Effect of electrolyte nature in mass transport of a neutral solute in a microtube with porous wall

Abstract

Electroosmotic flow in a microchannel is an active area in microfluidics. Microchannels with porous wall are advantageous due to selective separation and enhanced mass transport. An economic and innovative method to fabricate hollow microtubes and their application in electrokinetics are illustrated. Effects of asymmetric electrolyte on mass transport of a neutral macrosolute in the microtube with porous wall are investigated. The combined velocity profile including both pressure-driven and electroosmotic flow is modeled for different electrolytes. It is found from the study that the addition of higher valency asymmetric electrolyte (3:1) increases transport of neutral solutes across the porous wall compared to its symmetric counterpart (1:1). The developed model was validated with the experimental results, using a cartridge having hollow microtubes with porous wall. This study would be helpful to select an appropriate electrolyte, improving the design, and performance prediction of microfluidic devices.