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通过动力学和等温吸附实验,研究了不同初始氨氮浓度下水溶铵、交换铵和固定铵在中砂上的吸附规律。结果表明,吸附平衡时各种形态铵含量随初始氨氮浓度增加而增大。3种形态铵吸附行为符合准二级动力学方程。吸附速率常数K大小顺序为：固定铵〉交换铵〉水溶铵,初始速率：固定铵〈交换铵〈水溶铵。随着初始氨氮浓度的增加,水溶铵占总铵的比重由40%上升到65%,其吸附的主要限制步骤为颗粒间扩散。交换铵对总铵的贡献率维持在25%左右,吸附饱和后有所降低,初始氨氮浓度为交换铵吸附的主要限制步骤。固定铵达到饱和时,吸附量只有26.18 mg/kg,对总铵的贡献率由33%下降到9%。“,”Kinetics and adsorption isotherm experiments were investigated on the adsorption of ammonium in solution,exchangeable ammonium and fixed ammonium by medium sand in different initial concentrations of NH4Cl.The results showed that,the adsorption capacities of three forms of ammonium increased as initial concentration increased.Three forms of ammonium followed the pseudo-second-order equation and the rate constants were determined.The values of rate constantly decreased in the order： fixed ammonium exchangeable ammonium ammonium in solution.However the initial rates increased in the same order.The limiting process of ammonium in solution might be intraparticle diffusion,and the proportion increased from 40% to 65%.The proportion of exchangeable ammonium to total ammonium maintained at 25%,while decreased after the maximum adsorption.The initial concentrations of NH4Cl might be the limiting step.The saturated adsorption amount of fixed ammonium was just 26.18 mg/kg.And the proportion to total adsorption decreased from 33% to 9%.