A simple technology for arsenic removal from drinking water using hydrotalcite.

The use of a synthetically prepared clay material, hydrotalcite (HT), for the removal of arsenite (As(III)) and arsenate (As(V)) from drinking water is described. Percolation through HT of water containing 500-1000 microg/L As (levels often found in As-contaminated well water) produced leachate with As levels well below 10 microg/L. The technology could be coupled to that used in less-developed regions for removing organisms from drinking water, viz. leaching through porous pots and filter candles. The 'spent' HT is easily converted into valuable phosphatic fertilizer that would have an insignificant effect on soil arsenic levels, thereby reducing the overall cost of manufacture and distribution.