The chitosan microspheres loaded with model drug, salicylate molecular, are prepared, and the dielectric spectroscopy of this kind of suspension is measured, meanwhile a significant relaxation is observed for the micr...The chitosan microspheres loaded with model drug, salicylate molecular, are prepared, and the dielectric spectroscopy of this kind of suspension is measured, meanwhile a significant relaxation is observed for the microspheres suspension. By the modeling analytic of the relaxation, the parameters, which can reflect the properties of microspheres and continuous medium, are obtained. Furthermore, the releasing process of microspheres in aqueous phase is monitored real-timely, namely, by analyzing the time-dependent variation of the parameters reflecting the relaxation characteristics and electrical parameters in each phase the releasing process is detected. The research shows that the controlled release process of chitosan microspheres loaded with salicylate in aqueous phase is divided into three phases according to different releasing mechanisms. At the release stage, the quantitative relation between the phase parameters obtained by dielectric analysis and the amount of the salicylate carried in microspheres was derived, and a real-time monitoring method was established through releasing material in the microspheres at different times obtained by measuring and analyzing the dielectric spectroscopy.展开更多
A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sor...A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory.The effect of H_(2)S on Hg^(0)adsorption was also investigated.The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon.In the absence of H_(2)S at a low temperature(≤100℃),the Hg^(0)removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%.This value is significantly higher than that of coconut shell activated carbon,which is approximately 45%.H_(2)S significantly enhanced the Hg^(0)removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures(100–180℃).The hierarchical porous structure facilitated the diffusion and adsorption of H_(2)S and Hg^(0),while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H_(2)S,contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent.The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg^(0)temperature-programmed desorption tests.Density functional theory was employed to elucidate the adsorption and transformation of Hg^(0)on the sorbent surface.H_(2)S adsorbed and dissociated on the sorbent surface,generating active sulfur species that reacted with gaseous Hg^(0)to form HgS.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 20976015 and 20673014)
文摘The chitosan microspheres loaded with model drug, salicylate molecular, are prepared, and the dielectric spectroscopy of this kind of suspension is measured, meanwhile a significant relaxation is observed for the microspheres suspension. By the modeling analytic of the relaxation, the parameters, which can reflect the properties of microspheres and continuous medium, are obtained. Furthermore, the releasing process of microspheres in aqueous phase is monitored real-timely, namely, by analyzing the time-dependent variation of the parameters reflecting the relaxation characteristics and electrical parameters in each phase the releasing process is detected. The research shows that the controlled release process of chitosan microspheres loaded with salicylate in aqueous phase is divided into three phases according to different releasing mechanisms. At the release stage, the quantitative relation between the phase parameters obtained by dielectric analysis and the amount of the salicylate carried in microspheres was derived, and a real-time monitoring method was established through releasing material in the microspheres at different times obtained by measuring and analyzing the dielectric spectroscopy.
基金supported by National Natural Science Foundation of China(Grant Nos.51976108 and U1906232)Shihezi University Self Funded Support Project(ZZZC2023069).
文摘A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization.The Hg^(0)adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory.The effect of H_(2)S on Hg^(0)adsorption was also investigated.The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon.In the absence of H_(2)S at a low temperature(≤100℃),the Hg^(0)removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%.This value is significantly higher than that of coconut shell activated carbon,which is approximately 45%.H_(2)S significantly enhanced the Hg^(0)removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures(100–180℃).The hierarchical porous structure facilitated the diffusion and adsorption of H_(2)S and Hg^(0),while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H_(2)S,contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent.The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg^(0)temperature-programmed desorption tests.Density functional theory was employed to elucidate the adsorption and transformation of Hg^(0)on the sorbent surface.H_(2)S adsorbed and dissociated on the sorbent surface,generating active sulfur species that reacted with gaseous Hg^(0)to form HgS.
