Variation of power generation at different buffer types and conductivities in single chamber microbial fuel cells

Joo Youn Nam, Hyun Woo Kim, Kyeong Ho Lim, Hang Sik Shin, Bruce E. Logan

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

Microbial fuel cells (MFCs) are operated with solutions containing various chemical species required for the growth of electrochemically active microorganisms including nutrients and vitamins, substrates, and chemical buffers. Many different buffers are used in laboratory media, but the effects of these buffers and their inherent electrolyte conductivities have not been examined relative to current generation in MFCs. We investigated the effect of several common buffers (phosphate, MES, HEPES, and PIPES) on power production in single chambered MFCs compared to a non-buffered control. At the same concentrations the buffers produced different solution conductivities which resulted in different ohmic resistances and power densities. Increasing the solution conductivities to the same values using NaCl produced comparable power densities for all buffers. Very large increases in conductivity resulted in a rapid voltage drop at high current densities. Our results suggest that solution conductivity at a specific pH for each buffer is more important in MFC studies than the buffer itself given relatively constant pH conditions. Based on our analysis of internal resistance and a set neutral pH, phosphate and PIPES are the most useful buffers of those examined here because pH was maintained close to the pKa of the buffer, maximizing the ability of the buffer to contribute to increase current generation at high power densities.

Original languageEnglish (US)
Pages (from-to)1155-1159
Number of pages5
JournalBiosensors and Bioelectronics
Volume25
Issue number5
DOIs
StatePublished - Jan 15 2010

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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