Commercial Carbon Blacks Research Articles

Recycled Carbon Black/High-Density Polyethylene Composite from Waste Tires: Manufacturing, Testing, and Aging Characterization

This study addresses the global issue of recycling used vehicle tires, typically burned out or trimmed to be reused in playground floors or road banks. In this study, we explore a novel environmentally responsive approach to decomposing and recovering the carbon black particles contained in tires (25–30 wt.%) by vacuum pyrolysis. Given that carbon black is well known for its UV protection in plastics, the objective of this research is to provide an ecological alternative to commercial carbon black of fossil origin by recycling the carbon black (rCB) from used tires. In our research, we create a composite material using rCB and high-density polyethylene (HDPE). In this article, we present the environmental aging studies carried out on this composite material. The topographic evolution of the samples with aging and the oxidation kinetics of the surface and through the thickness were studied. The Beer–Lambert law is used to relate the oxidative index to the characteristic depth of the samples. The UV photons are observed to penetrate up to 54% less with the addition of 6 wt.% of rCB compared to virgin HDPE. In this work, the addition of rCB as filler for HDPE used for outdoor applications has demonstrated to be an antioxidant for UV protection and a good substitute for commercial carbon black for industrial goods.

Solar steam generation enabled by carbon black: The impact of particle size and nanostructure

AbstractHere, commercial carbon black (CB) grades are characterized in detail to determine the link between their physicochemical properties and solar steam generation performance. The CB nanoparticles used here have surface mean primary particle diameters of 11–406 nm resulting in specific surface areas of 8–300 m2/g. Thermogravimetric analysis, dynamic light scattering, Raman spectroscopy, and x‐ray diffraction reveal that fine CB nanoparticles form large agglomerates, have a more disordered nanostructure and larger organic carbon content than coarse CB grades. Most importantly, UV–vis spectroscopy and Mie theory show that increasing the particle size from 14 to 406 nm reduces the light absorption of CB dispersed in water up to 86%. So, the water evaporation flux of suspensions containing 11–14 nm CB nanoparticles is up to 25% larger than that obtained for suspensions of 406 nm particles. Thus, good control of particle size is essential to optimize the solar steam generation enabled by CB.

Harnessing the Potential of Hollow Graphitic Carbon Nanocages for Enhanced Methanol Oxidation Using PtRu Nanoparticles.

Direct Methanol Fuel Cell (DMFC) is a powerful system for generating electrical energy for various applications. However, there are several limitations that hinder the commercialization of DMFCs, such as the expense of platinum (Pt) at market price, sluggish methanol oxidation reaction (MOR) due to carbon monoxide (CO) formation, and slow electrooxidation kinetics. This work introduces carbon nanocages (CNCs) that were obtained through the pyrolysis of polypyrrole (Ppy) as the carbon source. The CNCs were characterized using BET, XRD, HRTEM, TEM, SEM, and FTIR techniques. The CNCs derived from the Ppy source, pyrolyzed at 750 °C, exhibited the best morphologies with a high specific surface area of 416 m2g-1, allowing for good metal dispersion. Subsequently, PtRu catalyst was doped onto the CNC-Ppy750 support using chemical reduction and microwave-assisted methods. In electrochemical tests, the PtRu/CNC-Ppy750 electrocatalyst demonstrated improved CO tolerance and higher performance in MOR compared to PtRu-supported commercial carbon black (CB), with values of 427 mA mg-1 and 248 mA mg-1, respectively. The superior MOR performance of PtRu/CNC-Ppy750 was attributed to its high surface area of CNC support, uniform dispersion of PtRu catalyst, and small PtRu nanoparticles on the CNC. In DMFC single-cell tests, the PtRu/CNC-Ppy750 exhibited higher performance, approximately 1.7 times higher than PtRu/CB. In conclusion, the PtRu/CNC-PPy750 represents a promising electrocatalyst candidate for MOR and anodic DMFC applications.

Facile and scalable synthesis of N-doped carbon based Ni electrocatalyst for efficient CO2 reduction to CO

Electrochemical reduction of CO2 into valuable chemical products could be realized by reasonable design of effective electrocatalysts with atomically dispersed active sites, but the task presents challenges for chemistry because of the lack of facile and scalable synthetic route. Therefore nitrogen-doped porous carbon supported Ni electrocatalyst is presented via a facile synthetic method. In the first step, commercial carbon black was oxidized by HNO3 to generate organic group followed by absorption of Ni ions. Secondly, calcination under NH3 atmosphere led to N doped carbon based Ni catalyst which exhibited excellent catalytic performance with approximate 95 % Faradaic efficiency for CO, which is helpful for chemists to reasonable design and scalable preparation of economical and efficient catalysts.

Unveiling the surface of carbon black via scanning probe microscopy and chemical state analysis

Carbon black (CB) has wide range of industrial applications, including in the manufacturing of automobile tires, rubber products, inks, and plastics. To improve the properties of the target products and establish recycling systems, it must be fully characterized. However, characterization of CB is challenging owing to its structural complexity and the limitation of conventionally used experimental techniques, especially for surface structures at the nanoscale. In this study, we characterized the surface structures of two commercial CB via atomic force and scanning tunneling microscopy. Analysis of well-dispersed aggregates on atomically flat solid surfaces revealed primary particles of diverse sizes. The particle surfaces lacked edges, grooves, and steps that should be observed between stacked graphene sheets, which contradicts the widely accepted crystallite model. Observed images suggest that the graphene sheets exhibit a size distribution, inferring that multiple non-uniformly sized small graphene sheets are stacked turbostratically, with each sheet displaying a localized curvature rather than the ideal planar form. Varying size of sheets and curvature indicate the presence of a decent number of edges terminated with hydrogen and oxygen-containing functional groups. This interpretation was corroborated by conventional spectroscopic techniques: Raman spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption, and infrared absorption spectroscopy.

Hydrogen peroxide electrosynthesis using commercial carbon blacks as catalysts: the influence of surface properties and adsorption performance

AbstractBACKGROUNDSurface properties and adsorption performance of carbon materials play a crucial role in the electrochemical two‐electron oxygen reduction to produce H2O2. However, there is still a lack of in‐depth research on commercial carbon blacks in this area. Herein, four typical commercial carbon blacks (Acetylene black (AB), Ketjen black EC 600JD, Vulcan XC 72 and Black Pearls 2000) were used as cathode catalysts to generate H2O2. Surface chemistry and pore structure of electrodes of the four carbon blacks were systematically characterized, and their effects on H2O2 adsorption, electrochemical generation and degradation were investigated.RESULTSAmong the four carbon blacks, AB has the highest content of C–O–C/COOH and CO, which are active groups catalyzing the two‐electron oxygen reduction reaction to generate H2O2. AB has the lowest level of defects and highest degree of graphitization, and AB‐modified graphite felt electrode (AB‐Ele) has the largest average pore diameter, smallest specific surface area and smaller charge transfer resistance. H2O2 production using AB‐Ele is the largest and reaches 567.7 mg L−1 at 180 min under a current density of 5 mA cm−2, and only decreases by 17.6% after 10 repeated uses.CONCLUSIONOverall, rich oxygen‐containing functional groups such as C–O–C, COOH and CO, high degree of graphitization, suitable surface area and porosity as well as weak H2O2 adsorption performance are beneficial for the two‐electron oxygen reduction reaction to generate H2O2. AB‐modified graphite felt electrode exhibits good catalytic activity and reusability in H2O2 electrosynthesis, demonstrating promising application prospects. © 2024 Society of Chemical Industry (SCI).

Recycled from waste tires carbon black/high‐density polyethylene composite: Multi‐scale mechanical properties and polymer aging

AbstractThis study addresses the global issue of recycling vehicle rubbish tires by a vacuum pyrolysis process, exploring a novel environmentally responsive approach for thermal decomposition and recovery of the carbon black particles contained in tires (25–30 wt%). Carbon black is typically used for its UV protection in plastics and abrasion resistance in composites and rubbers. This research aims at providing an eco‐responsible alternative to commercial carbon black of fossil origin by recycling the carbon black (rCB) from end‐of‐life tires. A particle reinforced composite material was developed containing rCB and high‐density polyethylene. For comparison purposes, an identical composite was manufactured using commercial carbon black (CB). Accelerated aging studies have been carried out on the materials. Topographic evolution of the samples with aging and oxidation kinetic of the surface and through the thickness were studied. Multiscale mechanical properties have been evaluated for a more comprehensive understanding of the mechanisms involved in the degradation. A comparison of the different materials properties was carried out in order to highlight the various elements linked to the degradation and UV protection of materials. This work helps demonstrating the feasibility of using recycled carbon black particles from waste tires as a high‐performance filler for plastics and composites.Highlights Recycled carbon black (rCB) is an eco approach of revalorizing tire waste. Vacuum pyrolysis successfully allows recovery of reusable rCB. The rCB acts as a photon absorber, limiting degradation of HDPE. The rCB limits the cross‐linking responsible of embrittlement of HDPE. A critical carbonyl index of 20 marks the occurrence of cracks and degradation.

Catalytic performance of modified carbon black on methane decomposition for hydrogen production.

Carbon-based catalysts catalyze methane decomposition to produce hydrogen is a very attractive technical route. Carbon black in carbon-based catalysts has the advantages of high catalytic activity, good stability and better tolerance to toxic impurities such as sulphur in the feedstock, which has become a hot topic of research for many scientists. In this work, the effect of heat treatment on the structural and surface properties of carbon blacks and their catalytic performance in hydrogen production from methane decomposition was investigated. A commercial carbon blacks N110 was selected to heat treatment with nitrogen or carbon dioxide atmosphere at 850 °C, respectively. The Raman spectrums indicated that the graphitization degree of modified carbon under two atmospheres were promoted with the treatment time increasing. BET results revealed that the specific surface area of the carbon black treated under carbon dioxide increased, while the specific surface area was unchanged for that of the carbon black treated under nitrogen. The catalytic test of the two modified carbon blacks for methane decomposition exhibited the almost same activity, which meant that the graphitization degree of carbon black is the key factor for methane decomposition rather than the specific surface area. It was suggested that highly graphitized carbon black could be used as the potential catalysts for hydrogen production from methane decomposition.

Fabrication of carbon black nanoparticles from green algae and sugarcane bagasse

There are several industrial uses for carbon black (CB), an extremely fine powdered form of elemental carbon that is made up of coalesced particle aggregates and almost spherical colloidal particles. Most carbon black is produced from petroleum-derived feedstock, so there is a need to find an alternative method to produce CB, which relies on renewable resources such as algae and agricultural waste. A process involving hydrolysis, carbonization, and pyrolysis of green algae and sugarcane bagasse was developed, as the optimal hydrolysis conditions (16N sulfuric acid, 70 °C, 1 h, 1:30 g/ml GA or SC to sulfuric acid ratio), a hydrolysis ratio of 62% for SC and 85% for GA were achieved. The acidic solution was carbonized using a water bath, and the solid carbon was then further pyrolyzed at 900 °C. The obtained carbon black has a high carbon content of about 90% which is confirmed by EDX, XRD, and XPS analysis. By comparison carbon black from sugar cane bagasse (CBB) and carbon black from green algae Ulva lactuca (CBG) with commercial carbon black (CCB) it showed the same morphology which was confirmed by SEM analysis. The BET data, showed the high specific surface area of prepared CB, which was 605 (m2/g) for CBB and 424 (m2/g) for CBG compared with commercial carbon black (CBB) was 50 (m2/g), also the mean pore diameter of CBB, CBG and CCB indicated that CBB and CBG were rich in micropores, but CCB was rich in mesoporous according to IUPAC classification. This study might have created a technique that can be used to make carbon black from different kinds of biomass.

Enhanced advanced oxidation treatment through the synergy of chloride ion activation and electro-Fenton process

A photoelectrocatalytic system has been developed utilizing the WO3@BiVO4 photoanode and the oxidized carbon black (CB) cathode, enabling the synergistic advanced oxidation treatment by combining chlorine radicals and hydroxyl radicals. The WO3@BiVO4 heterojunction is prepared through hydrothermal growth of BiVO4 onto the surface of WO3 synaptic structure. The as-prepared WO3@BiVO4|Pt system demonstrates a remarkable degradation efficiency of organic pollutants with 97.1 % in 30 min under visible light irradiation with a 1.2 V bias, which is 1.24 times higher compared to the WO3|Pt system. Furthermore, even when utilizing actual seawater as the electrolyte, the treatment efficacy remains high at 92.8 % within 20 min. The oxidized CB cathode is obtained by calcining commercial CB in the air atmosphere. The WO3@BiVO4|CB system achieves the degradation efficiency of 85.9 % within 10 min in simulated seawater, utilizing the electro-Fenton process at 0.2 V. The WO3@BiVO4|CB system effectively removes organic pollutants through the synergistic effect of combining the WO3@BiVO4 photoanode with CB-A cathode. Additionally, impressive degradation efficiency of 97.8 % is achieved in 15 min when using simulated seawater as the electrolyte. The •OH, •Cl, and •Cl2− play the key role in the WB|CB-A synergistic system. The combined action of anodic active chlorine radicals and cathodic electro-Fenton process in the WO3@BiVO4|CB system demonstrates effective microorganism sterilization, resulting in a 92.5 % reduction within 15 min

Performance of Full-Component Coal Gasification Fine Slag: High-Value Utilization as Reinforcing Material in Styrene-Butadiene Rubber (ESBR) for Replacing Carbon Black.

Ultrafine, highly active coal gasification slag (HCGS) was produced via a sustainable, green dry-ball-milling method. Coal gasification fine slag (CGS), a potential environmental pollutant, was used as a new source of rubber filler without pre-treatment, enabling waste utilisation. HCGS was added to styrene-butadiene rubber (ESBR) composites, and the effects of HCGS and the filler content on the mechanical and thermal stabilities of SBR were evaluated. The procedure conforms to important green metrics, requiring no solvent or additional reagent, or solvent-assistance for product collection. HCGS reduced the scorch time (t10) and curing time (t90) of the filled ESBR composites relative to those of pure SBR and improved the mechanical parameters. The tensile strength at 50 phr reached 10.91 MPa, and the tear strength at 90 phr reached 64.92 kN/m, corresponding to 9.4- and 3.92-fold increases relative to that of SBR filled with HCGS, respectively. HCGS exerted a reinforcing effect on ESBR, comparable to that of commercial carbon black (CB) N330. HCGS improves the binding between rubber molecules and filler particles and captures the rubber chain, thereby limiting its movement. HCGS is potentially applicable as a CB substitute in the rubber industry, with environmental and economic benefits in the disposal of CGS.

Carbon black preparation by partial oxidation of spent tyre pyrolysis oil – Influence of temperature, residence time and oxygen to feed ratio

Preparation of carbon black (CB) by partial oxidation of the spent tyre pyrolysis oil (STPO) and its heavy residue fraction (HRF) was systematically studied using a lab-scale drop tube furnace. The effect of furnace operating temperature (T: 1100 to 1400 °C), residence time (tr: 5 to 60 s) and oxygen to feed ratio (O/F: 174 to 732) on the yield and quality of CB was examined using the response surface methodology (RSM). T was shown to have the most significant influence on CB yield and properties. While the CB yield was also influenced by tr, the quality was more sensitively dependent on T and O/F. The predicted optimal tr and O/F were approximately the same for both feedstocks (60 s and 174, respectively). However, T was higher for the HRF feedstock (1368 °C) than the STPO feedstock (1331 °C) due to the abundance of more viscous heavy hydrocarbons in HRF. Validation experiments under the aforementioned conditions demonstrated the models’ ability to predict responses accurately. The CB from both feedstocks had low contents of ash (<0.03%), volatiles (∼0.5%), sulphur (<0.7%), and high carbon (≥95%). The BET surface area and average primary particle size for CB from STPO and HRF were comparable to those of commercial CBs from fossil fuel feedstock. The CB from HRF had a higher carboxyl oxygen functional group (18%) compared to the CB from STPO (∼13%) and commercial CB (<5%).

CHARACTERIZATION OF STICKY DEBRIS GENERATED DURING SMEAR WEAR

ABSTRACT Smear wear behavior has often been observed during rubber abrasion, especially under mild test severities. It generates degraded sticky rubber debris that often produces erratic measurements of abrasion weight loss. Various practical methods to avoid or remove the debris from the abrasion test surface have been reported, such as applying a drying powder lubricant. However, the detailed mechanism of smear wear behavior is still not clear. Various characterization techniques are applied to investigate the smear wear of both an unfilled NR model compound and a commercial carbon black (CB)–filled SBR tire tread compound obtained during blade abrasion testing. The debris showed lower molecular weight and higher oxygen content than the virgin materials. In addition, 75% of the smear wear was found to be de-crosslinked during smear wear, as detected by the double quantum-NMR technique. For the first time, it is demonstrated that both the polymer itself and crosslinking points are broken down during smear wear. The effect of the smear layer on friction and abrasion is also discussed.

Correlating oxygen functionalities and electrochemical durability of carbon supports for electrocatalysts

Achieving high durability of the polymer electrolyte membrane (PEM) fuel cell catalysts remains a major challenge. While most of the research focuses on the active phase, carbon support remains overlooked. In this study durability of carbon support materials for Pt alloy nanoparticles is critically evaluated. First graphene derivative (GD) based carbon supports with different chemical properties are prepared and utilized along with widely used commercial carbon black (CB) material. High-temperature electrochemical accelerated degradation tests (HT-ADTs) combined with X-ray photoelectron spectroscopy (XPS) show that the total amount of oxygen functionalities, the type of oxygen functionalities, and sp2 carbon content play a crucial role in carbon support durability. The observations were confirmed with the direct online measurements of carbon corrosion via an advanced in-situ technique – an electrochemical cell coupled with a mass spectrometer (EC-MS). We report that increasing the content of sp2 carbon and decreasing carboxyl functional groups have the most beneficial effect on stability. The study provides important guidelines for tailoring the carbon support properties and their relationship to the durability of the electrocatalyst, which could be crucial for producing more stable catalysts and achieving the Department of Energy's fuel cell system lifetime targets. Moreover, the innovative carbon design approach presented here could be applied in other fields such as batteries, supercapacitors, sensors and others.

Natural Rubber Composites Using Hydrothermally Carbonized Hardwood Waste Biomass as a Partial Reinforcing Filler-Part II: Mechanical, Thermal and Ageing (Chemical) Properties.

Natural rubber composites were reinforced by the co-fillers 'hydrochar' (HC), obtained by hydrothermal carbonization of hardwood sawdust and commercial carbon black (CB). The content of the combined fillers was kept constant while their ratio was varied. The aim was to test the suitability of HC as a partial filler in natural rubber. Due to its larger particle size and hence smaller specific surface area, large amounts of HC reduced the crosslinking density in the composites. On the other hand, due to its unsaturated organic character, HC was found to display interesting chemical effects: if it was used as the exclusive filler component, it displayed a very strong anti-oxidizing effect, which greatly stabilized the rubber composite against oxidative crosslinking (and hence embrittlement). HC also affected the vulcanization kinetics in different ways, depending on the HC/CB ratio. Composites with HC/CB ratios 20/30 and 10/40 displayed interesting chemical stabilization in combination with fairly good mechanical properties. The performed analyses included vulcanization kinetics, tensile properties, determination of density of permanent and reversible crosslinking in dry and swollen states, chemical stability tests including TGA, thermo-oxidative aging tests in air at 180 °C, simulated weathering in real use conditions ('Florida test'), and thermo-mechanical analyses of degraded samples. Generally, the results indicate that HC could be a promising filler material due to its specific reactivity.

Cobalt-nitrogen-carbon sites on carbon aerogels for enhanced electrocatalytic CO2 activity

Developing highly-efficient electrocatalysts with metal-nitrogen-carbon (M−NxC) sites for electrochemical CO2 reduction reaction (CO2RR) towards carbon monoxide (CO) is an effective way towards carbon neutralization. Herein, nitrogen-doped carbon aerogels (N-CA) supported Co-NxC sites with cobalt phthalocyanine (CoPc) as precursor via pyrolysis (500 ℃) strategy is reported. The CoPc@N-CA-500 catalyst with the average pore size of 8.57 nm, displays a wide potential window from −0.5 to −0.9 V vs. RHE with the CO Faradaic efficiency (FECO) over 80%. It also exhibits the maximal FECO of 92.48%, the CO partial current density of 21.72 mA cm−2, CO turnover frequency (TOFCO) of 1.23 s−1 and stability over 20 h (under −0.8 V vs. RHE), which is significantly higher than that of CoPc@CB-500 (53.91%, 4.47 mA cm−2, 0.14 s−1) with the average pore size of 2.54 nm, while selecting commercial carbon black (CB) as the carrier. The superior activity of CoPc@N-CA-500 could be attributed to its unique porous system, which not only promotes the mass transfer of CO2 molecules to facilitate the CO2RR kinetic, but is beneficial to expose Co active sites. Meanwhile, a home-made zinc-CO2 battery with CoPc@N-CA-500 as cathode achieved a peak power density of 0.69 mW cm−2 and maximum FECO of 87.41%.

Improving graphenic quality by oxidative liberation of crosslinks in non-graphitizable carbons

This work assesses the potential for improving the crystallinity of non-graphitizable carbon materials by oxidative liberation of crosslinks. A model non-graphitizable carbon – sucrose char and two commercial carbon blacks of varied nanostructure have been used to study crystallinity improvements at two oxidative burnout levels. The virgin materials have been compared to their partially oxidized counterparts at a series of heat treatment temperatures using X-ray diffraction for bulk crystallinity analysis and high-resolution transmission electron microscopy for nanostructural characterization. Remarkable improvements were observed in the case of sucrose char where non-graphitizable sponge-like particles transformed into highly ordered graphenic flakes by the mechanism of oxidative liberation of crosslinks. The in-plane crystallite size and stacking height tripled after the liberation of the restrictive crosslinks. Molecular level changes after partial oxidation have been assessed using Raman spectroscopy while X-ray photoelectron spectroscopy is used to assess changes in elemental composition. Notable improvements were also observed in carbon blacks with the development of longer and lower tortuosity lamellae accompanied by expanded particle sizes. Fringe analysis algorithms have been applied to obtain lamellae statistics and highlight nuances in the nanostructure changes after partial oxidation and heat treatment.

Valorization of polluted biomass waste for manufacturing sustainable cathode materials for the production of hydrogen peroxide

A circular economy approach was followed to convert biomass wastes polluted with metals (obtained from phytoremediation processes) to generate electroactive carbon materials to be used in the electrochemical production of hydrogen peroxide. Carbon materials were pretreated using hydrothermal carbonization at 200ºC and 130 g soil mL−1 water and post treated through pyrolysis at different temperatures (300ºC, 500ºC and 1000ºC) and using different chemical precursors as KOH or H3PO4. These materials would modify the carbon paper (CP) cathodes to substitute the commonly used carbon black (CB), that comes from fossil fuels. Porosity, thermochemical behavior, electrical conductivity, electrocatalytic response and H2O2 accumulation tests were evaluated to determine the potential performance of these materials in the electrochemical production of hydrogen peroxide. Delays in mass losses observed in thermogravimetric studies indicate the improvement of the thermal stability of materials which are related with the highest electrical conductivity (that correspond to hydrochar pyrolyzed at 1000 ºC). High specific surface areas (1097 and 704 m2/g) were also found with hydrochars treated with chemical precursors with values even superior to commercial CB. Results show that all activated hydrochars present electrocatalytic activity towards the production of hydrogen peroxide and that the materials chemically activated with KOH can achieve a 70% of the H2O2 production obtained with commercial CB. Moreover, it was found that the presence of metals in the synthesized materials may promote a Fenton-like reaction, increasing by 40% the generation of hydroxyl radicals with respect to commercial CB. This paramount finding opens the window for the use of this phytoremediation waste to produce sustainable electrode materials for upgraded electrochemical advanced oxidation processes.

Influence of a novel coupling agent on the performance of recovered carbon black filled natural rubber

Using recovered carbon black (rCB) from end-of-life tires to replace commercialized carbon blacks has drawn great attention in recent years. But rCB has poor reinforcement properties in comparison with such commercial carbon blacks like carbon black N330 when used in tire rubber composites. In this study, carbon black N330 was replaced at different proportions (50% and 100%) by rCB in natural rubber (NR) compounds used for tire tread rubber. The influence of a novel coupling agent, sodium (Z)-4-((4-aminophenyl) amino)-4-oxobut-2-enoate, on the reinforcement properties of rCB was studied. The addition of the coupling agent improved the dispersion of rCB and increased the content of bound rubber of NR compounds, and increased tensile strength, modulus at 100% and 300% strains of NR vulcanizates. The coupling agent also weakened the Payne effect and reduced the rolling resistance of NR vulcanizates filled rCB. Using the coupling agent is a simple and effective approach to the high-valued application of rCB in NR.

Damage Effect of Amorphous Carbon Black Nanoparticle Aggregates on Model Phospholipid Membranes: Surface Charge, Exposure Concentration and Time Dependence.

Commercial nano-scale carbon blacks (CB) are being harnessed widely and may impose potentially hazardous effects because of their unique properties, especially if they have been modified to grow reactive functional groups on their surface. Cytotoxicity of CB has been well studied but the membrane damage mechanisms and role of surface modification are still open to debate. Negatively and positively charged giant unilamellar vesicles (GUVs) were prepared using three lipids as model cell membranes to examine the mechanistic damage of CB and MCB (modified by acidic potassium permanganate) aggregates. Optical images showed that both anionic CB and MCB disrupted the positively charged but not the negatively charged GUVs. This disruption deteriorated with the rise and extension of exposure concentration and time. Lipids extraction caused by CBNs (CB and MCB together are called CBNs) was found. MCB caused more severe disruption than CB. MCB was enveloped into vesicles through an endocytosis-like process at 120 mg/L. MCB mediated the gelation of GUVs, perhaps through C-O-P bonding bridges. The lower hydrodynamic diameter and more negative charges may have been responsible for the distinction effect of MCB over CB. The adhesion and bonding of CBNs to the membrane were favored by electrostatic interaction and the practical application of CBNs warrants more attention.