微滤膜部分堵塞过滤模型的建立和机理探讨

Establishment and Mechanism Investigation of Partial Blocking Filtration Model of Microfiltration

摘要: 膜过滤机理是目前膜过滤工艺需要研究解决的关键问题之一。为描述微滤过程的速率变化数学模型,通过假设膜通道均为连通的网络型通道,将Kozeny-Carman方程与Darcy方程联立,建立了微滤膜部分堵塞过滤机理模型,并以孔隙率与水力半径为关键因素,推导了基于Darcy方程的微滤速率变化规律。在恒压条件下,通过醋酸纤维素(CA)平板膜死端过滤实验对上述模型进行了验证,在线测定了微滤速率和滤液量随时间的变化关系。结果表明:实验测得的数据和推导的模型基本吻合;且微滤存在Hermans-Bredee的3种机理(即机理指数n=2,3/2,1)以外的堵塞过滤机理,即n=4/3次方的机理。本文提出的部分堵塞过滤机理,可以与传统精密过滤中的基于Poiseuilles方程的堵塞过滤理论一起,应用于包括微-超滤的精密过滤研究中。

Abstract: Membrane filtration mechanism is one of major study projects for membrane filtration process.In order to depict the mathematic model for microfiltration(MF) velocity variation,the partial blocking filtration model for MF membrane was established by supposing web passage of membranes and correlating Kozeny-Carman equation with Darcy law.The variation rule of MF velocity was derived using porosity and hydraulic radius as key factors.The established model was proved by dead-end filtration test using cellulose ...