Nanoscale Carbon Materials for Contaminant Separation - Nanotechnologies for Water Environment Applications - page 297

DB) coated fibers. The enhancement factor of MWNT coated fibers (in the range of
616-1756) was much higher than that of activated carbon coated fibers (193-423) and
PDMS-DB (139-384). The limits of detection (S/N = 3) and the limits of quantification
(S/N = 8) of PBDEs by MWNT coated fibers were in the range of 3.6-8.6 ng/L and 9.6-
22.9 ng/L, respectively.
10.3.5.2 Preconcentration Using Fullerene
Miguel Valcarcel and co-workers have explored the analytical potential of C 60
fullerene as an SPE adsorbent for chelates or ion pairs of metal ions (Gallego et al.,
1994; Petit de Pena et al., 1995, 1997; González et al., 1999) and organometallic
compounds (Baena et al., 2000a; Ballesteros et al., 2000; Baena et al., 2002; Munoz et
al., 2004a; Munoz et al., 2005) from aqueous solutions. The determination of lead,
copper, cadmium, and cobalt was conducted via preconcentration of the trace metal ions
using fullerene as a sorbent. The metal ions were first reacted with ammonium
pyrrolidine dithiocarbamate (APDC) to form chelates or ion pairs, and then sorbed onto
a fullerene column. Better sensitivity and selectivity were obtained with neutral chelates
than by ion-pair formation (Petit de Pena et al., 1995, 1997). Fullerene exhibited a
higher preconcentration factor than did conventional adsorbents (e.g. RP-C 18 , activated
carbon and resins). Not only were metal ions determined in water sample but also in
biological samples (Petit de Pena et al., 1995, 1997; González et al., 1999).
C 60 fullerene had low adsorption capability for organic compounds such as
carbamates, phenols, PAH, amines, with efficiencies less than 60%, which is less
effective than conventional adsorbents XAD-2 (Ballesteros et al., 2000). In contrast,
fullerene showed good efficiency for various organometallic compounds (Baena et al.,
2000b; Ballesteros et al., 2000; Baena et al., 2002; Munoz et al., 2004a; Munoz et al.,
2004b, 2005). Organolead (Baena et al., 2002), organomercury (Munoz et al., 2004b)
and butyltin (Munoz et al., 2004a) were chelated with diethyldithiocarbamates before
being preconcentrated with a fullerene column. C 60 and C 70 fullerene was found to be
superior as a sorbent for organometallic complexes, compared to RP-C18, silica gel 100
(Ballesteros et al., 2000), and graphitized carbon black (Munoz et al., 2005). The method
was successfully applied to the determination of lead, mercury, and tin compounds in
drinking water, river water, seawater, rainwater, wastewater and coastal sediment
samples (Munoz et al., 2004a; Munoz et al., 2004b, 2005).
10.4 Adsorptive Removal on Mesoporous Carbon
Mesoporous carbon not only inherits high adsorption capacity, based on its large
specific surface area, from other carbon-based materials (e.g., activated carbon) but also
possesses a wide pore structure from mesoporous materials. Therefore, it becomes rather