Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H2 fermentation and MECs

Li, Yan-Hong; Bai, Yan-Xia; Pan, Chun-Mei; Li, Wei-Wei; Zheng, Hui-Qin; Zhang, Jing-Nan; Fan, Yao-Ting; Hou, Hong-Wei

Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H2 fermentation and MECs

2015

The enhanced H₂ production from maize straw had been achieved through the two-stage process of integrating H₂ 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 H₂ production through H₂ 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 °C. The maximum H₂ yield, H₂ production rate, and H₂ content was 115.1 mL/g-TVS, 2.6 mL/g-TVS/h, and 48.9 % by H₂ fermentation, respectively. In addition, the effluent from H₂ fermentation was used as feedstock of MECs for additional H₂ production. The maximum H₂ yield of 1060 mL/g-COD appeared at an applied voltage of 0.8 V, and total COD removal reached about 35 %. The overall H₂ 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.

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