Renewable carbon-based materials for enhanced ion concentration polarization in sustainable separation devices

Abstract

Renewable carbon-based materials derived from sugarcane harvest residues were used as a porous medium to study the enhancement effect of ion concentration polarization as an emerging electrolyte separation concept. A home-made cell for continuous electrolyte flow including two electrodes was used to study this process. A set of continuous flow runs using 0.1 mM KCl solution were performed under applied electric potentials between 0.0-5.0 V. A decrease of the outlet ion conductivity was obtained when the electric potential was applied to the cell. The depletion effect increased when flow velocities were lower and the phenomenon was reversible as the voltage was turned off. A 25 % conductivity drop was achieved for an electrolyte flow rate of 0.7 ccm. The conductivity drop was higher for less permeable porous medium, i.e., tighter biochar porous material. This is an example of how renewable biomass-derived materials can be integrated into the manufacturing of new separation devices.