300
V. A. Zazhigalov et al.
50 ml). The sorption degree (S) and adsorption capacity (a) were calculated by the
Eqs. 18.6 and 18.7:
S =
C 0 − C p
C 0
× 100%,
(18.6)
a =
C 0 − C p
× V
m c
,
(18.7)
where Ã, adsorption capacity, g/l; C 0 , initial concentration of dye solution, g/l; C Ó ,
equilibrium concentration, g/l; V, solution volume, ml; and m c, sorbent mass, g.
18.3 Results and Discussion
Figure 18.1 shows the XRD patterns of CeO 2 -MoO 3 samples with different CeO 2
and MoO 3 content after sonochemical modification and initial composition CeO 2 -
MoO 3 = 50:50 for comparison. Any new reflexes were observed in diffractograms.
The XRD patterns exhibit sharp peaks of crystalline α-MoO 3 . It was established
that treatment leads to an increase of MoO 3 reflex intensity and changes the ratio of
intensity of the main peaks of MoO 3 for the planes (020) and (040). The last reflex
is dominant for the samples after treatment in comparison with initial mixtures.
The intensity of all reflexes connected with CeO 2 decreases after UST. As result
after treatment, the ratio between intensity of the crystallographic planes of MoO 3
(040)/CeO 2 (111) increases and in major degree for the sample Ce/Mo = 50:50
where the change from 3.44 up to 13.2 was observed. The calculation of the particle
dimensions shows that after UST, the crystallite size of CeO 2 decreases for all
compositions from 53–56 nm up to 35–45 nm. The most complex situation was
observed for MoO 3 (Table 18.1). The treatment leads to a decrease of particle
dimensions according (020) to the plane and their sizes according (040) to the
plane rest practically without change (or little increase of the size was observed).
The obtained results permit to conclude that the chaotic destruction of CeO 2 and
anisotropic deformation of MoO 3 proceed at sonochemical treatment of the oxides
mixtures. The chemical reaction between components reported in [3] was not
observed which can be connected with different raw materials used.
On the other hand, the destruction of initial oxides can be accompanied by
formation of defects in their structure. This fact confirms by EPR data which
demonstrate an appearance of Ce +3 signal with g = 1.96 on the background of the
singlet signal with g = 1.98 which can assigned to Mo 5+ in MoO 3 for the samples
after treatment.
The dimension of the oxides particles size leads to an increase of the samples
specific surface area in 2–4 times (Table 18.1). Analogous changes in value of SSA
were observed after sonochemical treatment of ZnO-MoO 3 system [13, 14].
V. A. Zazhigalov et al.
50 ml). The sorption degree (S) and adsorption capacity (a) were calculated by the
Eqs. 18.6 and 18.7:
S =
C 0 − C p
C 0
× 100%,
(18.6)
a =
C 0 − C p
× V
m c
,
(18.7)
where Ã, adsorption capacity, g/l; C 0 , initial concentration of dye solution, g/l; C Ó ,
equilibrium concentration, g/l; V, solution volume, ml; and m c, sorbent mass, g.
18.3 Results and Discussion
Figure 18.1 shows the XRD patterns of CeO 2 -MoO 3 samples with different CeO 2
and MoO 3 content after sonochemical modification and initial composition CeO 2 -
MoO 3 = 50:50 for comparison. Any new reflexes were observed in diffractograms.
The XRD patterns exhibit sharp peaks of crystalline α-MoO 3 . It was established
that treatment leads to an increase of MoO 3 reflex intensity and changes the ratio of
intensity of the main peaks of MoO 3 for the planes (020) and (040). The last reflex
is dominant for the samples after treatment in comparison with initial mixtures.
The intensity of all reflexes connected with CeO 2 decreases after UST. As result
after treatment, the ratio between intensity of the crystallographic planes of MoO 3
(040)/CeO 2 (111) increases and in major degree for the sample Ce/Mo = 50:50
where the change from 3.44 up to 13.2 was observed. The calculation of the particle
dimensions shows that after UST, the crystallite size of CeO 2 decreases for all
compositions from 53–56 nm up to 35–45 nm. The most complex situation was
observed for MoO 3 (Table 18.1). The treatment leads to a decrease of particle
dimensions according (020) to the plane and their sizes according (040) to the
plane rest practically without change (or little increase of the size was observed).
The obtained results permit to conclude that the chaotic destruction of CeO 2 and
anisotropic deformation of MoO 3 proceed at sonochemical treatment of the oxides
mixtures. The chemical reaction between components reported in [3] was not
observed which can be connected with different raw materials used.
On the other hand, the destruction of initial oxides can be accompanied by
formation of defects in their structure. This fact confirms by EPR data which
demonstrate an appearance of Ce +3 signal with g = 1.96 on the background of the
singlet signal with g = 1.98 which can assigned to Mo 5+ in MoO 3 for the samples
after treatment.
The dimension of the oxides particles size leads to an increase of the samples
specific surface area in 2–4 times (Table 18.1). Analogous changes in value of SSA
were observed after sonochemical treatment of ZnO-MoO 3 system [13, 14].