Water Science & Technology: Water Supply Vol 1 No 2 pp 167–173 © IWA Publishing 2001
Removal of arsenate from drinking water with a natural manganese oxide in
the presence of competing anions
S Ouvrard*, M-O Simonnot** and M Sardin***
*
Laboratoire des Sciences du Génie Chimique, CNRS-ENSIC-INPL,1
rue Gradville, BP 451,54001 Nancy Cedex, France
**
Laboratoire des Sciences du Génie Chimique, CNRS-ENSIC-INPL,1
rue Gradville, BP 451,54001 Nancy Cedex, France
Ecole Européenne d'Ingénieurs en Génie des
Matériaux, INPL, 6 rue B. Lepage, BP 630, 54010 Nancy Cedex, France
***
Laboratoire des Sciences du Génie Chimique, CNRS-ENSIC-INPL,1
rue Gradville, BP 451,54001 Nancy Cedex, France
ABSTRACT
The efficiency of arsenic removal from drinking water in adsorption
processes using natural oxides may be influenced by the presence of other
adsorbable anions. The present paper focuses on the study of arsenate
adsorption by a natural manganese oxide. The objective is to determine
which of the anions usually present in drinking water may be adsorbed:
hydrogen carbonate, sulfate, chloride, nitrate, phosphate and arsenate.
A kinetic batch experiment was conducted with a natural drinking water,
leading to a first qualitative selection: nitrate and chloride have little
interaction with the adsorbent, sulfate and hydrogen carbonate are adsorbed
while phosphate and arsenate are strongly adsorbed. Then column experiments
were run with aqueous solutions containing either chloride, sulfate, etc.
The previous trends were confirmed and the equilibrium isotherms of the
adsorbable anions were built by integration of the breakthrough curves.
The isotherms fitted with a Langmuir model showed that the capacitieswere low (a few  mol.g-1). The affinity order was
determined from the isotherm initial slopes: arsenate ≫ phosphate
> hydrogen carbonate ≌ sulfate. Given the strong affinity of the
adsorbent for arsenate and the low arsenate concentration in drinking
water, the process selectivity for As traces from drinking water is ensured.
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