Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H-2 fermentation and MECs

摘要

The enhanced H-2 production from maize straw had been achieved through the two-stage process of integrating H-2 fermentation and microbial electrolysis cells (MECs) in the present work. Several key parameters affecting hydrolysis of maize straw through subcritical H2O were optimized by orthogonal design for saccharification of maize straw followed by H-2 production through H-2 fermentation. The maximum reducing sugar (RS) content of maize straw reached 469.7 mg/g-TS under the optimal hydrolysis condition with subcritical H2O combining with dilute HCl of 0.3 % at 230 A degrees C. The maximum H-2 yield, H-2 production rate, and H-2 content was 115.1 mL/g-TVS, 2.6 mL/g-TVS/h, and 48.9 % by H-2 fermentation, respectively. In addition, the effluent from H-2 fermentation was used as feedstock of MECs for additional H-2 production. The maximum H-2 yield of 1060 mL/g-COD appeared at an applied voltage of 0.8 V, and total COD removal reached about 35 %. The overall H-2 yield from maize straw reached 318.5 mL/g-TVS through two-stage processes. The structural characterization of maize straw was also carefully investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectra.