人工湿地不同基质对氨氮的吸附特性研究

过量氮是引发水体富营养化的重要原因之一,氮的去除是控制水体富营养化的关键,其中人工湿地中基质对氨氮的去除是人工湿地处理污水的重要途径。通过基质氨氮吸附动力学、等温吸附以及基质饱和吸附后氨氮解吸实验,研究沸石、红泥、水洗砂、炉渣4种人工湿地基质净化氨氮的效果,评价其饱和吸附后氨氮解吸可能造成的二次污染风险及基质去除氨氮的主要途径。结果表明：4种基质对氨氮的吸附量顺序依次为沸石〉红泥〉炉渣〉水洗砂;沸石去除氨氮的途径以离子交换为主,物理吸附作用很小;炉渣的离子交换作用和物理吸附作用效果相当。从氨氮的解吸率来看,沸石的解吸率最小,红泥次之,炉渣和水洗砂的解吸率较大。综合评价,沸石更适合作为人工湿地污水去除氨氮的基质。

Study on ammonia nitrogen adsorption characteristics of different substrates in constructed wetland

Excessive nitrogen is one of important elements related to eutrophication of water.The nitrogen removal by the substrate plays a key role to control the water eutrophication,and it is an important technology to control the sewage in constructed wetland.Adsorption dynamics of ammonia nitrogen combined with isothermal adsorption and adsorption-desorption experiments was did to study the ammonia nitrogen removal effect of the four substrates of zeolite,red mud,water washing sand and slag,and to evaluate the possible secondary pollution risk caused by the ammonia nitrogen desorption of the four substrates.The results showed that the order of the four substrates adsorption capacity to ammonia nitrogen was followed that zeolite red mud slagwater washing sand.The ion exchange function was the main way of removing ammonia nitrogen by zeolite,and zeolite had the worst physical adsorption ability,whereas slag had almost the same physical adsorption and ion exchange capacities.Seen from the ammonia nitrogen desorption rate,the zeolite was smallest,followed by the red mud,and the other two substrates desorption capacity were very high.So to some extent,the zeolite was a more suitable substrate for removing ammonia nitrogen in constructed wetland sewage.