Research progress of optical monitoring technologies for membrane fouling

Abstract

Optical monitoring technologies can be used to monitor membrane fouling in real-time and online with the in-situ, fast and nondestructive advantages, which are of great significance for the in-depth understanding of membrane fouling and the optimization of fouling control strategies. In this paper, several kinds of optical real-time monitoring technologies for membrane fouling that had been studied and developed rapidly in recent years were reviewed, including microscopic imaging techniques such as direct observation through membrane, optical coherence tomography and laser confocal microscopy, molecular spectroscopies such as excitation-emission matrix and Raman spectroscopy, and particle image velocimetry. The principles, the typical applications in fouling characterization of these techniques and the derivative techniques were described comprehensively, and the advantages and disadvantages of each technique were analyzed from the aspects of monitoring area and foulant information provided. Finally, the future development direction of the optical monitoring technologies was put forward, which would promote the application of these technologies in the membrane water treatment industries.

Keywords

• membrane fouling
• optical technology
• real-time monitoring
• microscopic imaging
• molecular spectroscopy