Search

• This work presents a simple and efficient strategy for optimizing lignin structure. • Lignin with different chemical structures can be prepared effectively by solvent fractionation. • This work has developed high-quality lignin-based materials for the supercapacitors, sensors and moist-electric generators. It is a challenge to develop simple and efficient methods to optimize the lignin structure for preparing high-performance lignin-based carbon nanofibers (CFs). Herein, a novel and effective strategy for preparing high-performance lignin-based CFs is designed. Lignin samples with different chemical structures are prepared by polymerization modification and fractionation. This strategy completely gets over the dependence on petroleum-based polymers in the electrospinning process, and makes the lignin-based CFs show good performance in energy storage, temperature sensor, and moisture power generators. The specific capacitance and energy density of lignin-based supercapacitors reach 357.2 F/g and 31.5 Wh/kg, respectively. The CFs exhibit good flame retardancy and thermal sensitivity (about 1 s). In addition, moisture power generators assembled with CFs exhibit great potential. The output voltage of moisture power generators has a linear relationship with the number of devices. With the increase of series equipment, the output voltage of 5 series connected moisture power generators reaches 4.7 V. This work provides a new approach to prepare high-performance lignin-based CFs, which has a good application prospect in the fields of energy storage, sensor and power generation. [ABSTRACT FROM AUTHOR]

Developing a simple and effective method for optimizing lignin structure is a key challenge for the application of biomass-based carbon nanofibers in energy storage and moisture-enabled electricity generation fields. In this work, an effective strategy is designed to prepare novel biomass-based carbon nanofibers. Carbon quantum dots (CQDs) are introduced as functional components into biomass-based carbon nanofibers to optimize the inherent structural defects of lignin. The introduction of CQDs effectively reduces the interaction between lignin macromolecules, thereby increasing the flexibility of lignin macromolecule chain segments. The obtained biomass-based carbon nanofibers exhibit excellent microfiber morphologies and a high degree of graphitization. The specific capacitance and energy density for biomass-based carbon nanofibers as the energy storage device reach 294.4 F/g and 28.3 W h/kg, respectively. Furthermore, the biomass-based moist-electric generator shows high power generation efficiency, the output voltage and output current of a single device reach 0.75 V and 1.8 μA, respectively. Notably, as the number of biomass-based moist-electric generators in series or parallel increases, the overall output efficiency of the device system has a linear relationship, which means that a sufficient number of biomass-based moist-electric generator devices can meet the power supply requirements of larger power systems. This work puts forward a promising strategy to prepare low-consumption, high-performance, and environmentally friendly biomass-based carbon nanofibers for the supercapacitors and moist-electric generators. [Display omitted] • The introduction of CQDs optimize the inherent structural defects of lignin. • CQDs improve the fiber morphology and graphitization degree of carbon nanofibers. • Biomass-based carbon nanofibers exhibit excellent electrochemical performance. • Biomass-based carbon nanofibers can be used for a novel moist-electric generator. • The preparation of novel biomass-based carbon nanofibers was proposed. [ABSTRACT FROM AUTHOR]

With the development of renewable energy technologies, the demand for efficient energy storage systems is growing. Supercapacitors have attracted considerable attention as efficient electrical energy storage devices because of their excellent power density, fast charging and discharging capabilities, and long cycle life. Carbon nanofibers are widely used as electrode materials in supercapacitors because of their excellent mechanical properties, electrical conductivity, and light weight. Although environmental factors are increasingly driving the application of circular economy concepts in materials science, lignin is an underutilized but promising environmentally benign electrode material for supercapacitors. Lignin-based carbon nanofibers are ideal for preparing high-performance supercapacitor electrode materials owing to their unique chemical stability, abundance, and environmental friendliness. Electrospinning is a well-known technique for producing large quantities of uniform lignin-based nanofibers, and is the simplest method for the large-scale production of lignin-based carbon nanofibers with specific diameters. This paper reviews the latest research progress in the preparation of lignin-based carbon nanofibers using the electrospinning technology, discusses the prospects of their application in supercapacitors, and analyzes the current challenges and future development directions. This is expected to have an enlightening effect on subsequent research. [Display omitted] [ABSTRACT FROM AUTHOR]

Synchronous meteorological data from 9688 cases of patients in the Second People's Hospital of HeFei in AnHui province, China, who suffered from hypertension, cerebrovascular disease, cardiopathy, upper respiratory tract infection, and chronic bronchitis, were analyzed. The results show that there are five kinds of weather processes that greatly affect these diseases. This study provides evidence of the importance of enhancing the people's knowledge of preventing disease and improving the medical– weather service. [ABSTRACT FROM AUTHOR]

• We first put forward the concept: a precursor fiber is a tree. It not only has good thermal stability of lignin, but also has flexibility of cellulose. • With the introduction of covalent-bond connection, the precursor fibers exhibit a large molecular weight, uniform molecular weight distribution, excellent thermal stability, and good spinnability. • The properties of resulting pure biomass-based carbon fibers are effectively improved by controlling the formation of covalent-bonds between lignin and cellulose-acetate. • The resulting pure biomass-based carbon fibers show independent filamentous morphology, uniform diameter, large surface area, excellent mechanical property and power storage capacity. • This work is a very valuable reference to the preparation of renewable and low-cost controllable fiber supercapacitor. The morphological collapse of pure biomass-based carbon nanofibers (CNFs) is due to the poor thermal stability of cellulose. Inspired by nature, cellulose and lignin are linked by covalent-bonds in trees made wood extensible and stable. In this work, an effective strategy was presented to mimic this biological structure for the preparation of biomass-based CNFs. Epichlorohydrin (ECH) is used to form the covalent-bonds between lignin and cellulose-acetate (CA) for a novel precursor material. With the introduction of covalent-bonds, precursor materials not only exhibit the spinnability of cellulose, but also possess the thermal stability of lignin. After carbonization, the pure biomass-based CNFs are successfully prepared and exhibit independent filamentous morphology, uniform diameter, large surface area, and power storage capacity. The specific capacitance of 320.3 F/g is obtained by using the CNFs-6 (prepared with 10 % ECH content) as super-capacitor. Simultaneously, the biomass-based CNFs super-capacitor device delivers a high energy density of 30.2 Wh/ kg at the power density of 400 W/kg. These results indicate that the introduction of covalent-bonds can effectively increase the energy storage properties significantly. This novel strategy showed a successful route for the preparation of high quality and low cost biomass-based CNFs. [ABSTRACT FROM AUTHOR]

The hydrophobic TiO2/lignin based carbon nanofibers (TiO2@CFs) composite with high photocatalytic efficiency and excellent cycle performance is successfully prepared by the method of electrospinning and thermo-treatment. The results of FTIR, SEM and EDS analyses show that the TiO2 nano-particles are uniformly and firmly coated on the surface of CFs. Due to good hydrophobicity and high electrical conductivity of CFs, such unique properties endow TiO2@CFs composites with enhanced light energy utilization efficiency and photocatalytic efficiency because of their floatability on the solution, high adsorptive capacity of MB, and low recombination of photo-generated electrons and holes. Compared with the commercial TiO2 powder, the degradation rate toward MB of TiO2@CFs is improved about 2.62 and 3.02 times at 30 and 15 min, respectively, under static state and xenon lamp irradiation. The degradation rate of TiO2@CFs toward MB reaches 62.77% within 15 min under static state, and further increase to 87.28% after 30 min. In addition, the removal rate of MB can be obtained up to 91.5% even after four cycles at a stirring speed of 200 RPM. Therefore, these unique material structures make it become a promising photocatalytic material. [ABSTRACT FROM AUTHOR]

Lignin is a low-cost and sustainable alternative precursor for manufacturing carbon fibers (CFs). However, the properties of lignin-based CFs are inferior due to the heterogeneity and complex three-dimensional structure of lignin. In this work, a facile stepwise fractionation extraction method is devised to extract lignin. This stepwise fractionation extraction method effectively removes the small molecular branching structure of lignin, thus obtaining fractionated lignin with a high molecular weight, narrow polydispersity index, and linear structure. Based on the results of XRD and Raman spectroscopy, the high molecular weight, narrow polydispersity index, and linear structure are conducive to improving the graphitization degree of CFs. Compared with the lignin-based CFs from original lignin, the tensile strength and Young's modulus of the lignin-based CFs from the fractionated lignin increase significantly, extraordinarily approaching those of PAN-based CFs. This facile stepwise fractionation extraction method for lignin is promising for the industrial production of high performance lignin-based CFs. [ABSTRACT FROM AUTHOR]

CO 2 is the main pollutant in biogas, reducing its calorific value. Among various technological methods to eliminate carbon dioxide from biogas, membrane separation technology stands out for large-scale industrial biogas purification due to its advantages. The selection of membrane material and preparation process are key factors in membrane separation technology. In this study, a premixing process was initially used to blend different masses of packed molecular sieves TS-1 (or ZSM-5) and cellulose derivatives (ethyl cellulose, cellulose acetate) separately. These mixtures were then coated onto porous PVDF substrates using a coating process to create various bilayer hybrid composite membranes. Among these, PVDF/EC-ZSM-5 (containing 15 % ZSM-5) bilayer hybrid composite membrane is the most fitting. For CO 2 /CH 4 gas mixtures, the gas selectivity of this membrane surpassed Robeson's 1991 standard line (the CO 2 permeability was 597.48 Barrer, and the CO 2 /CH 4 selectivity was 9.14). Overall, this composite membrane, made for the first time from PVDF, ZSM-5, and EC, is expected to be a promising CO 2 selective separation membrane material for biogas purification in large-scale industrial processes due to its simple production process. [Display omitted] [ABSTRACT FROM AUTHOR]

• A biomass porous carbon material was synthesized using rape pollen as the precursor. • The K-RPC demonstrates exceptional iodine capture performance. • A maximum adsorption capacity of 3842 mg/g for iodine vapor. • A superior iodine removal efficiency from cyclohexane solution, reaching 411 mg/g. • Potential future applications of raape pollen will enhance the utilization. The efficient adsorption and storage of radioactive iodine from uranium fission reactions is essential for safe nuclear energy. Bio-based adsorption materials have gained significant attention in the field of radioactive contaminants removal. This is primarily due to their numerous advantages, including a wide range of raw material sources, low cost, ease of preparation, low toxicity, high removal efficiency and stable storage. In this study, rape pollen was chosen as sources of biomass porous carbon, which possesses a micron-sized ellipsoidal shape, homogeneous size, porous structure with sparsely linked network inside, and high carbon content. A biomass derived porous carbon (K-RPC) was synthesized by pretreatment, heat treatment, and advanced treatment techniques. The results indicate that the K-RPC exhibited a hierarchical porous structure with homogeneous and wormhole-like micro- or nanopores, and high specific surface area. The K-RPC demonstrates exceptional iodine capture performance, the capacity surpasses that of most bio-based adsorbents. Remarkably, the maximum adsorption capacity of iodine vapor is approximately fifteen times higher than that of commercial silver exchanged zeolite. The adsorption mechanism, primarily characterized by chemisorption. This study is the first attempt to apply pollen in the field of iodine capture, and the biomass porous carbon extracted from rape pollen has the potential to be a cost-effective iodine adsorption material. [ABSTRACT FROM AUTHOR]

Biomass is regarded as a carbonaceous solid renewable resource with significant potential. Extensive research has been conducted to explore its application as a sustainable raw material for the development of advanced carbon materials. Natural rape pollen is an abundant and renewable biomass material that possesses distinctive characteristics such as spherical porosity, large pore size, high specific surface area, and a hollow structure. These unique properties have garnered significant attention due to the material's high yield, low cost, and environmentally friendly nature. Rape pollen has gained significant attention as a biotemplate for the synthesis of functional materials with controllable micro/nanostructures, owing to its well-developed porosity and specific open hierarchical scaffolds. This paper presents a comprehensive review on the utilization of rape pollen for the synthesis of porous carbon materials, which have found significant applications in catalysts, supercapacitors, separation, and adsorbent materials. The study explores the recent advancements in the preparation of rape pollen-based porous carbon materials and provides an in-depth analysis of their facilitating roles and reaction mechanisms in various applications. Finally, the potential future applications of rape pollen in various industries are anticipated to enhance the utilization of these valuable biomass resources. [Display omitted] • Natural rape pollen is an abundant and renewable carbon material. • Rape pollen possesses distinctive characteristics. • The synthesis of porous carbon materials using rape pollen is reviewed. • It has applications in catalysts, supercapacitors, separation and adsorption. • Potential future applications of rape pollen will enhance the utilization. [ABSTRACT FROM AUTHOR]

In this paper, introducing stochastic dynamics into an optimal competitive Hopfield network model (OCHOM), we propose a new algorithm that permits temporary energy increases which helps the OCHOM escape from local minima. The goal of the maximum cut problem, which is an NP-complete problem, is to partition the node set of an undirected graph into two parts in order to maximize the cardinality of the set of edges cut by the partition. The problem has many important applications including the design of VLSI circuits and design of communication networks. Recently, Galán-Marín et al. proposed the OCHOM, which can guarantee convergence to a global/local minimum of the energy function, and performs better than the other competitive neural approaches. However, the OCHOM has no mechanism to escape from local minima. The proposed algorithm introduces stochastic dynamics which helps the OCHOM escape from local minima, and it is applied to the maximum cut problem. A number of instances have been simulated to verify the proposed algorithm. [ABSTRACT FROM AUTHOR]

In contrast to conventional particles characterized by isotropic surfaces, Janus particles possess anisotropic surfaces, resulting in unique physicochemical properties and functional attributes. In recent times, there has been a surge in interest regarding the synthesis of Janus particles using biological macromolecules. Various synthesis techniques have been developed for the fabrication of Janus materials derived from biomass. These methods include electrospinning, freeze-drying, secondary casting film formation, self-assembly technology, and other approaches. In the realm of Janus composite materials, those derived from biomass have found extensive applications in diverse domains including oil-water separation, sensors, photocatalysis, and medical materials. This article provides a systematic introduction to the classification of Janus materials, with a specific focus on various types of biomass-based Janus materials (mainly cellulose-based Janus materials, lignin-based Janus materials and protein-based Janus materials) and the methods used for their preparation. This work will not only deepen the understanding of biomass-based Janus materials, but also contribute to the development of new methods for designing biomass-based Janus structures to optimize biomass utilization. [Display omitted] [ABSTRACT FROM AUTHOR]

The traditional fluorinated porous material with super-hydrophobicity and super-oleophilicity is an effective strategy for oil-water separation. However, in recent years, fluorinated materials have been classified as "Emerging Environmental Pollutants" by U. S. Environmental Protection Agency because of difficult degradation and bio-accumulation. It is unacceptable to introduce new pollutants while solving environmental disasters. Therefore, it is great requirement to explore a low-cost, environmentally friendly, and renewable technique for the fabrication of novel porous materials with super-hydrophobicity and super-oleophilicity to separate oil-water mixtures. In this work, renewable beeswax, lignin, and cotton have been chosen to prepare the biomass-based porous materials with super-hydrophobicity and super-oleophilicity for oil-water separation. The mixture of beeswax and lignin is modified on the surface of cotton to obtain the biomass-based porous materials with super-hydrophobicity and super-oleophilicity. The beeswax and lignin provide low surface energy and micro/nanoscale structures, respectively. The introduction of lignin effectively improves the thermal stability of the porous materials. The apparent contact angle still remains to be above 150° after a long-time heating. The porous materials effectively separate oil-water mixtures and have good absorption effect for heavy oil (density greater than water). Moreover, the porous materials are easily recyclable after reactivation. This strategy of preparing oil-water separation materials from renewable natural polymers not only helps to clean the environment, but also helps to recover valuable oil. Unlabelled Image • All raw materials are green and renewable. • Lignin effectively improves the thermal stability of the porous materials and expand the application range of materials. • The recovery rate of porous materials for heavy oil reaches up to 93.78%. [ABSTRACT FROM AUTHOR]

In this study, a kind of non-precious glass bead catalyst was prepared by a subcritical water treatment method for the depolymerization of poplar lignin. The subcritical water treatment time significantly affected the surface morphology, surface area, and active metal content of glass bead catalysts. Flaky and fibrous morphologies were found on the glass bead surface after it was treated for 60 min and 120 min, respectively. Based on the GC-MS results of monomeric products, the glass beads treated for 60 min had higher catalytic activity as compared to those treated for 120 min. The characterization results of lignin residues suggest that the glass beads are effective to prevent the repolymerization of lignin. Furthermore, the glass bead catalysts can be recycled to catalyze the depolymerization of lignin, and the yield of the monomeric products remains above 12 wt%. [ABSTRACT FROM AUTHOR]

Graphical abstract This methodology solved the problem that original edible super-hydrophobic coating could not go through the process of high temperature sterilization, and widened the potential applications of functional food packaging. Abstract Edible super-hydrophobic coatings have attracted great attentions as they can avoid the waste of liquid foods, such as honey and milk, adhered to the inside of containers. However, the poor thermal stabilities of edible super-hydrophobic coatings restrict their applications. In this work, a thermo-resistant edible super-hydrophobic coating has been fabricated using beeswax and coffee, which are approved by U.S. Food and Drug Administration. This coating surface has the similar micro/nanoscale structure to that of the leaf surface. A variety of liquid foods can freely roll on this coating surface in spherical. This special wetting property effectively reduces the residue of liquid foods, when they are poured out of the containers. With the introduction of coffee lignin, the thermal stability and adhesive force of the coating increases significantly. The apparent contact angle of this coating can remain to be above 150° after a long-time heating and flushing. This thermo-resistant edible super-hydrophobic coating can solve the problem that original edible super-hydrophobic coating is not resistant to high temperature, and has a broad application prospect in the field of functional food packaging. [ABSTRACT FROM AUTHOR]

Abstract: Gravitational search algorithm (GSA) is the one of the newest developed nature-inspired heuristics for optimization problem. It is designed based on the Newtonian gravity and has shown excellent search abilities when applying it to optimization problems. Nevertheless, GSA still has some disadvantages such as slow convergence speed and local optima trapping problems. To alleviate these inherent drawbacks and enhance the performance of GSA, chaos, which is of ergodicity and stochasticity, is incorporated into GSA by two kinds of methods. One method uses chaos to generate chaotic sequences to substitute random sequences, while another one uses chaos to act as a local search approach. The resultant hybrid algorithms, called chaotic gravitation search algorithms (CGSA1 and CGSA2), thus reasonably have advantages of both GSA and chaos. Eight widely used benchmark numerical optimization problems are chosen from the literature as the test suit. Experimental results demonstrate that both CGSA1 and CGSA2 perform better than GSA and other five chaotic particle swarm optimization. [Copyright &y& Elsevier]

• Hydrogel dressing exhibits excellent self-healing properties and bactericidal activity. • The recovery percentage of self-healing tensile force reaches 95.6%. • After simple treatment, hydrogel dressing can be reused more than 5 times. Trees are made of cellulose, hemicellulose and lignin linked by covalent bonds and supramolecular interactions. Among them, the lignin with three-dimensional structure plays a role in supporting the structure of the tree. Inspired by the nature of the tree, we have designed and synthesized a novel lignin/poly(ionic liquids) composite hydrogel dressing with excellent mechanical strength, self-healing properties, bactericidal activity, and antioxidant activity. This self-healing hydrogel dressing is obtained by the supramolecular interactions between the lignin/poly(ionic liquids) compounds. The introduction of lignin can effectively improve the mechanical properties of the hydrogel dressing. And the bactericidal poly (ionic liquid) modified on the lignin surface through covalent bonds endows this hydrogel dressing good antibacterial activity and self-healing properties. Wound healing model of rats and histomorphological evaluation results suggest that this hydrogel dressing promotes wound healing. Furthermore, the hydrogel dressing still maintains its excellent performances after simple high-temperature disinfection, and can be reused for many times. [ABSTRACT FROM AUTHOR]

Although PVA–chitosan composite hydrogel has excellent biocompatibility and antibacterial ability, its poor mechanical strength limits its application for wound dressings. Furthermore, PVA–chitosan composite hydrogel cannot satisfy the requirements of wound dressing as an environmental conditioner to accelerate wound healing. In this work, a novel lignin–chitosan–PVA composite hydrogel was prepared as wound dressing. The introduction of lignin effectively improved the mechanical strength (tensile stress is up to 46.87 MPa), protein adsorption capacity, and wound environmental regulation ability of the hydrogel. In a murine wound model, the lignin–chitosan–PVA composite hydrogel significantly accelerated wound healing. The developed hydrogel provides new opportunities for highly efficient skin wound care and management. Unlabelled Image [ABSTRACT FROM AUTHOR]