Effects of electrolyte total dissolved solids (TDS) on performance and anodic microbes of microbial fuel cells

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 ) 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.