ABSTRACT
The evaluate the behavior of As in presence of PO43-, column leaching experiments were conducted. Glass column was filled with 30 g of metal free sand (grain size < 1 mm) that reached up to a height of 15 cm in the column. On the top of sand, 0.5 g of iron wool was placed. In this fashion two such columns were prepared. Column 1 was leached with 100 μg/L of As, while column 2 was leached with a mixture containing 100 μg/L of As and 3 mg/L of PO43−. The leaching solutions were passed at a rate of 3 mL/min in respective columns at room temperature. The columns were sealed properly to avoid any intrusion of atmospheric gases that may alter the redox conditions once generated in the column. Both the columns were run simultaneously for a period of 7 d and the leachate samples were collected at every 12 h, i.e. twice a day. pH, Eh and conductivity was measured at the time of sampling, later, leachates were analyzed for As, iron (Fe) and PO43−. Arsenic, Fe, P were measured from ICP-AES (Perkin-Elmer), however P concentrations were later converted into PO4.
