滨海含水介质胶体对垃圾渗滤液氨氮的吸附特征

Adsorption of ammonia-nitrogen in landfill leachate on the colloids of beach water-bearing media

根据天津含水介质的结构和组成，选择代表性的2种含水介质，分析了土样和胶体的主要物理和化学性质，系统测定不同胶体对氨氮吸附的动力学曲线和吸附等温线，并分析了胶体粒径、ξ电位、电泳淌度对吸附作用的影响。结果表明，含水介质胶体对氨氮的吸附动力学过程为对数曲线，其平衡时间约为20-24h；不同胶体的吸附等温线均为直线型理想吸附，并且当水相中氨氮浓度低于一定浓度时，不但不产生吸附，反而使胶体中的残留氨氮释放出来；胶体颗粒细，比表面积大，表面能大，吸附能力就越大；胶体的ξ电位和淌度愈高，胶体的稳定性愈大，与铵离子接触的机会多，容易吸附铵离子。

On the basis of the field investigation of ammonia-nitrogen contaminated by landfills in the Tianjin shallow groundwater, two representative water-bearing media were sampled in the Tianjin coastal plain, and their and colloid＇s major physico-chemical properties were analyzed respectively. The dynamic curves and isotherms of ammonia-nitrogen adsorption on the colloid of water-bearing media were measured and the influence of particle size, zeta （ξ） potential and electrophoretic mobility on the adsorption were evaluated. The research results show that the kinetics of ammonia-nitrogen adsorption on the colloid is the logarithmic curve, and the equilibrium period of the adsorption lasts for 20 - 24 hours, and all the adsorption isotherms are straight. In addition, It is found the colloids release out the ammonia nitrogen rather than adsorb the aqueous ammonia nitrogen when the ammonia nitrogen content is lower than a certain value. The smaller colloid particle is, the stronger the adsorptive capacity of ammonium ion on colloid. With increasing of the zeta （ξ） potential and eleetrophoretic mobility of colloid particle surface, the adsorptive capacity of ammonium ion on colloid goes up.