AlCl3、MgCl2、CaCl2和腐殖酸对高浊度体系细颗粒泥沙絮凝的影响

以细颗粒泥沙为主的河口区往往存在最大浑浊带,对高浊度体系细颗粒泥沙的絮凝研究有助于了解最大浑浊带的形成机制。本文通过实验研究AlCl3,MgCl2,CaCl2和腐殖酸四种絮凝剂对长江口细颗粒泥沙浊度变化的影响,从絮凝率、絮团粒径和Zeta电位变化三方面综合分析了四种絮凝剂对泥沙絮凝的作用机理。结果表明:1)随着金属离子浓度增大细颗粒泥沙絮凝率逐渐增大,粒径增大,而电位绝对值变小;随着腐殖酸浓度增大细颗粒泥沙絮凝率降低,粒径增大,电位绝对值增大;2)各絮凝剂单独存在时的絮凝机理与多组分复合絮凝作用机理有明显不同,C-P-OM复合絮凝模式能够较好地揭示长江口高浊度区细颗粒泥沙絮凝体的形成机制。

Effects of AlCl3, MgCl2, CaCl2 and humus on the flocculation of fine sediments in the high-turbid system of the Changjiang Estuary

The turbidity maximum(TM) often exists in the estuary area with fine sediments,and the study on the flocculation of fine sediments in the high-turbid system is of great help in the understanding of the mechanism of the formation of TM.In the present paper,the effects of AlCl_3,MgCl_2,CaCl_2 and humus on the turbidity of the fine sediments in the Changjiang Estuary have been studied,and the flocculating mechanism of the fine sediments has been analyzed through the synthetic study of the aspects of flocculation/coagulation power(F),diameter(D) and Zeta potential(Z) of the flocculation. The results show that: 1) with the increase of concentration of metallic cations,F and D become greater and Z becomes smaller;while with increase of the concentration of humus,F becomes smaller,but D and Z become greater;2) the flocculating mechanism of individual flocculant is distinctly different from the complex flocculating mechanism,and the flocculation model of C-P-OM can successfully illustrate the mechanism of the formation of the fine sediments in the high-trubid area of the Changjiang Estuary.