2 Multifunctional Magnetic Nanocomposites on the Base of Magnetite. . .
39
The study of DR adsorption isotherm on the surface of the Fe 3 O 4 /H£ nanocomposite was carried out in a range of equilibrium concentrations ´ 0 = 0.1–
1.04 mg/ml. The experimental results prove that an increase in an equilibrium
concentration of DR does not lead to a saturated adsorption of the surface of the
Fe 3 O 4 /H£ adsorbent.
The concavity (S-type) of the initial section of the isotherm relative to the axis of
concentrations and the absence of saturation in the studied interval of equilibrium
concentrations can be connected with a polymolecular type of adsorption and an
insignificant porosity of the nanocomposite surface. Besides, the S-type of the
isotherm may be caused, to a certain extent, by a joint adsorption of sodium chloride
because a DR adsorption occurred from a physiological fluid. The coefficient of
distribution (E, ml/g) of doxorubicin between the nanocomposite surface and the
fluid was 366.8 ml/g at £ = 91.7 mg/g.
During the study of DR adsorption on the surface of Fe 3 O 4 /H£ nanocomposite
as a function of time (Fig. 2.4), it was found that during the first 2 hours, 60–
70% of the substance is adsorbed and during 24 h the adsorption occurs almost
completely (93–97%). The relationship of the degree of doxorubicin removal (R,
%) vs. solutions concentration and an adsorption time is shown in Table 2.2.
The results of desorption (£ D , mg/g) study are given in Fig. 2.5 and Table 2.3.
The experimental relationships of desorption vs. time indicate that the DR release
decreases as its quantity on the NC surface grows. At a quantity of adsorbed DR
of 20–50 mg/g, 80–60% of DR is desorbed, respectively, while at large quantities
of desorbed DR (100–150 mg/g), the release almost does not occur. Most of DR is
desorbed during 20 min for all the studied concentrations.
0 20 40 60 80 100 120 140 160 180
400
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
A (mg/g)
τ, min.
Fig. 2.4 Time-dependent τ desorption of DR (£ D ) from the surface of Fe 3 O 4 /H£/DR NC into
saline solution at different initial quantities of DR immobilized by adsorption
39
The study of DR adsorption isotherm on the surface of the Fe 3 O 4 /H£ nanocomposite was carried out in a range of equilibrium concentrations ´ 0 = 0.1–
1.04 mg/ml. The experimental results prove that an increase in an equilibrium
concentration of DR does not lead to a saturated adsorption of the surface of the
Fe 3 O 4 /H£ adsorbent.
The concavity (S-type) of the initial section of the isotherm relative to the axis of
concentrations and the absence of saturation in the studied interval of equilibrium
concentrations can be connected with a polymolecular type of adsorption and an
insignificant porosity of the nanocomposite surface. Besides, the S-type of the
isotherm may be caused, to a certain extent, by a joint adsorption of sodium chloride
because a DR adsorption occurred from a physiological fluid. The coefficient of
distribution (E, ml/g) of doxorubicin between the nanocomposite surface and the
fluid was 366.8 ml/g at £ = 91.7 mg/g.
During the study of DR adsorption on the surface of Fe 3 O 4 /H£ nanocomposite
as a function of time (Fig. 2.4), it was found that during the first 2 hours, 60–
70% of the substance is adsorbed and during 24 h the adsorption occurs almost
completely (93–97%). The relationship of the degree of doxorubicin removal (R,
%) vs. solutions concentration and an adsorption time is shown in Table 2.2.
The results of desorption (£ D , mg/g) study are given in Fig. 2.5 and Table 2.3.
The experimental relationships of desorption vs. time indicate that the DR release
decreases as its quantity on the NC surface grows. At a quantity of adsorbed DR
of 20–50 mg/g, 80–60% of DR is desorbed, respectively, while at large quantities
of desorbed DR (100–150 mg/g), the release almost does not occur. Most of DR is
desorbed during 20 min for all the studied concentrations.
0 20 40 60 80 100 120 140 160 180
400
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
A (mg/g)
τ, min.
Fig. 2.4 Time-dependent τ desorption of DR (£ D ) from the surface of Fe 3 O 4 /H£/DR NC into
saline solution at different initial quantities of DR immobilized by adsorption