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中国南方离子型稀土矿区土壤氨氮污染日趋严重。埃洛石是矿区土壤的主要粘土成分之一。研究了埃洛石对氨氮的饱和吸附量、吸附影响因素及其吸附动力学特点。结果表明:在T=303 K、p H=5.6条件下,氨氮初始浓度增至600 mg/L左右(接近原地浸矿工艺实际使用的最初浸矿剂浓度的1/2)时,埃洛石和矿区土壤对氨氮的吸附达饱和,饱和吸附量为1.66 mg/g左右;随NH_4~+-N初始浓度、p H值(3.0~6.0)、温度(288~313 K)的升高,埃洛石及矿区土壤对氨氮的吸附量增大;埃洛石对氨氮的吸附符合Langmuir等温方程和Freundlich等温方程,可近似认为离子型稀土矿区土壤对氨氮的吸附易于进行;埃洛石对氨氮的吸附过程符合准二级动力学方程。
Soil ammonia nitrogen pollution in ion-type rare earth mining areas in southern China is increasingly serious. Halloysite is one of the major clay components of the soil in the mining area. The adsorption capacity, adsorptive capacity and adsorption kinetics of halloysite to ammonia nitrogen were studied. The results show that when the initial concentration of ammonia nitrogen is increased to about 600 mg / L at T = 303 K, p H = 5.6 (close to 1/2 of the original concentration of the original leaching agent actually used in the in situ leaching process) The adsorption of ammonia nitrogen in the rock and mining area was saturated with a saturated adsorption amount of 1.66 mg / g. With the initial concentration of NH 4 + -N, the values of p H (3.0-6.0), temperature (288-313 K) The adsorption amount of ammonia nitrogen in loess and mining area increased. The adsorption of ammonia-nitrogen by halloysite accorded with Langmuir isotherm equation and Freundlich isothermal equation. It can be concluded that the adsorption of ammonia nitrogen to the soil in ion-type rare earth mine is easy. Adsorption process in line with quasi-second-order kinetic equation.