Abstract

Effects of total dissolved solids (TDS) of electrolyte on performance and anodic microbes were studied in double-chamber microbial fuel cells (MFC) with batch operation. Results showed that the optimum voltage output (355 mV, 1000 Ω) and power generation (578 mW/m²) were achieved at TDS 20 g/L and 5 g/L, respectively. There were positive correlations between electrolyte TDS and voltage outputs at TDS 10 g/L and 20 g/L, but negative ones at TDS 30 g/L. Operations of the MFCs at TDS 30 g/L were not stable. Chemical oxygen demand (COD) removal rates decreased while coulombic efficiencies (CEs) increased with increased TDS. Anodic microbe species varied a lot at different TDS conditions. Main anodic microbes (Alcaligenes, Gordonia and Syntrophaceae) at lower TDS disappeared in MFCs at TDS 30 g/L. TDS as high as 30 g/L was harmful to the MFC system.

Key words: Microbial fuel cell, total dissolved solids (TDS), anodic microbe.

Abbreviation

BLAST, Basic Local Alignment Search Tool; CE, coulombic efficiency; COD, chemical oxygen demand; DGGE, denaturing gradient gel electrophoresis; DNA, deoxyribonucleic acid; MFC, microbial fuel cell; PCR,polymerase chain reaction; TDS, total dissolved solid; MDC, microbial desalination cells; rRNA, ribosomal ribonucleic acid; NCBI, national center for biotechnology information.