Preparation of Nanosized TiO2-Photocatalyst From-Sludge (TFS) and the Characteristics of Concrete Sidewalk Blocks Using TFS

In this study, nano-sized low cost titanium dioxide (TFS) was prepared using sludge from sewage treatment and performance was verified. To remove air pollutants, the photocatalytic degradation of methylene blue and efflorescence characteristics is assessed according to the mixing ratio of the nano-sized TFS by applying them to concrete sidewalk blocks. The photocatalytic degradation performance of concrete sidewalk blocks shows that the methylene blue removal rate of specimens containing 2.5%, 5%, and 10% of nano-sized TFS is 29%, 27%, and 38%, respectively. When the nano-sized TFS is mingled on the surface of the sidewalk block, the performance of anti-corrosion and antifouling showed excellency mainly due to the moisture blocking derived by the antifouling function of photocatalysts.

Remediation of Olive Mill Industry Wastewater with Titanium Dioxide (TiO2), Silisium Dioxide (SiO2) and Zinc Oxide (ZnO) Using Ultrasound

The effects of nano-sized metal oxides namely titanium dioxide (TiO2 ), silisium dioxide (SiO2 ) and zinc oxide (ZnO) on the ultrasound of olive mill effluent wastewater (OMW) in Turkey were investigated. 150 min ultrasound alone provided 61%, 50%, 61% and 66% dissolved chemical oxygen demand (CODdis), color, total phenol and total aromatic amines (TAAs) removals, respectively, at 25o C. The maximum TAAs (90%), total phenol (97%), color (94%) and CODdis (97%) removals were obtained with 5 mg/l nano-sized ZnO, 4 mg/l nano-sized TiO2 , 4 mg/l nanosized TiO2 and 4 mg/l nano- sized TiO2 , respectively, throughout ultrasound.

Nanophotocatalysis for the Removal of Pharmaceutical Residues from Water Bodies: State of Art and Recent Trends

Background: The occurrence of pharmaceuticals in surface and drinking water is ubiquitous and is a major concern of researchers. These compounds cause a destructive impact on aquatic and terrestrial life forms and the removal of these compounds from the environment is a challenging issue. Existent conventional wastewater treatment processes are generally inefficacious because of their low degradation efficiency and inadequate techniques associated with the disposal of adsorbed pollutants during comparatively effective methods like the adsorption process. Remediation method: Semiconductor mediated photocatalysis is an attractive technology for the efficient removal of pharmaceutical compounds. Among various semiconductors, TiO2 and ZnO based photocatalysts gained much interest during the last years because of their efficiency in decomposing and mineralizing the lethal organic pollutants with the utilization of UV-visible light. Incessant efforts are being undertaken for tuning the physicochemical, optical and electronic properties of these photocatalysts to strengthen their overall photocatalytic performance with good recycling efficiency. Results: This review attempts to showcase the recent progress in the rational design and fabrication of nanosized TiO2 and ZnO photocatalysts for the removal of pollutants derived from the pharmaceutical industry and hospital wastes. Conclusion: Photocatalysis involving TiO2 and ZnO provides a positive impact on pollution management and could be successfully applied to remove pharmaceuticals from wastewater streams. Structure modifications, introduction of heteroatoms and integration of polymers with these nanophotocatalysts offer leapfrogging opportunities for broader applications in the field of photocatalysis.

Comparative Photo-Electrochemical and Photocatalytic Studies with Nanosized TiO2 Photocatalysts towards Organic Pollutants Oxidation

The size of TiO2 can significantly affect both its photocatalytic and photo-electrochemical properties, thus altering the photooxidation of organic pollutants in air or water. In this work, we give an account of the photo-electrochemical and photocatalytic features of some nanosized TiO2 commercial powders towards a model reaction, the photooxidation of acetone. Cyclic voltammograms (CV) of TiO2 particulate electrodes under UV illumination experiments were carried out in either saturated O2 or N2 solutions for a direct correlation with the photocatalytic process. In addition, the effect of different reaction conditions on the photocatalytic efficiency under UV light in both aqueous and gaseous phases was also investigated. CV curves with the addition of acetone under UV light showed a negative shift of the photocurrent onset, confirming the efficient transfer of photoproduced reactive oxygen species (ROSs), e.g., hydroxyl radicals or holes to acetone molecules. The photocatalytic experiments showed that the two nano-sized samples exhibit the best photocatalytic performance. The different photoactivity of the larger-sized samples is probably attributed to their morphological differences, affecting both the amount and distribution of free ROSs involved in the photooxidation reaction. Finally, a direct correlation between the photocatalytic measurements in gas phase and the photo-electrochemical measurements in aqueous phase is given, thus evincing the important role of the substrate-surface interaction with similar acetone concentrations.

Electrospun Eco-Friendly Materials Based on Poly(3-hydroxybutyrate) (PHB) and TiO2 with Antifungal Activity Prospective for Esca Treatment

Esca is a type of grapevine trunk disease that severely affects vine yield and longevity. Phaeomoniella chlamydospora (P. chlamydospora) is one of the main fungi associated with esca. The aim of the present study was to obtain eco-friendly materials with potential antifungal activity against P. chlamydospora based on biodegradable and biocompatible poly(3-hydroxybutyrate) (PHB), nanosized TiO2-anatase (nanoTiO2), and chitosan oligomers (COS) by conjunction of electrospinning and electrospraying. One-pot electrospinning of a suspension of nanosized TiO2 nanoparticles in PHB solution resulted in materials in which TiO2 was incorporated within the fibers (design type “in”). Simultaneous electrospinning of PHB solution and electrospraying of the dispersion of nanosized TiO2 in COS solution enabled the preparation of materials consisting of PHB fibers on which TiO2 was deposited on the fibers’ surface (design type “on”). Several methods including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), thermogravimetric analyses (TGA) and water contact angle were utilized to characterize the obtained materials. The incorporation of nanoTiO2 in the PHB fibers, as well as nanoTiO2 deposition onto the surface of the PHB fibers resulted in increased roughness and hydrophobicity of the obtained composite fibrous materials. Moreover, TiO2-on-PHB fibrous material exhibited complete inhibition of fungal growth of P. chlamydospora. Therefore, the obtained eco-friendly fibrous materials based on PHB and nanoTiO2 are promising candidates for protection against esca in agriculture.