Cellulose Pulp Research Articles

Renewable and high-purity hydrogen from lignocellulosic biomass in a biorefinery approach

Unprecedented efforts are being deployed to develop hydrogen production from bioresources in a circular economy approach, yet their implementation remains scarce. Today’s Challenges are associated with the shortage in the value chain, lack of large-scale production infrastructure, high costs, and low efficiency of current solutions. Herein, we report a hydrogen production route from cellulose pulp, integrating biomass fractionation and gasification in a biorefinery approach. Softwood sawdust undergoes formic acid organosolv treatment to extract cellulose, followed by steam gasification. High-purity hydrogen-rich syngas at a concentration of 56.3 vol% and a yield of 40 gH2/kgcellulose was produced. Char gasification offers the advantage of producing free-tar syngas reducing cleaning costs and mitigating downstream issues. A comprehensive assessment of mass and energy balance along the hydrogen value chain revealed an efficiency of 26.5% for hydrogen production, with an energy requirement of 111.1 kWh/kgH2. Optimizing solvent recovery and valorization of other constituents as added-value products in a biorefinery approach would further improve the process and entice its industrial takeoff.

Silicates as alternative pretreatment for cellulose pulp to obtain nanofibrils for application in biodegradable packaging: a technical review

Silicates as alternative pretreatment for cellulose pulp to obtain nanofibrils for application in biodegradable packaging: a technical review

Aqueous exfoliation and dispersion of monolayer and bilayer graphene from graphite using sulfated cellulose nanofibrils.

Amphiphilic sulfated cellulose nanofibrils were synthesized with yields in excess of 99% by sulfation of dissolving pulp cellulose using chlorosulfonic acid in anhydrous N,N-dimethyl formamide followed by high-speed blending. The sulfation level was stoichiometrically tunable to between 1.48 and 2.23 mmol g-1. The optimized SCNF demonstrated the ability to act as an effective dispersant for graphene produced via exfoliation in aqueous media, allowing for the production of aqueous stabilized graphene with 3.9 ± 0.3 wt% graphite to graphene conversion and suspended solids comprised of 19.5 ± 1.5 wt% graphene. Graphene exfoliated with SCNF was observed to consist exclusively of mono- and bilayers, with 42% of sheets being monolayer. Furthermore, it was demonstrated that SCNF defibrillation and graphene exfoliation could be combined into a single one-pot process.

Use of iron ore tailings as partial replacement for cement on cementitious composites production with vegetable fibers

The mining industry has been expanding and consequently increasing the associated environmental impacts, especially regarding this process's high volume of iron ore tailings (IOT) disposal. The best way to solve the problems caused by IOT is to develop large-scale utilization technologies that may consume large quantities of it. This study aims to evaluate the influence of incorporating IOTs on the mechanical, physical, microstructural, and morphological properties of extruded fiber-cement reinforced with eucalyptus cellulose pulp. For its use, IOT was characterized by the inhibition index, pozzolanic test, and granulometric, chemical, morphological, and X-ray diffraction analyses. The fiber-cement flat slabs were prepared by replacing cement using 10%, 20%, 30%, and 40% of IOT and the control treatment, generating specimens measuring 20x30x200mm (height x width x length). The composites were characterized for physical, mechanical, and microstructural properties before and after exposure to weathering by accelerated aging test. This study showed an improvement in fiber durability with the increase in IOT content as a function of the waste’s pozzolanic activity and an improvement in physical properties using 10% cement replaced by IOT. All treatments tested at 28 days presented values within trading standards limits. However, the treatments with 10% and 20% of IOT met the most demanding criteria. Thus, using iron ore waste as a substitute for raw materials in cementitious composites may reduce the difficulties of IOT disposal and save natural resources, leading to more sustainable constructions.

Fungal loosenin-like proteins boost the cellulolytic enzyme conversion of pretreated wood fiber and cellulosic pulps

Microbial expansin-related proteins, including loosenins, can disrupt cellulose networks and increase enzyme accessibility to cellulosic substrates. Herein, four loosenins from Phanerochaete carnosa (PcaLOOLs), and a PcaLOOL fused to a family 63 carbohydrate-binding module, were compared for ability to boost the cellulolytic deconstruction of steam pretreated softwood (SSW) and kraft pulps from softwood (ND-BSKP) and hardwood (ND-BHKP). Amending the Cellic® CTec-2 cellulase cocktail with PcaLOOLs increased reducing products from SSW by up to 40 %, corresponding to 28 % higher glucose yield. Amending Cellic® CTec-2 with PcaLOOLs also increased the release of glucose from ND-BSKP and ND-BHKP by 82 % and 28 %, respectively. Xylose release from ND-BSKP and ND-BHKP increased by 47 % and 57 %, respectively, highlighting the potential of PcaLOOLs to enhance hemicellulose recovery. Scanning electron microscopy and fiber image analysis revealed fibrillation and curlation of ND-BSKP after PcaLOOL treatment, consistent with increasing enzyme accessibility to targeted substrates.

Green oleogels based on elm pulp cellulose nanofibers: effect of the nanofibrillation pre-treatment on their thermo-rheological behavior

Sustainable lubricating oleogels were obtained based on elm (Ulmus minor Mill.) pulp cellulose nanofibers in castor oil. Before their nanofibrillation, two samples of the same bleached pulp were subjected to two different pre-treatments, either mechanical PFI (Paper and Fibre Research Institute) refining or chemical TEMPO-mediated oxidation. Their effect on the oleogels’ viscous flow and oscillatory shear behaviors was determined at different temperatures. Very pronounced differences were observed between these oleogels. The oleogel from the chemically-pretreated nanofibers showed evidences of being much more sensitive to both temperature and large shear deformations. Hence, its shear modulus underwent a very remarkable decay of 95.8% when subjected to a non-linear stress value of 100 Pa for 30 min. In turn, under the same conditions, a decay of only 41.4% was observed for the oleogel based on the nanofiber from the mechanically-pretreated nanofibers.Graphical abstract

Nanostructured Cellulose-Based Aerogels: Influence of Chemical/Mechanical Cascade Processes on Quality Index for Benchmarking Dye Pollutant Adsorbents in Wastewater Treatment.

(1) Background: Nanostructured cellulose has emerged as an efficient bio-adsorbent aerogel material, offering biocompatibility and renewable sourcing advantages. This study focuses on isolating (ligno)cellulose nanofibers ((L)CNFs) from barley straw and producing aerogels to develop sustainable and highly efficient decontamination systems. (2) Methods: (Ligno)cellulose pulp has been isolated from barley straw through a pulping process, and was subsequently deconstructed into nanofibers employing various pre-treatment methods (TEMPO-mediated oxidation process or PFI beater mechanical treatment) followed by the high-pressure homogenization (HPH) process. (3) Results: The aerogels made by (L)CNFs, with a higher crystallinity degree, larger aspect ratio, lower shrinkage rate, and higher Young's modulus than cellulose aerogels, successfully adsorb and remove organic dye pollutants from wastewater. (L)CNF-based aerogels, with a quality index (determined using four characterization parameters) above 70%, exhibited outstanding contaminant removal capacity over 80%. The high specific surface area of nanocellulose isolated using the TEMPO oxidation process significantly enhanced the affinity and interactions between hydroxyl and carboxyl groups of nanofibers and cationic groups of contaminants. The efficacy in adsorbing cationic dyes in wastewater onto the aerogels was verified by the Langmuir adsorption isotherm model. (4) Conclusions: This study offers insights into designing and applying advanced (L)CNF-based aerogels as efficient wastewater decontamination and environmental remediation platforms.

Effect of apple polyphenols on physicochemical properties of pea starch/pulp cellulose nanofiber composite biodegradable films

A pea starch (PS) and pulp cellulose nanofibers (CNF-P) hybrid matrix biodegradable film was prepared using apple polyphenol (AP) as the active substance. SEM and thermogravimetric analyses showed that apple polyphenols could be uniformly distributed and form hydrogen bonds with the matrix, and the increase in crystallinity improved the thermal stability of the films (the final residue of the films increased from 22.66 % to 31.82 %). The TS and EAB of the films reached their maximum values of 11.14 ± 1.73 MPa and 71.55 ± 8.8 %, respectively, at an AP content of 1.5 %. It should be noted that the antioxidant properties of the films were significantly positively correlated with the AP content, and the DPPH radical scavenging rate of the films reached 73.77 % at an AP content of 4.5 %, which was about 49 times higher than that of the control film. The same trend was observed in the UV–vis spectra. In addition, the total color difference and water solubility of the membranes increased from 4.29 ± 0.29 to 31.86 ± 1.90 and from 20.01 ± 0.97 % to 21.70 ± 1.99 %, respectively, and the biodegradability also showed an upward trend. These findings provide a theoretical basis and data support for the development of multifunctional biodegradable food packaging materials.

Analysis of the commercial eucalyptus plantation sector in Uruguay from a macroeconomic perspective

The Uruguayan forest sector has developed based on commercial pine and eucalyptus plantations. This process has been based on the installation of vertically integrated companies, with foreign capital and some local capital, investment funds and medium and small industries. In addition to these groups, there are contractor companies in which several of the activities of the primary sector are outsourced, as well as some of the industry. Investment attraction factors are diverse and related not only to productive conditions, e.g., growth rates, but also to institutional conditions, e.g., macroeconomic stability. With the development of the forest sector, there is currently a preponderance of eucalyptus plantations over pine plantations. This characteristic has implications in terms of the products to be obtained and, therefore, the industries to be developed, and the markets to be accessed. The presentation analyzes the evolution of the participation of the forest sector in Uruguay's macroeconomy, considering its share in the country's exports as well as in international trade, with emphasis on the products obtained from eucalyptus plantations. The scope and limitations of the available data for Uruguay are considered. Finally, the importance of including the value of ecosystem services provided by the forest in the traditional macroeconomic valuation is discussed. Results show that Uruguay has an important participation in non-coniferous wood markets. According to FAO data, in 2022, Uruguay's production ranked 8th among non-coniferous pulpwood producing countries, after Chile, up one place from the previous year. The same year Uruguay ranked 10th in terms of production of bleached wood pulp. Furthermore, it is expected that the wood pulp will increase with the new operations of the third pulp mill. Furthermore, cellulose pulp ranked 3rd among Uruguay's export products in 2022, after beef and soybeans, and 2nd in the previous year. The results of this research are of interest to potential investors in the Uruguayan forest sector as well as to policymakers. Potential investors in the Uruguayan forest sector may find insights into the industry's growth potential. Policymakers can use this information to make informed decisions that support the development and regulation of the sector for the benefit of both the economy and the environment.

Structure and properties variations of regenerated cellulose fibers induced by metal ion impurity

In the ionic liquids (ILs) method for processing regenerated cellulose fiber (RCF), which is a high-performance ecologically benign product, metal ion impurities (such as Fe3+ and Cu2+) of cellulose might inevitably remain in the recycled ILs and coagulation bath. The presence of metal ions might negatively impact the properties of the manufactured RCFs and obstruct their applications, which are urgent to be made clear. For this research, the solvent for dissolving wood pulp cellulose (WPC) was 1-ethyl-3-methylimidazolium diethyl phosphate ([Emim]DEP) with various metal ion concentrations. The effect of metal ions in IL on the dissolution of cellulose was investigated by Molecular Dynamics simulations. Rheological analysis and degree of polymerization (DP) analysis were adopted to evaluate the influence on fiber spinnability of different spinning solution metal ion concentrations and various dissolving times. Further, the morphology and mechanical performances of the RCFs variation regulation were also thoroughly researched. The findings showed that the presence of metal ions in the spinning solution affected the DP, crystallinity, and orientation factor of RCFs, which will influence their stress more sensitively than the strain. These findings can serve as a practical guide for the commercial manufacture of emerging fiber.

Experimental studies of dynamic compression of cellulose pulp fibers

The ability to control the structure of the wood-pulp fiber cell wall is an attractive means to obtain increased accessibility to the fiber interior, providing routes for functionalization of the fibers that support further processing and novel material concepts, e.g. improved degree of polymerization, nanofiltration as demonstrated in previous studies. It has been proposed that dynamic compression and decompression of the cellulose pulp fibers in the wet state make it possible to modify the cell wall significantly.We hypothesize that hydrostatic pressure exerted on fibers fully submerged in water will increase the accessibility of the fiber wall by penetrating the fiber through weak spots in the cell wall. To pursue this, we have developed an experimental facility that can subject wet cellulose pulp samples to a pressure pulse ∼10 ms long and with a peak pressure of ∼300 MPa. The experiment is thus specifically designed to elucidate the effect of a rapid high-pressure pulse passing through the cellulose sample and enables studies of changes in structural properties over different size ranges. Different characterization techniques, including Scanning electron microscopy, X-ray diffraction, and wide- and small-angle X-ray scattering, have been used to evaluate the material exposed to pulsed pressure. The mechanism of pressure build-up is estimated computationally to complement the results. Key findings from the experiments consider a decrease in crystallinity and changes in the surface morphology of the cellulose sample.

The Effect of Different Concentration of NaOH on Mechanical Properties of Allium sativum L. Peels Thin Sheet Paper

Allium sativum L. peels were used as raw material to obtain cellulosic pulps for paper making. The peels were treated with sodium hydroxide at different concentrations (5%, 12.5%, and 20%) before the paper production. The sheets were measured for weight and thickness and evaluated for tensile, tear and bursting strength. The chemical compositions of the peels were analysed. The results indicated that the peels are suitable for papermaking due to the appropriate contents of cellulose (37.22%), hemicellulose (35.21%) and lignin (9.96%) values. The colour of the sheets varies from dark to light brown when the amount of sodium hydroxide solution was increased. It was estimated that the weight of peels was in the range of 5.0 - 6.5 % of garlic clove. All the sheet samples have uniform weight and thickness. The results showed that increasing sodium hydroxide concentration from 5% to 20% decreased tensile and bursting strength, except tearing strength. Two kinds of microscopic observations showed that peels treated with the highest sodium hydroxide concentration had a fine and thin layer of binder within the fibres. The sheets appear to be transparent with due to a decrease in the tensile and bursting strength except for the tear strength.

TEMPO-oxidized nanofibrillated cellulose as potential carrier for sustained antibacterial delivery

Designing a suitable, cost-effective nanocarrier with an ability to capture and deliver antibiotics for restricting microbial spread remains an unmet need. A simple two-stepped strategy involving citric acid-induced hydrolysis of cellulose pulp (NFC) followed by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) mediated oxidation to obtain carboxylated nano fibrillated cellulose (TNFC-5) with high carboxyl content (1.12 mmol/g) has been explored. TNFC-5 so obtained was able to capture remarkable extent of antibiotics (drug loading (DL) > 40 % and entrapment efficiency (EE) >80 %) irrespective of their hydrophilicity as in, triclosan (hydrophobic) and ampicillin sodium (hydrophilic). In silico molecular docking study revealed the excess carboxyl content in nanocellulose imparted the strongest binding affinity to antibiotics via H-bonding. A slower and sustained release of triclosan was observed for TNFC-5 than that of NFC, reiterating the enhanced binding efficiency of the drugs with TNFC-5. Well-dispersed triclosan loaded TNFC-5 displayed sustained antibacterial activity against Escherichia coli and Staphylococcus aureus up to one week. Thus, TNFC-5 has been demonstrated as a green, cheap, and eco-friendly alternative to the other biodegradable nanocarriers for carrying antibiotics with high DL and EE, thereby reducing the wastage of expensive drugs while ensuring a sustained antibacterial effect. Our study established that the drug loaded nanofibers (TNFC-5) might act as a promising candidate to penetrate through biofilm for treating serious bacterial infections by retarding their growth and eventually eradicating bacterial colonies.

Obtaining Cellulose Nanocrystals from Olive Tree Pruning Waste and Evaluation of Their Influence as a Reinforcement on Biocomposites

The objective of this work is to improve the mechanical properties of polylactic acid (PLA) by incorporating cellulose nanocrystals (CNC) previously obtained from a cellulose pulp extracted from olive tree pruning (OTP) waste. Composites were manufactured by melt processing and injection moulding to evaluate the effect of the introduction of CNC with conventional manufacturing methods. This OTP-cellulose pulp was subjected to a further purification process by bleaching, thus bringing the cellulose content up to 86.1%wt. This highly purified cellulose was hydrolysed with sulfuric acid to obtain CNCs with an average length of 267 nm and a degradation temperature of 300 °C. The CNCs obtained were used in different percentages (1, 3, and 5%wt.) as reinforcement in the manufacture of PLA-based composites. The effect of incorporating CNC into PLA matrix on the mechanical, water absorption, thermal, structural, and morphological properties was studied. Maximum tensile stress and Young’s modulus improved by 87 and 58%, respectively, by incorporating 3 and 5%wt. CNC. Charpy impact strength increased by 21% with 3%wt. These results were attributed to the good dispersion of CNCs in the matrix, which was corroborated by SEM images. Crystallinity index, glass transition, and melting temperatures were maintained.

Indole acetic-producing bacteria promote the root development of Acacia mearnsii cuttings

ABSTRACT Black wattle (Acacia mearnsii) is one of the most important commercial tree species in southern Brazil, where it is planted for multiple uses, such as cellulose pulp production and tannin extraction. Recently, forest companies have been directing their efforts towards vegetative propagation to improve the productivity of black-wattle plantations. However, rooting rates of this species are low, even when treated with the synthetic auxin indole-3-butyric acid (IBA). Thus, rooting black-wattle cuttings is still considered a bottleneck for industry development. On the other hand, it is known that inoculating cuttings with indole acetic acid (IAA)-producing bacteria can be an efficient method for increasing vegetative propagation. This study investigated the potential of two bacterial strains to promote root development in black wattle. The strains SEMIA 436 and 439 (Agrobacterium radiobacter), previously isolated from the common bean and detected as high-IAA producers, were also evaluated in relation to their colonisation capacity in seedling roots. Results showed that inoculation with both strains increased rooting rates by 20−30% compared with non-treated and IBA-treated cuttings. Moreover, inoculation increased root dry mass, length and volume. Strain SEMIA 436 demonstrated higher colonisation capacity.

Taxonomic composition and carbohydrate-active enzyme content in microbial enrichments from pulp mill anaerobic granules after cultivation on lignocellulosic substrates

Metagenomes of lignocellulose-degrading microbial communities are reservoirs of carbohydrate-active enzymes relevant to biomass processing. Whereas several metagenomes of natural digestive systems have been sequenced, the current study analyses metagenomes originating from an industrial anaerobic digester that processes effluent from a cellulose pulp mill. Both 16S ribosomal DNA and metagenome sequences were obtained following anaerobic cultivation of the digester inoculum on cellulose and pretreated (steam exploded) poplar wood chips. The community composition and profile of predicted carbohydrate-active enzymes were then analyzed in detail. Recognized lignocellulose degraders were abundant in the resulting cultures, including populations belonging to Clostridiales and Bacteroidales orders. Poorly defined taxonomic lineages previously identified in other lignocellulose-degrading communities were also detected, including the uncultivated Firmicutes lineage OPB54 which represented nearly 10% of the cellulose-fed enrichment even though it was not detected in the bioreactor inoculum. In total, 3580 genes encoding carbohydrate-active enzymes were identified through metagenome sequencing. Similar to earlier enrichments of animal digestive systems, the profile encoded by the bioreactor inoculum following enrichment on pretreated wood was distinguished from the cellulose counterpart by a higher occurrence of enzymes predicted to act on pectin. The majority (> 93%) of carbohydrate-active enzymes predicted to act on plant polysaccharides were identified in the metagenome assembled genomes, permitting taxonomic assignment. The taxonomic assignment revealed that only a small selection of organisms directly participates in plant polysaccharide deconstruction and supports the rest of the community.

Profitable and environmentally responsible recycling of fibers and reactive dyes from afterlife cotton textiles via controlled dye hydrolysis, fiber swelling and dissolution

We have developed sustainable cotton recycling to provide high-quality cellulose fibers as well as dyes. Because of the lack of simple, non-destructive, and environmentally responsible discoloration technologies, recycled cellulosic products have lower and inconsistent quality and thus limited values. For example, recycling cotton via the spinning of colored cotton into colored cellulose fibers faces challenges since dyes seriously disrupt the spinnability of cellulose dopes. Here, we demonstrate a clean technology to completely recycle all reactive dyed cotton and dyes via controlled dye hydrolysis, fiber swelling, and dissolution. Controlled dye hydrolysis cleaved the covalent bonds between reactive dyes and cellulose. Fiber swelling in N-Methylmorpholine N-oxide (NMMO)/water almost eliminated the physical interactions between dyes and cellulose. As a result, dyes, with different functional groups and chromogenic structures, were separated from cotton. The discolored cotton in NMMO demonstrated desirable spinnability without adding any new cellulose pulp. The high molecular weight makes 100% recycled lyocell fibers tougher than wood-derived lyocell. Separated reactive dyes, with unchanged chromogenic structures, demonstrate desirable dyeability as acid dyes. Recycling cotton is cost-effective to obtain cellulose pulp, the starting materials to produce lyocell, compared to the classic Kraft wood process. The NMMO was recyclable and provided consistent results of cotton discoloration for at least 5 use cycles.

Implications of Particle Size in the Extraction of Cellulose from the Calamagrostis Intermedia Species

This research aimed to elucidate the implications of particle size on cellulose extraction from the species Calamagrostis intermedia, endemic to Ecuador. Within the versatile cellulose extraction and trade industry, using timber sources results in a relentless environmental impact, mainly when no resource rationing occurs during the washing or bleaching phases. The investigation incorporated a sample pretreatment encompassing a drying, grinding, and sieving study, followed by an alkaline extraction. The study found that particle size significantly affected the quantity of fiber and cellulose pulp extracted from samples previously dried at 65°C with particle sizes of 300 and 106 μm. Characterization tests revealed variations in the color and texture of the extracted cellulose, attributable to an ineffective delignification stage within the fiber bleaching process. Variations in molecular weight corresponding to 126.32 x 103 g/mol were identified among samples, and FTIR analysis presented a syringyl ring and lignin stretching. Optical microscopy exposed the absence of well-defined regions in the fibers and a readily observable crystalline network. In conclusion, particle size critically influences cellulose extraction from Calamagrostis intermedia, impacting the yield and properties of the resultant product, indicating that further optimization of the extraction and delignification process is required to enhance the quality of the extracted cellulose. Keywords: Calamagrostis intermedia; Particle Size; Cellulose Extraction

Resource recovery and reduction of tidal waste to produce cellulose through sulphur-free pulping

AbstractThe transition towards a sustainable cellulose industry needs more environmentally friendly technologies, including the use of lignocellulosic waste as alternative raw materials. This work shows the potential of dead biomass from the Andalusian Mediterranean coastline to obtain cellulosic pulp. With this purpose, predominant species in onshore residues (mainly Posidonia oceanica) were prepared, characterized, and subjected to a soda-anthraquinone pulping process. A central composite design was defined in order to relate the process conditions to the composition and characteristics of the cellulose pulp. It was concluded that polynomial models encompassing linear, quadratic, and binary effect parameters reproduce the experimental results satisfactorily. Results allowed to choose high anthraquinone dosage, alkali charge and temperature, low liquid/solid ratio and short time as a compromise solution, by which the brightness, ethanol–benzene extractives content, kappa number, lignin content and viscosity were near their optimal. Low values of liquid/solid ratio reduce water consumption, which is of utmost importance in cellulose industries likewise short time treatments to save energy.

A new approach for improving the antimicrobial activity of cellulose pulp

A new approach for improving the antimicrobial activity of cellulose pulp