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The chemical composition of black carbon is much more varied, and typically has a much lower proportion of elemental carbon, compared with carbon black. [8] [6] In some definitions, black carbon also includes charcoal, a type of matter where the chunks tend to be too large to have an aerosol form as is the case with soot. [11]
Carbon black (with subtypes acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal tar, vegetable matter, or petroleum products, including fuel oil, fluid catalytic cracking tar, and ethylene cracking in a limited supply of air.
Carbon black particle size is between 10 and 100 nm, while the surface particle size is between 20 and 1,500 m 2 /g. Generally speaking, small carbon black particles with a high surface area are darker, have higher viscosity and lower wettability, are harder to disperse, retain greater conductivity and absorb UV radiation well. [1] [2] [3] [7] [8]
Black carbon is in the air and circulates the globe. Black carbon travels along wind currents from Asian cities and accumulates over the Tibetan Plateau and Himalayan foothills. Black carbon (BC) is the light-absorbing refractory form of elemental carbon remaining after pyrolysis (e.g., charcoal) or produced by incomplete combustion (e.g., soot).
Photomicrograph made with a scanning electron microscope and back-scatter detector: cross section of fly ash particles. Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK)—plurale tantum: coal combustion residuals (CCRs)—is a coal combustion product that is composed of the particulates that are driven out of coal-fired boilers together with the flue gases.
The carbon is obtained as black powdery solid matter and forms a technical product which may be used e.g. as filler in the rubber industry, as pigment soot for inks and paints or as raw material for electrical components. The hydrogen may be discharged for the chemical industry or may be used for generating electricity. [4]
Black carbon (BC) or elemental carbon (EC), often called soot, is composed of pure carbon clusters, skeleton balls and fullerenes, and is one of the most important absorbing aerosol species in the atmosphere. It should be distinguished from organic carbon (OC): clustered or aggregated organic molecules on their own or permeating an EC buckyball.
The pollutant species black carbon appears gray or black due to the absorption of electromagnetic energy by partially mobile electrons in the graphitic microstructure of the black carbon particles. This absorption is purely ‘resistive’ and displays no resonant bands: consequently, the material appears gray rather than colored.