Optimization of membrane stack configuration for efficient hydrogen production in microbial reverse-electrodialysis electrolysis cells coupled with thermolytic solutions

Hydrogen production from continuous flow, microbial reverse-electrodialysis electrolysis cells treating fermentation wastewater

“…2A). This current production is similar to the maximum current obtained in previous tests ($50 A/m 3 , 4.0 A/m 2 ) at the start of a fed-batch tests using a smaller (60 mL, 7 cm 2 ) MREC that also contained 5 cell pairs, but different membranes (Selemion AMV and CMV, Asashi glass, Japan) (Luo et al, 2013). The electrode potentials were relatively constant, with À0.402 ± 0.009 V for the anode, and À0.726 ± 0.002 V for the cathode.…”

“…Previous work with RED stacks in microbial fuel cells (MFCs) have shown that using only a few cell pairs (one or two) increases MFC performance, but the incremental impact on power is diminished using additional cell pairs (Cusick et al, 2013). In an MREC study under fed-batch conditions using an acetate anolyte (30 mL), it was shown that adding cell pairs increased performance up to 5 cell pairs, but that the use of additional cell pairs (up to 7) did not further improve performance (Luo et al, 2013). This lack of an increase in performance with more cell pairs was attributed to the relatively high internal resistance of the stack, and the observation that adding more cell pairs produced only a minimal increase in current.…”

“…An ammonia bicarbonate HC solution was used in the stack in order to examine hydrogen gas production using a thermolytic solution that could be regenerated using waste heat. The RED stack had thin channels, and therefore improved power production, relative to those previously examined for hydrogen gas production in MRECs (Luo et al, 2013;Nam et al, 2012). Tests were initially conducted on stack performance using acetate, and a synthetic dark fermentation effluent, to better control the impact of feed solutions on system performance.…”

A comparison of mono- and multi-valent ions as stack feed solutions in microbial reverse-electrodialysis electrolysis cells and their effects on hydrogen generation

“…Kim and Logan (2011) reported that a five-cell paired RED stack could contribute approximately 0.5e0.6 V for hydrogen generation to the MREC system. A high hydrogen yield (3.4e3.5 mol-H 2 mole À1 -acetate) and efficient organic removal (87e94%) of the MREC system was demonstrated by Nam et al (2012) and Luo et al (2013) using 1.0 g L À1 sodium acetate as a substrate.…”

“…In recent years, the combined technology between microbial electrolysis cells (MEC) and reverse electrodialysis (RED), commonly referred to as microbial reverse-electrodialysis electrolysis cells (MREC), has been proposed as a new hydrogen gas production method (Kim and Logan, 2011;Nam et al, 2012;Luo et al, 2013;Watson et al, 2015). The major advantages of the MREC system compared to conventional technologies are that the MREC system can eliminate the required external energy for hydrogen generation and can also achieve relatively high hydrogen yield in addition to the efficient removal of organics.…”