摘要
三峡水库进入蓄水期后,入库流速和泥沙粒径降低,为细颗粒泥沙的絮凝过程创造了水动力条件。为了探究细颗粒泥沙絮凝过程的最佳环境条件及其对内源磷赋存与分布的影响,该文研究了泥沙粒径与浓度、pH、温度和水动力强度等环境因子对细颗粒泥沙絮凝及内源磷迁移与转化的影响。研究结果表明,泥沙粒径越小,絮凝度越大,对磷的吸附能力也越强,但其解吸潜力也越大。泥沙浓度与絮凝强度、磷吸附与解吸能力呈正比,且非磷灰石无机磷(NAIP)是发生解吸的主要磷形态。中性环境不利于细颗粒泥沙絮凝,当pH=5时,总磷吸附量和磷灰石无机磷(AIP)解吸量相对较大;当p H>8时,磷吸附能力减弱,而NAIP的解吸过程增强。温度升高能促进泥沙颗粒絮凝及其对磷的吸附作用,当解吸作用占主导地位时,温度增加也会促进解吸过程。有限强度的水体扰动形成的水动力条件可促进细颗粒泥沙絮凝及其对磷的吸附,但也为磷的解吸创造了有利条件。
After the Three Gorges Reservoir entered the impounding period,the flow velocity and sediment size of the reservoir decreased,creating hydrodynamic conditions for the flocculation process of fine sediment.The effects of environmental factors such as particle size and concentration,pH,temperature,and hydrodynamic strength on flocculation of finegrained sediments,as well as endogenous phosphorus migration and transformation were studied,in order to investigate the optimal environmental conditions for fine sediment flocculation and its effect on the occurrence and distribution of endogenous phosphorus.Results showed that the smaller the particle size,the higher the flocculation,and the more influential the adsorption capacity for phosphorus,but the more significant its desorption potential.Sediment concentration was directly proportional to flocculation strength,phosphorus adsorption,and desorption capacity.Moreover,non-apatite inorganic phosphorus(NAIP)was the main phosphorus form in which desorption occurs.The neutral environment was not conducive to the flocculation of fine particles.When pH was 5,the total phosphorus adsorption amount and apatite inorganic phosphorus(AIP)desorption amount were relatively large.The pH of 8 can weaken the phosphorus adsorption capacity,and then the desorption process of NAIP will be enhanced.Increasing temperature can promote the flocculation of sediment particles and their adsorption effect on phosphorus.If desorption was dominant,the increase in temperature also promoted the desorption process.The hydrodynamic conditions formed by the disturbance of water with limited strength can promote the flocculation of fine particles and their adsorption of phosphorus,but also it created favorable conditions for phosphorus desorption.
作者
李迪
陈垚
张彩
袁绍春
陈浬
LI Di;CHEN Yao;ZHANG Cai;YUAN Shaochun;CHEN Li(School of River and Ocean Engineering,Chongqing 400074,China;Engineering Laboratory of Environmental Hydraulic Engineering of Chongqing Municipal Development and Reform Commission,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2020年第3期66-73,共8页
Environmental Science & Technology
基金
重庆市教委科学技术研究项目(KJ1705140)
关键词
细颗粒泥沙
絮凝
磷
吸附
解吸
磷形态
fine sediment
flocculation
phosphorus
adsorption
desorption
phosphorus form
