正渗透是浓度驱动的膜技术,是指水通过选择性渗透膜从高水化学势区域向低水化学势区域的传递过程.本文介绍了正渗透的基本构成(驱动力、汲取液和正渗透膜材料),指出膜两侧的浓差极化是水通量性能的最大障碍,采用通量模型说明了膜在两种放置方向下存在的内浓差极化和外浓差极化,内浓差极化对驱动力的减小起着重要的作用;论述了膜材料、原料液浓度、汲取液浓度对正渗透和压力延迟渗透水通量的影响;此外,评述了正渗透过程的膜污染和能耗.%Forward osmosis (FO) is a concentration-driven membrane process, in which water transports across a semi-permeable membrane from a dilute feed solution into a concentrated draw solution. The basic factors of FO( driving force, draw solution and membrane materials )are introduced.The major hindrance to permeate water flux performance is the prevalence of concentration polarization on both sides of the membrane. Flux models that account for the presence of both internal and external concentration polarization for the two possible membrane orientations are presented.Internal concentration polarization is found to play a significant role in the reduction of driving force.This article comments the effect of membrane material, feed solution concentration, and draw solution concentration on FO and pressure-retarded osmosis (PRO) water flux performance. In addition,membrane fouling as well as energy consumption of FO is evaluated.
展开▼
