Jing Qian,Manman Lu,Shixia Cui,Taoyu Han,Stavros Avramidis,Shengquan Liu,Jiejie Sun
This study investigated the application risk and value of Cd-enriched poplar wood, focusing on its wood properties, leaching characteristics, and brown rot resistance. The results indicated that Cd deposition in cell walls significantly inhibited brown rot fungi, thereby enhancing decay resistance. Furthermore, the extent of improvement in brown rot resistance was linked to wood density: the higher the density of Cd-enriched poplar wood, the stronger its resistance to brown rot. As the Cd concentration increased, the Cd distribution abundance and the wood crystallinity gradually increased. Structural changes were observed, including fluctuating microfibril angle and double wall thickness of fibers and vessels. Cd concentrations exceeding 50 mg/kg altered the chemical composition of the cell walls. The binding form of Cd in wood cell wall showed a trend of bound Cd ＞ free Cd ＞ residual Cd. Cd leaching occurred under cyclic soaking in water, which may lead to secondary contamination. However, under the condition of 75 % relative humidity, Cd leaching was negligible, suggesting potential for safer use in controlled environments. These findings provide valuable insights into the management and application of Cd-enriched wood, especially in contexts where decay resistance is critical or in water-exposed environments.
Jie Wang,Junqing Meng,Chunhui Lyu,Yingpei Lyu,Lijuan Wang
Based on the successful utilization of polymer additives in drag reduction for long-distance transportation and the intricacies of their application in firefighting contexts, this study investigated the impact of additives on wood properties in forest fire suppression through a combination of experiments and molecular dynamics simulations, focusing on wettability, fluidity, and combustibility. Optimal concentrations of polymer solutions were determined through contact angle measurements and surface flow experiments. The effects of polymers on wood water retention, thermal stability, and microstructure were analyzed using thermogravimetric analysis, infrared spectroscopy, and wood impregnation experiments. Wetting and flow models of polymers on cellulose surfaces were simulated to elucidate the wetting mechanism and dynamic behavior of polymers during flow. The results revealed that polyacrylamide (PAM) and polyethylene oxide (PEO) promoted wood surface wetting, improved flowability, enhanced water retention, and delayed decomposition at optimal concentrations. PAM exhibited superior effects in flow stability, thermal stability, and liquid absorption enhancement, attributed to strong hydrogen bonding between PAM and surfaces, primarily through amide groups. During flow, PAM molecules gradually aggregated and moved as aggregates along the X-axis. In contrast, the PEO system relied on electrostatic forces between water and surfaces, with dynamic processes involving repeated stretching and shrinking of PEO molecular chains to facilitate water flow and enhance wetting. This research contributes to delineating the application conditions and benefits of polymer on wood surfaces, enhancing the efficacy and potential of drag-reducing agents in firefighting applications.
危险品化学品经营许可证（带存储）