改性天然沸石去除水中氨氮的研究

分别采用NaCl、KCl和CaCl2对黑龙江省某市天然沸石进行改性,考察了pH值、氨氮初始浓度以及温度对改性沸石交换性能的影响,并对改性沸石的交换动力学进行了研究.结果表明,NaCl和KCl改性对沸石原矿交换容量有不同程度提高,而KCl改性后容量有所降低.pH、NH4 初始浓度以及温度对交换性能有明显影响,pH 6.0附近沸石交换容量最大;NH4 初始浓度越高,反应速度越快,相同初始浓度下,钾型沸石交换速度较快,而沸石原矿交换速度最慢.采用Langmuir型离子交换等温线进行非线性回归的结果显示,低温有利于交换反应的进行.溶液中NH4 在改性沸石上的离子交换反应可采用Vermeulen模型描述,沸石原矿拟合相关系数较差.改性沸石多次再生后,其交换容量均有所降低.

Study of modified zeolite to remove ammonia nitrogen in water

Sodium chloride,potassium chloride and calcium chloride were adopted to modify the natural zeolite of Heilongjiang Province.The effects of pH,initial concentration of ammonia nitrogen and temperature on the ion exchange capability of modified zeolites were studied.Furthermore,kinetics of ion exchange was deduced.Results indicated that modification by sodium chloride and calcium chloride could improve the full exchange capabilities.But the full exchange capability was reduced when it was modified by potassium chloride.The pH of 6.0 seemed to be favorable to the exchange capabilities,and there was a positive correlation between the initial concentration of ammonia nitrogen and the velocity of ion exchange.Langmuir ion exchange isotherm indicated that low temperature was propitious to exchange reaction.Vermeulen model could be used to describe the ion exchange reactions of modification zeolites,but the zeolite ore showed a relatively bad correlation coefficient than others.The capabilities of modified zeolites were reduced by different degrees after many times of regeneration.