Open-pore polyether-type polyurethane foam
with a bulk density of 22 kg m
3
was cut into
small cylindrical plugs of 5 mm
•
10 mm
length and was used as a sorbent. The foam plugs
were first washed to remove organic and inorganic
impurities in the following sequence.
The foam plugs were first squeezed in acetone
for 30 min to open their pores, washed with
deionized water and dried at 80°C in an oven. The
dried foam plugs were then soaked i
n 2 M hydro-
chloric acid solution for 2 h to remove all inor-
ganic impurities, washed with deionized water
until the washing was acid free and neutral, and
later dried at 80°C in an oven. The dried plugs
were soaked in acetone for 30 min to remove all
organic impurities. The foam was then pressed
between filter papers to remove excess acetone
and dried at 80°C, and stored for further use.
The total pore area measured using a
Micromeritic porosimeter was 67 m
2
g
1
, total
intrusion volume was 0.14 cm
3
g
1
and average
pore diameter was 8.3 nm.
All the reagents used in this work were of
analytical or analar grade, and all the solutions
were made in distilled deionized water. A
110m
Ag
(
t
1
:
2
248.9 day) tracer was prepared by irradiat-
ing specpure silver metal (Johnson and Matthey)
in the PARR-1 Research Reactor of this institute
at a flux density of 5
10
13
ncm
2
s
1
for 32 h.
The irradiated metal was dissolved in few drops of
concentrated nitric acid and evaporated to dry-
ness, and then dissolved in deionized water for
further use. The radionuclidic purity was checked