Kraft Pulp Research Articles

A Novel combined thermal evaporation and solvothermal approach to produce highly crystalline and compact CIG(S1-xSex)2 thin films

This research introduces a novel approach that combines thermal evaporation with cost-effective solvothermal methods to produce highly crystalline CIGSe thin films. By avoiding the use of expensive and pure target materials and reducing the selenization step, this method offers an alternative to co-evaporation or sputtering techniques. The study investigates the growth mechanism and sulfurization of the films, resulting in improved crystallinity, absence of secondary impurities, and compact morphology. The sulfurization process is achieved at a low temperature using a safe and convenient method, enhancing the film properties for high-performance solar cells. In this study, the CIGSe powder was synthesized using the solvothermal technique and thermally evaporated onto Mo-coated glass substrates. The resulting films exhibited improved crystallinity and a single-phase structure upon RTP annealing at 600 °C. Characterization techniques confirmed the presence of chalcopyrite crystal structure and the coexistence of CISe, CIGSe, and CGSe phases within the films. The sulfurization process, conducted at a relatively low temperature of 500 °C using an RTP furnace, led to compact morphology, increased grain size, and the absence of secondary phases. These findings demonstrate the feasibility of the proposed approach for fabricating efficient and environmentally friendly CIGSe-based solar cells.

Facile and complete sulfuric acid leaching of zinc ferrite assisted by copper powder: Leaching mechanism and kinetics investigation

Zinc ferrite is a dominant phase in mass solid wastes generated from zinc or iron production, which causes the obstacle of metal recovery and recycling. A facile and efficient sulfuric acid leaching process of zinc ferrite assisted by copper powder was proposed in this study. The effects of factors on the leaching of zinc ferrite and copper were investigated. The results showed that zinc ferrite and copper were coupled and leached. The complete dissolution of zinc ferrite was obtained with wide ranges of leaching conditions. The shortest time for the complete dissolution of zinc ferrite was 10 min at 80 ℃ under the conditions: copper to zinc ferrite molar ratio of 1.5, sulfuric acid concentration of 100 g/L, liquid to solid ratio of 30 mL/g, and copper powder of + 38.5–20 μm. The least consumption of copper to realize the complete dissolution of zinc ferrite was 27.15%. The leaching kinetics was studied by the shrinking core model. It was found that zinc ferrite leaching assisted by copper was controlled by surface chemical reaction. The apparent activation energies for zinc, iron, and copper are 56 kJ/mol, 56 kJ/mol, and 50 kJ/mol, respectively. Characterization of the leaching residues and determination of iron and copper species in the leaching solution showed galvanic corrosion took place between zinc ferrite and copper, enhancing their acid dissolution.

Pulp delignification and refining: impact on the supramolecular structure of softwood fibers

The effect on softwood fiber wall nanostructure of kraft cooking, oxygen delignification and refining was evaluated by X-ray scattering. A recently developed simulation method for modelling small angle X-ray scattering (SAXS) data was used to estimate the apparent average sizes of solids (AAPS) and interstitial spaces in the fiber wall (AACS). Fiber saturation point and wide angle X-ray scattering were also used to calculate the pore volume in the fiber wall and the crystallite size of the fibril, respectively. The experimental modelled SAXS data was able to give consistent values for each kraft-cooked and oxygen-delignified pulp. Kraft delignification seems to have the major influence on the fiber nanostructure modification, while oxygen delignification has little or no significant impact even for different kappa numbers. The particle sizes values were more stable than the cavities sizes and no significant differences were seen between different delignification processes, refining or delignification degree. Pulps evaluated after PFI-refining, showed an increase in the fiber wall porosity evaluated by FSP and an increase in the interstitial spaces in the fiber wall, while the crystallite size and the particle sizes were very little or not affected at all.

Cellulose nanofibrils derived from pulp as a high performance separator for lithium‐ion batteries

AbstractCellulose nanofibrils (CNFs) from hardwood bleached kraft pulp (HwBKP) are produced via enzymatic, chemical, and mechanical treatment. A nanoporous structured CNF‐based separator is produced, and the electrochemical performance, morphology, and thermal stability analyses are performed in comparison to the commercial polyethylene separator. The results obtained show that the electrolyte‐philic CNF separator has capacity retention of 88.6% over 200 cycles and very good ionic conductivity and wettability results due to its high hydrophilic nature. At 140°C, the CNF separator was resilient to heat and remained intact. The CNF separator reflects high thermal resistance and good electrolyte uptake properties that are among the mandatory requirements of a separator hence, a promising contender for use in lithium‐ion batteries.

From Genes to Bioleaching: Unraveling Sulfur Metabolism in Acidithiobacillus Genus.

Sulfur oxidation stands as a pivotal process within the Earth's sulfur cycle, in which Acidithiobacillus species emerge as skillful sulfur-oxidizing bacteria. They are able to efficiently oxidize several reduced inorganic sulfur compounds (RISCs) under extreme conditions for their autotrophic growth. This unique characteristic has made these bacteria a useful tool in bioleaching and biological desulfurization applications. Extensive research has unraveled diverse sulfur metabolism pathways and their corresponding regulatory systems. The metabolic arsenal of the Acidithiobacillus genus includes oxidative enzymes such as: (i) elemental sulfur oxidation enzymes, like sulfur dioxygenase (SDO), sulfur oxygenase reductase (SOR), and heterodisulfide reductase (HDR-like system); (ii) enzymes involved in thiosulfate oxidation pathways, including the sulfur oxidation (Sox) system, tetrathionate hydrolase (TetH), and thiosulfate quinone oxidoreductase (TQO); (iii) sulfide oxidation enzymes, like sulfide:quinone oxidoreductase (SQR); and (iv) sulfite oxidation pathways, such as sulfite oxidase (SOX). This review summarizes the current state of the art of sulfur metabolic processes in Acidithiobacillus species, which are key players of industrial biomining processes. Furthermore, this manuscript highlights the existing challenges and barriers to further exploring the sulfur metabolism of this peculiar extremophilic genus.

The Effect of Cellulose Nanofibres on Dewatering during Wet-Forming and the Mechanical Properties of Thermoformed Specimens Made of Thermomechanical and Kraft Pulps.

Due to environmental concerns regarding single-use plastic materials, major efforts are being made to develop new material concepts based on biodegradable and renewable resources, e.g., wood pulp. In this study, we assessed two types of wood pulp fibres, i.e., thermomechanical pulp (TMP) and Kraft pulp fibres, and tested the performance of the fibres in wet-moulding and thermopressing trials. Kraft pulp fibres appeared to retain more water than TMP, increasing the dewatering time during wet-moulding and apparently increasing the compression resistance of the pulp during thermoforming. Additionally, cellulose nanofibres (CNF) were added to the pulps, which improved the mechanical properties of the final thermopressed specimens. However, the addition of CNF to the pulps (from 2 to 6%) had a further decrease in the dewatering efficiency in the wet-moulding process, and this effect was more pronounced in the Kraft pulp specimens. The mechanical performance of the thermoformed specimens was in the same range as the plastic materials that are conventionally used in food packaging, i.e., modulus 0.6-1.2 GPa, strength 49 MPa and elongation 6-9%. Finally, this study demonstrates the potential of wood pulps to form three-dimensional thermoformed products.

Polydopamine modified cellulose nanocrystals (CNC) for efficient cellulase immobilization towards advanced bamboo fiber flexibility and tissue softness

Herein, a green facile approach to improve the flexibility of unbleached bamboo kraft pulp (UBKP) via an immobilized enzyme technology is proposed. Polydopamine (PDA) acts as versatile modification and coating materials of cellulose nanocrystals (CNC) for assembling versatile bio-carriers (PDA@CNC). Cellulase biomacromolecules are efficiently immobilized on PDA@CNC to form cellulase@PDA@CNC nanocomposites. The relative enzyme activity, temperature/pH tolerance, and storage stability of cellulase were significantly improved after immobilization. The degree of polymerization treated UBKP decreased by 5.42 % (25 U/g pulp) compared to the control sample. The flexibility of treated fibers was 6.61 × 1014/(N·m2), which was 96.93 % higher (25 U/g) compared to the control and 3.88 times higher than that of the blank fibers. Cellulase@PDA@CNC performs excellent accessibility to fiber structure and induces high degree of fibrillation and hydrolysis of UBKP fibers, which contributes high softness of obtained tissue handsheets. The bio-carrier PDA@CNC within paper framework may further enhance tissue tensile strength. This study proposes a practical and environmentally friendly immobilization approach of cellulase@PDA@CNC for improving the hydrolysis efficiency and flexibility of UBKP fibers, which provides the possibility to maintain the strength of tissue paper while improving its softness, thus broadening the high-value application of immobilized enzyme technology in tissue production.

Role of intrinsic and extrinsic xylan in softwood kraft pulp fiber networks

Xylan is primarily found in the secondary cell wall of plants providing strength and integrity. To take advantage of the reinforcing effect of xylan in papermaking, it is crucial to understand its role in pulp fibers, as it undergoes substantial changes during pulping. However, the contributions of xylan that is added afterwards (extrinsic) and xylan present after pulping (intrinsic) remain largely unexplored. Here, we partially degraded xylan from refined bleached softwood kraft pulp (BSKP) and adsorbed xylan onto BSKP. Enzymatic degradation of 1 % xylan resulted in an open hand sheet structure, while adsorption of 3 % xylan created a denser fiber network. The mechanical properties improved with adsorbed xylan, but decreased more significantly after enzymatic treatment. We propose that the enhancement in mechanical properties by adsorbed extrinsic xylan is due to increased fiber-fiber bonds and sheet density, while the deterioration in mechanical properties of the enzyme treated pulp is caused by the opposite effect. These findings suggest that xylan is decisive for fiber network strength. However, intrinsic xylan is more critical, and the same properties cannot be achieved by readsorbing xylan onto the fibers. Therefore, pulping parameters should be selected to preserve intrinsic xylan within the fibers to maintain paper strength.

Kraft Lignin: A Valuable, Sustainable Resource, Opportunities and Challenges.

Kraft lignin, a by-product from the production of pulp, is currently incinerated in the recovery boiler during the chemical recovery cycle, generating valuable bioenergy and recycling inorganic chemicals to the pulping process operation. Removing lignin from the black liquor or its gasification lowers the recovery boiler load enabling increased pulp production. During the past ten years, lignin separation technologies have emerged and the interest of the research community to valorize this underutilized resource has been invigorated. The aim of this review is to give (1) a dedicated overview of the kraft process with a focus on the lignin, (2) an overview of applications that are being developed, and (3) a techno-economic and life cycle asseeements of value chains from black liquor to different products. Overall, it is anticipated that this effort will inspire further work for developing and using kraft lignin as a commodity raw material for new applications undeniably promoting pivotal global sustainability concerns.

A new look at the kinetics of oxygen delignification of softwood kraft pulp

Abstract Using a Berty-type CSTR reactor, Ji (2007. Kinetics and mechanism of oxygen delignification, Ph.D. thesis. The University of Maine) obtained oxygen delignification kinetics first order in lignin when neglecting the higher initial delignification phase. In the present study the same Berty/CSTR reactor with an improved temperature control was used to determine the oxygen delignification kinetics of Southern Pine kraft pulp, with the kinetics now corrected for lignin removed by oxygen-free alkaline leaching. This removes the initial high delignification rate peak so that the kinetics over the entire lignin range can be modelled as first order in “reactive” lignin, which is lignin corrected for a small amount of unreactive lignin. It suggests that softwood pulp oxygen delignification consists of two contributions; phenolic delignification and alkaline leaching. The initial alkaline leaching phase is mathematically described by semi-infinite alkaline diffusion of dissolved lignin trapped in the cell wall after pulp washing. For phenolic delignification, the reaction orders in alkali concentration and oxygen of the power law delignification equation are 0.3 and 0.44 respectively, while the activation energy is 63 kJ/mol. Taking into account the unreactive HexA, the small amount of unreactive lignin, and the lignin removed by alkaline leaching, the kappa number is well predicted by the new delignification kinetics.

Deciphering the Influence of Anionic Electrons of Surface-Functionalized Two-Dimensional Electrides in Lithium-Sulfur Batteries.

Using transition metal compounds as sulfur hosts is regarded as a promising approach to suppress the polysulfide shuttle and accelerate redox kinetics for lithium-sulfur (Li-S) batteries. Herein, we report that a new kind of compound, electrides (exotic ionic crystalline materials in which electrons serve as anions), is efficient sulfur hosts for Li-S batteries for the first time. Based on the first-principles calculations, we found that two-dimensional (2D) electrides M2C (M = Sc, Y) exhibit unprecedentedly strong binding strength toward sulfur species and surface functionalization is necessary to passivate their activity. The 2D electrides modified with the F-functional group exhibit the best performance in terms of the adsorption energy and sulfur reduction process. A comparative study with a nonelectride reveals that the anionic electrons (AEs) of electrides aid in anchoring the soluble polysulfides. These results open an avenue for the application of electrides in Li-S batteries.

Optimizing the separation of xylose/xylan from eucalyptus woodchips in the autohydrolysis process

AbstractEffective separation of various components in biomass is critical for biorefinery. Autohydrolysis is a commercialized unit operation to remove hemicelluloses, such as xylan, in producing high‐quality cellulose (the so‐called dissolving pulp) in the pre‐hydrolysis kraft process. In the present study, the autohydrolysis of eucalyptus woodchips was investigated for the purpose of producing dissolving pulps, with a focus on the production of cellulose acetate grade dissolving pulp. First, the effects of liquid‐to‐solid ratio, maximum temperature, and time on hemicelluloses removal were comprehensively studied, and the total xylose saccharides concentration and total xylose saccharides yield were determined as a function of the P factor and log(Ro). The three‐variable Box–Behnken design of the response surface methodology was followed to optimize the autohydrolysis conditions, aiming to achieving the maximum removal of xylan. The as‐obtained optimal conditions were: liquid‐to‐solid ratio of 5.5 mL · g−1, maximum temperature of 165°C, and time of 120 min, with its P factor of 867 h and log(Ro) of 4.03. Under these conditions, the total xylose saccharides concentration was 16.43 g · L−1. Furthermore, the autohydrolysis yield was investigated. The results showed that the purity of as‐prepared cellulose substrate as a result of autohydrolysis at a P factor of 867 h (log(Ro) of 4.03) can meet the stringent requirement of cellulose acetate grade dissolving pulp. Furthermore, the pre‐hydrolysis liquor compositions were compared between the typical autohydrolysis conditions for rayon grade dissolving pulp (a P factor of 690 h and log(Ro) of 3.91) and the optimal conditions (a P factor of 867 h and log(Ro) of 4.03).

Electrochemical Hydrogen Sulfide Decomposition Using Proton Conducting Ceramic for Pure Hydrogen Production

Hydrogen sulfide (H2S) is a substance that occurs during the process of processing sulfur, which is abundant in fossil fuels such as oil and natural gas, into high-quality fuel. Due to its high toxicity, it is classified as harmful industrial waste and removal in the process of discharging is essential. Until now, refiners have used the Claus process and the Wet Sulfuric Acid (WSA) process, which reacts hydrogen sulfide with oxygen to release it in the form of water or sulfuric acid. These processes require a huge amount of heat energy and only aim to remove hydrogen sulfide, so they emit hydrogen atoms contained in hydrogen sulfide in the form of water and sulfuric acid. Because hydrogen is an eco-friendly energy source that has recently been in the spotlight, hydrogen sulfide can be a valuable resource if hydrogen can be extracted from hydrogen sulfide. In this study, an electrochemical process that decomposes hydrogen sulfide and obtains hydrogen from hydrogen sulfide, replacing the conventional hydrogen sulfide removal process was proposed. To achieve this goal, thermodynamics of this reaction was analyzed and a solid oxide electrochemical cell based on proton conducting ceramic was fabricated for operating at high temperature and using perovskite structured electrodes. Experiments were then conducted to decompose hydrogen sulfide using fabricated cells and found that about 40 ppm, 100 sccm of hydrogen sulfide was decomposed at 600 oC by applying 0.5 V, 0.57 mA/cm2. Through this, the feasibility of the process was confirmed, and the durability test and regeneration process of the anode electrode were proceeded to solve degradation caused by sulfur deposits. In this study, a process has been proposed to effectively produce hydrogen of high value as an energy source, as well as to remove industrial waste hydrogen sulfide. It is expected that waste disposal and energy source production can be simultaneously produced in a clean and efficient way if cell performance improvement, removal of sulfur poison, and large systemization are applied to oil refiners' processes.

Microbial communities related to the sulfur cycle in the Sansha Yongle Blue Hole.

The Sansha Yongle Blue Hole (SYBH), the deepest blue hole in the world, is an excellent habitat for revealing biogeochemical cycles in the anaerobic environment. However, how sulfur cycling is mediated by microorganisms in the SYBH hasn't been fully understood. In this study, the water layers of the SYBH were divided into oxic zone, hypoxic zone, anoxic zone I and II, and microbial-mediated sulfur cycling in the SYBH was comprehensively interpreted. The 16S rRNA genes/transcripts analyses showed that the microbial community structures associated with the sulfur cycling in each zone had distinctive features. Sulfur-oxidizing bacteria were mostly constituted by Gammaproteobacteria, Alphaproteobacteria, Campylobacterota, and Chlorobia above the anoxic zone I and sulfate-reducing bacteria were dominated by Desulfobacterota in anoxic zones. Metagenomic analyses showed that the sulfide-oxidation-related gene sqr and genes encoding the Sox system were mainly distributed in the anoxic zone I, while genes related to dissimilatory sulfate reduction and sulfur intermediate metabolite reduction were mainly distributed in the anoxic zone II, indicating different sulfur metabolic processes between these two zones. Moreover, sulfur-metabolism-related genes were identified in 81 metagenome-assembled genomes (MAGs), indicating a high diversity of microbial communities involved in sulfur cycling. Among them, three MAGs from the candidate phyla JdFR-76 and AABM5-125-24 with genes related to dissimilatory sulfate reduction exhibited distinctive metabolic features. Our results showed unique and novel microbial populations in the SYBH sulfur cycle correlated to the sharp redox gradients, revealing complex biogeochemical processes in this extreme environment. IMPORTANCE Oxygen-deficient regions in the global ocean are expanding rapidly and affect the growth, reproduction and ecological processes of marine organisms. The anaerobic water body of about 150 m in the Sansha Yongle Blue Hole (SYBH) provided a suitable environment to study the specific microbial metabolism in anaerobic seawater. Here, we found that the vertical distributions of the total and active communities of sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) were different in each water layer of the SYBH according to the dissolved oxygen content. Genes related to sulfur metabolism also showed distinct stratification characteristics. Furthermore, we have obtained diverse metagenome-assembled genomes, some of which exhibit special sulfur metabolic characteristics, especially candidate phyla JdFR-76 and AABM5-125-24 were identified as potential novel SRB. The results of this study will promote further understanding of the sulfur cycle in extreme environments, as well as the environmental adaptability of microorganisms in blue holes.

Sulfation of agarose with ammonium sulfamate: A combined experimental and theoretical study

Agarose sulfates are bioactive modified polysaccharides important for application. To obtain the bioactive agarose derivatives and expand the range of their potential use, the modification with some functional groups is needed. Agarose sulfates exhibit the anticoagulant, hypolipidemic, and other-type bioactivity. In this study, different methods for preparation of agarose sulfates using nontoxic ammonium sulfamate are investigated. Several activators and catalysts of the process of sulfation with ammonium sulfamate are examined. It is shown that urea does not significantly activate ammonium sulfamate in the sulfation reaction, while potassium permanganate ensures a sulfur content of up to 13.2 wt% in the synthesized agarose sulfate. When Lewis acids (titanium and aluminum oxides) are used, the sulfur content in agarose sulfates can only reach 7.3 wt%. The catalysts with the Brønsted acid sites used in the synthesis of sulfated agarose can provide sulfur contents of up to 14.6 wt% in it. The incorporation of a sulfate group into the agarose molecule has been confirmed by elemental analysis and Fourier-transform infrared spectroscopy: the absorption bands at 1249 cm‒1 have been observed in the spectra. The X-ray diffraction and atomic force microscopy studies have revealed no ammonium sulfamate inclusions. According to the X-ray diffraction patterns, sulfation of agarose enhances its X-ray amorphism. It has been established from the atomic force microscopy images that the incorporation of a sulfate group into the agarose molecule changes the size of particles on the film surface from 42 to 80 nm. The theoretical examination of initial and sulfated agarose has been carried out within the density functional theory. The molecular geometry, vibration assignments, HOMO‒LUMO, molecular electrostatic potential maps, and electronic properties of the substances have been established by the quantum-chemical calculations in the framework of the density functional theory.

Microcrystalline cellulose and by-products from the pulp and paper industry as reinforcing fibres for polybutylene succinate-based composites: A comparative study

This study focussed on the development of fully biodegradable composites based on polybutylene succinate (PBS) in combination with raw materials from different processing stages of the pulp and paper industry. Sulfite pulp (SP), kraft pulp (KP) and screened sludge residue (SL) from wastewater treatment plants (WWTP) were investigated as reinforcing fibres contributing to a circular economy. We report a comparative study of the physicochemical properties and mechanical performance of PBS composites reinforced with these cellulosic raw fibres and commercial pure microcrystalline cellulose (MC). The composites were characterised in tensile strength, elongation at break, modulus of elasticity, water absorption and wettability. The incorporation of the fibres into the polymer matrix was also investigated using torque rheometry. Critical concentrations were obtained with maximum incorporation in the range of 15–20 wt% for SP/KP and 25–30 wt% for SL. SP and KP composites showed at least as good physicochemical and mechanical properties as MC at the concentrations studied (0–20 wt%). SP-composites showed the highest tensile strength and modulus of elasticity. It was shown that these fibres from the pulp and paper industry can be used as reinforcement for PBS matrices without additional chemical purification and provide a valuable alternative to commercial microcrystalline cellulose.

Prussian Blue Analogues Derived Heterostructured CoS2/FeS2 Particles Anchored on Carbon Nanosheets as Anodes for Boosted Sodium Storage Properties

AbstractPyrite FeS2 has emerged as promising anode material for sodium‐ion batteries (SIBs). Nevertheless, low electrical conductivity, large volume variation and shuttling effect generally lead to low specific capacity and inferior rate capability, greatly impeding its practical application. Here, heterostructured CoS2/FeS2 particles anchored on ultrathin carbon nanosheets (denoted as CoS2/FeS2/C) have been fabricated using a simple and facile co‐precipitation combined with carbonization and gas sulfurization processes. The combination of bifunctional N‐doped carbon nanosheets and unique heterostructure can provide better electrical conductivity, enhanced ion diffusion kinetics and offer reinforced structural integrity. Benefitting from the compositional and structural advantages, the as‐prepared CoS2/FeS2/C hybrid composite exhibits boosted sodium storage properties, including outstanding rate capability (500.4 mA h g−1 at 5 A g−1) and cycling stability with a retention of 95.8 % after 700 cycles.

Performance improvement of the liquid-fed SO2-depolarized electrolyzers for anolyte with high H2SO4 concentration

As the hydrogen producing step of the hybrid sulfur process, SO2-depolarized electrolysis (SDE) needs to be operated with anolyte of high H2SO4 concentration, aiming at the high hydrogen production efficiency. However, the SDE cell is facing the challenge of rising impedance when anolyte H2SO4 concentration is increased. In this study, the performance of liquid-fed SDE cells is improved by using a thinner PEM and three-dimensional anode, especially for the anolyte with high H2SO4 concentration. The underlying mechanism of the SDE performance improvement is also discussed. The results show that effectively reducing the concentration polarization impedance is the key to improving the SDE performance. Significantly different from what is expected, PEM thickness reduction could not sharply decrease ohmic impedance. Instead, the application of thin PEMs can significantly reduce the concentration polarization impedance of the cathode reaction. As for the application of three-dimensional anode, it decreases anode concentration polarization dramatically. Finally, the combination of PEM thickness reduction and three-dimensional anode greatly improves the SDE performance of the electrolyzer. The influence of operating conditions on performance is studied for the optimized cell GF-212. When the anolyte H2SO4 concentration set at 50 wt%, the current density could reach 560 mA/cm2 at 1.0 V cell voltage, 360 mL/min anolyte flow rate and 80 °C.

Simultaneous phosphorization and sulfuration to Synergistically promote the supercapacitor performance of heterogeneous (CoxNi1-x)2P/CoxNi1-xS hydrangea-like microspheres

How to effectively improve supercapacitors performances through electrode materials design is still an urgent task. Herein, a facile precursor strategy combining solvothermal synthesis and upstream gas method is proposed to regulate the structure and composition of the supercapacitor electrode material through doping and compositing. The precursors, CoxNi1-x microspheres, are synthesized through a facile solvothermal reaction with nickel/cobalt acetate in methanol without addition of any surfactants or templates, achieving the integration of cobalt and nickel species into a single structure. A subsequent simultaneous phosphorization and sulfuration process through an upstream gas method makes the CoxNi1-x precursor microspheres transform to heterogeneous (CoxNi1-x)2P/CoxNi1-xS microspheres in one step. The resulted (CoxNi1-x)2P/CoxNi1-xS microspheres show great enhanced supercapacitor performances with a high specific capacitance (1561 F g−1 at 1 A g−1 current density) and excellent cycling stability (a 89.7% capacitance retention after 5000 cycles at 10 A g−1) due to synergistic effects resulted from the coexistence of multiple elements, as well as the unique interface and structure caused by in-situ two-phase compositing, which can accelerate charge transfer and increase available active sites. Our study proves that simultaneous phosphorization and sulfuration is an effective means to adjust the microstructure of the electrode materials and thus promote their electrochemical performances.

Assessing the Genotoxicity of Cellulose Nanomaterials in a Co-Culture of Human Lung Epithelial Cells and Monocyte-Derived Macrophages.

Cellulose micro/nanomaterials (CMNMs) are innovative materials with a wide spectrum of industrial and biomedical applications. Although cellulose has been recognized as a safe material, the unique properties of its nanosized forms have raised concerns about their safety for human health. Genotoxicity is an endpoint that must be assessed to ensure that no carcinogenic risks are associated with exposure to nanomaterials. In this study, we evaluated the genotoxicity of two types of cellulose micro/nanofibrils (CMF and CNF) and one sample of cellulose nanocrystals (CNC), obtained from industrial bleached Eucalyptus globulus kraft pulp. For that, we exposed co-cultures of human alveolar epithelial A549 cells and THP-1 monocyte-derived macrophages to a concentration range of each CMNM and used the micronucleus (MN) and comet assays. Our results showed that only the lowest concentrations of the CMF sample were able to induce DNA strand breaks (FPG-comet assay). However, none of the three CMNMs produced significant chromosomal alterations (MN assay). These findings, together with results from previous in vitro studies using monocultures of A549 cells, indicate that the tested CNF and CNC are not genotoxic under the conditions tested, while the CMF display a low genotoxic potential.