天然斜发沸石对氨氮的快速吸附特性研究

摘要

The characteristics of ammonia nitrogen adsorption on the clinoptilolite was studied by static shaking table experiment , and the effect of clinoptilolite dosage and metal cations on quick adsorption of ammonium on the clinoptilolite investigated .The results indicated that the adsorption of ammonia nitrogen on clinoptilolite was fitted well with the Langmuir isotherm , and the maximum adsorption capacity was 12.903 mg/g.The removal rate increased with the decrease of the clinoptilolite size , and the adsorption process followed the pseudo-second-order kinetics model.Ammonium cations were exchanged with Na + primarily, and then Ca2+.With the increase of ammonia nitrogen concentration and the extension of absorption time , the ratio of Na +to removed NH 4+decreased , and vice versa of Ca 2+to removed NH 4+.Clinoptilolite dosage was proportional to the ammonia nitrogen removal rate and the total metal cations released to water .With increasing dosage of the clinoptilolite , the ratio of Na +to removed NH4+increased from 1.222 to 1.383.The inhibitory effect of clinoptilolite adsorption of ammonia nitrogen was in the order of K+>Ca2+>Na +>Mg2+, when the adsorption solution was added with four cations respectively .%通过静态摇床试验研究了天然斜发沸石对氨氮的吸附特性，以及沸石投加量和外加金属阳离子对其快速吸附氨氮特性的影响。结果表明，沸石对氨氮的等温吸附过程更符合Langmuir吸附模型，其最大吸附量为12.903 mg/g；沸石粒径减小，有利于沸石对氨氮的交换吸附，不同粒径沸石对氨氮的吸附均符合准二级动力学过程；斜发沸石中与氨氮进行离子交换的阳离子主要为Na＋，其次为Ca2＋，随着吸附氨氮浓度的升高或吸附时间的延长，Na＋与NH4＋吸附去除量的比值呈下降趋势，而Ca2＋的比值呈上升趋势。沸石投加量与氨氮去除率和沸石释放至水中的总金属阳离子浓度成正比，随着投加量增加Na＋与NH4＋吸附去除量的比值由1.222增至1.383；溶液中分别加入40 mg/L的K＋，Na＋，Ca2＋，Mg2＋4种离子，对沸石吸附氨氮产生抑制作用的强弱顺序为 K＋＞Ca2＋＞Na＋＞Mg2＋。