Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University, 400044, China.
School of Civil Engineering, Key Laboratory of Water Supply & Sewage Engineering (Ministry of Housing and Urban-Rural Development), Chang'an University, Xi'an, 710054, PR China.
Chemosphere. 2020 Aug;253:126720. doi: 10.1016/j.chemosphere.2020.126720. Epub 2020 Apr 12.
To understand the biofilm formation of biofilm-based processes in wastewater treatment plants (WWTPs), the interaction mechanisms between extracted extracellular polymeric substances (EPS) and three model carrier surfaces (i.e., negatively charged hydrophilic silica, positively charged hydrophilic alumina, and neutral charged hydrophobic polystyrene) were investigated employing a laboratory quartz crystal microbalance with dissipation monitoring equipment (QCM-D) and an atomic force microscope (AFM). The data suggested that surface charge and hydrophobicity of both EPS and carriers played significant roles in the interaction behaviors. Moreover, increases in ionic strength could lead to the increasing zeta potential and hydrophobicity of EPS. It is worth noting that long-range DLVO forces dominated the EPS deposition on carriers in lower ionic strength while short-range Lewis acid-base (AB) interaction controlled the adhesion behaviors in higher ionic strength. Besides, the presence of calcium ions contributed to the adhesion behaviors because of strong charge neutralization and hydrophobic effect. Bound EPS (BEPS) showed higher affinity to model carriers than dissolved EPS (DEPS), which conformed to XDLVO prediction rather than classical DLVO model. Overall, these results provide insights into the influence mechanisms of carrier characteristics, ionic strength, calcium ion and EPS components on the interaction between EPS and representative carriers, contributing to predict and regulate biofilm formation in biofilm-based processes.
为了理解废水处理厂（WWTP）中生物膜基工艺的生物膜形成，采用带有耗散监测的实验室石英晶体微天平（QCM-D）和原子力显微镜（AFM）研究了提取的胞外聚合物（EPS）与三种模型载体表面（带负电荷的亲水性二氧化硅、带正电荷的亲水性氧化铝和不带电荷的疏水性聚苯乙烯）之间的相互作用机制。数据表明，EPS 和载体的表面电荷和疏水性对相互作用行为都起着重要作用。此外，离子强度的增加会导致 EPS 的zeta 电位和疏水性增加。值得注意的是，在较低离子强度下，长程 DLVO 力主导 EPS 在载体上的沉积，而在较高离子强度下，短程路易斯酸碱（AB）相互作用控制附着行为。此外，钙离子的存在由于强电荷中和和疏水作用有助于附着行为。与溶解态 EPS（DEPS）相比，结合态 EPS（BEPS）对模型载体表现出更高的亲和力，这与 XDLVO 预测一致，而不是经典的 DLVO 模型。总的来说，这些结果深入了解了载体特性、离子强度、钙离子和 EPS 成分对 EPS 与代表性载体相互作用的影响机制，有助于预测和调控生物膜基工艺中的生物膜形成。
