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| Performance of selected materials for the purification of cadmium contaminated irrigation water |
| Received:March 19, 2016 |
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| KeyWord:cadmium;irrigation water;materials;adsorption characteristics |
| Author Name | Affiliation | E-mail | | HE Jun-qiang | Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Agricultural Resources and Regional Planning Institute of Chinese Academy of Agricultural Sciences, Beijing 100081, China | | | LI Ju-mei | Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Agricultural Resources and Regional Planning Institute of Chinese Academy of Agricultural Sciences, Beijing 100081, China | lijumei@caas.cn | | MA Yi-bing | Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Agricultural Resources and Regional Planning Institute of Chinese Academy of Agricultural Sciences, Beijing 100081, China | | | JI Xiong-hui | Institute of Soil and Fertilizer, Hunan Academy of Agricultural Sciences, Changsha 410125, China
Ministry of Agriculture Key Laboratory of Agriculture Environment in Middle Reach Plain of Yangtze River, Changsha 410125, China | | | ZHAO Hui-wei | The Semi-arid Agriculture Science and Technology Research Center of China, Shijiazhuang 050051, China | |
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| Abstract: |
| Irrigation with Cd contaminated water is one of important sources to lead to high risk for safety of agricultural products and human health risk in paddy soil.The key to rapid purification of Cd contaminated irrigation water is the selection of cost effective large-size porous adsorbent.Anisothermal adsorption and dynamic simulation experiment was designed, three isothermal adsorptions equations(Langmuir, Freundlich and Tempkin) and the BDST(bed depth service time) model were applied to characterize the Cd adsorption performance of four materials that were red mud particles, limestone, zeolite and rape straw, aiming to provide theoretical basis for the practical applications of the materials.When the Cd concentration of equilibrium solution was 10 μg·L-1, the amount of adsorbed Cd in water with electric conductivity of 0.79 mS·cm-1 was in the order as limestone 175.7 g·m-3 > zeolite 46.2 g·m-3 > red mud particle 20.7 g·m-3 > rape straw 3.7 g·m-3; the amount of adsorbed Cd in the dynamic experiment was in the order as red mud particle 1776 g·m-3 > limestone 1767 m-3 > zeolite 1704 g·m-3 > rape straw 837 g·m-3. In purification process,all four materials are able to raise the pH of irrigation water and are in the order as red mud > limestone and zeolite > rape straw. The Cd adsorption by limestone and zeolite from irrigation water is affected by ionic strength which increases with the increase of Cd concentration in balance solution.Compared with limestone and zeolite, the ionic strength in simulated solution has little influence on the purification performance of rape straw and red mud particle. The Cd adsorption affinity of rape straw in irrigation water was significantly higher than that of other three materials.However, the Cd adsorption capacity of rape straw is relatively small. And, the Cd dynamic purification efficiency of rape straw on Cd contaminated irrigation watershowed obvious attenuation trend with the prolonging of the purification time. |
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