9 research outputs found
Elimination of arsenic traces contained in liquid effluents by chromatographic treatment
Our present work is included in a development plan of a two-step
detoxication process of arsenical by-products originated from
chemical warfare destruction effluents [1]. The first method
studied was classical anion exchange chromatography. Less than 1%
of the anion exchanger capacity is used to fix arsenate ions for a
Cl/AsO concentration ratio equal to 100. Because of
the lack of anion exchanger selectivity, the use of more selective
adsorbents has been investigated, namely a macroporous cation exchange
resin (BioRad AGMP-50 resin). We confirm that the As and
As retention does not depend on the nature of the resin
functional groups and that only the ferric hydroxide precipitate is
involved in the retention. We also show that the arsenic available
exchanger capacity is not significantly affected by high concentrations
in chloride ions (1 mol L), and it seems that the kinetics of
arsenite and arsenate ions fixation is better in presence of chlorides.
The use of the exchanger for the complete detoxication of arsenic trace
(10Â ppm) solutions in presence of high contents in chlorides
(1 to 3 mol L) leads to an effluent volume equal to 280 and
540Â times the resin bed volume, for AsIII and AsV respectively.
The effluent thereby obtained has an arsenic concentration lower
than the M.C.L. (100Â ppb)