Nanoconfined Liquid Phase Nanoextraction Based on Carbon Nanofibers.

An innovative and versatile microextraction technique based on nanoconfined solvent on carbon nanofibers has been conceived, realized, optimized, and presented here. The extraction capabilities of this technique toward polar, medium polar, and/or nonpolar substances can be easily modulated based on the nanoconfined solvent used. The so-called nanoconfined liquid phase nanoextraction showed excellent characteristics in terms of extraction recoveries, extraction time (≤1 min), reliability, and versatility. A needle-tip device has been realized on the base of this extraction process to allow direct extraction procedures and minimally invasive testing: this device guarantees a safe insertion in aqueous or soft samples, and it allows a fast and minimally invasive analyte extraction. Due to its versatility, chemical stability, and mechanical flexibility, nanoconfined liquid phase nanoextraction can be considered a powerful candidate for high-throughput analyses of biological samples.

Carbon-based photoelectrochemical sensors: recent developments and future prospects.

Owing to the considerable potential of photoelectrochemical (PEC) sensors, they have gained significant attention in the analysis of biological, environmental, and food markers. However, the limited charge mass transfer efficiency and rapid recombination of electron hole pairs have become obstacles in the development of PEC sensors. In this case, considering the unique advantages of carbon-based materials, they can be used as photosensitizers, supporting materials and conductive substrates and coupled with semiconductors to prepare composite materials, solving the above problems. In addition, there are many types of carbon materials, which can have semiconductor properties and form heterojunctions after coupling with semiconductors, effectively promoting the separation of electron hole pairs. Herein, we aimed to provide a comprehensive analysis of reports on carbon-based PEC sensors by introducing their research and application status and discussing future development trends in this field. In particular, the types and performance improvement strategies of carbon-based electrodes and the working principles of carbon-based PEC sensors are explained. Furthermore, the applications of carbon-based photoelectric sensors in environmental monitoring, biomedicine, and food detection are highlighted. Finally, the current limitations in the research on carbon-based PEC sensors are emphasized and the need to enhance the sensitivity and selectivity through material modification, structural design, improved device performance, and other strategies are emphasized.

Effect of nano-silica spheres template on CO2 capture of exchange resin-based nanoporous carbons.

In this work, a nanoporous carbon-based adsorbent with a higher specific surface area was directly prepared from polystyrene-based cation exchange resin (PCER) by carbonization of a mixture of nano-silica spheres. The silica/PCER composites were carbonized at 1173 K with different silica/PCER ratios. The effects of nano-silica spheres content on the pore structures of nanoporous carbons were investigated by N2 full isotherms. The CO2 capture capacity was measured by CO2 isothermal adsorption at 298 K and 1 bar. From the results, it was found that the nano-silica spheres/PCER ratio had a major influence on the CO2 capture capacity and the textural properties of the prepared nanoporous carbons. The specific surface area and total pore volume, as well as the pore size of the nanoporous carbons increased with increasing silica/PCER ratio.

Quantitative analysis of the current status and research trends of biochar research - A scientific bibliometric analysis based on global research achievements from 2003 to 2023.

Biochar has excellent physical and chemical properties such as porosity, high carbon content, high cation exchange capacity, and rich surface functional groups and has been widely used in environmental remediation. Over the past 20 years, although various reviews have described the application of biochar as an environmentally friendly multifunctional material in environmental remediation, no comprehensive summary and analysis of the research trends in this field exists. To promote the rapid and stable development of the field of biochar, the current state of research on biochar is clarified using the bibliometric method in this report, and potential development directions and challenges for the future are identified. All relevant biochar literature from 2003-2023 was collected from the Chinese National Knowledge Infrastructure and Web of Science Core Collection. A total of 6,119 published Chinese papers and 25,174 English papers were selected for the quantitative analysis. CiteSpace, VOSviewer, and Scimago graphics software was used to summarize the numbers of papers published over the years, as well as the countries, institutions, and authors that published the most articles. Secondly, using keyword co-occurrence and emergence analysis, the recognized research hotspots in different areas such as adsorbents, soil remediation, catalytic oxidation, supercapacitors, and "biochar-microbial" synergy were analyzed. Finally, the prospects and challenges of biochar were assessed to provide new perspectives for further promoting its development in technological, economic, environmental, and other aspects.

The mechanical, optical, and thermal properties of graphene influencing its pre-clinical use in treating neurological diseases.

Rapid progress in nanotechnology has advanced fundamental neuroscience and innovative treatment using combined diagnostic and therapeutic applications. The atomic scale tunability of nanomaterials, which can interact with biological systems, has attracted interest in emerging multidisciplinary fields. Graphene, a two-dimensional nanocarbon, has gained increasing attention in neuroscience due to its unique honeycomb structure and functional properties. Hydrophobic planar sheets of graphene can be effectively loaded with aromatic molecules to produce a defect-free and stable dispersion. The optical and thermal properties of graphene make it suitable for biosensing and bioimaging applications. In addition, graphene and its derivatives functionalized with tailored bioactive molecules can cross the blood-brain barrier for drug delivery, substantially improving their biological property. Therefore, graphene-based materials have promising potential for possible application in neuroscience. Herein, we aimed to summarize the important properties of graphene materials required for their application in neuroscience, the interaction between graphene-based materials and various cells in the central and peripheral nervous systems, and their potential clinical applications in recording electrodes, drug delivery, treatment, and as nerve scaffolds for neurological diseases. Finally, we offer insights into the prospects and limitations to aid graphene development in neuroscience research and nanotherapeutics that can be used clinically.

Fast removal of phenolic compounds from water using hierarchical porous carbon nanofibers membrane.

Water pollution is becoming increasingly serious and seriously endangering human health, especially the direct emissions of phenolic compounds. An integrated sample pre-treatment and derivatization method based on a biopolymers/TEOS-based carbon nanofibers microextraction that allows rapid extraction (5 min), followed by separation and highly sensitive detection of phenolic compounds by gas chromatography‒mass spectrometry (GC-MS) analysis, is described. The developed methodology, coupled with GC-MS, allowed low detection limits (0.03-0.32 ng mL‒1), good linearities (0.5-200 ng mL‒1) and recoveries (73.58-85.76%) to be achieved in a few steps and short time. Based on the high adsorption properties of materials, the on-line removal device of phenolic compounds in water was designed. The elimination rate of phenolic compounds in water was higher than 73.58% at 1 mL min‒1 and three cycles. The elimination strategy for the phenolic compounds is very versatile and is easy to apply.

Improvement of the electrical conductivity of carbon fibers through the growth of carbon nanofibers.

In this work, carbon nanofibers (CNFs) were synthesized on carbon fiber (CF) surfaces precoated with metal-doped mesoporous silica films. Fe, Ni, and Co were doped in the mesoporous silica films and played the role of catalysts for the decomposition of acetylene to grow CNFs on the CF surfaces. The chemical composition and surface structure of CFs before and after the growth of the CNFs were investigated by EDX, N2 full isotherms, and SEM. The electrical property of the CFs was investigated using a four-probe volume resistivity tester. The SEM results indicated that the CNFs with diameters of 20-100 nm grew uniformly and densely on the CF surfaces. The diameter and length distributions of the CNFs were found to be dependent on the metal that was doped in the mesoporous silica films. The electrical properties of the CFs were enhanced after the CNFs' growth on the CF surfaces, and the CNFs grown over the Ni catalyst with the narrowest diameter distribution gave the lowest volume resistivity to the CFs.

Polyamide/Chitosan/Tetraethyl Orthosilicate Electrospun Nanofibers for a Novel and Promising Drug Carrier.

Chitosan (CS), the only alkaline polysaccharose available in nature, has always been a promising candidate for drug delivery owing to its excellent biodegradability and biocompatibility. However, inherent solubility and polycationic properties of CS largely hinder electrospinning, which is an efficient method of fabricating nanofibers for drug carriers. To solve this problem and extend the applications of CS, polyamide/chitosan/tetraethyl orthosilicate (PA/CS/TEOS) composite nanofibers were successfully prepared as drug carriers in this study via electrospinning. The PA/CS/TEOS ratios significantly influenced the nanofiber morphology. As the content of each was increased, the beads among the membranes increased initially and then decreased, determined by scanning electron microscopy (SEM). The morphology of the optimum membranes with the ratio of 1:0.13:0.67 was smoother with less beads and uniform fiber diameter. Finally, the membranes with optimum ratios were used as carriers of ofloxacin in the study of drug release performance to identify their future feasibility, which revealed an initial fast release followed by a relatively stable release.

Carbon Nanofibers-Based Nanoconfined Liquid Phase Filtration for the Rapid Removal of Chlorinated Pesticides from Ginseng Extracts.

A rapid nanoconfined liquid phase filtration system (NLPF) based on solvent-confined carbon nanofibers/carbon fiber materials (CNFs/CFs) was proposed to effectively remove chlorinated pesticides from ginsenosides-containing ginseng extracts. A series of major parameters that may affect the separation performance of the CNFs-NLPF method were extensively investigated, including the water solubility of nanoconfined solvents, filtration rate, ethanol content of the ginseng extracts, and reusability of the material for repeated adsorption. The developed method showed a high removal efficiency of pesticides (85.5-97.5%), high retainment rate of ginsenosides (95.4-98.9%), and consistent reproducibility (RSD < 11.8%). Furthermore, the feasibility of the CNFs-NLPF technique to be scaled-up for industrial application was systematically explored by analyzing large-volume ginseng extract (1 L), which also verified its excellent modifiable characteristic. This filtration method exhibits promising potential as a practical tool for removing pesticide residues and other organic pollutants in food samples to assure food quality and safeguard human health.

A review: recent advances in preparations and applications of heteroatom-doped carbon quantum dots.

Carbon quantum dots (CQDs) are widely used in optoelectronic catalysis, biological imaging, and ion probes owing to their low toxicity, stable photoluminescence, and ease of chemical modification. However, the low fluorescence yield and monochromatic fluorescence of CQDs limit their practical applications. This review summarizes the commonly used approaches for improving the fluorescence efficiency of CQDs doped with non-metallic (heteroatom) elements. Herein, three types of heteroatom-doped CQDs have been investigated: (1) CQDs doped with a single heteroatom; (2) CQDs doped with two heteroatoms; and (3) CQDs doped with three heteroatoms. The limitations and future perspectives of doped CQDs from the viewpoint of producing CQDs for specific applications, especially for bioimaging and light emitting diodes, have also been discussed herein.

Recent developments and emerging trends of mass spectrometric methods in plant hormone analysis: a review.

Plant hormones are naturally occurring small molecule compounds which are present at trace amounts in plant. They play a pivotal role in the regulation of plant growth. The biological activity of plant hormones depends on their concentrations in the plant, thus, accurate determination of plant hormone is paramount. However, the complex plant matrix, wide polarity range and low concentration of plant hormones are the main hindrances to effective analyses of plant hormone even when state-of-the-art analytical techniques are employed. These factors substantially influence the accuracy of analytical results. So far, significant progress has been realized in the analysis of plant hormones, particularly in sample pretreatment techniques and mass spectrometric methods. This review describes the classic extraction and modern microextraction techniques used to analyze plant hormone. Advancements in solid phase microextraction (SPME) methods have been driven by the ever-increasing requirement for dynamic and in vivo identification of the spatial distribution of plant hormones in real-life plant samples, which would contribute greatly to the burgeoning field of plant hormone investigation. In this review, we describe advances in various aspects of mass spectrometry methods. Many fragmentation patterns are analyzed to provide the theoretical basis for the establishment of a mass spectral database for the analysis of plant hormones. We hope to provide a technical guide for further discovery of new plant hormones. More than 140 research studies on plant hormone published in the past decade are reviewed, with a particular emphasis on the recent advances in mass spectrometry and sample pretreatment techniques in the analysis of plant hormone. The potential progress for further research in plant hormones analysis is also highlighted.

Simultaneous determination of multiple phytohormones in tomato by ionic liquid-functionalized carbon fibers-based solid-phase microextraction coupled with liquid chromatography-mass spectrometry.

Phytohormones are interrelated by synergistic or antagonistic crosstalk and play important roles in the regulation of plant growth and development. In order to understand the interaction between phytohormones in the plant physiological network, it is necessary to determine trace levels of multiple phytohormones simultaneously in a complex matrix. Here, we synthesized ionic liquids containing different functional groups and modified the surface of carbon fibers with them. Based on these carbon fibers-ionic liquid (CFs-IL) materials, a solid phase microextraction method was developed to enable the simultaneous extraction of phytohormones. The adsorption specificity of multiple phytohormones was studied by identifying the hydrophobic, electrostatic, and π-π interactions, as well as hydrogen bonds, which favor simultaneous extraction of the relevant acidic, alkaline and neutral phytohormones by improving compatibility. The proposed method, coupled with liquid chromatography-tandem mass spectrometry, was applied to the simultaneous determination of 13 acidic, alkaline and neutral phytohormones in tomato. The limits of quantification were found to be in the range of 0.32-54.05 ng mL-1 and 4.6-185.8 pg mL-1, respectively, when measured by QQQ and Q-TOF. All of the relative recoveries were in the range of 94.40-113.37% with RSDs ≤15.36% (n = 3) for spiked tomato samples. This method is expected to be widely applied to multiple phytohormones analysis for in-depth researches concerning the physiological networks of plants.

Fast on-fiber derivatization and GC/MS analysis of phytohormones in wheat based on pencil-type coated carbon fibers.

New coated carbon fibers (CCFs) have been synthesized, characterized and used as solid phase microextraction (SPME) matrix for the analysis of phytohormones (jasmonic acid, indole-3-acetic acid, and abscisic acid) in wheat samples. The SPME device, realized inserting CCFs in a pencil-type device, when coupled with gas chromatography-mass spectrometry, provides in few steps high recovery values (79-112%), fast on-fiber derivatization (30 s), good method reproducibility (RSD < 20%), low detection limits (0.5-2.1 ng g-1). The pencil-type CCFs-SPME device was successfully employed for the determination of phytohormone in wheat samples, allowing simple and quick extraction/derivatization/injection processes. The proposed device can be then considered as a promising and functional tool for fast and reliable extraction and preconcentration of analytes from real samples, allowing a simple derivatization procedure and direct injection in the chromatographic instrumentation.

The complete chloroplast genome of Melilotus albus: an important source of forage species.

Melilotus albus belongs to the legume family. It is known as the greatest potential forage crop and native to Eurasia and North Africa. The nitrogen fixation rate of Melilotus albus is superior to other legumes, making it beneficial for crop rotations. Melilotus albus has also been a species with good forage productivity and is more and more important in the medicinal value of its high coumarin content. In this study, the complete chloroplast genome of Melilotus albus was assembled and analysed. The complete chloroplast genome of Melilotus albus was 127,205 bp in length. It harbours 108 functional genes, including 76 protein-coding genes, 28 transfer RNA, and four ribosomal RNA genes species. The overall nucleotide composition was: 33.3% A, 33.1% T, 16.3% C, and 17.3% G, with a total A + T rich content of 66.4%. Phylogenetic relationship analysis showed that Melilotus albus has closely related to Medicago.

Glucose/Graphene-Based Aerogels for Gas Adsorption and Electric Double Layer Capacitors.

In this study, three-dimensional glucose/graphene-based aerogels (G/GAs) were synthesized using the hydrothermal reduction and CO2 activation method. Graphene oxide (GO) was used as a matrix, and glucose was used as a binder for the orientation of the GO morphology in an aqueous media. We determined that G/GAs exhibited narrow mesopore size distribution, a high surface area (763 m² g-1), and hierarchical macroporous and mesoporous structures. These features contributed to G/GAs being promising adsorbents for the removal of CO2 (76.5 mg g-1 at 298 K), CH4 (16.8 mg g-1 at 298 K), and H2 (12.1 mg g-1 at 77 K). G/GAs presented excellent electrochemical performance, featuring a high specific capacitance of 305.5 F g-1 at 1 A g-1, and good cyclic stability of 98.5% retention after 10,000 consecutive charge-discharge cycles at 10 A g-1. This study provided an efficient approach for preparing graphene aerogels exhibiting hierarchical porosity for gas adsorption and supercapacitors.

Influence of MgO template on carbon dioxide adsorption of cation exchange resin-based nanoporous carbon.

In this work, porous carbons with well-developed pore structures were directly prepared from a weak acid cation exchange resin (CER) by the carbonization of a mixture with Mg acetate in different ratios. The effect of the Mg acetate-to-CER ratio on the pore structure and CO(2) adsorption capacities of the obtained porous carbons was studied. The textural properties and morphologies of the porous carbons were analyzed via N(2)/77K adsorption/desorption isotherms, SEM, and TEM, respectively. The CO(2) adsorption capacities of the prepared porous carbons were measured at 298 K and 1 bar and 30 bar. By dissolving the MgO template, the porous carbons exhibited high specific surface areas (326-1276 m(2)/g) and high pore volumes (0.258-0.687 cm(3)/g). The CO(2) adsorption capacities of the porous carbons were enhanced to 164.4 mg/g at 1 bar and 1045 mg/g at 30 bar by increasing the Mg acetate-to-CER ratio. This result indicates that CER was one of the carbon precursors to producing the porous structure, as well as for improving the CO(2) adsorption capacities of the carbon species.

Effect of exfoliation temperature on carbon dioxide capture of graphene nanoplates.

Thermally exfoliated graphene nanoplates were found to be a novel high efficiency sorbent for the capture of CO(2). The exfoliated graphene nanoplates were expanded successfully from graphite oxide by a low-heat treatment at temperatures ranging from 150 to 400°C under vacuum conditions. The texture was analyzed by N(2) full isotherms and XRD. The CO(2) capture characteristics of the graphene nanoplates at 25°C and 30 bar were examined using a pressure-composition-temperature apparatus. The inter-layer spacing of the graphene layers and pore structure on the CO(2) capture capacities were studied as a function of the processing conditions. The prepared graphene nanoplates exhibited high capture capacities, up to 248 wt.%, at 25°C and 30 bar. The improved CO(2) capture capacity of the graphene nanoplates was attributed to the larger inter-layer spacing and higher interior void volume.

Effect of heat treatment on CO2 adsorption of KOH-activated graphite nanofibers.

In this work, graphite nanofibers (GNFs) were successfully expanded intercalating KOH followed by heat treatment in the temperature range of 700-1000 °C. The aim was to improve the CO(2) adsorption capacity of the GNFs by increasing the porosity of GNFs. The effects of heat treatment on the pore structures of GNFs were investigated by N(2) full isotherms, XRD, SEM, and TEM. The CO(2) adsorption capacity was measured by CO(2) isothermal adsorption at 25 °C and 1 atm. From the results, it was found that the activation temperature had a major influence on CO(2) adsorption capacity and textural properties of GNFs. The specific surface area, total pore volume, and mesopore volume of the GNFs increased after heat treatment. The CO(2) adsorption isotherms showed that G-900 exhibited the best CO(2) adsorption capacity with 59.2 mg/g.

Effect of fluorination of carbon nanotubes on superhydrophobic properties of fluoro-based films.

In this work, we prepared multi-walled carbon nanotubes (MWCNTs) thin films on glass substrates with transparent, conductive, and superhydrophobic properties. MWCNTs were dispersed in fluoropolymer (FP) solutions for modification of their surface by grafting FP. A dip-coating process was used to prepare the films at a continuous speed and different numbers of coatings. The chemical compositions and microstructures of the prepared film surface were also investigated by using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The film showed 83.5% transmittance and a sheet resistance of 1.38x10(4)Omegasq(-1), and a high contact angle of 160.2 degrees . The 3D MWCNTs networks and the low surface energy of the FP play important roles in creating the superhydrophobic surface of the MWCNTs film.