Removal of arsenic from polluted water through adsorption onto selected soil

An arsenic contamination survey was conducted in Lake Datunhai which is contaminated by arsenic in Southwest China. The arsenic-contaminated=soil was selected and the arsenic adsorption on the soil solid in the polluted water was studied through field investigation and laboratory experiments. The results showed that the red soil in survey area contains a relatively large amount of arsenic in a range of 36.41-153.52 mg/kg, which is higher than the National Soil Environmental Quality Standard Grade III. The arsenic pollution in the surveyed lake was relatively serious, as the amount of arsenic contained in the water of lake Datunhai was between 0.23 and 0.663 mg/L. The amount of arsenic in the sediment was between 273 and 755 mg/kg. The results of laboratory adsorption experiments with different soils showed that when the ratio of soil and water was 3.5/1000, the amount of arsenic in the water sample taken from the lake reduces from 0.3 mg/L to 0.03 mg/L, which would satisfy the Water Quality Standard Grade III (below 0.05 mg/L). The selected red soil was relatively effective for arsenic absorption. Based on theoretical calculations, the thickness of sediment will increase by about 0.95 cm by applying fixed arsenic solid on arsenic polluted water treatment.