Kaolin / siderite synthetic material preparation and properties of arsenic removal from groundwater

Abstract：Kaolin and siderite activated by KOH were adopted as the main raw materials, the peanut shell acidified by phosphoric acid served as the pore-forming material, and then arsenate-removing material was obtained by the high-temperature activation method. The performance of the arsenate-removing material under the condition of normal temperature and pressure was studied in orthogonal captive adsorption tests. The results show that, when weight ratio of the kaolin, siderite and peanut shell was 2∶2∶1, KOH concentration was 0.3 mol/L, soaking time was 6 h and activation temperature was 900℃, the removal efficiency of arsenate was the best, even attaining to 95%. The adsorption material was filled in a plexiglass column 40mm in diameter and 450mm in length for dynamic continuous adsorption experiments. The results show that the material could maintain an effective removal of arsenate for 20 hours or so and the removal efficiency of arsenate could reach 84%. The adsorption behavior meets the Langmuir isotherm.