Carbon Black and Soot: Two Different Substances

Abstract

Carbon blacks are manufactured under controlled conditions for commercial use primarily in the rubber, painting, and printing industries. In contrast, soots are unwanted byproducts from the combustion of carbon-based materials for the generation of energy or heat, or for the disposal of waste. Unfortunately, the terms carbon black and soot often have been used interchangeably; however, carbon black is physically and chemically distinct from soot. Greater than 97% of carbon black consists of elemental carbon arranged as aciniform particulate. Depending on the type of soot, the relative amount of carbon (< 60% of the total particle mass), the type of particulate carbon, and particle characteristics (size, shape, and heterogeneity) can vary considerably. For both carbon black and soot, other elements and chemical compounds are associated with the particulate carbon. Total inorganics (ash) represent < 1% of the carbon black particle mass. Organic compounds can be extracted from particle surfaces (solvent extractable fraction [SOF]), and for carbon black, also are < 1% of the particle mass. Soots have much greater percentages of ash, SOF, or both, than carbon black. There has been concern about the adsorbed organic compounds because of potential biologic activity. For carbon black, the SOF is strongly adherent to carbon surfaces and is not released by biological fluids. The types of organic compounds consist primarily of unsubstituted polycyclic aromatic hydrocarbons and are not as biologically potent as those compounds present in soot. Thus, carbon black is distinctly different from soot, and when discussing potential health effects, care must be taken to differentiate between the two types of carbon-based particles.

Evaluation of elemental carbon as a marker for diesel particulate matter

“…The developing convention is to use BC as the definition of optical measurements of light-absorbing carbon (Novakov, 1984;Goldberg, 1985) and EC as the definition of refractory carbon measured by thermal/optical carbon analyzers. The term Carbon Black should only be used to describe the commercially produced commodity that is used in the rubber, painting and printing industries (Watson and Valberg, 2001). These specific definitions are used in this paper.…”

Ns-Soot: A Material-Based Term for Strongly Light-Absorbing Carbonaceous Particles

“…Soot, on the other hand, according to wide usage in combustion research, is carbon-rich material that condenses from the vapor phase during combustion (Figure 1; Ishiguro et al 1997;Richter and Howard 2000;Watson and Valberg 2001). However, no consensus exists in the atmospheric science community about whether soot is a part of BC, BC is a part of soot, or BC is equivalent to soot.…”

Beyond the basics: A systematic approach for comprehensive analysis of organic materials in Asian lacquers

“…These materials are extremely complex and their formulations depend on the source material, heating conditions and method of collection (Watson & Valberg, 2001;Achten et al, 2015). A small number of polycyclic aromatic compounds have been observed in black lacquers that are absent in transparent lacquers, and these have been assigned to soot in the RAdICAL workbook.…”