Enhancement of methane production by anaerobic digestion of corn straw with hydrogen-nanobubble water

[Display omitted] •H2-nanobubble water(H2-NBW) was proposed to enhance bio-methane production.•The bio-methane yields were increased by 11.54%∼25.29% with H2-NBW.•The maximum cumulative methane yield was 254.36 mL·g-VS-1 with 60% H2-NBW.•Cellulose and hemicellulose degradation rate increased by 33% and 25.7% respectively.•Removal rates of TS and VS can be increased by 27.93% and 21.47% respectively. Hydrogen-nanobubble water was proposed to enhance methane production by anaerobic digestion (AD) with corn straw. The effects of H2-nanobubble water (H2-NBW) amounts (0%, 20%, 40%, 60%, 80%, and 100%) on methane production characteristics of corn straw were explored. The results showed that the methane yields were increased by 11.54%∼25.29% compared with the control group(CK), and the maximum cumulative methane production reached to 254.36 mL·g-VS-1 when the H2-NBW addition was of 60%. Interestingly, the maximum methane concentration increased by 4.37% compared with CK. H2-NBW addition can destroy the cellulose structure of corn straw, reduce the crystallinity of cellulose, and promote the hydrolysis. The degradation rate of cellulose and hemicellulose were increased by 20%∼33% and 13% ∼25.7% respectively, and the removal rate of TS and VS were increased by 6.82%-27.93% and 8.52%-21.47%, respectively. The modified Gompertz equation fitted the cumulative methane production curves very well, with high correlation coefficients (R2 > 0.992).