IMPROVEMENT THE EXOELECTROGENIC BIOANODE AND STUDY THE HYDROGEN PRODUCTION IN A SINGLE CHAMBER MICROBIAL ELECTROCHEMICAL CELL

BHARATH GANDU, Department Of Chemical Engineering, Ariel University, ARIEL, ISRAEL
SHMUEL ROZENFELD, Department Of Chemical Engineering, Ariel University, Ariel, Israel
ALEX SCHECHTER, Department Of Chemical Engineering, Ariel University, Ariel, Israel
RIVKA CAHAN, Department Of Chemical Engineering, Ariel University, Ariel, Israel

Microbial Electrolysis Cells (MEC) are facilities that are mostly comprised of dual chambers, anode and cathode. In the anode chamber, there is an attachment of an exoelectrogenic biofilm (that biodegrade several carbon sources to H₂O and CO₂), as a result there is a generation of electrons and protons. The electrons travel to the cathode through an external circuit and the protons through a proton-selective membrane. In the cathode chamber under anaerobic conditions, there is a reduction of H+ ions to hydrogen. This reduction process occurs under low external voltage of 0.2-0.6 V.  MECs have potential application in bioenergy sector but the development of this technique is still in its infancy, due to the limitations of the process, viz., biofilm growth, management of suitably applied potential, materials used, etc., Simple design and operation of the cell are the priorities for configuration of MEC scale-up and successful application. Single-chamber membrane-free MECs are simple in design, easier to construct, compared to double chamber MEC.

In this study, the carbon cloth anode in the single chamber MEC was pretreated with acids. The bioanode was composed of exoelectrogenic Geobacter suferreducens biofilm growing by utilizing an acetate as the carbon source.  Progressive enrichment of exoelectrogenic bacteria Geobacter suferreducens was observed on the anode during 30 days of operation at an applied potential of +0.3 V vs Ag/AgCl reference electrode, an average current density exhibited of 2.4 mA cm^-2 was observed in chronoamperometry and simultaneously H₂ production evaluation rate was 1.39 m³ H₂. D^-1.m^-3. This study was compared with control experiments without pretreatment of the anode, where the current density was 0.4 mA cm^-2 and H₂ production evaluation rate was 0.278 m³ H₂.D^-1.m^-3. This study demonstrates the improvement of H₂ production on using pretreated bioanode of carbon textile.