How to extend the lifetime of RO membrane? From the perspective of the end-of-life RO membrane autopsy

Abstract

The lifetime of reverse osmosis (RO) membranes would be shortened by membrane fouling during the applications, resulting in the generation of a huge number of discarded RO membrane modules each year. To extend the lifetime of RO membranes, in this work, end-of-life RO membranes collected from four typical RO applications, including boiler feed water treatment, water reuse, surface water treatment, and seawater desalination were autopsied to reveal the fouling layer characteristics. The morphologies and primary compositions of the membrane fouling layers were evaluated. It was found that proteins, polysaccharides, and the scales of Si, Fe, and Al presented in all the fouling layers of the analyzed end-of-life RO membranes, while the contents varied depending on the applications. On this basis, the formation process of the fouling layers was revealed; the general and specific lifetime extension strategies of the RO membrane for various water treatment processes were proposed.