Carbon Black Samples Research Articles

Microwave irradiation on carbon black: Studies on the transformation of particles into nano-balls, nano-sticks and nano-onion like structures

The solid-state transformation behavior of carbon black (CB) nanoparticles after irradiated with microwave energy was studied with and without influence of a metal catalyst. The CB sample was exposed to microwave radiation at power of 900W from the oven and collected after 15min and after 30min and 45min of irradiation. The samples were characterized using X-ray diffraction measurements, Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis. Characterization of the samples prepared without catalyst shows that microwave irradiation can transform CB nanoparticles into nano–balls and nano–stick like structures. While nanoballs of almost 300–500nm diameter are visible in all the samples irrespective of microwave irradiation time, amorphous nano-stick like structure are present only in the sample collected after 30min of microwave irradiation. CB irradiated together with a metal catalyst resulted in metal-encapsulated onion like structures with perfectly arranged graphene layers.

The impact of physicochemical properties of coal on direct carbon solid oxide fuel cells

Two different coals were investigated, both before and after purification with inorganic acids, as solid fuels in a direct carbon solid oxide fuel cell (DC-SOFC). Prior to electrochemical investigations, elemental and technical analyses of both raw and purified coal samples were performed. It was found that the applied purification process considerably reduced the total amount of sulphur and mineral matter in the investigated coals. The phase composition of mineral matter in ash was also analysed, using the X-ray diffraction method as well as infrared spectroscopy. The reactivity of these coals in a CO2 atmosphere was investigated. It was found that the purified coal samples exhibited greater chemical reactivity than pure carbon black samples. The electrochemical oxidation of the raw and purified coal samples was investigated at a temperature range of 600–850 °C on the surface of an 8YSZ electrolyte. Lower values of current density and power were acquired from a DC-SOFC supplied with powdered coal containing higher amounts (8 wt.%) of mineral matter compared to coal with 4 wt.%. It was found that negative impact of silica and kaolinite contained in the former sample exceeded that expected from a sample containing 6 wt% of mineral matter on the process of electrochemical oxidation on the 8YSZ and Ni-YSZ surface.An improvement was observed in the performance of a DC-SOFC with a Ni-YSZ anode due to the presence of additional CO from the gasification of coals within the DC-SOFC.

Identifying and quantifying amorphous and crystalline content in complex powdered samples: application to archaeological carbon blacks

Carbon black materials have been frequently used from prehistory as pigments for drawings and paintings and also as dyes, inks and cosmetics, since they are easy to make by burning organic matter. However, the carbonaceous phases they form are often ill-ordered and not easy to characterize. Five carbon black Roman micro samples found in vessels in houses in Pompeii were studied. These precious powders correspond to mixed phase samples that contain both crystalline and ill-ordered components. Here, a methodological approach that accomplishes the identification, quantification and mapping of the different phases in these heterogeneous samples using synchrotron-based techniques is proposed. The results were compared with those from scanning electron microscopy. Information about the nature of the mixtures and the origin of carbon black pigments is obtained. The use of charred vegetable materials is concluded, independently of the shape and the nature of the container.

Mechanical and Morphological Properties of Nano Filler Polyester Composites

This research is focusing on mechanical and morphological properties of unsaturated polyester (UP) reinforced with two different types of filler which is nano size clay Cloisite 30B (C30B) and Carbon Black (CB). Samples were fabricated via hand lay-up and open molding technique. Percentages of Cloisite 30B & Carbon Black (CB) used vary from 0, 2, 4, 6, 8 and 10 wt%. The mechanical properties were evaluated by impact, flexural and hardness testing. Result shows that the mechanical strength of C30B was better compare to CB filled composite. The combination of UP with C30B helps to improve the properties due to the high surface area of nanosize filler in the matrix. The result shows that increasing of filler content had increased mechanical properties of composites. Optimum percentage represent good mechanical properties are 4% for both fillers. SEM images showed that rough surface image indicate to agglomeration of filler in the matrix for CB sample and smooth surface image on C30B sample indicate to homogenous blending between filler and matrix polyester. SEM images proved that mechanical properties result indicate that C30B polyester composite is a good reinforcement compare to CB polyester composite.

Physico-chemical characterization and source tracking of black carbon at a suburban site in Beijing

Particles from ambient air and combustion sources including vehicle emission, coal combustion and biomass burning were collected and chemically pretreated with the purpose of obtaining isolated BC (black carbon) samples. TEM (transmission electron microscopy) results indicate that BC from combustion sources shows various patterns, and airborne BC appears spherical and about 50nm in diameter with a homogeneous surface and turbostratic structure. The BET (Barrett–Emmett–Teller) results suggest that the surface areas of these BC particles fall in the range of 3–23m2/g, with a total pore volume of 0.03–0.05cm3/g and a mean pore diameter of 7–53nm. The nitrogen adsorption–desorption isotherms are indicative of the accumulation mode and uniform pore size. O2-TPO (temperature programmed oxidation) profiles suggest that the airborne BC oxidation could be classified as the oxidation of amorphous carbon, which falls in the range of 406–490°C with peaks at 418, 423 and 475°C, respectively. Generally, the BC characteristics and source analysis suggest that airborne BC most likely comes from diesel vehicle emission at this site.

The Effects of Ash and Black Carbon (Biochar) on Germination of Different Tree Species

AbstractForest fires generate large amounts of ash and biochar, or black carbon (BC), that cover the soil surface, interacting with the soil’s constituents and its seedbank. This study concerns reproductive ecology assessments supported by molecular characterisation to improve our understanding of the effects of fire and fire residues on the germination behaviour of 12 arboreal species with a wide geographic distribution. For this purpose, we analysed the effects of three ash and one BC concentration on the germination of Acacia dealbata Link, A. longifolia (Andrews) Willd., A. mearnsii De Wild., A. melanoxylon R. Br., Pinus nigra Arnold, P. pinaster Aiton, P. radiata D. Don, P. sylvestris L., Quercus ilex L., Q. pyrenaica Willd., Q. robur L., and Q. rubra L. Each tree species was exposed to ash and BC created from its foliage or twigs (except for Q. rubra, which was exposed to ash and BC of Ulex europaeus L.). We monitored germination percentage, the T50 parameter, and tracked the development of germination over time (up to 1 yr). The BC of A. dealbata, P. pinaster, and Q. robur was analysed by pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) to assess the molecular composition. In six species, ash inhibited the germination, while in another five species, germination was not affected by ash or by BC. In Q. rubra, ash and BC stimulated its germination. This stimulating effect of the BC on Q. rubra is likely to be related to the chemical composition of the ash and BC obtained from Ulex feedstock. The BC of U. europaeus has a very different molecular composition than the other BC samples analysed, which, together with other factors, probably allowed for its germination stimulating effects.

Mechanical Pressure Induced Capacitance Changes of Polyisoprene/Nanostructured Carbon Black Composite Samples

Polyisoprene/nanostructured carbon black (PNCB) composite samples with different amount of carbon black (CB) filler were prepared. Investigations of mechanical pressure induced relative capacitance changes (RCC) depending on frequency (20 Hz – 2 MHz) were conducted. It was found that PNCB samples show pronounced and rather complex RCC effect, which depends on frequency, amount of filler (1 – 10 phr of CB) and pressure (from 0 to 234 kPa). At a certain frequency and a certain filler amount RCC effect changes its sign. Pressure induced capacitance changes at least for low CB filler concentrations are caused by piezopermittivity property of the PNCB composite.

The Properties of Nanodispersed Carbon Black Particles After Thermal Treatment

The effect of thermal treatment at the temperature ranging from 800 to 2800°С on electrical resistance, specific adsorption surface and Raman spectrum of nanodispersed carbon black samples was investigated. It was determined that during the temperature increase, at first, the sample electrical resistance decreases (till the temperature of 1100 - 1600°С), and then rises. Specific adsorption surface decreases to geometrical one with the increase of the treatment temperature. New band appears within the range of ∼ 2570 cm-1 in Raman spectra after the thermal treatment at the temperature of 2000°С and higher.

Transmission electron microscopy study of the graphene layer transformation of carbon black under laser irradiation

The formation of carbon nanoparticles with ordered structure under nanosecond-duration pulsed laser irradiation of the carbon black samples has been studied. Electron microscopic images of the original and irradiated samples have been obtained and analyzed using the Digital Micrograph software package (Gatan). The length and curvature of graphene layers in high- and low-dispersive carbon black samples have been calculated. The distance between graphene layers (d002) has been measured. It was shown that the distance d002 decreases with an increase in the irradiation energy density.

Electrical conductivity behaviour of sheared poly(methyl methacrylate)/carbon black composites

Abstract The electrical conductivity behaviour of unsheared (static) and sheared poly(methyl methacrylate)/carbon black (CB) composite disc-shaped samples with various CB concentrations as a function of the radial position were investigated and analysed. It was found that the angular averaged electrical conductivity of the static samples is independent of the radius and CB concentration. In comparison to that, the angular averaged electrical conductivity of the samples with a shear history is decreasing as a function of the radius due to the linear increase of the deformation from the centre to the rim of the samples. It is shown, that this effect is less pronounced increasing the composite concentration. A simple model is proposed to explain this behaviour. The results obtained in this study are in a very good agreement with the investigations performed via coupled electrical and rheological measurements and provide a deeper insight into structural changes in conductive polymer composites induced by shear deformations.

Control of carbon black aggregate size by using polystyrene-polyethylene oxide non ionic diblock copolymers

The fine fraction of carbon black (CB) sample N234, initially prepared by the furnace process, was obtained by sieving and it was then dispersed in aqueous medium at various aqueous phase pH. Further, adsorption from water onto this non porous CB particles, of polystyrene-polyethylene oxide (PS-PEO), non ionic diblock copolymers, having molecular weights, Mw=2000 and Mw=4000g/mol, were investigated at ambient temperature. For the bare CB particles, prepared in the absence of copolymers, the TEM micrographs show aggregates and/or agglomerates having sizes depending of the aqueous phase pH, and formed from fused primary particles having sizes in the range 13–17nm. These aggregates develop intra-porosity that result from their branching shape. The CB bare particles prepared in acidic aqueous dispersion form mostly ellipsoidal agglomerates having sizes exceeding 500nm. However, by increasing the pH of the medium from pH=3 to pH=10, and after drying the CB dispersion, aggregates shaped as “bunch” of grapes and having smaller sizes are observed by TEM. The microelectrophoresis studies of these dispersions indicate that the CB particles are positively and negatively surface charged at pH values, respectively, below and above the Isoelectrical point (IEP) which is about pH∼6. Such electrokinetic behavior of the CB aqueous dispersion results from the presence on the CB surface of acidic and basic functional groups. However, upon PS-PEO copolymers adsorption onto CB, reduction in the magnitude of zeta potential, and shift of the Isoelectrical point (IEP) to lower pH values were observed. Such IEP shift is related to the copolymer adsorption on the Stern layer and to the position of the shear plane in the electrical double layer. In addition, the copolymer adsorption was found to reduce the CB particle size achieving a minimum value in water of about 200nm, resulting in sterically stable CB aqueous dispersions.

Sorption properties for black carbon (wood char) after long term exposure in soils

Amending soil with black carbon (BC) can change the sorption properties of the soil. However, there is some concern based on studies that deal with newly produced BC and barely consider the possible changes in sorption properties for BC after being amended in soil. This study uses newly produced BC and historical BC samples, along with soils containing high levels of historical BC and adjacent soils without visible BC, to compare their diuron, atrazine and Cu2+ sorption properties. Compared with newly produced BC, historical BC exhibited reduced (56–91%) sorption capacity for diuron and atrazine but 2–5 times enhanced sorption capacity of Cu2+. These changes in sorption properties can be interpreted via the formation of surface functional groups in BC. Whereas the sorption capacity for diuron and atrazine was reduced with historical BC, the sorption capacity of BC-containing soils was higher than for the adjacent soils, indicating that BC possessed stronger sorption capacity than non-BC material. A biological assay revealed reduced herbicide efficiency for the newly produced BC, and even the historical BC still exerted an influence on reducing herbicide efficiency. Along with its recalcitrance in environments, BC has a significant long term effect on the toxicity of contaminants and soil fertility.

Purification of fire derived markers for μg scale isotope analysis (δ13C, Δ14C) using high performance liquid chromatography (HPLC)

Black carbon (BC) is the residue of incomplete biomass combustion. It is ubiquitous in nature and, due to its relative persistence, is an important factor in Earth’s slow-cycling carbon pool. This resistant nature makes pure BC one of the most used materials for 14C dating to elucidate its formation date or residence time in the environment. However, most BC samples cannot be physically separated from their matrices, precluding accurate 14C values. Here we present a method for radiocarbon dating of the oxidation products of BC, benzene polycarboxylic acids, thereby circumventing interference from extraneous carbon. Individual compounds were isolated using high performance liquid chromatography (HPLC) and converted to CO2 via wet chemical oxidation for 13C and 14C isotope analysis. A detailed assessment was performed to identify and quantify sources of extraneous carbon contamination using two process standards with distinct isotopic signatures. The average blank was 1.6±0.7μgC and had an average radiocarbon content of 0.90±0.50 F14C. We successfully analyzed the 14C content of individual benzene polycarboxylic acids with a sample size as small as 20–30μgC after correcting for the presence of the average blank. The combination of δ13C and F14C analysis helps interpret the results and enables monitoring of extraneous carbon contribution in a fast and cost efficient way. Such a molecular approach to radiocarbon dating of BC residues enables the expansion of isotopic BC studies to samples that have either been too small or strongly affected by non-fire derived carbon.

Prediction of absorption coefficients by pulsed laser induced photoacoustic measurements

In the current study, a pulsed laser induced photoacoustic spectroscopy setup was designed and developed, aiming its application in clinical diagnostics. The setup was optimized with carbon black samples in water and with various tryptophan concentrations at 281nm excitations. The sensitivity of the setup was estimated by determining minimum detectable concentration of tryptophan in water at the same excitation, and was found to be 0.035mM. The photoacoustic experiments were also performed with various tryptophan concentrations at 281nm excitation for predicting optical absorption coefficients in them and for comparing the outcomes with the spectrophotometrically-determined absorption coefficients for the same samples. Absorption coefficients for a few serum samples, obtained from some healthy female volunteers, were also determined through photoacoustic and spectrophotometric measurements at the same excitations, which showed good agreement between them, indicating its clinical implications.

Characterization of Black Carbon Collected from Candle Light and Automobile Exhaust Pipe

Black carbon contributes to global warming and melting of polar ice as well as causing respiratory diseases. However, it is also an inexpensive, easily available carbon nano material for elementary chemistry experiments. In this study, black carbon samples collected from candle light and automobile exhaust pipes have been investigated to examine their compositions and surface characteristics. The observed broad G and D bands and amorphous <TEX>$sp^3$</TEX> band in their Raman spectra as well as the high intensity of the D (defect) band reveal that black carbon is principally made of amorphous graphite. The black carbon deposits in automobile exhaust pipes are apparently more amorphous, probably due to the shorter time allowed for formation of the carbonaceous matter. An exceptionally large water contact angle (<TEX>$159.7^{\circ}$</TEX>) is observed on black carbon, confirming its superhydrophobicity. The surface roughness evidently plays an important role for the contact angle much larger than that of crystalline graphite (<TEX>$98.3^{\circ}$</TEX>). According to the Sassie-Baxter equation, less than 1% the area actually in contact with the water drop.

Microstructural Effect of Carbon Blacks for the Application in Lithium Ion Batteries

Carbon blacks commercially available (Super P, SP and Ketjen black, KB) and synthesized by a liquid phase plasma process (SC) were compared for the lithium ion battery applications as an anode material. All the carbon black samples were spherical with sizes in the range of 30–50 nm. The Brunauer–Emett–Teller (BET) specific surface areas of the SP, KB, and SC samples were measured to be 62, 1452, and 895 m2/g, respectively. The overall fraction of the ordered structure, represented by the ratio of the G-band to the D-band (G/D raio) from Raman spectra, was highest for the SC sample. A large specific surface area of the samples was found to play an important role in storing lithium ions, contributing to high initial charge capacities, 2050 mAh/g for KB and 1542 mAh/g for SC. The initial charge–discharge coulombic efficiency of the samples was strongly influenced by the solid electrolyte interface (SEI) formation behavior. The behavior of SEI formation seemed to be affected by the microstructural characteristics of the carbon blacks such as crystallinity and G/D ratio. The SC sample having a high G/D ratio and a slight variation without a peak of dQ/dV with potential showed a small initial capacity irreversibility.

Influence of carbon black in polychloroprene organoclay nanocomposite with improved mechanical, electrical and morphology characteristics

The effect of carbon black on nanoclay filled polychloroprene (CR) composites has been investigated. The nanoclay loading is fixed at 5 part per hundred rubbers (phr), and carbon black loading varied from 5 to 20 phr in rubber compounds. The rubber nanocomposites are prepared in laboratory by mixing in two-roll mill. The addition of nanoclay enhances mechanical properties especially tear strength and decreases water absorption without change in electrical properties compared to gum rubber vulcanisates. Wide angle X-ray diffraction and transmission electron microscopy are used to study the microstructure of CR nanocomposites. The addition of 5 parts of nanoclay to 15 phr carbon black filled samples shows synergistic effect between the fillers and suggests that the reinforcement is due to a more developed filler network formation in hybrid filler system than that in single phase filler. Significant improvement in mechanical, electrical and low water absorption properties has been obtained with these nanoclay and carbon black filled rubber nanocomposites. The paper concludes that nanocomposites containing a mixture of organoclay and carbon black in right proportion can be a substitute for rubber components used in underwater cable and device encapsulation applications.

Serum protein oxidation by diesel exhaust particles: Effects on oxidative stress and inflammatory response in vitro

Considerable evidence shows a key role for protein modification in the adverse effects of chemicals; however, the interaction of diesel exhaust particles (DEP) with proteins and the resulting biological activity remains unclear. DEP and carbon black (CB) suspensions with and without bovine serum albumin (BSA) were used to elucidate the biological effects of air pollutants. The DEP and CB samples were then divided into suspensions and supernatants. Two important goals of the interaction of DEP with BSA were as follows: (1) understanding BSA modification by particles and (2) investigating the effects of particles bound with BSA and the corresponding supernatants on cellular oxidative stress and inflammation. We observed significant free amino groups production was caused by DEP. Using liquid chromatography–mass spectrometry (LC−MS), we observed that BSA was significantly oxidised by DEP in the supernatants and that the peptides ETYGDMADCCEK, MPCTEDYLSLILNR and TVMENFVAFVDK, derived BSA-DEP conjugates, were also oxidised. In A549 cells, DEP-BSA suspensions and the corresponding supernatants reduced 8-hydroxy-2′-deoxyguanosine (8-OHdG) production and increased interleukin-6 (IL-6) levels when compared to DEP solutions without BSA. Our findings suggest that oxidatively modified forms of BSA caused by DEP could lead to oxidative stress and the activation of inflammation.

Mapping the Electrical Conductivity of Poly(methyl methacrylate)/Carbon Black Composites Prior to and after Shear

In this letter, the electrical conductivity of disklike poly(methyl methacrylate)/carbon black composite samples was investigated prior to and after a shear process. Novel electrical conductivity maps of the samples as a function of the position were obtained. It was found that the electrical conductivity after angular averaging of the static (nonsheared) sample is, as expected, independent of the radius. However, for the sheared sample, the electrical conductivity is decreasing from the center to the outer rim of the sample. This is attributed to the interplay of destruction and buildup effects of the applied linear shear stress on the agglomerate network.

Broadly tunable quantum cascade laser in cantilever-enhanced photoacoustic infrared spectroscopy of solids

An external cavity quantum cascade laser (EC-QCL) is applied in the photoacoustic detection of solid samples. The EC-QCL used has a broad tuning range of 676 cm−1 (970–1,646 cm−1) in the mid-infrared region, which enables accurate broadband spectroscopy of large molecules. The high spectral power density of the EC-QCL is combined with an extremely sensitive optical cantilever microphone of the photoacoustic detector to achieve an ultimate sensitivity. The carbon black, polyethylene, and hair fiber samples were measured with the EC-QCL photoacoustic detection using electrical amplitude modulation to demonstrate the possibilities of the setup. The same measurements were repeated with a Fourier transform infrared (FTIR) spectrometer combined with a photoacoustic detector for a comparison. The EC-QCL photoacoustic setup yielded roughly a decade better signal-to-noise ratios than the FTIR setup with the same measurement time.