초록
<P><B>Abstract</B></P> <P>Manganese doped magnetic carbon (MDMC) was synthesized to enhance bio-hydrogen (H<SUB>2</SUB>) process under the mesophilic and thermophilic conditions. MDMC characterization showed that MnFe<SUB>2</SUB>O<SUB>4</SUB>, Fe<SUB>2</SUB>O<SUB>3</SUB> and few MnCO<SUB>3</SUB> were adhered to activated carbon and formed MDMC whose specific surface area and average pore size were 110.92 m<SUP>2</SUP>·g<SUP>−1</SUP> and 3.2 nm, respectively. Suitable concentration of MDMC promoted while high dosage suppressed the H<SUB>2</SUB> production of glucose through anaerobic fermentation by heat-treated sludge. The highest yields of 211 and 148 ml H<SUB>2</SUB>/g glucose were obtained at 400 mg/L (37 °C) and 600 mg/L MDMC (55 °C), being 55.8% and 19.3% higher than that of the control groups, respectively. Some possible mechanisms were proposed as follows: appropriate concentration of MDMC provided considerable and favorable sites for microbial colonization, released trace elements (e.g. Mn, Fe) into liquid for the microbial growth, and promoted the direct inter-species electron transfer. Moreover, MDMC could be recycled by magnetic separation after bio-H<SUB>2</SUB> process due to its magnetism.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MDMC was synthesized, containing MnFe<SUB>2</SUB>O<SUB>4</SUB>, Fe<SUB>2</SUB>O<SUB>3</SUB>, MnCO<SUB>3</SUB> and AC. </LI> <LI> Suitable addition of MDMC obtained the highest H<SUB>2</SUB> yield in bio-H<SUB>2</SUB> process. </LI> <LI> The H<SUB>2</SUB> yields amended with MDMCs increased by 9.6–55.8 %. </LI> <LI> MDMC enriched bacteria and promoted their growths and H<SUP>+</SUP> transfer rates. </LI> <LI> MDMC could be recycled by magnetic separation after bio-H<SUB>2</SUB> production. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>MnFe<SUB>2</SUB>O<SUB>4</SUB>, Fe<SUB>2</SUB>O<SUB>3</SUB> and few MnCO<SUB>3</SUB> were adhered to activated carbon, fabricating the manganese doped magnetic carbon (MDMC) that was employed to stimulate bio- hydrogen (H<SUB>2</SUB>) production. Results showed that suitable amount of MDMC increased H<SUB>2</SUB> yield through providing a composite carrier and trace elements like Fe and Mn for H<SUB>2</SUB> production bacteria. MDMC could be also recycled via magnetic separation after the bio-process due to its magnetism.</P> <P>[DISPLAY OMISSION]</P>