초록
<P><B>Abstract</B></P> <P>The feasibility and efficiency of magnetite nanoparticles (Fe<SUB>3</SUB>O<SUB>4</SUB>NPs) enhanced bio-hydrogen production from glucose anaerobic fermentation were evaluated in this study. The results demonstrated that the maximum hydrogen yield (HY) of 12.97 mL H<SUB>2</SUB>/g-VSS was obtained with 50 mg/L and 40–60 nm of Fe<SUB>3</SUB>O<SUB>4</SUB>NPs in batch experiments. Moreover, the optimum dosage of Fe<SUB>3</SUB>O<SUB>4</SUB>NPs produced hydrogen production (HP) of 4.95 L H<SUB>2</SUB>/d in an expanded granular sludge bed (EGSB) reactor. Fe<SUB>3</SUB>O<SUB>4</SUB>NPs involved could promote ethanol and acetic acid accumulation. Fe<SUP>2+</SUP> as by-product of iron corrosion could effectively promote the activity of key coenzymes and soluble microbial products (SMPs). Importantly, Fe<SUB>3</SUB>O<SUB>4</SUB>NPs addition resulted in the formation of electronic conductor chains to enhance the electron transport efficiency in the granular sludge. Microbial community analysis revealed that the relative abundance of butyrate-hydrogen-producing bacteria (<I>Clostridium</I>) decreased from 40.55% to 11.45%, while the relative abundance of ethanol-hydrogen-producing bacteria (<I>Acetanaerobacterium</I> and <I>Ethanoligenens</I>) increased from 19.62% to 35.35% with Fe<SUB>3</SUB>O<SUB>4</SUB>NPs involved, confirming that the fermentation type was transformed from butyrate-type to ethanol-type, which finally facilitated more hydrogen production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fe<SUB>3</SUB>O<SUB>4</SUB>NPs was used in glucose anaerobic fermentation by EGSB reactor. </LI> <LI> Addition of 50 mg/L and 40–60 nm Fe<SUB>3</SUB>O<SUB>4</SUB>NPs improved H<SUB>2</SUB> production by 53.7%. </LI> <LI> Fe<SUB>3</SUB>O<SUB>4</SUB>NPs could enhance key coenzymes activity and electron transfer efficiency. </LI> <LI> Fe<SUP>2+</SUP> as by-product of Fe<SUB>3</SUB>O<SUB>4</SUB>NPs corrosion increased SMPs content effectively. </LI> <LI> Fe<SUB>3</SUB>O<SUB>4</SUB>NPs could facilitate ethanol-producing bacteria growth and richness. </LI> </UL> </P>