Nano-sized Carbon Particles Research Articles

Bioengineered dual fluorescent carbon nano dots from Indian long pepper leaves for multifaceted environmental and health utilities.

In this article, we present the synthesis of Piper longum leaves-derived ethanolic carbon dots (PLECDs) using the most simplistic environmentally friendly solvothermal carbonization method. The PLECDs fluoresced pink color with maximum emission at 670nm at 397nm excitation. Additionally, the dried PLECDs dissolved in water showed green fluorescence with higher emission at 452nm at 370nm excitation. The UV spectra showed peaks in the UV region (271.25nm and 320.79nm) and a noticeable tail in the visible region, signifying the efficient synthesis of nano-sized carbon particles and the Mie scattering effect. Various functional groups (-OH, -N-H, -C-H, -C = C, -C-N, and -C-O) were identified using Fourier transform infrared spectroscopy (FTIR). Its nanocrystalline property was revealed by the sharp peaks in the X-ray diffraction (XRD). High-resolution transmission electron microscopy (HRTEM) photomicrograph displayed a roughly spherical structure with a mean size of 2.835nm. The energy dispersive X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) revealed the elemental abundance of C, O, and N. The high-performance thin-layer chromatography (HPTLC) fingerprint of PLECDs showed an altered pattern than its precursor (Piper longum leaves ethanolic extract or PLLEE). The PLECDs sensed Cu2+ selectively with a limit of detection (LOD) and limit of quantification (LOQ) of 0.063μM and 0.193μM, respectively. It showed excellent cytotoxicity toward MDA-MB-231 (human breast cancer), SiHa (human cervical carcinoma), and B16F10 (murine melanoma) cell lines with excellent in vitro bioimaging outcomes. It also has free radical scavenging activity. The PLECDs also showed outstanding bacterial biocompatibility, pH-dependent fluorescence stability, photostability, physicochemical stability, and thermal stability.

The role of Carica papaya latex bio-catalyst and thermal shock in water on synthesizing rice husk

A bio-catalyst made of natural resources, such as Carica papaya latex, is very challenging for nanoparticle separation. In addition, differences in thermal conditions between nanoparticles affect the movement of substances in the separation process. The study experimentally investigated the role of Carica papaya latex bio-catalyst and thermal shock in water on synthesizing rice husk (RH). The synthesis retained the Mg and C elements attached to SiO2, which were generally neglected during the process. The study's objective was to evaluate the effectiveness of biocatalysts and thermal effects on the separation of Mg-SiO2-C from rice husk carbon nanoparticles (CNPs-RH). The research involved various treatment processes, such as RH pyrolysis in obtaining charcoal, High energy milling (HEM) to have carbon particles, and washing to get nano-sized carbon particles. The bonding of elemental compounds to rice husk carbon particles (CPs-RH) was released using NaOH and coagulation using a bio-catalyst. Coagulated CPs-RH was injected into water at a temperature of 60–70 °C to have a thermal shock effect for H2O clusters in Na+ and Mg2+ ions attached to the surface of the nanoparticles. Several tests were carried out, such as the SEM-EDX, TEM, XRD, and FTIR tests, to investigate the two nanoparticle clusters formed up to the nanometer scale. The results indicated that CNPs-RH nanoparticles consist of spherical particles with a diameter of 1.2 nm, while Mg-SiO2-C nanoparticles have a diameter of 0.6 nm. Both are classified as amorphous. Based on the FTIR test, CNPs-RH is hydrophilic, while Mg-SiO2-C is hydrophobic. Thermal shock in water strengthens the ion's mobility, increasing the interfacial dipole forces between nanoparticles and accelerating the separation process.

Hydrothermal synthesis of bentonite carbon composites for ultra-high temperature filtration control in water-based drilling fluid

In this study, bentonite hydrothermal carbon composites (BHCCs) were fabricated by green and facile hydrothermal carbonization, employing glucose as the carbon source and bentonite as the template. BHCCs were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The effects of the BHCCs on the rheological and filtration properties of bentonite dispersions were investigated before and after thermal aging at 220 °C and 240 °C, respectively. The results demonstrated that, unlike conventional synthetic polymers, the BHCCs exhibited a minor influence on the rheology of bentonite dispersion and had extraordinary filtration control both before and after ultra-high-temperature aging. The incorporation of BHCCs helped introduce the oxygenated groups with carbon species, thereby enhancing the dispersion stability of bentonite particles. The spherical nano-sized carbon particles in BHCCs filled the gaps between large particles in the filter cake. The above factors contributed to excellent filtration control under hostile, high-temperature conditions.

CO2-free hydrogen production by liquid-phase plasma cracking from benzene over perovskite catalysts

A method for producing hydrogen from liquid benzene without CO2 generation using plasma is proposed. A liquid plasma was emitted from the liquid reactant to crack liquid benzene to produce hydrogen. The only gaseous product was H2 and no CO2 was formed. Carbon crystals were produced as a solid product. To increase the decomposition efficiency of liquid benzene and the efficiency of hydrogen production, perovskite was applied as a catalyst. The reaction produced nano-sized carbon particles with hydrogen as the main product without impurities. The crystal size of carbon black was very small (<10 nm) and uniform. The carbon products were similar in crystal shape and size regardless of the reaction time. Liquid benzene is decomposed by active species in the liquid plasma to produce hydrogen and carbon without catalyst injection. When the perovskite catalyst was applied to the reaction using liquid plasma, the hydrogen production rate and carbon yield were significantly increased. Liquid benzene simultaneously produces hydrogen and carbon black through a decomposition reaction by liquid plasma. The LPP cracking process of liquid benzene can be evaluated as a ‘green hydrogen’ production technology that does not generate CO2.

A new process for minimizing residual silicon and carbon of reaction-bonded silicon carbide via chemical vapor deposition

In order to reduce the amount of excess silicon and carbon, reaction-bonded silicon carbide was fabricated by liquid silicon infiltration using a porous carbon preform prepared by chemical vapor deposition. A carbon preform was fabricated at 1100−1400 ℃ at 6.6 kPa for 1 h using acetylene. The deposited carbon preform has a porous structure with nano-sized carbon particles and uniform pore size distribution. Depending on the deposition temperature of the carbon preform, the porosity, the pore size, and the size of the carbon particles were controlled. As the deposition temperature increased, the porosity and average pore size increased, but the average carbon particle size decreased. The residual silicon of the prepared reaction-bonded silicon carbide was 2.7 % when the porosity of the carbon preform deposited at 1100 °C was 51.1 %. The hardness increased up to 21.7 GPa as the amount of the residual silicon reduced.

Potential release of nano-carbon black from tire-wear particles through the weathering effect

Carbon black (CB) is commercially produced by the partial combustion of hydrocarbons, mainly used as a reinforcing material in tires. Generally, driving cars emit a considerable amount of particulate matter (PM), and this acts as a major source of PM in urban areas. While exhaust PM emissions are strictly regulated and controlled by the government, non-exhaust PM emissions from tire-wear and break-wear have been overlooked. Additionally, as CB is tightly bound in the rubber matrix of tire-wear particles (TWP), the possibility of nanoparticle exposure from TWP has also been ruled out. However, TWP could be fragmented through the weathering effect, continuous abrasion on the road, and resuspension. Therefore, in this study, we investigated the potential release of nano-CB from TWP through the weathering effect using a ball milling process. With increasing milling time, countless free-bound nanoparticles were detached from the parent TWP samples. Based on several analyses of elemental composition, morphological change, and crystallinity, it is possible to define the free-bound nanoparticles as nano-CB. Additionally, nanosized carbon-based materials were found in real-time field tests on highways. Therefore, it has been confirmed that nanosized carbon particles can be released from TWP or exhaust PM.

Effect of carbonaceous nanomaterials’ reinforcement on mechanical properties of aluminium metal-based nanocomposite: A review

Nano sized carbon particles, reinforced with aluminium matrix, are used in almost every engineering sector. The potentials of most common nano carbon particles (e.g., graphene and carbon nanotube; CNT) have already been explored exhaustly. Nonetheless, new particles, for reinforcements, are always in demand to meet the pace of modern industry. In this regard, carbon nano reinforcements like nanodiamond, fullerenes, carbon onions, and carbon black with aluminium matrix composites can be the game changer for future novel and high performing engineering materials. These materials have demonstrated significant enhancement in mechanical properties in the form of nanocomposite with aluminium metal as matrix. Present review critically discusses various reports published on aforementioned (less explored) carbonaceous nanomaterials’ reinforcement in aluminium nanocomposite. Article reviews the advancements in mechanical properties of these carbon nanostructures and aluminium metal matrix composite with related mechanisms too. Various new methods of composite synthesis, nanomaterial modification, and interfacial interaction improvement are discussed too. Prime facie, it can be concluded that carbonaceous nanomaterials’ reinforcement in aluminium metal-based nanocomposite significantly enahce the mechanical properties of resulting composite.

Synthesis and Characterization of Nano Activated Carbon from Annatto Peels (Bixa orellana L.) Viewed from Temperature Activation and Impregnation Ratio of H3PO4

Nano activated carbon is activated carbon with nano-sized carbon particles and can be synthesized from cellulose-containing materials such as the Annatto peels. In this study, the synthesis of nano activated carbon of the Annatto peels was carried out in terms of activation temperature variations and the carbon impregnation ratio of 50% H3PO4 acid and determining the characteristics of nano activated carbon from Annatto peels (NAPAC). The activation method used is the impregnation of carbon in 50% H3PO4 with a ratio of 1: 3; 1: 4; 1: 5; 1: 6; and 1: 7 (w/w) for 24 hours and heating at 400; 500; 600; 700; and 800 °C for one hour. Nano activated carbon from Annatto peels (NAPAC) was characterized by Infrared Spectrophotometer (FTIR), X-ray Diffractometer (XRD), and Transmission Electron Microscope (TEM). The results of the study showed that the NAPAC can be synthesized from Annatto peels with activation by 50% H3PO4 at the temperature of 500°C and the impregnation ratio of 1:5 (w/w). The result of characterization using FT-IR, XRD and TEM showed that NAPAC contains a group of functions O-H, C-H, C=, C=C dan C-O/P=O with an amorphous carbon structure and the range of particles diameter at 22-36 nm

Migration of carbon nanoparticles to the surface of the melt of polymer composite material

The results of a study of the migration of electrically conductive nanosized carbon particles of various types to the surface of the melt of the polymer composite are presented. The real-time measurement of the kinetics of changes in the electrical conductivity of the melt of the polymer composite at a constant temperature, separately for the bulk and surface components of the electrical conductivity, made it possible to identify the basic features of the process. The results obtained indicate that the formation of a surface layer of a composite saturated with electrically conductive nanoparticles is common when using filler nanoparticles with a different form factor. The role of polymer macromolecules in the kinetics of migration of carbon nanoparticles to the melt surface of a polymer composite material is discussed.

Absolute luminescence quantum yield for nanosized carbon particles in water as a function of excitation wavelength.

The absolute luminescence quantum yield Q as a function of excitation wavelength λex in a wide spectral range 270-470nm was measured for the first time for the group of carbon nanoparticles dispersed in water: carbon dots (CD), detonation nanodiamonds (DND), as well as detonation nanodiamonds decorated with carbon dots (CD-DND). The luminescence quantum yield for DND increased after functionalization; the CD-decorated DND demonstrated significantly higher Q values in the UV region of excitation. We found that the quantum yield for CD luminescence is 4-8 times higher than that for CD-DND luminescence, and 20 times higher than that for DND luminescence. Roughly three spectral regions can be distinguished within the Q(λex): below 330nm, 330-390nm and 390-470nm. Conclusions are drawn about the number of chromophores of the studied nanoparticles and transfer of photoexcitation energy in the systems under consideration.

Migration of Carbon Nanoparticles to the Surface of a Polymer Composite Melt

The results of a study of migration of electrically conductive nano-sized carbon particles of different types to the surface of molten polymer composite are presented. The real-time measurements of the changes in electrical conductivity of the polymer composite melt at a constant temperature, carried out separately for the bulk and surface conductivity components, revealed the basic features of the process. The results indicate that the formation of a surface layer saturated with electrically conductive nanoparticles is a general phenomenon for composites where filler nanoparticles with different aspect ratios are used. The role of polymer macromolecules in the kinetics of migration of carbon nanoparticles to the polymer composite melt surface is discussed.

Highly porous carbon nanofoams synthesized from gas-phase plasma for symmetric supercapacitors

Highly porous carbon nanofoams (CNFs) could be massively synthesized at room temperature from acetylene gas precursor by a plasma-enhanced chemical vapor deposition technique. The synthesized CNFs had a three-dimensional framework structure composed of aggregations of nano-sized spherical carbon particles, in which the open-connected micron- and nano-pores were hierarchically distributed. Afterwards, thermal treatment and nitrogen doping process were conducted to enhance both electrical conductivity and electrochemical properties of the CNFs. The nitrogen-doped CNFs (N-CNFs) exhibited very high specific surface area of up to 920.4 m2 g−1 and a pore volume of approximately 0.70 cm3 g−1. Due to their hierarchical porous structure, large ion-accessible surface area, and good conductivity for fast ion sorption and electron transfer, the N-CNFs exhibited excellent electrochemical performance for supercapacitor application, such as high specific capacitance of 362.6F g−1 at a current density of 1 A g−1 and super stability in cycle life test. In addition, a symmetric supercapacitor assembled with N-CNFs could deliver a maximum energy density of 24.4 Wh kg−1 and a power density of 8.8 kW kg−1.

Prolonged exposure to carbon nanoparticles induced methylome remodeling and gene expression in zebrafish heart.

Growing black carbon (BC) emission has become one of the major urgent environmental issues facing human beings. Usually, BC or BC-containing carbon nanoparticles (CNPs) were recognized as non-directly toxic components of atmospheric particulate matter. However, epidemiology studies have provided much evidence of the associations of exposure of particulate-containing carbon particles with cardiovascular diseases. There are still no related studies to support the epidemiological conclusions. Hence, in this article we exposed adult zebrafish to CNPs for 60days, and then explored the heart location and potential adverse effects on cardiac tissues of these nanosized carbon particles. Our results first showed direct visualization of cardiac endothelial uptake and heart deposition of CNPs in zebrafish. In addition, CNPs caused significant ultrastructural alterations in myocardial tissue and induced the expression of inflammatory cytokines in a dose-dependent manner, resulting in sub-endocardial inflammation and cell apoptosis. Moreover, our data demonstrated the perturbations caused by CNPs on DNA methylation, suggesting that DNA methylome remodeling might play a critical role in CNP-induced cardiotoxicity in zebrafish heart. Therefore, this study not only proved a laboratory link between CNP exposure and cardiotoxicity in vivo, but also indicated a possible toxicity mechanism involved.

ANÁLISE ESTATÍSTICA APLICADA AOS PARÂMETROS DE SÍNTESE DE FAUJASITA Na-X

Devido às sua estrutura altamente regular e características microporos com dimensões regulares e superfície específica, as zeólitas, especialmente as sintéticas tem encontrado várias aplicações industriais como componentes em catalisadores heterogêneos. Entretanto, em muitas das aplicações petroquímicas, a estrutura microporosa impõe limitações à difusão das moléculas de reagentes e produtos e se torna um problema. Muito esforço de pesquisa na síntese de outras estruturas zeolíticas com diâmetros de microporos mais largos ou estruturas mistas contendo micro e mesoporos tem sido feito. Neste estudo, foi realizado um delineamento experimental baseado na metodologia de Placket &amp; Burman para selecionar as variáveis que tem maior efeito na síntese de zeólita do tipo faujasita (FAU-X) com baixa relação molar SiO2/Al2O3 para posteriormente fixar as melhores condições e verificar o efeito da introdução de partículas funcionalizadas de carbono nanométricas na geração de estruturas mesoporosas.

Effect of carbon black content and particle size on the phase evolution of aluminum oxy nitride (AlON)

In this work aluminum Oxy-nitride (γ-AlON) crystals were synthesized by Co-precipitation processing from Al(NO3)3 solution, magnesium acetate and nanosized carbon particles as the source of Al3+, Mg2+ and reducing agent, respectively. The effects of the nanosized carbon and Mg2+ content and particle size on the formation of AlON phase were investigated by means of XRD, SEM and EDS analysis. Our results indicated that AlON powder could be synthesized when the resultant precursors were calcined at 1700°C for 2h under flowing N2. Under optimal additional content of C (7.1wt%), the resultant AlON powders exhibited the primary particle size of about 2–4µm with a specific surface area of 3m2/g.

Experimental study on the effect of nanosized carbon particles on fatigue resistance of asphalt binders

ABSTRACTThe present research study investigates the fatigue resistance of asphalt binders modified with carbon nanoparticles. Three different modified bitumens containing three different dosages of carbon nanoparticles were tested to capture fatigue properties under the concept of viscoelastic continuum damage mechanics through frequency sweep and linear amplitude sweep tests. Results show that adding carbon nanoparticles can enhance the fatigue life of neat asphalt binders.

Applications of graphene nano-sheets as anode diffusion layers in passive direct methanol fuel cells (DMFC)

The diffusion layer is an important structure in the membrane electrode assembly (MEA) of direct methanol fuel cells (DMFCs) that provide a support layer for catalysts, electronic channels, and gas–liquid mass transport channels. In this study, three types of carbon-based materials were used to fabricate anode diffusion layers – carbon black Vulcan® (CBV), M-15 grade graphene nanosheets (GM-15) and C-500 grade graphene nanosheets (GC-500). The microporous layers of cathodes were constructed with CBV. A carbon-based microporous layer with a 2 mg cm−2 loading was coated onto a PTFE-pretreated carbon cloth, while a Nafion-117 membrane was applied as the electrolyte to the DMFCs. Pt–Ru black and Pt black were used as anode and cathode electrode catalysts, each with loadings of 8 mg cm−2 and 4 mg cm−2, respectively. All tests were conducted using MEAs with active areas of 4 cm2 and air was supplied to single cells by passive modes. Surface morphology was studied using scanning electron microscopy (SEM), which produced pictures of complex network formations within the structures. CBV consists of nanosized carbon particles, while both GM-15 and GC-500 are made of stacks of graphene sheets with flaky structures that increase catalyst utilization. Performance tests of the DMFCs were conducted using a potentiostat that generated polarization curves. The highest peak power density of 13.7 mW cm−2 was obtained by the GC-500 anode diffusion layer using 3 M methanol as fuel. The energy efficiency of the passive DMFCs was approximately 10% with a specific energy of approximately 610 Wh kg−1, which is higher than that of conventional lithium-ion batteries, portraying the bright future of alternative energy sources for use in power applications for portable devices. The high power densities obtained by both graphene-based materials, GM-15 and GC-500, demonstrate that graphene is a material other than state of the art carbon black that has the potential to be used as a DMFC anode support material.

Ultrasound-assisted-pressure-induced-flow leading to superior polymer/carbon nanotube composites and foams

In the presented work, nano-sized carbon particles were coated onto the surface of semicrystalline polymer pellets and molded into an intermediate preform, with a honeycomb-like structure, at elevated temperatures and pressures. The preforms were further processed through pressure induced flow (PIF) at higher pressures or ultrasound assisted pressure induced flow (UAPIF) at lower pressures to achieve polymer nanocomposites with a co-continuous and ‘brick and mud’ structure. The particle-coated polymer pellets, preforms, and composites can be saturated or partially saturated with a blowing agent, so foaming may occur during or after molding to fabricate polymer nanocomposite foams with a layer-by-layer bimodal cell structure. Using polypropylene and carbon nanotubes as an example, and carbon dioxide as the blowing agent, we show that these new materials can provide superior mechanical and physical properties with good electrical conductivity and foam expansion ratio, not achievable by conventional nanocomposites and foams with the same composition.

Biomass derived palygorskite–carbon nanocomposites: Synthesis, characterisation and affinity to dye compounds

Clay minerals can act as a uniform dispersion medium for nano-sized carbon particles. However, literature on the preparation and characteristics of palygorskite–carbon nanocomposites is scant. Using a hydrothermal carbonisation technique this study developed two nanocomposites on fibrous palygorskite from starch: the first without a post-synthesis treatment (Composite 1); and the second with an activation at 550°C for 3h (ramp at 10°Cmin−1) under CO2 environment (200mLmin−1) (Composite 2). A uniform dispersion of nano-scale carbon spheres was formed on partially destroyed palygorskite structures. Composite 2, which indicated the formation of graphitised carbon nanoparticles, generated a 17-fold greater specific surface area than Composite 1 and also created micro- and mesopores in its structure. The nanocomposites, especially in Composite 1, contained organic surface functional groups (CH, CC, CO) and indicated variable affinity to cationic and anionic dye compounds. While Composite 2 adsorbed a larger amount of anionic orange II dye (23mgg−1), Composite 1 adsorbed more cationic methylene blue (46.3mgg−1). Isothermal and kinetic modelling of the adsorption data indicated that in addition to electrostatic attraction for methylene blue adsorption on both nanocomposites, a pore diffusion mechanism was involved and the boundary resistance was greater for orange II than methylene blue adsorption. Being a material developed from green biomass (starch) and an abundant natural resource (palygorskite), these nanocomposites have immense potential for application in environmental remediation including in situ immobilisation of contaminants in soil.

Change of Structure and Properties of Sintered Alloys under the Influence Nanosized Carbon Additives

There was considered influence of nanosized carbon additives on structural phase state and properties of the sintered alloys on the copper, iron and tungsten-cobalt base. There was demonstrated that under liquid phase sintering and crystallization process of powder compositions that contain nanosized carbon particles. non-dissolved fraction of nanosized additive could be stands as additional nucleation centers, that promotes atomization of structure. There was established that for alloys that could be form solid solutions with carbon or hardening carbide phases. nanosized diamond- graphite additives increase of hardness of sintered composites and improve its tribotechnical characteristics