苏州河网区河道沉积物磷的吸附释放特征研究

Characteristics of Phosphorus Sorption and Release on Sediments of the River Crossed Region of Suzhou City

研究了苏州河网区河道沉积物磷的吸附和释放行为,分析了沉积物的理化性质对磷吸附释放特征的影响,并探讨了其与上覆水水质的关系。结果表明,沉积物磷的饱和吸附量为191.1～771.6 mg/kg,吸附能力强,但不同沉积物差异大;磷平衡浓度(EPC0)变化范围为0.013～0.183 mg/L,自然条件下沉积物对上覆水富营养化的发生起到了缓解作用;本底吸附磷(NAP)值范围为12.43～215.3 mg/kg,河道沉积物上自带的可解吸磷含量高;沉积物磷的吸附与释放过程均包括两个阶段,即前2 h为快速吸附或释放,10 h后,基本达到一种动态平衡;各因子相关性分析显示:沉积物中无机磷和铝含量是控制磷吸附与释放参数的最主要物理化学因子,磷的吸附与释放参数与CEC、有机质、粒度、铁铝等相关性不显著,可能是由研究对象本身的特点所决定,沉积物磷的吸附与释放是多个因素综合作用的结果。

Phosphorus（P） sorption and release on sediments collected from the river crossed region of Suzhou city were studied.The effects of chemical-physical properties of the sediments on the characteristics of P sorption and release were discussed.Moreover,the relationship between P behavior on the sediments and river water quality was elucidated.The results showed that P saturated sorption capacities ranged from 191.1 mg/kg to 771.6 mg/kg,suggesting a strong P sorption potential on river sediments,however,there was a great variation among the sediment samples.The zero equilibrium P concentration（EPC0） of the sediments ranged from 0.013 mg/L to 0.1829 mg/L,indicating a potential sink of P of the sediments.The native absorbed P（NAP） was 12.43～215.3 mg/kg,indicating that there was a high potential risk of P released from the sediments.The process of P sorption and release contained a fast and a slow reaction phase.The fast reaction phase occurred within 2 hours,and the slow reaction phase followed.The analysis of co-relation showed that CEC,TOC,the grain size,Fe and Al had no significant influence on the parameters of P adsorption and release,however,the contents of various inorganic P and Al forms were responsible for them.Such a result might be controlled by the river sediment environment.P sorption and release characteristics on river sediments is a result from many different factors.