ΕΘΝΙΚΟ ΜΕΤΣΟΒΙΟ ΠΟΛΥΤΕΧΝΕΙΟ

Initially two solutions of the ECs were made in methanol as solvent (solution
A & B, from solution A came solution B) to achieve concentrations at environmental
levels. The solution used (solution B) had approximately 10 mg/L of the ECs studied.
The final solution was made with measured volume from solution B and tap water
from the lab (NTUA groundwater) so that the ECs were up to 1 or 2 μg/L. The final
solution was kept in a 200 L plastic bottle from HDPE, while solutions A & B were
kept in the refrigerator at -18 o C.
The pilot-scale system used four columns made from Plexiglas, which were
working down-flow under pressure. Each column was 5 cm diameter and 1,40 m
height. In the bottom of each column special valves were installed for sampling
(Figure 1). As sorbent material the Granular Activated Carbon Filtracarb CC60 was
used, bought from CHEMiTEC. Before each installation, GAC was put for one day in
furnace at 106 o C for drying.
At the bottom of each column were put 4 to 5 pieces of glaswolle to retain
GAC inside the column. The solvent was added to the system through a peristaltic
pump. From the bottom of each column and the 200 L bottle samples were taken at a
regular basis (3 or 4 times per week) at 100 mL volumetric flasks for further analysis.
The analytical method used (Samaras et al., 2011) included four stages :
acidisation with HCl to pH 2,5-3, solid phase extraction (Isollute C18 columns were
used from Biotage, installed in a proper aparatus – see Figure 2), derivatization
(Pyridine and a solution of BSTFA and TMCS were used) and analysis on GC/MS
(bought from Agilent Technologies).
Figure 1 : The pilot-scale GAC column system used.
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