2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
at 25 °C by the agitating at the speed of 150 rpm. The cells
were harvested from the growth medium by membrane filtration
(pore size 0.85 µm). Bacteria suspension was prepared
with concentration of bacteria 1.2 × 10 9 ml –1 in accordance to
MacFarland standards.
P r e p a r a t i o n o f C o p p e r M o d e l
S o l u t i o n s
The model solution of Cu (II) was prepared by dissolving
of CuSO 4 . 5H2 O in deionized water in various concentrations
ranging from 0.01; 0.02; 0.04; 0.06; 0.1; 0.5; 1; 1.5; 2; 2.5;
3 to 5 mM. Previous studies showed that at pH 5 is the most
effective copper sorption. The initial pH of the solutions was
adjusted to 5 by adding 0.1M HnO 3 or 0.1M naOH for the
biosorption experiments. Various Cu(II) concentrations and
concentration after sorption process were measured by atomic
absorption spectrofotometer (Varian AA240 Z, AA240
FS, Australia).
C o l u m n S t u d i e s
In this study glass columns were used for experiments.
The filtration column was 130 mm high with an inner diameter
of 40 mm. Column was packed with appropriate amounts
of each sorbent in layers (100 g of quartz sand, 0.5 g of bentonite
and 0.1 g of synthetic magnetite). 50 ml of bacteria suspension
was passed through the column to adjusted the adhesion
of bacteria cells. Two types of filtration columns were
prepared. In both types there was 45 mm depth of ceramic
medium, one reached with bacteria (biotic filter) and another
filter without bacteria medium (abiotic filter). Then 50 ml of
Cu(II) model solution was passed through the column at a
constant flow rate of 1.5 ml min –1 .
Fig. 3. Sorption columns
Results
Bioceramic filters composed of quartz sand + bentonite
+ synthetic magnetite + bacteria were used for the sorption
of copper. These two types of filters were compared in
sorption efficiency. The effect of initial concentration on the
percentage removal of copper by biotic and abiotic filters is
s500
shown in Fig. 2. Fig. 2. demonstrates that sorption was more
effective in case of biotic filters. The work was carried out at
the pH (5) of model solution because this pH value is for copper
sorption optimum. The maximum removal of Cu(II) was
attained at a concentration 63.5 mg dm –3 Cu. High removal
efficiency (> 95 %) was obtained over the copper (II) concentration
range 1–100 mg dm –3 . However the removal percentage
decreased with increasing the copper (II) concentration
( > 100 mg dm –3 ). Therefore this method seems to be suitable
for the removal of relatively lower concentration of copper.
Fig. 2. Effect of initial copper concentration on percent removal
of copper by biotic and abiotic filter
Conclusions
The present study showed that the bioceramic filters
based on quartz sand, bentonite, synthetic magnetite and bacteria
can be used as an effective adsorbent of copper. The
results of experiments showed high removal of copper by
both types of model filters at concentrations ranging from
0.01 to 1.5 mM Cu(II). At higher concentrations removal
of copper decreased. The percentage removal was more effective
in biotic filters with baceria medium; however the
difference compared with abiotic filter was not so marked.
Therefore in further experiments bacteria medium with higher
concentration of bacteria cells is needed. In the further
study various iron oxides (hematite, goethit) and clay minerals
(zeolite, kaolinite) will be used in experiments and their
sorption efficiency will be compare.
This work has been supported by the Slovak Academy of
Sciences (VEGA 2/0049/08).
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