Environmental Engineering Reference
In-Depth Information
Fig. 12.1 EMR spectra of
different concentrations of
Fe
2
O
3
in the samples.
(Reproduced with
permission)
Fig. 12.2 OH production by ZnO nanoparticles before (
black
) and after (
bold black
) broadband
visible light illumination using DMPO as a spin trap. (Reproduced with permission)
25
]. Sroiraya et al. [
26
] have studied TiO
2
nanoparticles irradiated with ultraviolet
light to detect hydroxyl radicals using EMR spectroscopy with spin trapping
technique. They have analyzed the effect of particle size, concentration, and
agglomeration effects. Authors have proposed a mechanism for the generation of
hydroxyl radical that can be used to support the antibacterial effect of TiO
2
photocatalysis.
12.4.4 CuO Nanoparticles
Prasetyanto et al. [
27
] have reported the preparation of CuO nanoparticles onto
SBA16 type mesoporous silica matrix using cyclam complex as precursor and also
by impregnation method. EMR of samples prepared by both these methods were
recorded. The spectrum of the CuO-SBA-16 (cyclam) could be described by an
axial spin Hamiltonian. Spin Hamiltonian parameters have been reported and
square planar symmetry for Cu(II) ions coordinated to four nitrogens has been
proposed by the authors. From the intensity pattern of EMR, authors were able to
compare the concentration of Cu(II) ions in the samples.
