长江科学院院报 ›› 2020, Vol. 37 ›› Issue (5): 15-22.DOI: 10.11988/ckyyb.20190119

• 水资源与环境 • 上一篇    下一篇

长江中下游江段泥沙对Pb2+的吸附特征

韩丁1,2, 黎睿1, 汤显强1,3, 胡园1, 郭伟杰1   

  1. 1.长江科学院 流域水环境研究所,武汉 430010;
    2.三峡大学 水利与环境学院,湖北 宜昌 443002;
    3.中国长江三峡集团有限公司 长江生态环境工程研究中心,北京 100089
  • 收稿日期:2019-01-30 出版日期:2020-05-01 发布日期:2020-06-10
  • 通讯作者: 汤显强(1981-),男,湖北竹溪人,教授级高级工程师,博士,主要从事水资源保护与水污染控制研究。E-mail:ckyshj@126.com
  • 作者简介:韩 丁(1994-),男,河北邢台人,硕士研究生,主要从事水资源保护与水污染控制研究。E-mail:839266116@qq.com
  • 基金资助:
    国家自然科学基金项目(41907401); 国家高层次人才特殊支持计划项目(CKSD2019542/SH); 中国长江三峡集团有限公司资助项目(201903145)

Adsorption of Pb2+ on Sediments in the Middle andLower Reaches of the Yangtze River

HAN Ding1,2, LI Rui1, TANG Xian-qiang1,3, HU Yuan1, GUO Wei-jie1   

  1. 1. Basin Water Environmental Department,Yangtze River Scientific Research Institute,Wuhan 430010,China;
    2. College of Hydraulic & Environmental Engineering,China Three Gorges University,Yichang 443002, China;
    3. Yangtze River Eco-environmental Engineering Research Center, China Three Gorges Corporation,Beijing 100089, China
  • Received:2019-01-30 Online:2020-05-01 Published:2020-06-10

摘要: 以长江中下游武汉至上海崇明岛江段河床泥沙样品为研究对象,通过振荡吸附试验研究了泥沙对Pb2+的吸附特征,分析了泥沙浓度、泥沙粒径、有机质含量等对Pb2+吸附的影响。结果表明:泥沙对Pb2+的吸附平衡时间为20 h,吸附动力学过程可以用准一级动力学、准二级动力学、Elovich方程对试验数据进行分析拟合,拟合系数均在0.85以上,尤以准二级动力学方程为佳,其拟合系数高达0.997 8。Langmuir模型对Pb2+的等温吸附的拟合系数R2均达到0.9以上,Pb2+的等温吸附过程为单分子层吸附,吸附大多发生在泥沙表面,主要为物理吸附过程。随着泥沙浓度的增加,吸附效率显著提高,当泥沙浓度增加为1 g/L时,吸附效率达到最大值(≈99.8%)。泥沙对Pb2+的吸附热力学参数ΔG<0,ΔH>0,表明该过程可以自发进行,升高温度有利于提高泥沙对Pb2+的吸附量;泥沙中有机质含量越高,平均吸附键能越大,两者呈显著正相关关系(R2=0.968 2, p<0.01)。泥沙对Pb2+吸附量总体呈现出随泥沙的粒径减小而增大的趋势,泥沙对Pb2+的吸附主要发生在粒径<0.074 mm的粒径分组中。应该加强对长江中下游水体含沙量及颗粒级配的监测,以随时掌握水沙变化对Pb2+等污染物迁移转化的影响。

关键词: 泥沙, Pb2+, 吸附, 重金属, 长江中下游

Abstract: The sediment samples from Wuhan to Chongming Island of Shanghai in the middle and lower reaches of the Yangtze River were collected for studying the characteristics of adsorption of Pb2+ by sediment via oscillatory adsorption test. The effects of sediment concentration, sediment particle size and organic matter content on Pb2+ adsorption were also analyzed. Results show that the adsorption of Pb2+on sediment reaches equilibrium after 20 hours. The adsorption kinetics can be analyzed and fitted by quasi-first-order kinetics, quasi-second-order kinetics and Elovich equation. The fitting coefficients are all above 0.85, and especially the fitting coefficient of quasi-second-order kinetics equation amounts to 0.997 8. The values of fitting correlation coefficient R2 of Langmuir model for isothermal adsorption of Pb2+ are all above 0.9. The isothermal adsorption process of Pb2+ is monolayer adsorption mostly on the surface of sediment mainly in the manner of physical adsorption.With the increase of sediment concentration,the adsorption efficiency enhances significantly.When the sediment concentration increases to 1 g/L, the adsorption efficiency reaches the maximum (≈99.8%). The thermodynamic parameters ΔG < 0 and ΔH > 0 of sediment adsorption for Pb2+ reveals that the process can be carried out spontaneously. Temperature rising is conducive to instigating the adsorption of Pb2+. Organic matter content is in a significant positive correlation (R2=0.968 2, p<0.01) with adsorption energy. The amount of Pb2+ adsorbed by sediment increases with the decrease of sediment particle size. The adsorption of Pb2+ by sediments mainly occurs in particle size groups smaller than 0.074 mm. Monitoring on the sediment concentration, particle size distribution and its chemical composition in the middle and lower reaches of the Yangtze River should be strengthened so as to keep abreast of the influence of water and sediment changes on the migration and transformation of pollutants such as Pb2+.

Key words: sediment, Pb2+, adsorption, heavy metal, middle and lower reaches of the Yangtze River

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