长江中下游浅水湖泊沉积物固定态铵特征及影响因素

Characteristic of Fixation Ammonium and Effecting Factors on the Sediments from Shallow Lakes in the Middle and Lower Reaches of the Yangtze River

研究了长江中下游浅水湖泊10个沉积物对氨氮固定的动力学和热力学特征,沉积物固定态铵含量与其理化参数的相关关系.结果表明：①湖泊沉积物对氨氮的固定具有相似的变化趋势,总体上均具有快反应和慢反应2个过程.在0～10 min内,各沉积物对氨氮的固定量均较大,快反应主要发生在前10 min内.而在10 min之后,沉积物对氨氮的固定量逐渐减小,12 h后基本达到平衡.②湖泊沉积物对氨氮固定的热力学等温线符合Langmuir方程.10个沉积物的本底固定态铵含量（w（NFN））、最大固铵量（Qmax）和固铵容量（w（NFN）＋Qmax）分别为157.73～462.74,35.58～348.45和201.17～748.94 mg/kg.③湖泊沉积物的本底固定态铵含量、最大固铵量均与固铵容量有极显著正相关关系.本底固定态铵含量与TN,TP,TOC,粘粒,Fe2O3含量及CEC有显著或极显著正相关关系;固铵容量与TN,TP,TOC含量和CEC有显著正相关关系;最大固铵速率与Fe2O3含量有显著正相关关系;最大固铵量与沉积物理化性质相关性较差.

Ammonium fixation kinetics and thermodynamics characteristic and effeeting factors of fixation ammonium on ten sediments from shallow lakes in the middle and lower reaches of the Yangtze River were investigated. The results indicate that ：①The processes of ammonium fixation onto sediments of various lakes have similar trend, generally including fast and slow reactions. The fast reaction mainly occurs within 10 minutes, But after it, the amount of ammonium fixation decrease gradually. After 12 hours, the fixation process reaches equilibrium. ② The ammonium fixation isotherm curve on the sediments of various lakes accord with Langmuir Equation. The contents of w （NFN）, Qmax and w（NFN） ＋ Qm,x of the ten sediments are 157.73 ～ 462.74, 35.58 ～348.45 and 201.17 ～748.94 mg/kg, respectively. ③ There exists remarkable positive correlation between w（NFN） and w（NFN） ＋ Q and also between Qmax and w（NFN） ＋ Qmax, of the sediments; the contents of TN, TP, TOC, Clay, Fe2O3 and CEC have remarkable positive correlation with w（NFN）, respectively. TN, TP, TOC and CEC have remarkable positive correlation with w （NFN） ＋ QMax, Vmax, have remarkable positive correlation with the contents of Fe2O2, and Qmax is not much related with the sediment physiochemical properties.