Browsing by Author "Munaweera, I"

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    Recent progress in visible-light active (VLA) TiO2 nano-structures for enhanced photocatalytic activity (PCA) and antibacterial properties: a review
    (Islamic Azad University, Shahreza Branch, 2021-09-01) Seneviratne, K. L; Munaweera, I; Peiris, S; Peiris, C. N; Kottegoda, N
    The applications of photocatalytic nanomaterial technology received intense scientific focus with the advent of nanotechnology. Applications based on TiO2 nanoparticles have shown promise of photocatalytic efficiency among many semiconductor metal oxides. Titanium dioxide is utilized in many practical applications such as water and air purification, self-cleaning of surfaces, and energy production. The major drawback with TiO2 based photocatalysts is the wide band gap, which requires UV light to produce the electron-hole pairs. This review article focus on techniques/methods to eliminate band gap which reduces photocatalytic efficiency. Application of semiconductor photocatalytic techniques to degrade organic pollutants and their antimicrobial activity is discussed here using model systems. Synthetic and natural nanohybrids are available today and have varying characteristics as options. Recently developed natural mineral based nanohybrids is the new trend in photocatalytic applications. It appears that the removal efficiency of existed photocatalysts is higher than that of synthetic products. Natural nanohybrids carry the advantages of low costs, avoiding extensive synthesizing conditions in future photocatalytic applications.
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    Visible Light Active Silver Decorated Iron Titanate/Titanium Dioxide Nanohybrid for Sterilization of Explants Grown by In Vitro Technique
    (John Wiley and Sons, 2022-12-04) Seneviratne, K .L; Munaweera, I; Peiris, S. E; Kodithuwakku, P; Peiris, C. N; Kottegoda, N
    Visible light (VL) active silver decorated iron titanate/titanium dioxide (Ag-FeTiO3/TiO2) nanohybrids derived from natural ilmenite sand effectively cleanse the exophytic plant pathogens in explants grown by in vitro techniques. VL active nanohybrid is synthesized by acid-hydrolysis of natural ilmenite, followed by precipitation of the lixivium and decoration with Ag onto FeTiO3/TiO2 nanoparticles, and finally calcination under a nitrogen environment to obtain Ag-FeTiO3/TiO2. A morphological study conducted using transmission electron microscopy (TEM) confirms the formation of Ag-FeTiO3/TiO2. Powder X-ray diffraction (PXRD) analysis shows that the nanohybrid primarily consists of anatase, iron titanate (FeTiO3), Ag2O, and Ag. X-ray photoelectron spectroscopy (XPS) study suggests the presence of Ag0/Ag2O/Fe2O3 composites on the FeTiO3/TiO2 particle surface. The optical band gap significantly changes from 3.14 eV (ilmenite) to 2.80 eV after the decoration of FeTiO3/TiO2 with Ag. This nanohybrid is utilized as a surface-sterilizing agent for in vitro establishment of the Dracaena sanderiana Sander ex Mast plant. Findings illustrate Ag-FeTiO3/TiO2 nanohybrid-based photo-sterilization leads to the survival of 90% of the microbes’ free cultures while the material can be re-used due to its photocatalytic behavior. Thus, the newly synthesized nanohybrid can replace harmful sterilization agents used in tissue culture techniques