Macro approach analysis of dark biohydrogen production in the presence of zero valent powered Fe°

Recent studies suggest that the supplementation of powdered Fe degrees generates a positive effect on anaerobic fermentation processes but the exact relationship between metals with biological systems has not been fully elucidated. Experimental tests on dark fermentation (DF) were carried out at different Fe degrees concentrations. The anaerobic corrosion (AC) of Fe degrees and the production of H-2 through DF of Organic Waste Market (OWM) were tested separately, and subsequently DF tests with Fe degrees at 1 g/L. and 2 g/L were carried out. A macroscopic dynamic study was conducted, using Roels approach based on relaxation times (tau(R)) to establish whether interactions between AC and DF phenomena exist. Experimental bioH(2) production and Fe degrees AC were fit by Gompertz and saturative models, respectively to estimate tau(R). The results of the macro-analysis suggest that both phenomena are concurrent, with tau(R) of the same order of magnitude, generating a positive symbiotic effect. The experimental tests of hydrogen production via DF in presence of 2 g/L of Fe degrees showed an increase of 46% compared with the control tests, of amount of gas and a greater H-2/CO2 ratio. The results suggest an enhancement of key enzymes activity due to the action of iron increasing bioH(2) production. (C) 2018 Elsevier Ltd. All rights reserved.