有机质对城市污染河道沉积物铵态氮吸附-解吸的影响

Effect of organic matter on adsorption / desorption of ammonium in the sediments of heavily polluted urban river

采集污染程度不同的城市河道沉积物(通吕运河、濠河和通甲河),在分析H2O2对沉积物有机质和铵态氮影响的基础上,分析沉积物在去除有机质前后铵态氮释放动力学和吸附热力学过程,研究城市污染河道沉积物有机质对铵态氮吸附-解吸的影响.结果表明:单位体积H2O2对有机质去除率随H2O2使用量增多而降低;去除有机质后,沉积物铵态氮含量显著增加,通吕运河、濠河和通甲河铵态氮最大含量分别是有机质去除前的4.16、3.55和2.85倍;沉积物对铵态氮的饱和吸附量随有机质含量减少而下降;沉积物铵态氮释放过程均表现为先快速释放,后减缓至平衡过程;去除有机质后,随着有机质含量的减少,沉积物铵态氮的最大释放量呈增大趋势;沉积物有机质和铵态氮含量是影响沉积物铵态氮释放的主要因素.

The effect of organic matter on ammonium release kinetics and adsorption isotherms of the sediments from different trophic level urban rivers（ named TL,HH and TJ） and its mechanism was discussed. The results showed the removal ratio of organic matter of per unit volume of H2O2 tended to decrease with volume of H2O2 increasing. The content of ammonium in sediments tended to increase significantly as sediment organic matter was removed by H2O2. Ammonium adsorption capacity tended to decrease with their organic matter contents decreasing. The equilibrium time of ammonium release was prolonged with the increasing of the organic matter contents in the studied sediment,and the amounts of the ammonium released increased first and then reached equilibrium gradually. Removal of organic matter could increase ammonium release capacity. The main factors affecting ammonium release were analyzed. Organic matter content and ammonium concentration were the key factors on ammonia release from sediments.