College of Environmental Science and Engineering, Textile Pollution Controlling Engineering Centre of Ministry of Ecology and Environment, Donghua University, Shanghai 201620, China.
College of Environmental Science and Engineering, Textile Pollution Controlling Engineering Centre of Ministry of Ecology and Environment, Donghua University, Shanghai 201620, China.
Water Res. 2024 Aug 15;260:121937. doi: 10.1016/j.watres.2024.121937. Epub 2024 Jun 12.
Reverse osmosis (RO) system has been increasingly applied for circulating cooling water (CCW) reclamation. Plasticizers, which may be dissolved into CCW system in plastic manufacturing industry, cannot be completely removed by the pretreatment prior to RO system, possibly leading to severe membrane biofouling. Deciphering the characteristics and mechanisms of RO membrane biofouling in the presence of trace plasticizers are of paramount importance to the development of effective fouling control strategies. Herein, we demonstrate that exposure to a low concentration (1 - 10 μg/L) of three typical plasticizers (Dibutyl phthalate (DBP), Tributyl phosphate (TBP) and 2,2,4-Trimethylpentane-1,3-diol (TMPD)) detected in pretreated real CCW promoted Escherichia coli biofilm formation. DBP, TBP and TMPD showed the highest stimulation at 5 or 10 μg/L with biomass increasing by 55.7 ± 8.2 %, 35.9 ± 9.5 % and 32.2 ± 14.7 % respectively, relative to the unexposed control. Accordingly, the bacteria upon exposure to trace plasticizers showed enhanced adenosine triphosphate (ATP) activity, stimulated extracellular polymeric substances (EPS) excretion and suppressed intracellular reactive oxygen species (ROS) induction, causing by upregulation of related genes. Long-term study further showed that the RO membranes flowing by the pretreated real CCW in a polypropylene plant exhibited a severer biofouling behavior than exposed control, and DBP and TBP parts played a key role in stimulation effects on bacterial proliferation. Overall, we demonstrate that RO membrane exposure to trace plasticizers in pretreated CCW can upregulate molecular processes and physiologic responses that accelerate membrane biofouling, which provides important implications for biofouling control strategies in membrane-based CCW treatment systems.
反渗透（RO）系统已越来越多地应用于循环冷却水（CCW）回收。在塑料制造行业中，可能会有增塑剂溶解到 CCW 系统中，但在进入 RO 系统之前的预处理无法将其完全去除，这可能导致严重的膜生物污染。解析痕量增塑剂存在时 RO 膜生物污染的特征和机制对于开发有效的防污控制策略至关重要。在此，我们证明了暴露于预处理实际 CCW 中检测到的三种典型增塑剂（邻苯二甲酸二丁酯（DBP）、磷酸三丁酯（TBP）和 2,2,4-三甲基戊烷-1,3-二醇（TMPD））的低浓度（1-10μg/L）会促进大肠杆菌生物膜的形成。DBP、TBP 和 TMPD 在 5 或 10μg/L 时表现出最高的刺激作用，生物量分别增加了 55.7±8.2%、35.9±9.5%和 32.2±14.7%，与未暴露的对照组相比。相应地，暴露于痕量增塑剂的细菌表现出增强的三磷酸腺苷（ATP）活性、刺激细胞外聚合物（EPS）排泄和抑制细胞内活性氧（ROS）诱导，这是通过相关基因的上调引起的。长期研究进一步表明，在聚丙烯工厂中，用预处理的实际 CCW 流过的 RO 膜表现出比暴露对照组更严重的生物污染行为，DBP 和 TBP 部分在刺激细菌增殖方面发挥了关键作用。总体而言，我们证明了 RO 膜暴露于预处理 CCW 中的痕量增塑剂可以上调分子过程和生理反应，从而加速膜生物污染，这为基于膜的 CCW 处理系统中的防污控制策略提供了重要启示。
