Comparison of copper and aluminum doped cobalt ferrate nanoparticles for improving biohydrogen production

Two various materials, copper and aluminum doped cobalt ferrite nanoparticles (NPs) were fabricated for investigating their effects of addition amounts on hydrogen (H₂) synthesis and process stability. CoCu_0.2Fe_1.8O₄NPs enhanced H₂ production more than CoAl_0.2Fe_1.8O₄ NPs under same condition. The highest H₂ yield of 212.25 ml/g glucose was found at optimal dosage of 300 mg/L CoCu_0.2Fe_1.8O₄ NPs, revealing the increases of 43.17% and 6.67% compared with the control without NPs and 300 mg/L CoAl_0.2Fe_1.8O₄ NPs groups, respectively. NPs level of more than 400 mg/L inhibited H₂ generation. Further investigations illustrated that CoCu_0.2Fe_1.8O₄ NPs were mainly distributed on extracellular polymer substance while CoAl_0.2Fe_1.8O₄ NPs were mostly enriched on cell membrane, which facilitated electron transfer behavior. Community structure composition demonstrated that CoCu_0.2Fe_1.8O₄ and CoAl_0.2Fe_1.8O₄ separately caused a 9.67% and 9.03% increase in Clostridium sensu stricto 1 compared with the control reactor without NPs exposure.