Kaolin Siderite Synthetic Material Preparation And Properties Of Arsenic Removal From Groundwater

The average content of arsenic in the nature is 1.8mg·kg-1. It will bring the arsenical chronic poisoning if that the content of arsenic in the drinking water is too high. In China, many areas have the problems of the parcel groundwater contain too much arsenic, and it leads parcel arsenical chronic poisoning. Some areas reach 0.5mg.L-1, exceed the National standards 10 times. So, in our country, disposal the "high arsenical content" groundwater is a question no time to delay.Kaolin and siderite are commonly used adsorbents. They have the characters of strong adsorption, cheap, easy to get, et cetera. Other literatures have a little treat of their abilities to dispose "high arsenical content" water. But their practical applications have to be further studied. In this study, kaolin and siderite are main materials to research an absorption material which can practical apply to "high arsenical content" water disposal. Main tasks are as follows:(1) Determine process conditions of adsorbents. Use the kaolin and siderite which were activated with KOH as the main raw materials and the peanut shell with Phosphoric acid acidification as the pore-forming material, and use the high-temperature activation method, The effect of arsenate removal under normal temperature and pressure by the synthetic material were studied in orthogonal captive adsorption tests. The results show that when weight ratio of the kaolin, siderite and peanut shell is 2:2:1, the concentration of KOH is 0.3 mol·L-1, the soaking time is 6h, the activation temperature is 900℃, the effect of arsenate removal is the best, can reach 95%.(2) Mensurate the basic performances of the material. Use the ways of captive tests and BET (Brunauer, Emmett and Teller) nitrogen adsorption to mensurate the adsorption conditions, adsorption capacity, surface area and the porosity. The results show that the adsorption behavior is fitted with Langmuir isotherm.(3) Design a arsenic-removal set and mensurate its arsenic-removal effects. Prepare 5 perspex columns which with the diameter 40mm and length 450mm, in series them, and take the adsorption materials into them with water under inflow, do dynamic adsorption tests. The results show that when dynamic adsorbing, the material can persist effectual remove the arsenic for about 20h, the effect of arsenate removal can reach 84%.