天然沸石吸附氨氮的影响因素分析和数值模拟

Analysis and numerical simulation of influencing factors on the adsorption of ammonia nitrogen by natural zeolite

为了考察天然沸石对氨氮污染物的吸附机制和去除效率,开展了一系列干扰因素下的批量吸附实验,考虑了氨氮浓度、吸附时间、pH值以及环境中可能存在的铁离子及腐植酸的影响。实验得到的氨氮吸附容量和去除效率结果表明,中性环境中沸石对氨氮的去除效果最好,铁离子及腐植酸与氨氮竞争吸附沸石位点,抑制沸石对氨氮的吸附。同时,通过土柱实验研究了氨氮在沸石柱中的运移,并引入基于截断单边稳定分布概率密度的输运模型(TOSD)来描述该过程,通过模拟参数表征了氨氮在沸石柱中的运移特性。结果表明,吸附作用和速率受限的质量交换对沸石中氨氮的运移发挥了主导作用。

To investigate the adsorption mechanism and removal efficiency of natural zeolite on ammonia nitrogen pollutants,batch adsorption experiments under a series of interfering factors were carried out,taking into account the effects of ammonia nitrogen concentration,adsorption time,pH,and the possible presence of iron ions and humic acid in the environment.The adsorption capacity and removal efficiency of ammonia nitrogen obtained from the experiments showed that zeolite was the most effective in removing ammonia nitrogen in a neutral environment,and that iron ions and humic acid competed with ammonia nitrogen for the adsorption sites on the zeolite,which inhibited the adsorption of ammonia nitrogen by zeolite.Meanwhile,the transport of ammonia nitrogen in the zeolite column was investigated by soil column experiment,and a transport model(TOSD)based on the tempered one-sided stable distribution probability density was introduced to describe the process,and the simulation parameters characterized the transport properties of ammonia nitrogen in the zeolite column.The results showed that adsorption and rate-limited mass exchange had a great influence on the transport of ammonia nitrogen in the zeolite.