due to special features of these materials such as large surface area, high mechanical
strength, high conductivity, and stability (Li et al. 2020; Mauter and Elimelech
2008). Based on their dimensionality, carbon-based nanomaterials are classified
into different categories: 0D carbon nanostructures having all the three dimensions
less than 100 nm (e.g. Buckminster fullerenes and quantum dots); 1D carbon
nanostructures having only one dimension larger than 100 nm and two dimensions
smaller than 100 nm (e.g. carbon nanotubes (CNTs) and carbon nanofibers (CNFs));
2D nanostructures having one dimension smaller than 100 nm (e.g. graphene); and
3D carbon nanostructures all dimensions are greater than 100 nm (e.g. carbon
sponges) (Visakh and Morlanes 2016).
9.3.1 Fullerenes
After diamond and graphite, fullerene (C 60 ) is third allotrope form of carbon, was
discovered in 1985 by Harold W. Kroto (University of Sussex, Brighton, England),
Robert F. Curl, and Richard E. Smalley (Rice University, Houston, Texas, USA)
(Kroto et al. 1985). Fullerene is excellent example of zero-dimensional carbon
nanostructures having all the three dimensions less than 100 nm. In addition to the
C 60 molecule, fullerene may have smaller (C 28 and C 36 ) and larger (C 70 , C 76 and
C 78 ) structures. Fullerene, C 60 has icosahedral symmetrically closed-cage structure
1) Naphthalene
2) Phenanthrene
3) Pyrene
7) Acenaphthene
8) Acenaphthylene
5) Anthracene
16) Fluoranthene
15) Fluorene
12) Benzo[a]pyrene
13) Benzo[g,h,i]perylene
14) Benzo[k]fluoranthene
4) Dibenzo[a,h]anthracene
6) Indeno[1,2,3-c,d]pyrene
9) Chrysene
10) Benzo[a]anthracene
11) Benzo[b]fluoranthene
Fig. 9.3 Structures of 16 PAHs
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