Nanostructured mesoporous titanium dioxide (TiO2) particles with high specific surface area and average crystallite domain sizes within 2 nm and 30 nm have been prepared via the sol-gel and hydrothermal procedures. The characteristics of produced nanoparticles have been tested using X-Ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FTIR), and Raman Spectroscopy as a function of temperature for their microstructural, porosity, morphological, structural and absorption properties. The as-synthesized TiO2 nanostructures were attempted as catalysts in Rhodamine B and Sudan III dyes' photocatalytic decomposition in a batch reactor with the assistance of Ultra Violet (UV) light. The results show that for catalysts calcined at 300 °C, ∼100 % decomposition of Sudan III dye was observed when Hydrothermal based catalyst was used whiles ∼94 % decomposition of Rhodamine B dye was observed using the sol-gel based catalysts. These synthesized TiO2 nanoparticles have promising potential applications in the light aided decomposition of a wide range of dye pollutants.

Biofilm formation on both animate and inanimate surfaces serves as an ideal bacterial reservoir for the spread of nosocomial infections. Designing surfaces with both superhydrophobic and antibacterial properties can help reduce initial bacterial attachment and subsequent biofilm formation. In the present study, a two-step approach is deployed to fabricate silver–polymethylhydrosiloxane (Ag–PMHS) nanocomposites, followed by a simple dip-coating deposition on anodized Al. Ag-nanoparticles (Ag-NPs) are synthesized in situ within a PMHS polymeric matrix. Morphological features of Ag–PMHS coating observed by scanning electron microscopy shows heterogeneous micro–nano-structures. The chemical compositions of these coatings were characterized using X-ray diffraction and attenuated total reflection-Fourier transform infrared spectroscopy, which indicate the presence of a low-energy PMHS polymer. The as-synthesized Ag–PMHS nanocomposite demonstrated excellent antibacterial properties against clinically relevant planktonic bacteria with zone of inhibition values of 25.3 ± 0.5, 24.8 ± 0.5, and 23.3 ± 3.6 mm for Pseudomonas aeruginosa (P.A) (Gram −ve), Escherichia coli (E. coli) (Gram −ve), and Staphylococcus aureus (S.A) (Gram +ve), respectively. The Ag–PMHS nanocomposite coating on anodized Al provides an anti-biofouling property with an adhesion reduction of 99.0, 99.5, and 99.3% for Pseudomomas aeruginosa (P.A), E. coli, and S. aureus (S.A), respectively. Interestingly, the coating maintained a stable contact angle of 158° after 90 days of immersion in saline water (3.5 wt % NaCl, pH 7.4). The Ag–PMHS nanocomposite coating on anodized Al described herein demonstrates excellent antibacterial and anti-biofouling properties owing to its inherent superhydrophobic property.

No abstract

Ag3PO4 photocatalyst has attracted interest of the scientific community in recent times due to its reported high efficiency for water oxidation and dye degradation. However, Ag3PO4 photo-corrodes if electron accepter such as AgNO3 is not used as scavenger. Synthesis of efficient Ag3PO4 followed by a simple protocol for regeneration of the photocatalyst is therefore a prerequisite for practical application. Herein, we present a facile method for the synthesis of a highly efficient Ag3PO4, whose photocatalytic efficiency was demonstrated using 3 different organic dyes: Methylene Blue (MB), Methyl orange (MO) and Rhodamine B (RhB) organic dyes for degradation tests. Approximately, 19 % of Ag3PO4 is converted to Ag0 after 4.30 hours of continuous UV-Vis irradiation in presence of MB organic dye. We have shown that the Ag/Ag3PO4 composite can be rejuvenated by a simple chemical oxidation step after several cycles of photocatalysis tests. At an optimal pH of 6.5, a mixture of cubic, rhombic dodecahedron, nanosphere and nanocrystals morphologies of the photocatalyst was formed. H2O2 served as the chemical oxidant to re-insert the surface metallic Ag into the Ag3PO4 photocatalyst but also as the agent that can control morphology of the regenerated as-prepared photocatalyst without the need for any other morphology controlling Agent (MCA). Surprisingly, the as- regenerated Ag3PO4 was found to have higher photocatalytic reactivity than the freshly made material and superior at least 17 times in comparison with the conventional Degussa TiO2, and some of TiO2 composites tested in this work.