天然沸石对水中氨氮吸附特性的研究

Characteristics of Ammonia Nitrogen Adsorption on Natural Zeolite in Water

以浙江缙云天然沸石为原料,分别用摇床和吸附柱实验研究了天然沸石对氨氮的静态和动态吸附特性。结果显示,在10、25、40℃温度下沸石吸附氨氮有显著差异（P〈0.05）。在25℃、氨氮初始浓度为50 mg·L^-1的条件下,1～2 mm沸石对氨氮的360 min吸附容量为4.05±0.02 mg·g^-1。沸石对氨氮的吸附过程遵循二级吸附动力学方程,沸石对氨氮的等温吸附可用Langmuir和Freundlich等温吸附方程拟合,相关性分析结果表明Langmuir方程达到极显著相关（P〈0.01）,可以更好地描述沸石吸附氨氮的热力学过程。随着沸石粒径与投加量的减小,沸石对氨氮的吸附量显著增加。在pH值6.0～8.0时,沸石对氨氮去除效果最好。动态试验显示,当氨氮浓度为50 mg·L^-1时,沸石的穿透时间约96 h,动态饱和吸附量为18.8 mg·g^-1。

Taking Zhejiang Jinyun natural zeolite as raw material, the static and dynamic characteristics of ammonia nitrogen adsorption were studied by shaking table and column experiment, respectively. Results showed that ammonia nitrogen adsorption by zeolite was significant difference （P〈0.05） at 10, 25, 40℃. At initial ammonia nitrogen concentration of 50 mg·L^-1, the adsorption capacity of 1 ～2 mm zeolite to ammonia nitrogen was 4.05±0.02 mg·g^-1 at 25℃ within 360 min. Adsorption process of ammonia nitrogen on natural zeolite followed two stage adsorption kinetics equation. Isothermal adsorption of ammonia nitrogen by zeolite could be fitted by both the Langmuir and Freundlich isothermal adsorption equation, and the correlation analysis of Langmuir equation was significant correlation （P〈0.01）, which could better describe the thermodynamic process of the ammonia nitrogen adsorption on zeolite. With reducing particle size and dosage of zeolite, adsorption capacity of zeolite to ammonia nitrogen increased significantly. The optimum adsorption capacity of ammonium was obtained at pH value in the range of 6.0-8.0. Dynamic tests showed when the ammonia nitrogen concentration was 50 mg·L^-1, zeolite of breakthrough time was about 96 h, the saturated adsorption capacity was 18.8 mg· g^-1.