| Abstract |
| Continuous removal of As(III) through oxidation and adsorption was investigated with column reactors packed with iron and manganese coated sand prepared at five different ratios of manganese and iron : MCS-alone(10:0), ICS-alone(0:10) and IMCS(3:7, 5:5, 7:3). The breakthrough of arsenic immediately occurred from a column reactor with MCS-alone. However, most of the arsenic present in the effluent was identified as As(V) due to an efficient and rapid oxidation of As(III) by MCS. While ten-times delayed breakthrough of arsenic was observed from a column reactor with ICS-alone. After complete breakthrough of arsenic, the removed total arsenic was 205 mg with 1 kg ICS. To find an optimum ratio of manganese and iron for the preparation of IMCS, the removal efficiency of As(III) was compared. The initial breakthrough of arsenic was quite similar in three IMCS filter media. When the IMCS prepared at higher ratio of Mn/Fe was used in the column reactor, the fraction of As3+ in the effluent decreased. Removal efficiency of As(III) was investigated with a pilot-scale filtration system packed with IMCS prepared at 5:5 ratio of manganese and iron. Breakthrough of total arsenic in the final-sampling position began after 54 days. Although the breakthrough of total arsenic in the final sampling position occurred after 58 days, the concentration of As(III) in the effluent was below 50 ppb up to 84 days. The treated amount of As(III) by IMCS media up to reaction time before appearance of 50 ppb arsenic was calculated as 26.0 mg/kg IMCS. |
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| Key Words |
| adsorption, arsenic, iron, manganese, oxidation |
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