沸石对降雨径流中氨氮的吸附特性

城市面源污染是重要水体污染源之一,降雨发生时,雨水径流会携带累积在路面、屋面的含有机物、氮磷、重金属等污染物质进入水体,其中氮磷是造成水体富营养化的重要因素。针对这一情况,采用不同种类沸石,对雨水径流中的氮磷进行了吸附研究,着重考察了沸石对氨氮的吸附动力学,吸附等温线特征,并考察了pH、共存阳离子以及COD对吸附能力的影响。结果表明,Na型改性沸石吸附性能优于其他2种,饱和吸附量达到9.09 mg/g,沸石的吸附过程符合准二级动力学模型。Mg2+、Ca2+对Na型改性沸石的影响较大,Na型改性沸石吸附氨氮的适宜pH为5~8。本研究为探索用物化方法来处理雨水提供了依据,Na型改性沸石可以作为吸附雨水中氨氮的优选吸附剂。

Adsorption characteristics of zeolites for ammonia-nitrogen in rainfall runoff

Non-point pollution is regarded as an important source of water pollution.When rainfall occurs, stormwater runoff carries pollutants accumulating in pavement or roof then flows into the waterbody.The runoff contains organics, nitrogen, phosphorus and heavy metal.Nitrogen and phosphorus, as important nutrient, can cause serious eutrophication of the urban waterbody.To remove ammonia from runoff, different zeolites were applied as adsorbent.Adsorption kinetics and isotherm of different zeolites on the removal of ammonia in water, as well as the effect of pH, coexisting cations and COD concentrations on adsorption were studied.The results reveal that the Na modified zeolite shows prominent adsorption capability, and its saturated adsorption capacity is 9.09 mg/g.The adsorption process follows the pseudo-second kinetics.Mg2+, Ca2+ are found to have significant effect on adsorption, and the best pH for adsorption is between 5~8.The study provided basic data for further research on the treatment of stormwater by adsorption and Na modified zeolite can be a suitable adsorbent.