几种土壤的氟吸附特性研究

Study on Adsorption Characters of Fluorine in Several Soils

采用室内试验方法,研究了4种土壤对氟吸附的特性。结果表明:(1)不同土壤对氟的吸附能力差异很大,随着初始浓度的增大,吸附量明显增大,净吸附量、解吸量也增大,表现为黄壤>红壤>紫色土>石灰土;土壤氟的解吸率随初始浓度的增大而增大,不同土壤间大小次序是石灰土>紫色土>红壤>黄壤。(2)土壤吸附氟后的平衡溶液pH值随氟加入浓度的增大而上升,不同土壤间次序是:石灰土>红壤>紫色土>黄壤。(3)拟合结果表明,Langmuir方程能够较好地拟合土壤对氟的吸附等温线。(4)土壤中氧化物是氟的重要吸附剂,对土壤氟吸附有重要贡献。(5)低分子有机酸对氟吸附的影响一方面表现为阴离子的竞争作用,另一方面表现为酸性条件下的促进作用。

Adsorption characters of fluorine in several soils were studied in this article. The results showed that: (1) the soils studied had different ability of fluorine adsorption, the amount of adsorption, net adsorption and amounts desorbed increased with the increase of concentration, and in an order as: yellow soil>red soil>purple soil>calcareous soil. The desorbed rate of fluorine also increased with the increase of concentration, and in an order as: calcareous soil>purple soil >red soil >yellow soil. (2) The pH- value of equilibrium liquid increased with the increase of concentration, in an order as: calcareous soil > red soil > purple soil >yellow soil. (3) Langmuir equation was suitable to describe the adsorption of fluorine. (4) Soil oxides were the important absorbent for fluorine, had an important contribution on fluorine adsorption. (5) The effects of organic acid with low molecular weight on fluorine adsorption included competitive adsorption of negative ion and stimulative effect because of acid environment.