Microcystis aeruginosa, as the most common cyanobacteria, often grows uncontrollably in eutrophic lakes with the accumulation of microcystin-LR (MC-LR) in water, which heavily pollutes water and hence imposes tremendous threat to aquatic animals and human beings. To remediate the harmful algae polluted water, here we synthesize a series of poly dimethyl diallyl ammonium chloride (PDDA) modified TiO₂ floating photocatalysts, PDDA@NPT-EGC, and apply them as a visible light driven multifunctional material. The fabricated PDDA@NPT-EGC composites have a worm-like structure with PDDA particles distributed on their surfaces, and the concentration of PDDA can affect the agglomerative condition and distribution of PDDA particles and the photoelectric properties of catalysts. Among these catalysts, the PDDA@NPT-EGC with 0.2 wt% PDDA (0.2PDDA@NPT-EGC) shows the highest adsorption and photocatalytic activity. Compared with the NPT-EGC, the dark adsorption efficiency for the 0.2PDDA@NPT-EGC after 3 h increases from 70.4% to 88.9%, and the total removal efficiency after visible light irradiation for 2 h increases from 77.8% to 92.6%. In addition, the 0.2PDDA@NPT-EGC exhibits a removal efficiency of 96.55% for photocatalytic degradation of MC-LR after irradiation for 3 h. The Adda side chain of MC-LR molecule is found to degradate gradually in the photocatalytic degradation process, indicative of the elimination of biotoxicity for MC-LR molecule in the reaction. We demonstrate that the 0.2PDDA@NPT-EGC is remarkably competitive in both algae inactivation and MC-LR removal, which shall hold substantial promise in remediation of algae pollution in eutrophic waters.

铜绿微囊藻是最常见的蓝细菌，通常在富营养化的湖泊中不受控制地生长，其中微囊藻毒素-LR（MC-LR）在水中积累，这严重污染了水，因此对水生动物和人类构成了巨大威胁。为了修复有害藻类污染的水，这里我们合成了一系列的聚二甲基二烯丙基氯化铵（PDDA）改性的TiO ₂浮动光催化剂PDDA @ NPT-EGC，并将其用作可见光驱动的多功能材料。制备的PDDA @ NPT-EGC复合材料具有蠕虫状结构，其表面分布有PDDA颗粒，PDDA的浓度会影响PDDA颗粒的团聚条件和分布以及催化剂的光电性能。在这些催化剂中，具有0.2重量％PDDA的PDDA @ NPT-EGC（0.2PDDA@NPT-EGC）显示出最高的吸附和光催化活性。与NPT-EGC相比，0.2PDDA @ NPT-EGC在3 h后的暗吸附效率从70.4％增加到88.9％，可见光照射2 h后的总去除效率从77.8％增加到92.6％。此外，0.2PDDA @ NPT-EGC的去除效率为96。辐照3 h后，MC-LR的光催化降解率为55％。发现MC-LR分子的Adda侧链在光催化降解过程中逐渐降解，表明消除了反应中MC-LR分子的生物毒性。我们证明了0.2PDDA@NPT-EGC在灭藻和去除MC-LR方面都具有明显的竞争力，这在修复富营养化水中的藻类污染方面将具有广阔的前景。