Sorption of Cu(II), Zn(II) and Pb(II) Ions in an Aqueous Solution on the pvc-acetylacetone Composites Elzbieta Radzyminska-Lenarcik and Katarzyna Witt

Sorption Time, h 
C
Cu(II)
, mol/dm
3
 
A 
B 
C 
D 
E 
0.5 
0.0064 0.0087 0.0096 0.0055 0.0052 
1 
0.0052 0.0080 0.0093 0.0046 0.0044 
2 
0.0045 0.0076 0.0092 0.0034 0.0029 
4 
0.0040 0.0070 0.0090 0.0020 0.0021 
8 
0.0036 0.0065 0.0091 0.0017 0.0019 
12 
0.0034 0.0065 0.0091 0.0015 0.0017 
24 
0.0033 0.0063 0.0090 0.0015 0.0016 
Table 5. Sorption time-dependent concentration of Pb(II) ions after the sorption on PVC-based 
composites promoted with acac. Initial concentration of Pb(II) ions C
0
= 0.01 mol/dm
3
. 
Sorption Time, h 
C
Pb(II)
, mol/dm
3
 
A 
B 
C 
D 
E 
0.5 
0.0087 0.0091 0.0098 0.0085 0.0088 
1 
0.0084 0.0088 0.0097 0.0076 0.0080 
2 
0.0077 0.0084 0.0096 0.0060 0.0074 
4 
0.0068 0.0082 0.0096 0.0052 0.0060 
8 
0.0065 0.0082 0.0095 0.0051 0.0058 
12 
0.0066 0.0081 0.0095 0.0050 0.0056 
24 
0.0067 0.0080 0.0094 0.0050 0.0055 
Results, which are presented in Tables 3–5, indicate that acac-free composite C does not bind 
any of the tested metal ions. Thus, the sorption of these cations from the solution determines 
formation of chelate complexes with acac contained in the composite. 
As is known, acac forms—stable complexes with many d-electron metals. This ability is 
illustrated by the following Equations (1). 
Therefore, the sorption efficiency of acac-containing composites is greater when compared to 
the same sorbents without this component. 
C
H
3
O
CH
3
O
-
C
H
3
O
CH
3
O
M
+
C
H
3
O
CH
3
O
- H
+
+ M
n+
(1) 

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Polymers 2019, 11, 513 
8 of 16 
The amount of metal ion, which are binded in complex compound depends on stability constants 
of this complexes with acac. 
The values of the logarithms stability constant of Zn(II), Cu(II) and Pb(II) complexes with acac 
are 5.05, 8.25 and 4.57, respectively [60]. 
The amount of metal ions adsorbed by 1 g of sorbent (q
t
) was calculated from Equation (2): 
=
(
0
−
) ∙
(2) 
where q
t
—sorption capacity [mg/g], V—volume of the solution [dm
3
], m—mass of the sorbent [g]. 
The values of the sorption capacity of the tested composites after 4 h of sorption are presented 
in Table 6.