AWWA WQTC64152

Iron based adsorbents are one of the favored techniques for the removal of arsenicfrom potable water sources. The available adsorbents show a high sorption capacity forarsenic and also for other contaminants. However, arsenic adsorption efficiency isinfluenced by pH and by interference and competition of phosphate, silica and otherdissolved matter. Tests with artificial water showed that silica at low concentrationsdepresses arsenic adsorption in systems without calcium or other divalent cations. Onthe opposite, high calcium concentrations could mask the negative influence of silica.A series of small scale column tests are conducted at various pH-values, silica- andcalcium concentrations. The results show that the co-adsorption of divalent cationsplays a key-role in understanding the interference of silica on arsenic removal systems.A better understanding of the influences of the water profile lead to better models forthe prediction of adsorption capacities without previous tests, they allow anappropriate pH if pH adjustment is a solution of choice. Includes 7 references, table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2006

Number of Pages:

5

File Size:

1 file , 330 KB