RESUMEN

Iron-clay-cyclodextrin composites were designed as sorbent catalysts to adsorb and oxidize pollutants from water. The clay-iron backbone served as a mechanical support and as a heterogeneous Fenton catalyst, and the cyclodextrin monomers or polymers cross-linked with polyfluorinated aromatic molecules were used to accommodate adsorption of the pollutants. The composite based on iron-clay-cyclodextrin-polymers (Fe-MMT-ßCD-DFB) exhibited superior adsorption and degradation of the model pollutants, bisphenol A (BPA), carbamazepine (CBZ), and perfluorooctanoic acid (PFOA), compared to the monomer-based composite and the native iron clay. The variety of adsorption sites, such as the polyfluorinated aromatic cross-linker, cyclodextrin toroid, and iron-clay surface, resulted in high adsorption affinity toward all pollutants; BPA was primarily adsorbed to the cyclodextrin functional groups, CBZ showed high affinity toward the Fe-MMT surface and the Fe-MMT-ßCD-DFB composite, whereas PFOA was adsorbed mainly to the ßCD-DFB polymer. Degradation, using H2O2, was highly efficient, reaching over 90% degradation in 1 h for BPA and CBZ and ∼80% for PFOA. The composite also showed excellent degradation efficiency in a multicomponent system with all three model pollutants. Furthermore, the composite's activity remained steady for five consecutive cycles of adsorption and degradation. The ability to remediate a broad range of pollutants, and the high overall removal exhibited by this novel material, demonstrates the potential for future application in water remediation technologies.

RESUMEN

Hydrogen trititanate (H2Ti3O7·2H2O) and hydrogen trititanate/Ag2O hybrid nanocomposites (NCs) with novel structure have been synthesized by a simple solvothermal route followed by Na+/H+ ion-exchange. Growths of hydrogen trititanate with nanofiber (HTNF) and nanotube (HTNT) morphologies and hydrogen trititanate-Ag2O (HTFAG and HTTAG) nanocomposites have been tailored by controlling the solvent media. Detailed microstructure characterization of all these samples have been carried out by Rietveld refinement of XRD data and analyzing FESEM/HRTEM micrographs and FTIR spectra. Band gap energies of all these semiconducting samples are obtained from UV-Vis absorption spectra. Both HTFAG and HTTAG NCs exhibit enhanced photocatalytic degradation of organic pollutant (Congo red dye) under visible light, in comparison to HTNF and HTNT respectively due to the formation of a heterojunction between H2Ti3O7·2H2O and Ag2O, which is supported by photoluminescence spectroscopy. HTFAG and HTTAG NCs also show superior antibacterial activity against both gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacteria compared to their pure counterparts. MTT assay reflects a sufficiently high percentage of cell viability and confirms the significant cytocompatibility of all the samples.

Asunto(s)

RESUMEN

Structurally characterised two polymeric complexes of Cu(ii) (3) and Mn(iii) (4) of the ligand L (2-(((2-(phenylamino)ethyl)imino)methyl)phenol) have been explored for catecholase-like activity, fluorescence recognition of histidine and catalytic activity towards coupling of aryl iodides with benzamide, leading to N-arylbenzamides. CuO nano-cubes (NCs) prepared by thermal decomposition of the Cu(ii) complex function as photocatalysts for the degradation of methylene blue. Cube-like morphology of CuO nanocrystal and flake-shaped micrometer order Cu(ii) complex have been established from the field emissive scanning electron microscopy (FESEM) images.

RESUMEN

Polyaniline intercalated vanadium oxide xerogel (PV) hybrid nanocomposite (NC) with novel structure has been successfully synthesized through a simple hydrothermal route. Detailed structure and microstructure characterization of PV NC is illustrated through Rietveld refinement of XRD data and FESEM/HRTEM images. Both FTIR and XPS spectra confirm the presence of PANI and water molecules within the NC and partial reduction of V5+ to V4+, corroborating with the results of XRD pattern analysis. Core-shell structure of PV NC, where PANI sheath layer acts as a shell covering around V2O5·nH2O crystalline core is confirmed from HRTEM images. Successive morphological changes of PV NC with different reaction time have been revealed from FESEM images. UV-vis spectra also confirm the formation of PV NC. Intercalation of water and PANI layers into V2O5·nH2O layer leads to a structural phase transition from orthorhombic to monoclinic phase due to substantial increase in interplanar spacing of (00l) of orthorhombic V2O5. The photocatalytic property of the as synthesized PV NC has been reported for the first time, with a promising photocatalytic activity for the degradation of organic dye, Rhodamine B (RhB) under visible light irradiation. It is attributed to a synergic effect in between PANI and V2O5·nH2O xerogel. The photocatalyst also shows remarkable real visible light photocatalytic activity with non-absorbing colorless test molecules like phenol and antibiotic kanamycin.