RESUMEN
In this study, a MT(Al)/calcium alginate [MT(Al)@CA] microsphere structure was prepared using sodium alginate (SA) and MT(Al). In order to achieve [MT(Al)@CA] microspheres with a high stability and chemical resistance, glutaraldehyde was used as the crosslinking agent to graft the microspheres and ethylenediamine (ED) into a new type of ED-functionalized MT(Al)@CA microsphere structure similar to a core-shell-type structure [MT(Al)@CA-ED]. This core-shell/bead-like structure was characterized and analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The adsorption performance of the core-shell/bead-like structure for As(V) in solution was studied. The effects of the initial As(V) concentration, reaction time, pH, and different reaction temperatures on the reaction process were studied. The results indicate that at a pH of 4, the removal rate of As(V) by the core-shell/bead-like MT(Al)@CA-ED could reach 94.85% after 150â¯min. The adsorption process is highly consistent with the Langmuir isotherm model (R2â¯=â¯0.9983) and pseudo-second-order kinetic model (R2â¯=â¯0.9973). The maximum adsorption capacity could reach 61.94â¯mg/g. Regeneration experiments showed that the adsorption efficiency of As(V) after six cycles was >80%.
Asunto(s)
Alginatos/química , Arsenicales/química , Bentonita/química , Etilenodiaminas/química , Iones/química , Microesferas , Adsorción , Concentración de Iones de Hidrógeno , Análisis Espectral , Temperatura , Contaminantes Químicos del Agua/químicaRESUMEN
In this work, amino-functionalized Santa Barbara Amorphous-15/calcium alginate (ASBA-15@CA) microspheres were fabricated and characterized by FTIR, SEM, XRD, TGA, and XPS analyses. The Pb(II) adsorption properties of the ASBA-15@CA microspheres were studied in terms of the effects of the adsorption time, adsorbent dose, solution pH, temperature, and initial concentration of Pb(II) on the adsorption capacity. At pHâ¯6 and 298â¯K, the adsorption reached equilibrium after 100â¯min and the sample exhibited a good adsorption effect, affording a maximum adsorption capacity of 1029.58â¯mg/g and a removal rate as high as 98.99%. The adsorption process conformed to the Langmuir model (R2â¯=â¯0.9937) and followed the pseudo-second-order kinetics model (R2â¯=â¯0.9995). Regeneration experiments showed that the removal rate of the sample reached 75% even after 6â¯cycles. Overall, this study provides new insights into the development of novel, highly efficient, and repeatable degradation materials for the removal of Pb(II).
Asunto(s)
Alginatos/química , Plomo/química , Dióxido de Silicio/química , Agua/química , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Microesferas , Temperatura , Contaminantes Químicos del Agua/química , Purificación del Agua/métodosRESUMEN
Aspernigerin (1), a novel cytotoxic alkaloid consisting of an unprecedented structural framework has been isolated from the extract of a culture of Aspergillus niger IFB-E003, an endophyte in Cyndon dactylon. Its structure was elucidated on the basis of comprehensive NMR spectral analysis and confirmed by single-crystal X-ray analysis. Aspernigerin (1) has been shown to be cytotoxic to the tumor cell lines nasopharynyeal epidermoid KB, cervical carcinoma Hela, and colorectal carcinoma SW1116 with corresponding IC(50) values of 22, 46, and 35 microM, respectively. A feasible total synthetic route for aspernigerin (1) has been established for further pharmacological research.