Immobilised rGO/TiO2 Nanocomposite for Multi-Cycle Removal of Methylene Blue Dye from an Aqueous Medium

This work presents the immobilisation of titanium dioxide (TiO2) nanoparticles (NPs) and reduced graphene oxide (rGO)-TiO2 nanocomposite on glass sheets for photocatalytic degradation of methylene blue (MB) under different radiation sources such as ultraviolet and simulated solar radiation. The TiO2 NPs and rGO-TiO2 nanocomposite were synthesised through a simple hydrothermal method of titanium isopropoxide precursor followed by calcination treatment. Deposition of prepared photocatalysts was performed by spin-coating method. Additionally, ethylene glycol was mixed with the prepared TiO2 NPs and rGO-TiO2 nanocomposite to enhance film adhesion on the glass surface. The photocatalytic activity under ultraviolet and simulated solar irradiation was examined. Further, the influence of different water matrices (milli-Q, river, lake, and seawater) and reactive species (h+, •OH, and e−) on the photocatalytic efficiency of the immobilised rGO/TiO2 nanocomposite was careful assessed. MB dye photocatalytic degradation was found to increase with increasing irradiation time for both irradiation sources. The immobilisation of prepared photocatalysts is very convenient for environment applications, due to easy separation and reusability, and the investigated rGO/TiO2-coated glass sheets demonstrated high efficiency in removing MB dye from an aqueous medium during five consecutive cycles.

How the Ti Precursor is Involved in the Effectiveness of Pt-TiO2 Materials in Photodegrading Methyl Orange

As other studies have demonstrated, improving the effectiveness of TiO2 for environmental remediation requires that the properties of this oxide be modified using different synthesis methods. In the current study, labprepared TiO2 was synthesized using the hydrothermal method and two different Ti precursors (titanium butoxide and titanium isopropoxide). After the synthesis, the obtained titania was also modified using photodeposition by platinum nanoparticles. This study aims to evaluate the effectiveness of the photocatalytic materials prepared in photodegrading methyl orange. The Ti precursors used in the TiO2 synthesis had a slight effect on the physicochemical properties of the oxide obtained. When titanium butoxide was used as a precursor, we observed a change in the bandgap value and some material with the largest surface area. Additionally, the addition of Pt increased the absorption of TiO2 in the visible region of the electromagnetic spectrum and slightly decreased the bandgap value of this oxide. The photocatalyst prepared using titanium isopropoxide as a precursor showed the most remarkable effectiveness in the degradation rate of methyl orange. This is the result of the lower band gap value of this material which leads to easier transport of the photogenerated charges during the photocatalytic reaction. We also observed that the addition of Pt has a detrimental effect on the effectiveness of TiO2 in dye degradation, which may be due to possible obstruction of the dye-photocatalyst interaction on the TiO2 surface because of the Pt nanoparticles observed by tem. The effectiveness of commercial TiO2 in methyl orange degradation is slightly higher than that observed in other evaluated solids.

Degradation of pharmaceutical antibiotic (ciprofloxacin) by photocatalysis process using sol-gel based titanium dioxide nanoparticles

This study is an attempt to the removal of Ciprofloxacin (CIP) antibiotic from simulated wastewater using a photocatalytic process. The photocatalytic process was carried out in a photocatalytic reactor in the presence of TiO2 nanoparticles. TiO2 nanoparticles were successfully prepared in a laboratory scale using sol-gel method with titanium-isopropoxide (TTIP) as titanium precursor. Prepared material was found very effective to the removal of CIP antibiotic. The maximum removal efficiency of 87.95% of ciprofloxacin from aqueous solution was achieved at the pH 5, catalyst doze of 40 mg L−1 with initial concentration of ciprofloxacin 5 mg L−1, and the reaction time of 100 min additionally; material characterization of TiO2 was presented in detail in terms of XRD, SEM, UV, and FTIR. It has been found that at the optimum condition the total operating cost indicated for the removal of ciprofloxacin from aqueous solution is 786.56 (INR/kg of CIP removal). This technique demonstrated that photocatalytic reaction in presence of TiO2 nanoparticles is well applicable to treat pharmaceutical wastewater.

Synthesis and Transformation of Hollow Rutile Titania Wires by Single Spinneret Electrospinning with Sol-Gel Chemistry

The work described below was carried out to understand how to control the morphology of nanostructured titania calcined from electrospun nanofibers. This is the first report of hollow rutile nanofibers synthesized from electrospun nanofibers with short calcination time. Titanium isopropoxide was incorporated into the nanofibers as the titania precursor. The electrospinning technique was used to fabricate ceramic/polymer hybrid nanofibers. The electrospun nanofibers were then calcined to produce rutile titania nanofibers with different morphologies (hollow or solid nanofibers), which were characterized by SEM and TEM. The initial concentration of ceramic precursor and the calcination time were shown to control the morphology of the nanofiber. The hollow morphology was only obtained with a concentration of the precursor within a certain level and with short calcination times. The heat treatment profile contributed to particle growth. At longer times, the particle growth led to the closure of the hollow core and all the nanofibers resembled strings of solid particles. A formation mechanism for the hollow nanofibers is also proposed.

Pattern Visibility Enhancement by the Hybrimer Index-Matching Inter Layer in Oxide/Metal/Oxide-Structured Transparent Conductive Electrode on Flexible Polyethylene Terephthalate Substrates

For this study, we fabricated transparent Mn-doped tin oxide (MTO)/Ag/MTO films with refractive index-matching layer on a polyethylene terephthalate (PET) substrate. The hybrimer indexmatching layer containing TIP (Titanium isopropoxide) in hydroxy terminated PDMS (PDMS-OH) matrix was placed between the MTO/Ag/MTO multilayer and PET substrate. MTO and Ag were deposited by using RF/DC magnetron sputtering at room temperature, whereas a hybrimer mixture was spin-coated on the PET substrate after adjusting the molar ratios between the TIP and PDMS-OH. Pattern visibility was examined by comparing the differences in the reflectance and transmittance of MTO/Ag/MTO multilayer films before and after placing the hybrimer index-matching layer. As the PDMS-OH concentration increased, the reflectance difference at the wavelength of 550 nm (ΔR550nm) showed a tendency of decreasing from 0.66% to 0.53%. The index-matched MTO/Ag/MTO multilayer films showed the highest transmittance (>86% at 550 nm) at a molar ratio of 1:4.

Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

Optical Properties of ZnO, TiO2 and ZnO:TiO2 Composite Films

We report a fabrication and characterization of ZnO, TiO2 and ZnO:TiO2 composite thin films. The films were prepared on glass substrates by using the dip coating sol-gel method. ZnO was synthesized by using Zinc acetate dehydrated, glacial acetic acid and ethanol. Meanwhile, TiO2 was prepared by using titanium isopropoxide, acetic acid, isopropyl alcohol and methanol. The single sols were mixed with fixed molarity of 0.2 mol to obtain ZnO:TiO2 composite films. The optical properties of metal oxide, such as transmittance, absorbance and band gap were determined using UV-Vis spectrometer. FTIR was used to determine the chemical bonds of the materials. ZnO has the highest transmittance spectra (91%), followed by TiO2 (70%) and ZnO:TiO2 (35%) composite films. The absorbance edge shifted to the longer wavelength for ZnO:TiO2 composite film. The energy band gap of ZnO, TiO2 and ZnO: TiO2 composite were 3.8 eV, 3.6 eV and 3.5 eV, respectively.

Preparation and Optical Application of SiO2-TiO2 Composite Hardening Coatings with Controllable Refractive Index by Synchronous Polymerization

The homogeneous SiO2-TiO2 composite sols were prepared by organic-inorganic synchronous polymerization with titanium isopropoxide and tetrabutyl silicate as precursor. The organic-inorganic composite hard coating with Si-O-Ti as the framework was prepared by adding compound crosslinkers (up-401) and 3-Methacryloxypropyltrimethoxysilane (KH-560). The structure of the coating and the hardened film were characterized by infrared spectrum, scanning electron microscopy, atomic force microscopy, particle size analyzer and thermogravimetry. The refractive index, transmittance and hardness of the hardened film were measured by ellipsometry, UV-Vis spectrophotometer and hardness tester. By adjusting the ratio of Si/Ti and optimizing the reaction conditions, the hardness of the hardened film could reach 6H, and the refractive index could be adjusted from 1.55 to 1.76. At the same time, the application of hard coatings on the surface of optical lens were studied.

Selective kinetic growth and role of local coordination in forming Al2TiO5-based coatings at lower temperatures

Al2TiO5-based coatings made from aluminium- and titanium-isopropoxide co-deposition using MOCVD, offering reduced temperatures and timescales for its synthesis without binary phase formation.

Antifungal effects of ZnO, TiO2 and ZnO-TiO2 nanocomposite on Aspergillus flavus

This study aimed to synthesis ZnO, TiO2 and ZnO–TiO2 (ratio weight of 1/1 for Zn/Ti) nanoparticles using zinc acetate and titanium isopropoxide through the sol-gel method. Physicochemical and morphological characterization and antifungal properties evaluation like minimum inhibition concentration (MIC) and minimum fungicide concentration (MFC) of nanopowders were investigated against Aspergillus flavus at in vitro. All synthesized nanoparticles (50 µg/ml) showed fungal growth inhibition while ZnO-TiO2 showed higher antifungal activity against A. flavus than pure TiO2 and ZnO. TiO2 and ZnO-TiO2 (300 µg/ml) inhibited 100% of spur production. Pure ZnO and TiO2 showed pyramidal and spherical shapes, respectively whereas ZnO-TiO2 nanopowders illustrated both spherical and pyramidal shapes with grown particles on the surface. Based on our findings, low concentration (150 µg/ml) of ZnO-TiO2 showed higher ROS production and stress oxidative induction thus fungicide effect as compared to alone TiO2 and ZnO. In conclusion, ZnO-TiO2 nanostructure can be utilized as an effective antifungal compound but more studies need to be performed to understand the antifungal mechanism of the nanoparticles rather than ROS inducing apoptosis.