Hao Liu,Yaji Huang,Huikang Song,Tianhang Tang,Hao Shi,Lang Kai,Chenlu Yang
A novel pathway for the co-disposal of municipal solid waste incineration fly ash (MFA) and bottom slag (BS) with waste glass (WG) was proposed. Combined melting experiments and theoretical calculation were employed, which revealed the structural evolution of the CaO-Fe₂O₃-SiO₂ system and the underlying mechanisms of heavy metal immobilization. It was demonstrated that stable glassy products were obtained within a CaO/(Fe₂O₃+SiO₂) mass ratio ( M C / ( SF ) ) range of 0.13~0.41. The leaching concentrations of heavy metals in these vitrified products were suppressed to the relevant regulatory standards. With an increasing M C / ( SF ) , the glass network became more depolymerized, as evidenced by a higher population of low-connectivity Qⁿ units in the structure. However, under Fe₂O₃-enriched system, the Fe coordination shifted from solely tetrahedral [FeO₄] towards a mixed tetrahedral/octahedral environment. Moreover, Pb and Cd were incorporated into the glass matrix via interstitial doping. The depolymerized network dominated by CaO favored the Pb enrichment. Cd tended to be stabilized in the Fe-rich structure, facilitated by the formation of highly localized Cd-O bonds. This study elucidated the coupling effects of oxide composition on glass structure and heavy metal immobilization behavior, providing a fundamental theoretical basis for understanding and optimizing the vitrification process for solid waste treatment.
A self-healing coating containing an electrospun nanofibre encapsulating 3,4,5-trihydroxy benzoic acid cyclohexyl ester (GACE) was prepared. Scanning electron microscopy and transmission electron microscopy demonstrated that the nanofibre had a core–shell structure. The shell thickness of the electrospun fibre was approximately 270 nm, while the core thickness was approximately 380 nm. The self-healing process of the coating containing GACE nanofibres over a carbon steel surface was simulated in a 3.5 wt% NaCl solution for 30 days. Fourier-transform infrared spectroscopy analysis revealed that the synthesised GACE reacted with iron ions and formed a stable Fe–O–C compound, which could repair the scratched coating. The self-repair performance was evaluated through electrochemical measurements, and then a healing model was developed.
Lei Chen,He Wang,Yanping Sun,Yue Zhao,Huixiang Shi
Ferrihydrite (Fh), a precursor of more crystalline Fe (hydr)oxides, exhibits decent catalytic behavior; however, the instability of its amorphous structure limits its engineering applications. Siliceous ferrihydrite (FhSi) was readily synthesized in this study by co-precipitation. The formation of Fe–O–Si linkages did not alter the amorphous state of pure Fh, but increased the surface area (S BET ), reduced the point of zero charge (pH ZPC ), and prevented the leaching of more iron. X-ray diffraction, Mössbauer and pyridine-Fourier transform infrared (FTIR) spectroscopies, and potentiometric titration revealed the presence of silicon-occupied portions of growth sites on the Fh surface, which increased the coordination symmetry around the Fe atom and inhibited the transition of Fh to more stable crystalline Fe (hydr)oxides during repeated use. Meanwhile, the density of surface hydroxyl groups (Ds) and the total acid content of the catalytic system after five cycles of catalytic ozonation were 56.75 % and 63.58 % higher than those of freshly prepared system, thereby benefiting the catalysis of ozone for generating ·OH. In addition, the lower pH ZPC of the FhSi/O 3 system compared to that of the Fh/O 3 system promoted the generation of neutral surface-hydroxyl species on the surface of FhSi, which enabled a decent catalytic performance in alkaline solutions, regardless of the catalytic cycle. Moreover, the removal of humic acids (HA) followed a hydroxy radical reaction, which involved self-decomposition (14.15 %), catalytic ozonation (21.58 %), and peroxone and Fenton-like reactions (64.27 %).
危险品化学品经营许可证（带存储）