Comparison of calcium magnesium ferrite nanoparticles for boosting biohydrogen production.

Dark fermentation (DF) is an eco-friendly process that simultaneously achieves organic matter degradation and obtains hydrogen (H ₂ ). Nonetheless, low H ₂ yield mainly caused by poor activity of key microbes, is still a problem that requires being resolved. In this work, MgFe ₂ O ₄ and Ca _0.5 Mg _0.5 Fe ₂ O ₄ nanoparticles (NPs) were synthetized and served as additives to boost H ₂ form from DF. H ₂ productivity gradually increased with the rise of NPs, and declined when NPs exceeded their optimal dosages. The highest H ₂ yield was 183.6 ± 3.2 mL/g glucose at 100 mg/L of MgFe ₂ O ₄ NPs, being 35.2 % higher than that of the control yield (135.8 ± 3.1 mL/g glucose). However, the highest H ₂ yield of 171.9 ± 2.5 mL/g glucose occurred at 400 mg/L of Ca _0.5 Mg _0.5 Fe ₂ O ₄ NPs, increasing by 26.6 % over the control. Interestingly, the two NPs favored the butyric acid pathway for H ₂ synthesis. This provides guidance for multi-element oxide NPs used in DF.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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