Wang Xudong, Huang Danxi, Cheng Botao, Wang Lei
Key Laboratory of Membrane Separation of Shaanxi Province, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
R Soc Open Sci. 2018 Aug 15;5(8):180586. doi: 10.1098/rsos.180586. eCollection 2018 Aug.
Adsorption of organic matter on membranes plays a major role in determining the fouling behaviour of membranes. This study investigated effluent organic matter (EfOM) adsorption behaviour onto poly(vinylidene fluoride) (PVDF) membrane blended with SiO nanoparticles using quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). The QCM-D results suggested that low adsorption of EfOM and an EfOM layer with a non-rigid and open structure was formed on SiO-terminated membrane surfaces. Conformational assessment showed that EfOM undergoes adsorption via two steps: (i) in the initial stage, a rapid adsorption of EfOM accumulated onto the membrane; (ii) the change in dissipation was still occurring when the adsorption frequency reached balance, and the layer tended towards a more rearranged or organized secondary structure upon adsorption onto the more hydrophilic surface. For the AFM force test, when a self-made EfOM-coated probe approached the membrane, a 'jump-in' was observed for the hydrophobic membrane after repulsion at a small distance, while only repulsive forces were observed for PVDF/SiO membranes. This study demonstrated that the PVDF/SiO membrane changed the entire filtration process, forming a 'soft' open conformation in the foulant layer.
有机物在膜上的吸附在决定膜的污染行为方面起着主要作用。本研究使用具有耗散监测功能的石英晶体微天平（QCM-D）和原子力显微镜（AFM），研究了与SiO纳米颗粒共混的聚偏氟乙烯（PVDF）膜对出水有机物（EfOM）的吸附行为。QCM-D结果表明，EfOM在SiO端基化的膜表面吸附量较低，并形成了具有非刚性和开放结构的EfOM层。构象评估表明，EfOM通过两个步骤进行吸附：（i）在初始阶段，EfOM快速吸附并积累在膜上；（ii）当吸附频率达到平衡时，耗散仍在变化，并且在吸附到更亲水表面时，该层趋向于形成更重排或更有序的二级结构。对于AFM力测试，当自制的涂有EfOM的探针靠近膜时，疏水膜在小距离排斥后观察到“跳入”现象，而PVDF/SiO膜仅观察到排斥力。本研究表明，PVDF/SiO膜改变了整个过滤过程，在污垢层中形成了“柔软”的开放构象。
