Arsenic Removal Using Iron Oxide Loaded Alginate Beads

Abstract

The application of biopolymers (alginate), as sorbent supports, for the removal of arsenic from contaminated water has been investigated in the present study. Calcium alginate beads were placed in a column to form a fixed bed and treated (doped/coated) with hydrous ferric oxides. Three different types of modified alginate beads were examined for the removal of arsenic; the most efficient type was found to be doped with alginate and subsequently coated with iron oxides, whereas the other two types were calcium alginate beads doped or coated with iron oxides. The total amount of iron loaded on this material was found to be 3.9 mg of Fe/g of wet alginate bead. Approximately 230 bed volumes of a 50 μg/L As(V) solution were treated before the breakthrough point was reached, whereas the removal of As(III) was not as efficient, reaching the breakthrough point after the treatment of only 45 bed volumes. The results were modeled using the bed depth service time and empty bed residence time models.