Zhang Lixun, Tang Shengyin, Jiang Sunny
Department of Civil and Environmental Engineering, University of California, Irvine, California 92697, United States.
ACS ES T Water. 2023 Aug 29;3(9):3044-3056. doi: 10.1021/acsestwater.3c00240. eCollection 2023 Sep 8.
Microcystin-LR (MC-LR), the most common algal toxin in freshwater, poses an escalating threat to safe drinking water. This study aims to develop an engineered biofiltration system for water treatment, employing a composite of poly(diallyldimethylammonium chloride)-biochar (PDDA-BC) as a filtration medium. The objective is to capture MC-LR selectively and quickly from water, enabling subsequent biodegradation of toxin by bacteria embedded on the composite. The results showed that PDDA-BC exhibited a high selectivity in adsorbing MC-LR, even in the presence of competing natural organic matter and anions. The adsorption kinetics of MC-LR was faster, and capacity was greater compared to traditional adsorbents, achieving a capture rate of 98% for MC-LR (200 μg/L) within minutes to tens of minutes. Notably, the efficient adsorption of MC-LR was also observed in natural lake waters, underscoring the substantial potential of PDDA-BC for immobilizing MC-LR during biofiltration. Density functional theory calculations revealed that the synergetic effects of electrostatic interaction and π-π stacking predominantly contribute to the adsorption selectivity of MC-LR. Furthermore, experimental results validated that the combination of PDDA-BC with MC-degrading bacteria offered a promising and effective approach to achieve a sustainable removal of MC-LR through an "adsorption-biodegradation" process.
微囊藻毒素-LR（MC-LR）是淡水中最常见的藻类毒素，对安全饮用水构成了日益严重的威胁。本研究旨在开发一种用于水处理的工程生物过滤系统，采用聚二烯丙基二甲基氯化铵-生物炭（PDDA-BC）复合材料作为过滤介质。目标是从水中选择性快速捕获MC-LR，使嵌入复合材料的细菌随后对毒素进行生物降解。结果表明，即使在存在竞争性天然有机物和阴离子的情况下，PDDA-BC对MC-LR的吸附仍具有高选择性。与传统吸附剂相比，MC-LR的吸附动力学更快，吸附容量更大，在数分钟到数十分钟内对200μg/L的MC-LR捕获率达到98%。值得注意的是，在天然湖水中也观察到了MC-LR的高效吸附，这突出了PDDA-BC在生物过滤过程中固定MC-LR的巨大潜力。密度泛函理论计算表明，静电相互作用和π-π堆积的协同效应主要促成了MC-LR的吸附选择性。此外，实验结果证实，PDDA-BC与MC降解细菌的组合提供了一种有前景且有效的方法，通过“吸附-生物降解”过程实现MC-LR的可持续去除。
