Synthesis of Ti02 N anosized Powder Photocatalyst Via Solgel Method for Bacteria Inactivation Application

Titanium dioxide (Ti02) is the most widely used photocatalyst and has been applied for water and air purification and disinfection of microorganism. Anatase structured Ti02 is a wide bandgap (3.2 eV) semiconductor which, under UV light, is able to degrade chemicals and cell components of microorganisms. In this study, Ti02 nanopowder photocatalyst was synthesized by sol-gel process using a titanium chelate compound, titanium (di-isopropoxide) bis(acetylacetonate) (PTP) as the precursor. The precursor was hydrolyzed under an acidic catalyst condition, followed by reflux for 15 minutes and 1 hour. The precipitate powder obtained after filtration was calcined at 400°C. XRD analysis confirmed that the Ti02 powders A (15 minutes reflux) and B (1 hour reflux) have strongest peak at 25° which indicates anatase crystal structure. The particle size of powder A was smaller than the powder B as proved by calculation using Scherrer's equation. The crystallization temperature of Ti02 powder A was higher due to its smaller particles that needed more heat to crystallize than powder B as confirmed by TGIDTA. FESEM analysis showed powder A have homogenous spherical shape, contrast to powder B showing inhomogenous spherical shape and connected particle. The Ti02 photocatalyst activity in killing bacteria was investigated for 5 hours by varying the concentration 'of Ti02 and UV light intensity

Photocatalytic Degradation of Phenol over Highly Visible-Light Active BiOI/TiO2 Nanocomposite Photocatalyst

BiOI/TiO2 nanocomposites were successfully prepared by the two-step method, co-precipitation/solvothermal method. The amount of BiOI in the composites were varied as 0, 5.0, 7.5, 10.0 and 12.5 mol%. XRD results exhibited sharp and narrow diffraction peaks of both BiOI and TiO2 in all composite samples. Morphologies of as-prepared samples consisted of spherical shapes of TiO2 and nanosheets of BiOI. Difuse Reflectance UV-visible (DR-UV-vis) spectra of composites drastically shifted into the visible range and the reduced band gap energies were observed. The composits obviously showed an enhanced phenol degradation of ca. 6 times higher than that of pure BiOI, pure TiO2 and Degussa P25. The maximum photocatalytic activity of ca. 68% was found for 10.0 mol% BiOI/TiO2 nanocomposite because of its increased visible-light-harvesting ability and its efficient electron-hole separation efficiency as observed from DR-UV-vis and PL spectra results

Detoxification of Carcinogenic Dyes by Noble Metal (Ag, Au, Pt) Impregnated Titania Photocatalysts

Textile industries produce large quantities of waste water which is notoriously known to contain strong colour, suspended solids and COD. Although several treatment processes, such as filtration, coagulation, oxidation, ozonation, reverse osmosis, etc., have been practiced for many decades, they all have inherent limitations. They transfer the harmful pollutants from one phase to another and do not address detoxification. Semiconductor photocatalysis is a promising technique for photodegradation of hazardous chemicals found in waste waters. Among various semiconductors, TiO2 has been studied widely. However, the main drawbacks associated with TiO2 are (i) large band gap (Eg > 3.2 eV) (only UV active) and (ii) recombination of excitons. Dye sensitisation, coupling of semiconductors, and transitional metal doping are some of the methods reported to shift its optical response to visible region. Herein, nanoparticles of different noble metals such as Ag, Au and Pt were deposited on synthesised TiO2, characterized by XRD, TEM, FT-IR, BET, UV-Vis and AAS and were subjected to the degradation of some textile dyes namely Tartrazine (TAZ), Reactive Yellow-17 (RY-17) and Reactive Black-5 (RB-5) under both UV and visible irradiations. The reaction conditions such as catalyst concentration, dye concentration, pH, irradiation time, light intensity, and additives were optimized for complete decolourisation and discussed

Reduced Graphene Oxide/Waste-Derived TiO2 Composite Membranes: Preliminary Study of a New Material for Hybrid Wastewater Treatment

This work reports the preliminary results of the development of composite self-assembling membranes obtained by the combination of reduced graphene oxide (rGO) with commercial Degussa P25 titanium dioxide (TiO2). The purpose is to demonstrate the possibility of combining, in the same self-standing material, the capability to treat wastewater containing both inorganic and organic pollutants by exploiting the established ability of rGO to capture metal ions together with that of TiO2 to degrade organic substances. Moreover, this study also investigates the potential photocatalytic properties of tionite (TIO), to demonstrate the feasibility of replacing commercial TiO2 with such waste-derived TiO2-containing material, fulfilling a circular economy approach. Thus, rGO–TiO2 and rGO–TIO composite membranes, 1:1 by weight, were prepared and characterized by SEM-EDX, XRD, thermogravimetry, as well as by Raman and UV-Vis spectroscopies to verify the effective and homogeneous integration of the two components. Then, they were tested towards 3-mg L−1 aqueous synthetic solutions of Fe3+ and Cu2+ ions to evaluate their metal adsorption ability, with values of the order of 0.1–0.2 mmol gmembrane−1, comparable or even slightly higher than those of pristine rGO. Finally, the ability of the composites to degrade a common organic pesticide, i.e., Imidacloprid®, was assessed in preliminary photocatalysis experiments, in which maximum degradation efficiencies of 25% (after 3 h) for rGO–TiO2 and of 21% (after 1 h) for rGO–TIO were found. The result of tionite-containing membranes is particularly promising and worthy of further investigation, given that the anatase content of tionite is roughly 1/6 of the one in commercial TiO2

OPTICAL PROPERTIES AND PHOTO CATALYTIC ACTIVITIES OF TITANIA NANOFLOWERS SYNTHESIZED BY MICROWAVE IRRADIATION

Abstract: TiO 2 nanostructures with flower like morphology was synthesized by a simple microwave assisted acid hydrolysis of TiCl 3 . Tuning the morphology was achieved by the microwave treatment and the nature of the medium or the precipitating agent. As-synthesized titania nanoflowers, was characterized by X-ray diffraction (XRD), UV-Visible spectroscopy, Infrared spectroscopy (IR) and Scanning Electron Microscopy (SEM). The BET surface area, pore size distribution and pore volume of the samples were measured using a static volumetric system, Micromeritics ASAP 2010 equipment. The as-prepared TiO 2 nanoflowers appear to be single crystalline phase and the diameter is about 33.55 nm. The Photocatalytic activity studies reveal that the as-synthesized rutile titania nanoflowers show higher photocatalytic activity. In most cases, rutile TiO 2 nanoparticles show poor photocatalytic activities than the pure anatase phase. Interestingly, the single phase rutile TiO 2 nanocrystals with flower like morphology formed in the absence of any additives exhibited higher photocatalytic activity than the famous commercial photocatalyst Degussa P-25 on the photocatalytic degradation of Methyl Red

Magnetised titanium dioxide (TiO2) for water purification: preparation, characterisation and application

© 2014 Balaban Desalination Publications. All rights reserved. The study of titanium dioxide (TiO2) as a photocatalyst for water purification has attracted significant attention over the past four decades. However, the separation of photocatalyst from water suspension may be difficult, costly and jeopardise the use of this water treatment technology. Recently, the development and production of magnetised TiO2 have been achieved to offer a solution for the photocatalyst separation problem. This paper discusses the preparation techniques, characterisation and the applications of magnetised TiO2. Many researchers have studied magnetised TiO2 photocatalysts but the lack of articles discussing the water purification processes is still slowing any advance in this field. Here, the progress of the scientific research on preparation techniques to coat magnetic particles by materials such as organic polymers, silica, magnesia, and alumina are reviewed to compare and discuss recent findings. The doping of photoactive TiO2 photocatalyst into the magnetic-coated particles is also emphasised. In addition, the characterisation of magnetised TiO2 in terms of physicochemical properties and operating conditions produced by each technique are critically reviewed. Moreover, examples of applications of TiO2 and magnetised TiO2 photocatalyst in water purification are summarised. In general, the effectiveness of organic removal by magnetised TiO2 is still lower compared to single phase TiO2. The future prospect of this field is deliberated to develop a novel, economic and efficient magnetised TiO2 photocatalyst, which has high organic removal properties