有机质环境的高岭土动水絮凝特征研究

Flocculation characteristics of organic-rich kaolinite in turbulent flows

河口海岸地区黏性细颗粒泥沙的絮凝研究,特别是有机质与无机质联合作用下的泥沙絮凝研究,对探索河口海岸沉积动力学过程具有科学意义。选用无机质高岭土和可溶于水的有机质瓜儿豆胶,在动水条件下开展泥沙絮凝影响试验研究。采用自主研发的非侵入式絮凝体观测系统对动水条件下泥沙絮凝体及其分布进行直接观测,分析高岭土在不同悬沙浓度、水体紊动强度及瓜儿豆胶浓度等作用下的絮凝特征。研究结果表明:有机质显著促进高岭土的絮凝,使絮凝体中值粒径从70μm左右增大到200μm以上,但其对絮凝的促进作用有峰值效应,且达到峰值后会产生一定的抑制。较强水体紊动和较高悬沙浓度对絮凝体生长均产生一定的抑制作用。

The flocculation of fine-grain sediment in estuarine and coastal areas, especially the process under a coupling effect of both organic matter and inorganic matter, is scientific significance to explore the dynamic processes of sedimentation in those regions. In this study, the inorganic kaolinite and the water-soluble guar gum were selected to illustrate the coupling factor on sediment flocculation in turbulent waters by a laboratory experiment. A non-intrusive floc camera system was used to directly observe sediment flocs and their distributions in the experiment. The flocculation characteristics of kaolinite under different suspended sediment concentrations, water turbulence intensities, and guar gum concentrations were analyzed. The results show that the existence of organic matter significantly promotes the flocculation of kaolinite, with median particle size increasing from 70 μm to more than 200 μm. It also shows that the particle size reaches a peak, after which the flocculation will be inhibited.