Improvement of Microbial Electrolysis Cell Activity by Using Anode Based on Combined Plasma-Pretreated Carbon Cloth and Stainless Steel

Abstract

The anode activity in a microbial electrolysis cell (MEC) is known to be a limiting factor in hydrogen production. In this study, the MEC was constructed using different anode materials and a platinum-coated carbon-cloth cathode (CC). The anodes were comprised of CC, stainless steel (SS), and a combination of the two (COMB). The CC and SS anodes were also treated with plasma to improve their surface morphology and hydrophilic properties (CCP and SSP, respectively). A combined version of CCP attached to SS was also applied (COMBP). After construction of the MEC using the different anodes, we conducted electrochemical measurements and examination of biofilm viability. Under an applied voltage of 0.6 V (Ag/AgCl), the currents of a MEC based on CCP and COMBP were 11.66 ± 0.1331 and 16.36 ± 0.3172 A m−2, respectively, which are about three times higher compared to the untreated CC and COMB. A MEC utilizing an untreated SS anode exhibited current of only 0.3712 ± 0.0108 A m−2. The highest biofilm viability of 0.92 OD540 ± 0.07 and hydrogen production rate of 0.0736 ± 0.0022 m3 d−1 m−2 at 0.8 V were obtained in MECs based on the COMBP anode. To our knowledge, this is the first study that evaluated the effect of plasma-treated anodes and the use of a combined anode composed of SS and CC for hydrogen evolution in a MEC.

Keywords

• microbial electrolysis cell
• carbon cloth
• stainless steel
• cold low-pressure nitrogen plasma
• <i>Geobacter sulfurreducens</i>
• biofilm
• bioanode
• hydrogen production