The synthesis by direct coprecipitation and characterization of captopril (Cpl) and 5-aminosalicylic acid (5-ASA) intercalated ZnAl layered double hydroxides coated on MgFe2O4 magnetic core particles are reported. Powder XRD analysis shows the well-defined crystallite structure of the composites. TEM and XPS results reveal that a core-shell structure involving a drug-LDHs layer coated on MgFe2O4 particles is formed through Zn-O-Mg and/or Al-O-Mg link- ages. VSM measurements demonstrate that the novel mag- netic drug-inorganic composites possess considerable mag- netization.
Nano-MgO with various particle sizes, synthe- sized by different methods using Mg(NO3)2·6H2O, Na2CO3, Na2SO4, urea and ammonia solution as reactants, was used to carry out bactericidal experiments on Bacillus subtilis var. niger. The results were compared with the effect of TiO2, a common kind of photocatalytic material. The materials were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), low temperature N2 adsorp- tion-desorption measurements and FT-IR, and the results showed that the bactericidal ability of MgO increases with decreasing particle size. Nano-MgO and an interior wall-paint containing the material have better bactericidal effects than nono-TiO2 in both presence and absence of light. The bactericidal mechanism is discussed. The surface of MgO can generate high concentrations of O?2 which is highly active and can react with the peptide linkages in the coating walls of the spores. The spores are destroyed by the resulting damage to their structure.
Zn-Mg-Al-CO3 layered double hydroxides (LDHs) have been synthesized by a new method involving separate nucleation and aging steps. The Zn-Mg-Al-CO3 LDHs were characterized by XRD, FT-IR, ICP and TG-DTA. The limiting oxygen index and smoke density of composites of the LDHs with EVA-28 were determined. Incorporation of Zn2+ in the layers of the LDHs was found promoting mate- rial charring and smoke suppression. The mechanism of flame retardation and smoke suppression is discussed. The results show that Zn-Mg-Al-CO3 LDHs have better flame retarding and smoke suppressing effects than Mg-Al-CO3 LDHs.
