Power generation of microbial fuel cells (MFCs) with low cathodic platinum loading Carlo Santoro a,b , Baikun Li a,b, *, Pierangela Cristiani c , Gaetano Squadrito d a Department of Civil and Environmental Engineering, University of Connecticut, 261 Glenbrook Rd., Unit 2037, Storrs, CT 06269-2037, USA b Center for Clean Energy Engineering, University of Connecticut, 44 Weaver Rd., Storrs, CT 06269-5233, USA c RSEeRicerca sul Sistema Energetico S.p.A., Environment and Sustainable Development Department, Via Rubattino 54, 20100 Milan, Italy d CNR-ITAE (Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano”), Salita S. Lucia sopra Contesse 5, 98126 Messina, Italy article info Article history: Received 7 March 2012 Received in revised form 18 May 2012 Accepted 22 May 2012 Available online 3 July 2012 Keywords: Microbial fuel cell Platinum loading Solution conductivity Power generation COD removal abstract This study aims at investigating the effects of platinum (Pt) loadings on the cathodic reactions in Single Chamber Microbial Fuel Cells (SCMFCs) and developing cost-effective MFC operational protocols. The power generation of SCMFCs was examined with different Pt loadings (0.005e1 mgPt/cm 2 ) on cathodes. The results showed that the power generation of the SCMFCs with 0.5e1 mgPt/cm 2 were the highest in the tests, decreased 10 e15% at 0.01e0.25 mgPt/cm 2 , and decreased further 10e15% at 0.005 mgPt/cm 2 . The SCMFCs with Pt-free cathode (graphite) had the lowest power generation. In addition, the power generation of SCMFCs with different Pt loadings were compared in raw wastewater (Chemical oxygen demand (COD): 0.36 g/L) and wastewater enriched with sodium acetate (COD: 2.95 g/L). The solution conductivity in SCMFCs decreased with the degradation of organic substrates. Daily polarization curves (VeI ) showed a decrease in current genera- tion and an increase in ohmic losses over the operational period (8 days). The SCMFCs (with 0.5e1 mgPt/cm 2 at cathode) fed with wastewater and sodium acetate (NaOAc) reached the highest power generation (786 mW/m 2 ), while the SCMFCs (with 0.5e1 mgPt/cm 2 at cathode) fed only with wastewater obtained the lower power generation (81 mW/m 2 ). The study demonstrated that lowering the Pt loadings in two magnitude orders (1 to 0.01, 0.5 to 0.005 mgPt/cm 2 ) only reduced the power generation of 15e30%, and this reduction of the power generation become less substantial with the decrease in the solution conductivity of SCMFCs. Copyright ª 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Microbial fuel cell (MFC) is a new bio-technology capable of generating electricity from degrading organic compounds (e.g. hydrocarbon and protein) in wastewater. Nowadays waste- water treatment and energy production are the critical issues for environmental and energy sustainability. MFC technology can be an adequate answer to reduce the costs of wastewater treatment and produce environmentally friendly energy. Membraneless MFC is generally composed by an anodic chamber and a cathode. The anode is colonized by electro- active microorganisms to degrade organic substrates and * Corresponding author. Department of Civil and Environmental Engineering, University of Connecticut, 261 Glenbrook Rd., Unit 2037, Storrs, CT 06269-2037, USA. Tel.: þ1 860 486 2339 E-mail address: baikun@engr.uconn.edu (B. Li). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 38 (2013) 692 e700 0360-3199/$ e see front matter Copyright ª 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijhydene.2012.05.104