Quanguo Zhang

The high-efficient utilization technology of organic waste can alleviate the dual pressures of energy and the environment. The study investigated the effects of substrate ratio, substrate concentration, and temperature on biohydrogen yield, and further optimized the process conditions for co-digestion of food waste and fecal sludge as substrates for biological hydrogen production. The results of batch mode experiments show that when the ratio of food waste to fecal sludge is 5:1, substrate concentration is 60 g/L, and fermentation temperature is 40 °C, the system achieves maximum cumulative hydrogen production of 183 mL (equivalent to 32 mL/g VS). The response surface methodology (RSM) indicates that substrate ratio, substrate concentration, and temperature all exert remarkably significant effects on hydrogen yield (p < 0.01). In addition, the synergistic interaction between substrate ratio and temperature significantly influences hydrogen production performance (p < 0.05). This study elucidates the synergistic mechanism of key process factors in the co-digestion of food waste and fecal sludge for biohydrogen production. The findings provide a theoretical basis for the engineering application of organic waste to hydrogen technologies.

Bio-hydrogen and bio-methane co-production was a promising way to enhance the energy conversion efficiency, and enzyme loading and pH are key factors influencing anaerobic fermentation processes. Therefore, in this study, the co-production process of bio-hydrogen and bio-methane was evaluated based on the effect of enzyme loading (20%, 30%, and 40%) combined with initial pH (6.0, 7.0, 8.0, and 9.0). The results indicated that, compared with other conditions, 30% enzyme loading with an initial pH of 8.0 was more feasible for bio-hydrogen and bio-methane co-production from duckweed, achieving a bio-hydrogen yield of 114.56 mL/g total solid (TS) and a bio-methane yield of 260.32 mL/g TS. Under optimum condition, the energy conversion efficiency was 71.4%, which was 6-fold and 4.8-fold higher than that of the single bio-hydrogen production stage (pH 8, 40% and 10.2%) and single methane production stage (control group with 12.30%), respectively.

The growth and metabolism of photosynthetic bacteria play a significant role in the efficiency of substrate and energy conversion in photo-fermentation biohydrogen production (PFHP). In this paper, the influence of different concentrations of L-alanine (0.3–1.2 g/L), L-leucine (0.6–1.5 g/L), and L-serine (1–2.5 g/L) on the PFHP and microbial metabolism were investigated. The results showed that sole additions of L-alanine at 0.6 g/L, L-leucine at 0.9 g/L, and L-serine at 1.5 g/L to the PFHP could enhance the cumulative biohydrogen production to 260 ± 4.01 mL (39.04% increase), 267 ± 4.27 mL (42.78% increase), and 248 ± 3.97 mL (32.62% increase), respectively. An analysis of the scatter matrix plots indicated that three amino acid additives play a key role in increasing hydrogen production. This study helps to further explore the effect of amino acid-based additives on PFHP.

Realizing high quality organic–inorganic hybrid perovskite semiconductors with low trap states and reduced toxic-lead (Pb) usage is crucial for the development of sustainable clean photovoltaics. Here, two-phase technology with the advantages of rapid reaction, a simple operation process, low cost, and low-toxicity compared to the traditional method has been developed for the first time for the synthesis of Pb-free MASnI₃ single crystals with good crystallinity and stability. The study demonstrates that the reactant concentration, reaction time and temperature are key factors affecting the quality of the MASnI₃ single-crystal. The fabricated MASnI₃ single-crystal has an absorption onset of 1043 nm and exhibits a narrow bandgap of 1.19 eV. Photodetectors based on the MASnI₃ single crystal exhibit good repeatability. The growth mechanism is also proposed in this article, and MA₃Bi₂I₉ and MAPbI₃ single crystals were also successfully synthesized based on this technology. Therefore, this two-phase approach offers a novel and effective strategy for growing high-quality single crystals.

Comparison of the capacity of biological desulfurization of Thiobacillus ferrooxidans from different sulfur-containing substrates with or without additional ferrous iron