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) of 0.4 and 1.5 meq/g cationic demand, respectively, have been produced and used as biosorbents. Metal leaching from non-pyrolyzed black mass with HCl presented the highest critical metal extraction yield, obtaining up to 10 g/L of Co and more than 1 g/L of Cu, Mn and Ni. The adsorbents were tested under different dosages and pH conditions for the treatment of both synthetic multimetal solution (MMS), with Mn, Cu, Co, and Ni, and real BML, through a multiple step batch treatment to increase the selectivity towards each critical metal. For MMS treatments, the lowest pH (1-2) conditions are favorable for Co separation, reaching 135 g/g, while higher pH values (4-5) are better to recover Cu and Ni. Selectivity indexes between metals could reached values above 40 for the optimal conditions. For the treatment of BML, pH around 3 enhanced the selectivity of Al and pH of 5 of the Li. In this case, metal recoveries were higher than 30 g/g. When CNCs were used, more than 4 g/g of Co was adsorbed, recovering more than 99 % of the Co present in the waste. 99 % of Co purity was obtained at the optimal Co selective recovery conditions. Although the studied critical metals were strongly sorbed onto the nanocelluloses, a solution with a concentration of 2.5-5 g/L of these metals could be extracted from desorption tests.

This editorial considers Open Science, what it is, what are its potential benefits, what are the pillars of engagement upon which it rests, and what are some of the main challenges facing its further adoption by research communities. At its core, Open Science involves sharing not only the contents of a traditional research article, but also of any source data and methodologies upon which the reported findings are based. Though some extra work may be required, usually without anyone providing additional resources to do that work, continuous developments in digital technology are making Open Science easier to implement. While not all data is suitable to be shared, Open Science practices are widely supported within the wider research community and funding organizations.

The effect of gold (Au) addition on the anatase to rutile transition temperature (ART) of titanium dioxide (TiO2) was investigated. Concentrations of 2, 4, 8 and 16 mol. % of Au have been synthesised via a sol-gel technique and calcined at various temperatures (500-900 degrees C). The inclusion of gold improves the ART at 700 degrees C, maintaining 44.5 % anatase content for 4 % Au. Density functional theory studies indicated that the addition of Au in the anatase phase results in considerable lattice distortions, while Au 4d states and occupied Ti 3d orbitals contribute to the valence-conduction band energy gap upon doping. However, no sign of lattice substitution was observed in the experimental analysis. Instead, we demonstrate that the actual structure is well described by gold nanoparticles deposited on anatase and present a detailed DFT description of gold-modified anatase (101). All AuTiO2 samples exhibit reduced photocatalytic degradation properties compared to the control TiO2 at 500 degrees C. However, after calcining at 600 degrees C the addition of Au increases the photocatalytic activity of TiO2 from 49 % to 61 %, at an optimal concentration of 2 % Au-TiO2. The modification of titania with gold does push the transition temperature higher. However, this comes at the cost of reduced activity for 1,4-dioxane degradation, with the unmodified titania sample having better overall photocatalytic activity.

Vegetable trimmings can be used to stabilize edible O/W Pickering emulsions. The lignocellulosic biomass (LCB) from the leek trimmings was mechanically treated to produce high-yield lignocellulose micro and nanofibrils (LCF) using a high-pressure homogenizer (HPH). Different O/W phase ratios (20/80, 30/70, and 40/60 wt.%) were studied. The use of the micro/nano cellulosic fibers increased the stabilization of the Pickering emulsions by 30–40%. In all cases, stable emulsions were obtained, with emulsification indexes > 92%. The respective stabilization mechanism was thoroughly analysed from confocal laser scanning, and cryo-scanning electron microscopy, which showed the fibers are not coating the droplets but forming a network that traps the droplets and prevents coalescence. The most stable batch formulations, O/W 30/70 wt.% (LCB 4.2 wt.%) and O/W 40/60 wt.% (LCB 3.6 wt.%), were also studied in continuous mode using NETmix technology. Results show the scale-up feasibility of the production of Pickering emulsions containing LCF. Most significantly, this work proposes a continuous process to produce Pickering emulsions stabilized with a natural biopolymer extracted from leek trimmings, which is suitable to industrial manufacturing processes. This valorizes the vegetable trimmings that are usually tossed away as waste, creating new market niches and business models based on circular economy concepts. Graphical Abstract

The widespread use of synthetic plastics in packaging materials poses significant environmental challenges, prompting the search for biobased, biodegradable, and non-toxic alternatives. This study focuses on improving high-yield pulps (HYPs) as sustainable materials for packaging. Enhancing wet strength and barrier properties of papers from bleached chemi-thermomechanical pulps (BCTMPs) is crucial for their application in water- and air- resistant wrappers. Traditional wet strength agents raise environmental and health concerns; therefore, this research explores the use of lignin, in the form of microparticles (LMPs), as a natural biopolymer that offers a safer alternative. However, the low viscosity of LMPs hampers their dispersion as a coating, requiring thickening agents (such as cationic starch (CS), chitosan (CH) or sodium alginate) for an effective coating formulation. Results demonstrate a synergistic effect of LMP coatings with CH or CS, enhanced by hot-pressing at 260 °C for 30 s, which improves dry and wet mechanical properties and decreases air permeability. The use of LMPs as a water-resistant interlayer between BCTMP paper sheets further improves the wet tensile index to 40 kN·m/kg for CH + LMPs and 23 kN·m/kg for CS + LMPs interlayer, representing 55 and 38 % of their respective dry tensile indices.

(TEMPO)-mediated oxidation (TMO) is a widely recognized pretreatment for producing highly fibrillated cellulose nanofibrils (CNFs) because of its efficiency and selectivity. However, the challenges of scaling up this process is limiting its implementation. This study explores enhancing the production of oxidized pulps (OPs) by performing the TMO reaction within a pilot-plant twin-screw extruder (TSE). This approach aims to oxidize large volumes of cellulose at high concentrations while simultaneously applying a soft mechanical fibrillation, making the upscaling process more sustainable and feasible. OPs and CNFs were characterized and compared to those obtained from the traditional TMO pretreatment in a stirred reactor as well as those pretreated by mechanical TSE. Results demonstrate that TMO within the TSE is more efficient and increase the yield fibrillation using 0.8, 0.08 and 2 mmol/g pulp of NaBr, TEMPO and NaClO, respectively. Multiple TSE steps decrease polymerization degree, enhance the process yield, and reduce the number of large fibers. Gradual addition of oxidants in multiple TSE steps prevents harsh reaction conditions and avoids yellowing of the final products.