76
4 Investigation into the Adsorption of Cadmium and Lead …
where C e represents the final concentration of metal ions and C o is the initial concentration of metal ions in the mg/L. The GXCS was washed with deionized water after
desorption and was recycled for the next adsorption cycle. The procedure conducted
three phases of adsorption/desorption.
4.7 Theory of Evaluation of Data
Adsorption isotherms are the necessary component for the development of an adsorption process; in order to maximize the layout of an adsorption system, it is necessary
to create a connection suitable for the adsorption curve of equilibria; for the evaluation of adsorption parameters, a precise mathematical description of the equilibrium
adsorption capacity is needed in any particular system.
4.7.1 Adsorption Isotherms Model
The Langmuir and Freundlich models were used to assess the adsorption data of
metallic ions onto adsorbent. The formula of Langmuir and Freundlich models is
defined in 4.3 and 4.4, in their standard form. The Langmuir model is built on
the assumption that each adsorption site is similar and intensely comparable and
suggests that the adsorption takes place on the adsorbent at different uniform sites
and is applied effectively in single-layer adsorption systems [16].
C e
q e
=
C e
Q m
+
1
Q m b
(4.3)
where q e is the equilibrium metal adsorption amounts on the beads (mg/g), C e is
the equilibrium concentration of solute in the bulk solution. Q m and b represent
single-layer adsorption capacity and a constant related to the adsorption equilibrium
constant. The parameters of Langmuir model can be calculated from the slope and
intercept of the straight-line plot of C e /q e against C e .
The empirical isotherm Freundlich is related to the relationship of equilibrium
between heterogeneous surfaces.
log q e = log K f +
1
n
log C e
(4.4)
in this formula, K f and n depict the adsorption potential and adsorption intensity
accordingly and are dimensionless constant. Within standard adsorption conditions,
n values will vary between 1 and 10 [17]. The variables of the Freundlich model can
determine from the slope and intercept of the Log q e versus Log C e linear plot.
4 Investigation into the Adsorption of Cadmium and Lead …
where C e represents the final concentration of metal ions and C o is the initial concentration of metal ions in the mg/L. The GXCS was washed with deionized water after
desorption and was recycled for the next adsorption cycle. The procedure conducted
three phases of adsorption/desorption.
4.7 Theory of Evaluation of Data
Adsorption isotherms are the necessary component for the development of an adsorption process; in order to maximize the layout of an adsorption system, it is necessary
to create a connection suitable for the adsorption curve of equilibria; for the evaluation of adsorption parameters, a precise mathematical description of the equilibrium
adsorption capacity is needed in any particular system.
4.7.1 Adsorption Isotherms Model
The Langmuir and Freundlich models were used to assess the adsorption data of
metallic ions onto adsorbent. The formula of Langmuir and Freundlich models is
defined in 4.3 and 4.4, in their standard form. The Langmuir model is built on
the assumption that each adsorption site is similar and intensely comparable and
suggests that the adsorption takes place on the adsorbent at different uniform sites
and is applied effectively in single-layer adsorption systems [16].
C e
q e
=
C e
Q m
+
1
Q m b
(4.3)
where q e is the equilibrium metal adsorption amounts on the beads (mg/g), C e is
the equilibrium concentration of solute in the bulk solution. Q m and b represent
single-layer adsorption capacity and a constant related to the adsorption equilibrium
constant. The parameters of Langmuir model can be calculated from the slope and
intercept of the straight-line plot of C e /q e against C e .
The empirical isotherm Freundlich is related to the relationship of equilibrium
between heterogeneous surfaces.
log q e = log K f +
1
n
log C e
(4.4)
in this formula, K f and n depict the adsorption potential and adsorption intensity
accordingly and are dimensionless constant. Within standard adsorption conditions,
n values will vary between 1 and 10 [17]. The variables of the Freundlich model can
determine from the slope and intercept of the Log q e versus Log C e linear plot.