Electrodialysis (ED) removed volatile fatty acids (VFAs) from a continually-fed, hydrogen-producing fermenter. Simultaneously, electrochemical removal and adsorption removed gaseous H2 and CO2, respectively. Removing VFAs via ED in this novel process increased H2 yields by a factor of 3.75 from 0.24 mol H2 mol−1 hexose to 0.90 mol H2 mol−1 hexose. VFA production and substrate utilisation rates were consistent with the hypothesis that end product inhibition arrests H2 production. The methodology facilitated the recovery of 37 g of VFAs, and 30 L H2 that was more than 99% pure, both of which are valuable, energy dense chemicals. Typically, short hydraulic and solid retention times, and depressed pH levels are used to suppress methanogenesis, but this limits H2 production. To produce H2 from real world, low grade biomass containing complex carbohydrates, longer hydraulic retention times (HRTs) are required. The proposed system increased H2 yields via increased substrate utilisation over longer HRTs.

Original languageEnglish
Pages (from-to)46-52
Number of pages7
JournalBioresource Technology
Publication statusPublished - 30 Apr 2017

    Research areas

  • Biohydrogen, Electrodialysis, End product inhibition, Homoacetogenesis, Hydraulic retention time, Increased hydrolysis

ID: 613184