改性沸石吸附柱去除氨氮的研究.doc

摘 要 氨氮是引起水体富营养化和环境污染的重要物质，采用沸石去除水中氨氮是水污染控制领域的研究热点之一。沸石是一种廉价的非金属矿物，具有独特的吸附和离子交换性能。天然沸石在改性过程中, 硅的质量分数显著减少，而钠的质量分数增多. 这样有利于NH4+-N的交换反应，因此改性沸石对氨氮的吸附NH4+-N的性能加强。 本研究首先对天然沸石进行了改性，确定了最佳的改性条件，并通过采用动态法研究改性沸石吸附柱去除微污染水源中氨氮的规律，包括改性沸石的粒径大小、入水流速、初始氨浓度等参数的影响，绘制穿透曲线。通过研究，本文得出了以下结论：①沸石改性的最佳条件为：NaCl溶液浓度3mol/L，水浴温度70～75℃，时间3h；②NaCl改性沸石的去除率明显高于未改性的。相比之下对氨氮的去除率增加了8%；③沸石粒径越小，去除率越高，改性效果越好。沸石粒径在0.5-1mm是对氨氮的去除率最高；④入水流速越小，改性沸石对氨氮的去除率越高；⑤废水的初始浓度越低，改性沸石对氨氮的去除率越高。最高可到达74%. 关键词：改性沸石 氯化钠 氨氮 吸附 Abstract Ammonia-nitrogen(NH4+)is an important contaminant for eutrophication of water bodies and environmental pollution. Zeolite is a cheap non-metallic minerals,with unique adsorption and ion -exchange performance。 After natural zeolite is modified quality score of silicon significantly reduces，And quality score of Sodium increases。It helps in ammonium-ion exchange， so dsorption performance of modified zeolite strengthens。 At first the natural zeolite was modified by chemical approaches in the research,and choose the best modifying condition of zeolite.Then study its treatment effect of low concentration NH4+in column reactor and draw breakthrough curve, investigating such factors as pellet size, velocity of flow and nitial ammonia concentration etc. The main results of this research were as follows:ⅠUnder these circumstances:,c=3mol/l,T=70～75,the modification time3hours，we can get the the right modified zeolite; removal efficiency of zeolite modified with for ammonia nitrogen is significantly higher than unmodified 。In contrast to ，removal rate of ammonia nitrogen increases by 8%;ⅢThe smaller the modified zeolite particle size, the higher the modification ；Ⅴthe water velocity is smaller, removal of ammonia nitrogen is higher;Ⅳwastewater concentration is lower, the modified zeolite of removal rate of ammonia nitrogen is higher . The highest removal rate can reach 74 percent . Key words：modified zeolite ammonia nitroge wastewater adsorpti