岸滤系统对氨氮的吸附作用及影响因素分析

Adsorption of ammonia nitrogen by riverbank filtration system and influencing factors

岸滤系统对水质的净化作用是傍河取水过程中水质安全的重要保障.哈尔滨第一水源地为典型的松花江傍河水源地,本文以其岸滤系统为研究对象,通过静态吸附批实验分析不同深度含水层介质对氨氮的吸附去除特征,并研究了氨氮初始质量浓度、温度、pH等对含水层介质吸附氨氮的影响.结果表明:不同深度含水层介质对氨氮的吸附作用符合准二级动力学模型和Langmuir模型,吸附过程为单分子层吸附,受化学作用控制;随深度增加,含水层介质对氨氮的吸附能力减小,岸滤系统的净水能力减弱;氨氮吸附量与初始质量浓度呈正相关关系,含水层介质对NH^(+)_(4)的吸附为放热反应,温度升高抑制了吸附作用;pH增加,H^(+)对NH^(+)_(4)的竞争吸附作用减小,且含水层介质表面电负性增大,对NH^(+)_(4)的吸附能力增强.综合对比可知,在10℃的中性环境下,岸滤系统对氨氮污染物的吸附去除效果最佳.

Quality water purification of riverbank filtration system is an important guarantee for water safety in the water treatment process.A primary water source in Harbin is the Songhua Riverbank Source.Here the ammonia nitrogen adsorption-removal characteristics at different depth of aqueous media layers in static adsorption batch tests were analyzed,with effects of initial concentration,temperature,pH at different aqueous medium layer studied.Adsorption of ammonia nitrogen at different depths was found to conform to a quasi-second-order kinetic model and Langmuir model.The adsorption was of monolayer adsorption,controlled by chemical action.With increasing depth,adsorption capacity decreased,but water purification capacity decreased.Adsorption amount was positively correlated with initial concentration.Adsorption of NH^(+)_(4) was exothermic,inhibited by increasing temperature.With increasing pH,the competitive adsorption between H^(+) and NH^(+)_(4) decreased,surface electronegativity of aquifer media increased,leading to increased adsorption capacity of NH^(+)_(4).In neutral environment at 10℃,adsorption and removal was the best.