Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2022 Feb 1;806(Pt 1):150518. doi: 10.1016/j.scitotenv.2021.150518. Epub 2021 Sep 22.
In this study, for the first time, we developed a series of co-graft tannin-based flocculants, TA-g-P(AM-DMDAAC), with different charge densities (CDs) and molecular weights (MWs) and evaluated their algal-removal performances. The effects of TA-g-P(AM-DMDAAC) on the cell integrity of Microcystis aeruginosa and release of extracellular organic matter (EOM) and microcystin-leucine-arginine (MC-LR) in flocculation and floc storage were also studied. Results suggested that TA-g-P(AM-DMDAAC) could not only efficiently remove algal cells over a wide pH range (pH 3-11) but also EOM. CD and MW significantly affected flocculation performance and floc characteristics of TA-g-P(AM-DMDAAC). A higher CD helped achieve a higher removal efficiency of algal cells and EOM, whereas a higher MW resulted in the formation of larger and more compact flocs. Furthermore, the larger and denser flocs could better protect algal cells and reduce the release of EOM during floc storage. Notably, algal cells in the TA-g-P(AM-DMDAAC) flocs did not appear to show signs of massive rupture nor did they release EOM and MC-LR extensively for at least 20 days of storage. The abundance and easy availability of tannin resources effectively reduce the cost of preparing tannin-based flocculants. Therefore, TA-g-P(AM-DMDAAC) can have broad application prospects in the management of cyanobacteria bloom.
在这项研究中，我们首次开发了一系列具有不同电荷密度（CD）和分子量（MW）的单宁基共接枝絮凝剂 TA-g-P(AM-DMDAAC)，并评估了它们的除藻性能。还研究了 TA-g-P(AM-DMDAAC)对铜绿微囊藻细胞完整性的影响以及在絮凝和絮体储存过程中细胞外有机物（EOM）和微囊藻-亮氨酸-精氨酸（MC-LR）的释放。结果表明，TA-g-P(AM-DMDAAC)不仅可以在很宽的 pH 范围内（pH 3-11）有效地去除藻类细胞，还可以去除 EOM。CD 和 MW 显著影响 TA-g-P(AM-DMDAAC)的絮凝性能和絮体特性。较高的 CD 有助于提高藻类细胞和 EOM 的去除效率，而较高的 MW 则导致形成更大和更紧凑的絮体。此外，较大和较致密的絮体可以更好地保护藻类细胞，并在絮体储存过程中减少 EOM 的释放。值得注意的是，TA-g-P(AM-DMDAAC)絮体中的藻类细胞似乎没有出现大规模破裂的迹象，也没有广泛释放 EOM 和 MC-LR，至少在储存 20 天内没有出现这种情况。单宁资源的丰富和易得有效降低了制备单宁基絮凝剂的成本。因此，TA-g-P(AM-DMDAAC)在蓝藻水华的管理中具有广阔的应用前景。
