Arsenic removal from waste water by ozone oxidation combined with ferric precipitation

Abstract

The oxidation of As(III) to As(V) followed by precipitation and adsorption is thought to be the most effective process for removal of arsenic in industrial wastewater. In this work, the oxidation of As(III) to As(V) with ozone was carried out in an acidic solution. After oxidation, arsenic was removed by precipitation in an iron (III) sulfate system under ambient pressure at 90°C in acid. Batch experimental results show that ozone is quite effective in oxidizing As(III) at low pH. And more than 90% of 5g/l As(III) was removed from the acidic solution by precipitation with Fe₂(SO₄)₃ in 7-8 hours.