Experimental Research Into The Migration Of Ammonia In An Aqueous Medium

This paper combined theoretical research with laboratory simulation, took ammonia nitrogen adsorption kinetics, static adsorption and soil column simulation experiment as main research method with other groundwater pollution research methods to get an accurate and practical evaluation result, and thereby provided scientific support for soil and water pollution governance research. In order to research the conversion characteristics of three nitrogen in natural state, this paper placed different concentrations of ammonium chloride solution in the open room to determine continuously the concentration change of three nitrogen at a room temperature of 32°C. It can be obtained that the concentration of NH₄⁺-N decreased continuously over time, while the concentration of NO2_<sup>--N had a growth trend; the concentration of NO3_<sup>--N had a volatility change, and there was no obvious difference between the final concentration and initial concentration which indicated that the concentration of NO2_<sup>--N increased was not from NO3_<sup>--N but NH₄⁺-N. According to adsorption kinetics of ammonia nitrogen we learned that the strongest adsorption capacity of ammonia nitrogen is fine sand, the weakest is coarse sand and medium sand had a middle adsorption capacity. According to static adsorption experiment we learned that the ammonia nitrogen adsorption process of coarse sand, medium sand and fine sand respectively accord with Freundlich, Henry and Langmuir adsorption isothermal curve. Coarse sand and fine sand both belong to monolayer adsorption. When pH was between 4.91 and 9, the ammonia nitrogen adsorption quantity of sand was no obvious fluctuation with the change of PH; But under acidic?pH<4.91? and strongly alkaline?pH>10.96? conditions, the ammonia nitrogen adsorption quantity of sand had an obviously rising and descent tendency with the change of PH. This paper set up a nitrogen migration model of coarse sand, medium sand and fine sand, then used this model to fitting and calculate their lag coefficient and dispersion coefficient, and had a conclusion that the soil was finer, the barrier capability of NH₄⁺-N was stronger at the end of this paper. Therefore we can use this model to forecast the concentration changing trend of nitrogen which had a longitudinal migration in coarse sand, medium sand and fine sand.