Environmental Engineering Reference
In-Depth Information
4.
A
NALYSIS OF
T
OTAL
C
ADMIUM
,
C
ADMIUM
D
ETERMINATION AND
S
TATISTICAL
A
NALYSIS
Analysis of the total Cd was carried out in conditions for Cd analysis in
certification reference coal fly ash CTA-FFA-1 (the certified Cd content: 2.8
μg g
-1
) - Institute Nuclear Chemistry, Warsaw, Poland. Single-stage coal fly
ash digestion with the mixture of nitric(V) acid and chloric(VII) acid (2:1)
with accuracy > 98 %. Four replicates were used.
Coal fly ash samples were pulped with nitric(V) and chloric(VII) acids.
The total cadmium was determined in those solutions. The total cadmium
content was found to be 19.0 ± 1.1 mg · kg
-1
Cd.
Determination of cadmium by the flame atomic absorption spectrometry
method (FAAS) was performed directly in solutions and fly ash eluates [31]
with three replicates. Cd concentration in coal fly ash eluates was recalculated
to Cd concentration in appropriate metal fractions F(1) - F(5) and Cd
concentration in coal fly ash. Student correlation coefficient were calculated,
significance was set at p = 95 % and n = 4 [53]. Statistical analysis was
performed using MS Excel 2000 (Microsoft).The results are shown in Table 1.
n
[
]
i
∑
Cd
Figure 1. Summary concentration of Cd in coal fly ash (
)
for
individual
i
=
1
procedures of sequential extraction.
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