动水条件下平原河网沉积物对氨氮吸附热力学和动力学研究

Study on the Thermodynamics and Kinetics of Ammonia Nitrogen Adsorption by the Sediments of Plain River Network under Moving Water Conditions

  • 摘要: 在水域恒温振荡器振荡下,开展转速在113、119、128、139rpm下太湖河网沉积物对氮的吸附热力学实验和氮的吸附动力学实验。实验结果表明,S1采样点NH4+-N的最大吸附量分别为15.136、29.132、30.896、88.83mg/kg。S2采样点NH4+-N的最大吸附量分别为17.474、32.396、32.908、55.364mg/kg,符合Langmuir模型。同时,在不同转速的扰动下,太湖河网沉积物对NH4+-N的吸附动力学具有类似的变化趋势:吸附反应前10min吸附速率最快,第10~120min吸附缓慢渐渐趋于饱和值,120min以后吸附反应基本达到饱和状态,符合抛物线扩散模型。并且南溪沉积物比漕桥河沉积物对NH4+-N吸附能力更强。

     

    Abstract: Under the oscillation of a constant-temperature oscillator in the water area,experiments were carried out on the thermodynamics of nitrogen adsorption by sediments of the Taihu River network at 113 rpm,119 rpm,128 rpm,and 139 rpm and the kinetics of nitrogen adsorption. The results showed that the maximum adsorption capacity of NH4+-N at S1 sampling point was 15. 136 mg/kg,29. 132 mg/kg,30. 896 mg/kg,88. 83 mg/kg. The maximum adsorption capacity of NH4+-N at S2 sampling point was 17. 474 mg/kg,32. 396 mg/kg,32. 908 mg/kg,55. 364 mg/kg,which fits Langmuir model. At the same time,under the disturbance of different rotation speeds,the adsorption kinetics of NH4+-N in the sediments of the Taihu river network has a similar trend that the adsorption rate was the fastest in the first 5 minutes of the adsorption reaction,and the adsorption was slow and gradually became saturated from the 5 th minute to the 120 th minute. After 120 minutes,the adsorption reaction basically reached saturation,which conformed to the parabolic diffusion model. Moreover,the sediments in Nanxi had stronger NH4+-N adsorption capacity than the sediments in Caoqiao River.

     

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