Aspects of feed spacer modification are examined in this comprehensive review  Appropriate feed spacer design can do much to mitigate fouling in membrane modules  Continued effort is needed towards the enhancement of high flux and low-pressure drop in membrane modules  More work is needed on the relationship between feed spacer modification and underlying membrane performance

The use of an electrically conductive membrane has attracted significant interest in water treatment technology due to remarkable performance in fouling mitigation domain. In electrochemical systems, when external potential is applied, water electrolysis occurs and the generated gases efficiently clean the membrane surface. However, fabricating and integrating conductive membranes in current water treatment modules is challenging. The present work applies, for the first time, the electrolysis concept at the spacer component of the module rather than the membrane. Two types of materials were tested, a titanium metal spacer and a polymeric spacer. The polymeric spacer was made conductive via coating with a carbon-based ink comprised of graphene nanoplates (GNPs). A membrane system composed of the carbon coated/titanium metal spacer attached to the surface of a polyvinylidene fluoride (PVDF) microfiltration membrane and was assembled to the case of membrane module. The conductive spacers worked as an electrode (cathode) in electrochemical set-up. The membrane system was subjected to fouling and then exposed to periodic electrolysis, wherein in-situ cleaning of membrane surface by hydrogen bubbles generation at the spacer is applied.

Highlights ►Current trend for using electrically conductive feed spacer for fouling mitigation and enhanced water flux. ►A study is described into humic acid removal using 2 conductive coated feed spacer configurations and their performance in a water treatment system. ►Effects of feed concentration, formation of bubbles during periodic electrolysis, interval time for in situ feed spacer cleaning and enhanced water flux were also investigated. ►In situ electrochemical cleaning through generation of bubbles is a strong advantage for using conductive feed spacer.