Removal of arsenic from contaminated soils using different salt extractants

Abstract

This study presents an environmental-friendly and cost effective method for the extraction of arsenic from contaminated soils. Laboratory experiments using inorganic salts, potassium phosphate (KH₂PO₄), potassium chloride (KCl), potassium nitrate (KNO₃), potassium sulfate (K₂SO₄), and sodium perchlorate (NaClO₄) were evaluated as arsenic extractants. An Andosol soil was artificially contaminated with arsenite [As(III)] and arsenate [As(V)]. The soil was washed in a batch process with different salt solutions in the pH range 3–11 for 24 hours at 20°C. Among the various potassium and sodium salts tested, KH₂PO₄ was found to be highly effective in extracting arsenic from As(III)-soil attaining more than 80% and 40% from As(V)-soil in neutral pH range. Other salts were particularly ineffective in extraction of arsenic from both soils. More arsenic was extracted more from the As(III)-soil than the As(V)-soil.

Keywords:

• arsenite
• arsenate
• salt extraction
• soil contamination
• soil remediation.