Influence of iron and magnesium on kinetic and mechanism of biohydrogen production from high-strength wastewater.

In this study, iron/iron-magnesium (Fe/Fe-Mg) additives were prepared through the impregnation of granular activated carbon (GAC) with iron and iron-magnesium (GFM) to enhance biohydrogen production. The microscope observation and chemical analysis revealed that the GAC matrixes were well infused with Fe/Fe-Mg, while the X-ray diffraction analysis revealed the species of metal formed on the GAC as Fe and MgH. The synergistic effect of Fe and Mg in GFM allowed it for a shorter delay time and higher hydrogen production rate than other additives, indicating their possible use in stimulating the fast release of hydrogen in anaerobic digestion. The co-metabolites analysis revealed that additives ensured biohydrogen production through the different pathways. The plausible mechanisms were through hydrogenases ensured by Fe and hydrolysis by MgH. GFM gave the best organic matter and nutrient removal efficiency to outperform other additives, suggesting its ability for biohydrogen synthesis and simultaneous wastewater treatment.