Investigating the effects of iron and nickel nanoparticles on dark hydrogen fermentation from starch using central composite design

The effects of Fe-0 and Ni-0 nanoparticles on mesophilic dark hydrogen fermentation from starch were investigated using heat-shock pretreated anaerobic sludge in batch reactors. Starch concentration in the range of 0-20 g/L was used in the presence of 0-50 mg/L of each Fe-0 and Ni-0 nanoparticles while the initial pH of all experiments was adjusted to 7. The hydrogen production was optimized using response surface methodology (RSM) in a central composite design (CCD) mode. The results showed the significance of the linear effect of starch and Fe-0 concentrations, the interactive effect between Fe-0 and Ni-0 concentrations, and the squared effect of starch concentration on the biohydrogen production. The maximum yield of hydrogen production 149.8 mL/g-VS was obtained at starch, Fe-0 and Ni-0 concentrations of 5.37 g/L, 37.5 mg/L, and 37.5 mg/L, respectively. This was nearly 200% higher than those in the corresponding control test. Moreover, the analysis of metabolites indicated the hydrogen production through acetic acid pathway. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.