RESUMO
Hydrogen production from the electrolysis of coal slurry is a promising approach under the condition of low voltage (0.8-1.2 V) and medium temperature. However, the rate of hydrogen production is slugged by poor anode kinetics, under an electrochemical condition that results from the collision of the coal particles with the anode surface. This paper reports a novel process that consists of two steps: the oxidation of the coal slurry by ferric ions(III) in a hydrothermal reactor at a temperature of 120-160 °C and the electro-oxidation of ferric ions(II) in the electrochemical cell to produce hydrogen. This technique circumvents the technical issues experienced in the conventional coal slurry electrolysis process by adopting a two-step process consisting of solid-liquid reactions instead of solid-solid reactions. This indirect oxidation process produced a current density of 120 mA/cm2 at room temperature and a voltage of 1 V, which is higher than the values reported in the conventional processes. An investigation of the oxidation mechanism was carried out via scanning electron microscopy, Fourier-transform infrared spectroscopy and elemental analysis. The results obtained showed that the oxidation of coal by ferric ions occurs from the surface to the inner parts of the coal particles in a stepwise manner. It was also revealed that the ferric ions in the media increased the active interfaces both of the coal particles and of the anode electrode. This explains the high hydrogen production rate obtained from this process. This novel discovery can pave the way for the commercialization of coal slurry electrolysis.
RESUMO
The plant-microbe interaction can affect ecosystem function, and many studies have demonstrated that plant species influence relevant microorganisms. In this study, microbial communities in bulk soil, rhizosphere soil and phyllosphere from different maize varieties were investigated using high-throughput sequencing method. Results demonstrated that cultivar Gaoneng 1 (G1) showed higher bacterial diversity in soil (both bulk and rhizosphere soils) and lower bacterial diversity in the phyllosphere, while cultivar Gaoneng 2 (G2) had lower fungal diversity in both the soil and phyllosphere compare to the other cultivars. The bacterial community structure of soils among the three varieties was significantly different; however, no significant differences were found in the soil fungal community and phyllosphere bacterial and fungal community. The soil networks from cultivar G1 and phyllosphere networks from cultivar Zhengdan (ZD) have the highest complexity in contrast to the other two cultivars. In conclusion, the bacterial community structure in bulk soil of different cultivars was significantly different, so do the co-occurrence ecological networks of phyllosphere bacterial community. This study comprehensively analyzed the microbial community among different maize cultivars and could be useful for guiding practices, such as evaluation of new plant cultivars and quality predictions of these varieties at the microbial level.
