Biohydrogen production from organic solid waste has shown particular advantages over other methods owing to the combination of waste reduction and bioenergy production. In this study, biohydrogen production from the co-digestion of cattle manure and food waste was optimized in a mesophilic semi-continuous process. To maximize hydrogen production, the effects of the mixing ratio (the proportion of food waste in the substrate), substrate concentration, and hydraulic retention time (HRT) on the co-digestion were systematically analyzed using a Box–Behnken design. The results showed that strong interactive effects existed between the three factors, and they had a direct effect on the responses. Hydrogen was primarily produced via the butyrate pathway, which was accompanied by the competing heterolactic fermentation pathway. Propionate and valerate produced from lipids and proteins, respectively, were obtained along with butyrate. The optimal process parameters included a mixing ratio of 47% to 51%, a substrate concentration of 76 to 86 g L⁻¹, and an HRT of 2 d. Under these optimal conditions, the hydrogen production rate and hydrogen yield were higher than 1.00 L L⁻¹ d⁻¹ and 30.00 mL g⁻¹ VS, respectively, and the predicted results were consistent with the experimental data. The results indicate that the co-digestion of cattle manure and food waste is a practical and economically promising approach for biohydrogen production.

A series of efficient adsorbents were prepared by a wet-impregnation method for CO₂ separation from simulated biogas. A type of commercially available silica, named as FNG-II silica (FS), was selected as supports. FS was modified with a mixture of polyethyleneimine (PEI) and ethanolamine (MEA) to improve the initial CO₂ adsorption capacity and thermal stability of the adsorbents. The influence of different adsorbents on CO₂ adsorption performance was investigated by breakthrough experiments. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and N₂ adsorption–desorption isotherm were used to characterize the silica before and after impregnating amine. Additionally, the thermal stability of adsorbents was measured by differential thermal analysis (TDA). Silica impregnated with mixtures of MEA and PEI showed increased CO₂ adsorption performance and high thermal stability compared with those obtained from silica impregnated solely with MEA or PEI. With a simulated biogas flow rate of 100 mL/min at 0.2 MPa and 25 °C, FS-10%MEA-10%PEI exhibited a CO₂ adsorption capacity of ca. 64.68 mg/g which increased by 81 % in comparison to FS-20%PEI. The thermal stability of FS-10%MEA-10%PEI was evidently higher than that of FS-20%MEA, and a further improvement of thermal stability was achieved with the increasing value of PEI/MEA weight ratio. It was showed that MEA was able to impose a synergistic effect on the dispersion of PEI in the support, reduce the CO₂ diffusion resistance and thus increase CO₂ adsorption performance. Additionally, if the total percentage of amine was the same, FS impregnated by different ratios of PEI to MEA did not exhibit an obvious difference in CO₂ adsorption performance. FS-15%PEI-5%MEA could be regenerated under mild conditions without obvious loss of CO₂ adsorption activity.

In order to sustain control over soybean root rot, wheat-straw-fiber-based mulch film (WFM) coated with carbendazim (C) and chitosan (CS) mixture (C-CS-WFM) were prepared through bar coating technology. The Box–Behnken design method was employed to investigate the effects of chitosan concentration, wet film thickness, and carbendazim loading on the dry tensile strength (DTS), wet tensile strength (WTS), and air permeance (AP) of C-CS-WFM. Eventually, the optimization process parameters were determined as follows: a chitosan concentration of 1.83–2.39%, a wet film thickness of 18–24 μm, and a carbendazim loading of 0.05–0.12 g/m². These parameters achieved the desired physical properties of C-CS-WFM, i.e., the DTS is not less than 3.5 kN/m, the WTS is not less than 0.8 kN/m, and the AP does not exceed 2.1 μm/(Pa·s). The results showed that after the introduction of the C-CS coating, the DTS and WTS of C-CS-WFM were enhanced by 11.4% and 14.9%, respectively. In contrast, the AP was reduced by 15.6%. FT-IR analysis indicated that carbendazim was embedded in the C-CS composite material without any chemical interaction. Through SEM and sustained-release kinetic analysis, it was found that the sustained-release mechanism of C-CS-WFM conformed to the Ritger–Peppas kinetic model, and its release mechanism was the physical diffusion and matrix erosion. The results of the in vitro antifungal test and pot experiment demonstrated that C-CS-WFM could effectively inhibit the growth of Fusarium solani and promote the growth of plants. This study provided new ideas for the comprehensive prevention and control of soybean root rot.