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1.
Angew Chem Int Ed Engl ; : e202409629, 2024 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-39058372

RESUMO

Carbon aerogels (CAs) are attracting great attention for their multifunctional applications. Additionally, a large amount of biomass bits waste generated from agriculture and industry is regarded as the main carbon resource. However, the development of a facile, sustainable, and efficient method to produce CAs from biomass waste remains challenging. Here, a one-step Zn2+ ions glue triggered carbonization technology was reported to construct large-scale and high-performance CAs. Multiple biomass bits (wood bits, peanut shells, bamboo bits, and straw waste) were treated in the molten salt system (ZnCl2/KCl) at 300 °C for 2h to obtain large-block biomass bits derived CAs. Zn2+ ions as the glue cleavage cellulose hydrogen bonds of natural biomass, then facilitate dehydration crosslinking reaction between cellulose, hemicellulose, and lignin for re-constructing the whole block structure. The obtained CAs show high porosity (95%) and low density (0.078 g/cm3). Meanwhile, numerous of hydroxyl and carbonyl groups were well maintained during low temperature treated process, which facilitate chemical modification for various applications. For instance, amidoxime functionalized CAs were utilized as a filter for selective and highly efficient extraction of U(VI) from wastewater. The adsorption capacity and extraction efficiency reached 801.2 mg/g and 95% with a flux rate of 6.1×103 L/m2·h, respectively.

2.
J Colloid Interface Sci ; 673: 453-462, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38878379

RESUMO

Single-atom catalysts (SACs), with precisely controlled metal atom distribution and adjustable coordination architecture, have gained intensive concerns as efficient oxygen reduction reaction (ORR) electrocatalysts in Zn-air batteries (ZAB). The attainment of a monodispersed state for metallic atoms anchored on the carbonaceous substrate remains the foremost research priority; however, the persistent challenges lie in the relatively weak metal-support interactions and the instability of captured single atom active sites. Furthermore, in order to achieve rapid transport of O2 and other reactive substances within the carbon matrix, manufacturing SACs based on multi-stage porous carbon substrates is highly anticipated. Here, we propose a methodology for the fabrication of carbon aerogels (CA)-supported SACs utilizing papermaking nanofibers, which incorporates advanced strategies for N-atom self-doping, defect/vacancy introduction, and single-atom interface engineering. Specifically, taking advantages of using green and energy-efficient feedstocks, combining with a direct pore-forming template volatilization and chemical vapor deposition approach, we successfully developed N-doped carbon aerogels immobilized with separated iron sites (Fe-SAC@N/CA-Cd). The obtained Fe-SAC@N/CA-Cd exhibited substantially large specific surface area (SBET = 1173 m2/g) and a multi-level pore structure, which can effectively mitigate the random aggregation of Fe atoms during pyrolysis. As a result, it demonstrated appreciable activity and stability in catalyzing the ORR progress (E1/2 = 0.88 V, Eonset = 0.96 V). Furthermore, the assembled liquid electrolyte-state Zn-air batteries (LES-ZAB) and all-solid-state Zn-air battery (ASS-ZAB) also provides encouraging performance, with a peak power density of 169 mW cm-2 for LES-ZAB and a maximum power density of 124 mW cm-2 for ASS-ZAB.

3.
Adv Sci (Weinh) ; 11(26): e2401767, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38713745

RESUMO

Electromagnetic (EM) metamaterials have garnered considerable attention due to their capacity to achieve negative parameters, significantly influencing the integration of natural materials with artificially structural media. The emergence of carbon aerogels (CAs) offers an opportunity to create lightweight EM metamaterials, notable for their promising EM shielding or absorption effects. This paper introduces an efficient, low-cost method for fabricating CAs without requiring stringent drying conditions. By finely tuning the ZnCl2/lignin ratio, the porosity is controlled in CAs. This control leads to an epsilon-negative response in the radio-frequency region, driven by the intrinsic plasmonic state of the 3D carbon network, as opposed to traditional periodic building blocks. This approach yields a tunable and weakly epsilon-negative response, reaching an order of magnitude of -103 under MHz frequencies. Equivalent circuit analysis highlights the inductive characteristics of CAs, correlating their significant dielectric loss at low frequencies. Additionally, EM simulations are performed to evaluate the distribution of the electric field vector in epsilon-negative CAs, showcasing their potential for effective EM shielding. The lignin-derived, lightweight CAs with their tunable epsilon-negative response hold promise for pioneering new directions in EM metamaterials and broadening their application in diverse extreme conditions.

4.
Sci Total Environ ; 931: 172803, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38679107

RESUMO

Carbon aerogels were newly employed in adsorption for volatile organic compounds (VOCs) as an emerging material. In contrast, the microstructure and high carbon consumption are the primary factors restricting their application scenarios. Carbon nanotubes, recognized for their controllable cylindrical hollow structure and hydrophobic walls, generally possess higher adsorption capacities than typical carbon adsorbents. In this study, carbon nanotubes were grown on the surface of carbon aerogels using the chemical vapor deposition method by controlling different deposition conditions. The results showed that the modified samples displayed the maximum adsorption capacity of 145.0 mg/g and 178.3 mg/g for toluene and 1,2- dichlorobenzene, respectively. After ten regeneration cycles, the performance decreased by 7.9 % and 5.6 %, respectively. Meanwhile, the carbon replenishment was about 0.2 g/g, which is an excellent complement for carbon consumption. Various characterization patterns showed that deposition temperature was reflected in its deposition rate, deposition times influenced the formation of multi-walled carbon nanotubes, and deposition concentration affected the length of carbon nanotubes. This study offers valuable insight into the growth patterns of carbon nanotubes and the microscale regulation of carbon material surfaces, and this method is expected to be an effective means of carbon replenishment, carbon addition to carbon-poor materials, and enhancement of VOCs removal performance, and the growth mechanisms investigated are instructive for practical applications.

5.
Gels ; 10(3)2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38534598

RESUMO

Carbonaceous materials used in most electrochemical applications require high specific surface area, adequate pore size distribution, and high electrical conductivity to ensure good interaction with the electrolyte and fast electron transport. The development of transition metal doped graphene aerogels is a possible solution, since their structure, morphology, and electrical properties can be controlled during the synthesis process. This work aims to synthesize Ni-doped graphene aerogels to study the role of different nickel salts in the sol-gel reaction and their final properties. The characterization data show that, regardless of the nature of the Ni salts, the surface area, volume of micropores, and enveloped density decrease, while the porosity and electrical conductivity increase. However, differences in morphology, mesopore size distribution, degree of order of the carbon structure, and electrical conductivity were observed depending on the type of Ni salt. It was found that nickel nitrate results in a material with a broader mesopore distribution, higher electrical conductivity, and hence, higher electrochemical surface area, demonstrating that graphene aerogels can be easily synthesized with tailored properties to fit the requirements of specific electrochemical applications.

6.
ACS Appl Mater Interfaces ; 16(13): 16712-16723, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38506548

RESUMO

The fabrication of carbon aerogels with ultralow density, high electrical conductivity, and ultraelasticity still remains substantial challenges. This study utilizes electrospun polyimide aerogel as the source to fabricate flexible carbon nanofibrous aerogel (PI-CNA) capable of multifunctional applications. The lightweight PI-CNA based piezoresistive sensor shows a wide linear range (0-217 kPa), rapid response/recovery time, and fatigue resistance (12,000 cycles). More importantly, the superior pressure sensing enables the PI-CNA for all-range healthcare sensing, including pulse monitoring, physiological activity detection, speech recognition, and gait recognition. Moreover, the EMI SE and the A coefficient of the PI-CNA reach 45 dB and 0.62, respectively, indicating the outstanding absorption dominated EMI shielding effects due to the multiple reflections and absorption. Furthermore, PI-CNA exhibits satisfying Joule heating performance up to 120 °C with rapid response time (10-30 s) under low supply voltages (1.5-5 V) and possesses sufficient heating reliability and repeatability in long-term repeated heating/cooling cycles. The fabricated PI-CNA shows significant potential applications in wearable technologies, energy conversion, electronic skin, and artificial intelligence.

7.
ACS Appl Mater Interfaces ; 16(13): 16612-16621, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38509757

RESUMO

Developing excellent electromagnetic interference (EMI) shielding materials with robust EMI shielding efficiency (SE), high mechanical performance, and multifunctionality is imperative. Carbon materials are well recognized as promising alternatives for high-performance EMI shielding, but their high brittleness greatly hampers their applications. In this work, a cellulose nanofiber/reduced graphene oxide-glucose carbon aerogel (C-CNFs/rGO-glu) with high compression, elasticity, and excellent EMI shielding performance was fabricated by directional freeze-drying followed by carbonization. Specifically, the height and stress retention are 88% and 90.9%, respectively, after 100 cycles of compression release at a high strain of 70%. The electromagnetic shielding effectiveness of the aerogels reached 67.5 dB and presented an absorption-dominant shielding mechanism with a 97.5% absorption loss ratio. Further, the carbon aerogel could capture subtle electrical signals to monitor different human behaviors and showed excellent heat insulation and infrared stealth performance.

8.
Toxics ; 12(2)2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38393240

RESUMO

1,4-dioxane is a potential carcinogen in water and is difficult to deal with due to its robust cycloether bond and complete miscibility with water. To remove 1,4-dioxane in an economically viable and environmentally friendly way, a series of carbon aerogels were synthesized as adsorbents for 1,4-dioxane. The experiment results showed that adsorption performances were closely related to the preparation conditions of carbon aerogels, such as the molar ratio, heating rate, pyrolysis temperature and residence time, which were carefully controlled. Scanning electron microscope analysis revealed the presence of a three-dimensional porous network structure in carbon aerogels. Brunauer-Emmett-Teller analysis results demonstrated an increase in specific surface area (673.89 m2/g) and total pore volume after carbonization, with an increase in mesoporous porosity and a decrease in microporosity. When considering each variable individually, the highest specific surface area of prepared carbon aerogels was achieved at a pyrolysis temperature of 800 °C, a holding time of 1 h, and a heating rate of 2 °C/min. Under optimal experimental conditions, the adsorption removal of 1,4-dioxane by carbon aerogels exceeded 95%, following quasi-second-order kinetics and Langmuir isothermal adsorption isotherms, indicating that monolayer adsorption on the surface of carbon aerogels occurred. The maximum adsorption capacity obtained was 67.28 mg/g at a temperature of 318 K, which was attributed to the presence of a large proportion of mesopores and abundant micropores simultaneously in carbon aerogels. Furthermore, with the interference of chlorinated solvents such as trichloroethylene (TCE), the removal efficiency of 1,4-dioxane had no obvious inhibition effect. Regeneration experiments showed that after five continuous cycles, the carbon aerogels still kept a comparable adsorption capacity, which illustrates its potential application in 1,4-dioxane-polluted water purification.

9.
Adv Mater ; 36(7): e2308519, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37913824

RESUMO

With ultralight weight, low thermal conductivity, and extraordinary high-temperature resistance, carbon aerogels hold tremendous potential against severe thermal threats encountered by hypersonic vehicles during the in-orbit operation and re-entry process. However, current 3D aerogels are plagued by irreconcilable contradictions between adiabatic and mechanical performance due to monotonicity of the building blocks or uncontrollable assembly behavior. Herein, a spatially confined assembly strategy of multiscale low-dimensional nanocarbons is reported to decouple the stress and heat transfer. The nanofiber framework, a basis for transferring the loading strain, is covered by a continuous thin-film-like layer formed by the aggregation of nanoparticles, which in combination serve as the fundamental structural units for generating an elastic behavior while yielding compartments in aerogels to suppress the gaseous fluid thermal diffusion within distinct partitions. The resulting all-carbon aerogels with a hierarchical cellular structure and quasi-closed cell walls achieve the best thermomechanical and insulation trade-off, exhibiting flyweight density (24 mg cm-3 ), temperature-constant compressibility (-196-1600 °C), and a low thermal conductivity of 0.04 829 W m-1 K-1 at 300 °C. This strategy provides a remarkable thermal protection material in hostile environments for future aerospace exploration.

10.
Int J Biol Macromol ; 257(Pt 1): 128587, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38065463

RESUMO

Biomass-based carbon aerogels hold promising application prospect in the field of supercapacitors. In this research, starch was selected as a raw material for preparing carbon aerogels. The preparation process of starch hydrogels was simplified by using KOH, which can change starch suspension into hydrogels at room temperature. Moreover, the molecular mixing of KOH and starch was realized, so that KOH can be fully utilized in the activation process. The specific surface area of the starch-based carbon aerogels prepared by this method was 1349 m2/g, and the proportion of micropores was 43.7 %. Remarkably, as electrode materials for supercapacitors, the starch-based carbon aerogels exhibited outstanding electrochemical performance. In a three-electrode system, the carbon aerogels exhibited specific capacitance of 211.5 F/g at 0.5 A/g and 138.5 F/g at 10 A/g, suggesting their suitability for high-current applications. In a symmetrical supercapacitor configuration, the materials exhibited an energy density of 11.3 Wh/kg at a power density of 0.5 kW/kg and the specific capacitance can maintain 98.91 % after 10,000 cycles. Overall, this work provides a new method for mixing activators, which will foster potential advances in starch based carbon aerogels.


Assuntos
Carbono , Hidrogéis , Biomassa , Capacitância Elétrica , Amido
11.
J Environ Manage ; 347: 119114, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37783084

RESUMO

In this study, an in situ grown FeCo-Layered double hydroxide anchored to the surface of a bulk carbon aerogel (FeCo-LDH/CA) for contaminant degradation during the heterogeneous electro-Fenton (EF) process. The results exhibited that the FeCo-LDH/CA cathode achieved 100% of 2,4-dichlorophenol (2,4-DCP = 20 mg/L) degradation within 120 min at pH = 3, application current 20 mA, and Na2SO4 concentration 0.05 M. Moreover, the degradation efficiency was impressive in the range of pH = 2-9. The coexistence of the Fe (III)/Fe (II) and Co (III)/Co (II) as active sites on the cathode surface promoted the in-situ decomposition of H2O2 to form reactive oxygen species (ROS). •OH and O2- were confirmed to be the major degradation pollutants of ROS. Furthermore, density functional theory (DFT) was used to predict the reaction sites of 2,4-DCP, and its possible degradation pathways were proposed. The toxicity of intermediate products was evaluated and decreased after degradation. In addition, the eight cycle experiments and the degradation of other typical contaminants demonstrated the satisfactory stability and applicability of the synthetic cathode. This study presents the preparation of an efficient and stable EF cathode, further promoting the application of iron-based composites in wastewater treatment.


Assuntos
Carbono , Poluentes Químicos da Água , Carbono/química , Espécies Reativas de Oxigênio , Peróxido de Hidrogênio/química , Oxirredução , Poluentes Químicos da Água/química , Fenóis , Eletrodos
12.
Adv Mater ; 35(35): e2303943, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37402138

RESUMO

Al batteries have great potential for renewable energy storage owing to their low cost, high capacity, and safety. High energy density and adaptability to fluctuating electricity are major challenges. Here, a lightweight Al battery for fast storage of fluctuating energy is constructed based on a novel hierarchical porous dendrite-free carbon aerogel film (CAF) anode and an integrated graphite composite carbon aerogel film (GCAF) cathode. A new induced mechanism by the O-containing functional groups on the CAF anode is con-firmed for uniform Al deposition. The GCAF cathode possesses a higher mass utilization ratio due to the extremely high loading mass (9.5-10.0 mg cm-2 ) of graphite materials compared to conventional coated cathodes. Meanwhile, the volume expansion of the GCAF cathode is almost negligible, resulting in better cycling stability. The lightweight CAF‖GCAF full battery can adapt well to large and fluctuating current densities owing to its hierarchical porous structure. A large discharge capacity (115.6 mAh g-1 ) after 2000 cycles and a short charge time (7.0 min) at a high current density are obtained. The construction strategy of lightweight Al batteries based on carbon aerogel electrodes can promote the breakthrough of high-energy-density Al batteries adapted to the fast storage of fluctuating renewable energy.

13.
ACS Appl Mater Interfaces ; 15(24): 29609-29617, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37285222

RESUMO

Surface-enhanced Raman scattering (SERS), an ultra-sensitive and non-destructive analytic technique, has attracted wide attention from the scientific community. Despite its rapid development, limited hotspots on the SERS substrates have restricted their potential in practical applications. Herein, we developed a facile method to fabricate a flexible three-dimensional (3D) SERS substrate composed of silver nanoparticles (Ag NPs)-loaded carbon aerogels (CAs). Such a flexible Ag NPs/CAs substrate exhibited numerous hotspots, which can facilely be adjusted not only by tuning the density of Ag NPs but also by controlling the bending degree of the flexible substrate. In addition, the influence of hotspots on the local electric field enhancement was investigated by theoretical calculations. Moreover, the 3D network structure of the CAs with a large specific surface area and strong adsorption ability can improve the capture of target molecules. Consequently, the optimal Ag NPs/CAs substrate has a low detection limit of 10-12 M for rhodamine 6G molecules as well as good repeatability. Furthermore, based on the good performance of SERS detection of the Ag NPs/CAs substrate, it can also be practically used for the detection of thiram molecules on the surface of cherry tomatoes. Such a flexible 3D Ag NPs/CAs substrate has great potential for practical environmental monitoring applications.

14.
Front Chem ; 11: 1326454, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38260044

RESUMO

Lignin is considered a valuable renewable resource for building new chemicals and materials, particularly resins and polymers. The aromatic nature of lignin suggests a synthetic route for synthesizing organic aerogels (AGs) similar to the aqueous polycondensation of resorcinol with formaldehyde (FA). The structure and reactivity of lignin largely depend on the severity of the isolation method used, which challenges the development of new organic and carbon materials. Resorcinol aerogels are considered a source of porous carbon material, while lignin-based aerogels also possess great potential for the development of carbon materials, having a high carbon yield with a high specific surface area and microporosity. In the present study, the birch hydrolysis lignin and organosolv lignin extracted from pine were used to prepare AGs with formaldehyde, with the addition of 5-methylresorcinol in the range of 75%-25%, yielding monolithic mesoporous aerogels with a relatively high specific surface area of up to 343.4 m2/g. The obtained lignin-based AGs were further used as raw materials for the preparation of porous carbon aerogels (CAs) under well-controlled pyrolysis conditions with the morphology, especially porosity and the specific surface area, being dependent on the origin of lignin and its content in the starting material.

15.
Materials (Basel) ; 15(19)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36234226

RESUMO

The adsorption technique is widely used in water purification, and its efficiency can be significantly improved by target-specific adsorbent design. Research on iodine and its ion removal from water has attracted a great deal of interest due to increased concentrations in the environment and acute toxic effects, e.g., in human thyroid cells. In this work, the iodide removal performance of two high-surface-area resorcinol-formaldehyde-based carbon aerogels was studied under acidic conditions. The BET surface area was 790 m2/g (RF_ac) and 375 m2/g (RMF-GO), with a corresponding micropore ratio of 36 and 26%, respectively. Both aerogels showed outstanding adsorption capacity, exceeding the reported performance of other carbons and Ag-doped materials. Owing to its basic nature, the RMF-GO carbon aerogel showed higher I- capacity, up to 97 mg/g, than the acidic RF_ac, which reached a capacity of 82 mg/g. The surface chemistry of the aerogels also played a distinct role in the removal. In terms of kinetics, RF_ac removed 60% of the iodide ions and RMF-GO 30% within 8 h. The removal kinetics was of the first order, with a half-life of 1.94 and 1.70 h, respectively.

16.
ACS Nano ; 16(10): 15586-15626, 2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36226846

RESUMO

Benefiting from the inherent properties of ultralight weight, ultrahigh porosity, ultrahigh specific surface area, adjustable thermal/electrical conductivities, and mechanical flexibility, aerogels are considered ideal supporting alternatives to efficiently encapsulate phase change materials (PCMs) and rationalize phase transformation behaviors. The marriage of versatile aerogels and PCMs is a milestone in pioneering advanced multifunctional composite PCMs. Emerging aerogel-based composite PCMs with high energy storage density are accepted as a cutting-edge thermal energy storage (TES) concept, enabling advanced functionality of PCMs. Considering the lack of a timely and comprehensive review on aerogel-based composite PCMs, herein, we systematically retrospect the state-of-the-art advances of versatile aerogels for high-performance and multifunctional composite PCMs, with particular emphasis on advanced multiple functions, such as acoustic-thermal and solar-thermal-electricity energy conversion strategies, mechanical flexibility, flame retardancy, shape memory, intelligent grippers, and thermal infrared stealth. Emphasis is also given to the versatile roles of different aerogels in composite PCMs and the relationships between their architectures and thermophysical properties. This review also showcases the discovery of an interdisciplinary research field combining aerogels and 3D printing technology, which will contribute to pioneering cutting-edge PCMs. This review aims to arouse wider research interests among interdisciplinary fields and provide insightful guidance for the rational design of advanced multifunctional aerogel-based composite PCMs, thus facilitating the significant breakthroughs in both fundamental research and commercial applications.

17.
J Chromatogr A ; 1683: 463552, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36219967

RESUMO

To improve the extraction efficiency, availability, and stability of metal-organic framework (MOF) for pipette-tip solid-phase extraction (PT-SPE), a carbonized MOF-74/carbon aerogel composite (CMOF-74/CA) was developed. A carbon aerogel with a surface area of 547.7 m2 g-1 was prepared by carbonizing a watermelon peel. After that, via a hydrothermal reaction, the MOF-74 was in situ grown on the surface. After the pyrolysis at 700 °C for 2 h, the CMOF-74/CA composite was obtained. Through regulating the concentration of reactants, a series of MOF-74/CA and CMOF-74/CA materials were prepared. These materials were used to extract hexaconazole and diniconazole in fruits and vegetables before gas chromatography-flame ionization detection (GC-FID). The adsorbent type and amount, sample pH, and the desorption solvent type and volume were optimized factor by factor. Under the optimized conditions, a PT-SPE-GC-FID method was established. Moreover, good linearity in the concentration ranges of 0.098-200.0 mg kg-1 and 0.196-200.0 mg kg-1, and detection limits ranging between 0.033 and 0.065 mg kg-1 were achieved for two triazole fungicides (TFs). The relative standard deviations (n = 3) for intra-day and inter-day tests were in the ranges of 3.1-3.2% and 3.0-3.4%, respectively. The method showed satisfactory analytical performance in different samples with good relative recoveries in the range of 72.6-116%. Compared with some methods, it displayed wider linearity, better or comparable sensitivity, and enhanced analytical precision.


Assuntos
Fungicidas Industriais , Estruturas Metalorgânicas , Fungicidas Industriais/análise , Verduras , Frutas/química , Triazóis , Carbono , Solventes
18.
Nanomaterials (Basel) ; 12(15)2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35957152

RESUMO

Carbon aerogel (CA) based materials have multiple advantages, including high porosity, tunable molecular structures, and environmental compatibility. Increasing interest, which has focused on CAs as electrocatalysts for sustainable applications including oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and CO2 reduction reaction (CO2RR) has recently been raised. However, a systematic review covering the most recent progress to boost CA-based electrocatalysts for ORR/OER/HER/CO2RR is now absent. To eliminate the gap, this critical review provides a timely and comprehensive summarization of the applications, synthesis methods, and principles. Furthermore, prospects for emerging synthesis, screening, and construction methods are outlined.

19.
Food Chem ; 395: 133633, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-35816989

RESUMO

In order to develop environmentally friendly, economical and facile preparation method of carbon aerogels (CAs), the waste printing paper as the raw material was combined with graphene oxide and carboxylic multi-walled carbon nanotubes to produce CAs (ρ = 44 mg cm-3). The CAs with different composition were investigated, the addition of graphene oxide led to the reduction of adsorption sites and the reduction of extraction performance. But the carbon nanotubes made CAs have a better pore structure. The CAs as adsorbent were loaded into a pipette-tip for solid-phase extraction of hexaconazole and diniconazole. Coupled with gas chromatography, an analytical method was established under the optimized conditions. The limits of detection were between 0.08 and 0.32 mg kg-1, the linear ranges were 0.96-200.0 mg kg-1 and 0.24-200.0 mg kg-1. The relative recoveries were in the range of 81.0-119%. The results indicated that the method had potential application for the determination of triazole fungicides.


Assuntos
Fungicidas Industriais , Malus , Nanotubos de Carbono , Pyrus , Solanum lycopersicum , Cromatografia Líquida de Alta Pressão/métodos , Fungicidas Industriais/análise , Nanotubos de Carbono/química , Extração em Fase Sólida/métodos , Triazóis/análise
20.
J Colloid Interface Sci ; 605: 790-802, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34371424

RESUMO

Carbon aerogels are prepared by a thermal treating-freeze drying approach from chitosan, with glycine hydrochloride ionic liquid (IL) acting as solvent and nitrogen source. Different post-treatments such as ball milling and high temperature carbonization are employed to functionalize the obtained carbon aerogels with tuned properties, making it promising candidates as fluorescence material (NACs-Q), electrode material (FDC-800) and catalyst support (NACPd-C). NACs-Q is water-soluble quantum dot with average particle sizes of 3.8 nm, presenting excitation-/emission-independent and pH-sensitive properties, which could be used as sensor for testing acetone vapor or an "on-off-on" sensor for detections of Fe3+ and vitamin C in fruits. FDC-800 exhibits fluffy lamellar structure with developed micro-mesopores and nitrogen-containing groups on their surfaces, which is beneficial for building flexible solid-state supercapacitor with excellent performance, delivering a capacitance of 208F/g at 0.5 A/g, and achieving an energy density of 7.2 W h/kg at a power density of 50 W/kg. Moreover, NACPd-C can be used as catalyst for phenol hydrogenation, and phenol conversion of 100% with cyclohexanone selectivity of 98.3% is achieved, due to the synergetic effects of the Pd active-site, the N-containing groups, and the Lewis acid sites on the support.


Assuntos
Carbono , Quitosana , Capacitância Elétrica , Nitrogênio , Porosidade
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