A modified electrospinning (MES), which consists of a copper mesh collector and an air pump placed behind it, was presented to fabricate nanofiber membranes (NFMs) with controllable large pore sizes by adjusting the MES parameters, such as copper mesh size, air velocity, applied voltage, flow rate and collecting distance. The controllable preparation mechanism of NFMs with large pore sizes was systematically investigated by experimental research and theoretical analysis. And the effects of the copper mesh grid dimensions, air velocity, applied voltage, flow rate and collecting distance on the pore sizes of NFMs were demonstrated. The results showed that NFMs with large pores produced successfully by the MES, and the pore sizes were all micrometer scale. And the optimal average pore size reached 14.45 μm 2 at the grid size of copper mesh of 4 mm×4 mm, the air velocity of 5 m/s, the applied voltage of 12 kV, the flow rate of 1.0 mL/h and the collecting distance of 18 cm.
In this study, the atmospheric dielectric barrier discharge (DBD) plasma was proposed for the degradation of polystyrene microplastics (PS-MPs) for the first time, due to its ability to generate reactive oxygen species (ROS). The local temperature in plasma was found to play a crucial role, as it enhanced the degradation reaction induced by ROS when it exceeded the melting temperature of PS-MPs. Factors including applied voltage, air flow rate, and PS-MPs concentration were investigated, and the degradation products were analyzed. High plasma energy and adequate supply of ROS were pivotal in promoting degradation. At 20.1 kV, the degradation efficiency of PS-MPs reached 98.7% after 60 min treatment, with gases (mainly CO x , accounting for 96.4%) as the main degradation products. At a concentration of 1 wt%, the PS-MPs exhibited a remarkable conversion rate of 90.6% to CO x , showcasing the degradation performance and oxidation degree of this technology. Finally, the degradation mechanism of PS-MPs combined with the detection results of ROS was suggested. This work demonstrates that DBD plasma is a promising strategy for PS-MPs degradation, with high energy efficiency (8.80 mg/kJ) and degradation performance (98.7% within 1 h), providing direct evidence for the rapid and comprehensive treatment of MP pollutants.
This study effectively addresses the rapid deactivation of manganese-based catalysts in humid environments during ozone decomposition by introducing iron-doped manganese oxide octahedral molecular sieve (Fe-OMS-2) catalysts supported on activated carbon (AC). By optimizing the doping ratio of Fe-OMS-2, the Fe-OMS-2 0.5 /AC catalyst achieves nearly 100% ozone decomposition efficiency across a wide range of relative humidity levels (0 to 60%), even at elevated air flow rates of 800 L·g −1 ·h −1 , outperforming standalone AC, Fe-OMS-2, or a simple mixture of OMS-2 and AC. The Fe-OMS-2 0.5 /AC catalyst features a porous surface and a mesoporous structure, providing a substantial specific surface area that facilitates the uniform distribution of the Fe-OMS-2 active phase on the AC surface. The incorporation of Fe 3+ ions enhances electron transfer between valence state transitions of Mn, thereby improving the catalyst’s efficiency in ozone decomposition. Additionally, the AC component protects catalytic sites and enhances the catalyst’s humidity resistance. In conclusion, this research presents a novel strategy for developing highly efficient and cost-effective ozone decomposition catalysts that enhance dehumidification, significantly contributing to industrial ozone treatment technologies and advancing environmental protection.
危险品化学品经营许可证（带存储）