Abstract：
Clay-algae flocculation is a promising method to remove harmful algal blooms (HABs) in aquatic ecosystems. Many HAB-generating species, such as Microcystis aeruginosa (M. aeruginosa), a common species in lakes, produce toxins and harm the environment, human health, and the economy. Natural clays, such as bentonite and kaolinite, and modification of these clays have been applied to mitigate HABs by forming large aggregates and settling down. In this study, we aim to examine the impact of laponite, a commercially available smectite clay that is synthetic, transparent, compatible with human tissues, and degradable, on removing HABs. We compare the cell removal efficiencies (RE) of laponite, two natural clays, and their polyaluminum chloride (PAC)-modified versions through clay-algae flocculation experiments. Our results show that the optimum concentrations of laponite, bentonite, kaolinite, PAC-modified bentonite, and PAC-modified kaolinite to remove 80 % of the M. aeruginosa cells from the water column are 0.05 g/L, 2 g/L, 4 g/L, 2 g/L and 0.3 g/L respectively. Therefore, to achieve the same cell removal efficiency, the amount of laponite needed is 40 to 80 times less than bentonite and kaolinite, and 6 times less than PAC-modified kaolinite. We demonstrate that the superior performance of laponite clay is because of its smaller particle size, which increases the encounter rate between cells and clay particles. Furthermore, experiments using water samples from Powderhorn Lake confirmed laponite\'s effectiveness in mitigating HABs. Our price analysis also suggests that this commercially-available clay, laponite, can be used in the field at a relatively low cost.
摘要：
粘土-藻类絮凝是去除水生生态系统中有害藻华（HAB）的一种有前途的方法。许多产生HAB的物种，如铜绿微囊藻(M.铜绿假单胞菌)，湖泊中常见的物种，产生毒素和危害环境，人类健康,和经济。天然粘土,如膨润土和高岭石，这些粘土的改性已通过形成大骨料和沉降来减轻HAB。在这项研究中,我们的目的是研究锂皂石的影响，一种合成的市售蒙脱石粘土，透明,与人体组织相容，可降解，关于删除HAB。我们比较了锂皂石的细胞去除效率(RE)，两种天然粘土，以及通过粘土-藻类絮凝实验对其聚合氯化铝（PAC）改性的版本。我们的结果表明，锂皂石的最佳浓度，膨润土,高岭石,PAC改性膨润土,和PAC修饰的高岭石从水柱中去除80%的铜绿假单胞菌细胞是0.05g/L,2g/L,4g/L,2g/L和0.3g/L。因此,为了实现相同的细胞去除效率，锂皂石的用量比膨润土和高岭石少40到80倍，比PAC改性高岭石少6倍。我们证明了锂皂石粘土的优异性能是因为其粒径较小，这增加了细胞和粘土颗粒之间的相遇率。此外，使用Powderhorn湖的水样进行的实验证实了锂皂石在减轻HABs方面的有效性。我们的价格分析还表明，这种市售粘土，Laponite,可以以相对较低的成本在现场使用。
