H2O2-Enhanced As(III) Removal from Natural Waters by Fe(III) Coagulation at Neutral pH Values and Comparison with the Conventional Fe(II)-H2O2 Fenton Process

Arsenic is a naturally occurring contaminant in waters, which toxic and adversely affects human health. Therefore, treatment of water for arsenic removal very important production safe drinking water. Coagulation using Fe(III) salts the most frequently applied technology removal, but efficient mostly As(V) removal. As(III) usually requires application pre-oxidation step, mainly conducted by chemical or biological means. In this study, we show that coagulation presence H2O2 can be process has been never shown before literature. The results showed addition 8.7–43.7 mM hydrogen peroxide to was able increase effectiveness synthetic groundwater 15–20% providing residual concentrations well below regulatory limit 10 μg/L from initial 100 μg/L, at pH 7. enhanced affected solution pH. efficiency substantially declined alkaline values (pH > 8). Addition EDTA absence had strong inhibiting effect where almost zero when 88.38 μΜ were used. Radical quenching experiments with 50, 200 DMSO, methanol 2-propanol H2O2-coagulation slightly adverse on efficiency. This considered as indicative an adsorption/oxidation onto near surface iron oxide particles, formed hydrolysis Ferric ions. practice, suggest increases systems. finding because step omitted while treating contaminated As(III).