Abstract
Simultaneous CO(2) removal with renewable biofuel production can be achieved by methanogens through conversion of CO(2) and H(2) into CH(4). However, the low gas-liquid mass transfer (k (L) a) of H(2) limits the commercial application of this bioconversion. This study tested and compared the gas-liquid mass transfer of H(2) by using two stirred tank reactors (STRs) equipped with a micro-nano sparger (MNS) and common micro sparger (CMS), respectively. MNS was found to display superiority to CMS in methane production with the maximum methane evolution rate (MER) of 171.40 mmol/L(R)/d and 136.10 mmol/L(R)/d, along with a specific biomass growth rate of 0.15 d(-1) and 0.09 d(-1), respectively. Energy analysis indicated that the energy-productivity ratio for MNS was higher than that for CMS. This work suggests that MNS can be used as an applicable resolution to the limited k (L) a of H(2) and thus enhance the bioconversion of H(2) and CO(2) to CH(4).