Photocatalytic performance of Sn-doped and undoped TiO2 nanostructured thin films under UV and vis-lights

Screen-printed Sn-doped TiO2 nanoparticles for photocatalytic dye removal from wastewater: A technological perspective

TiO2 is widely used as a photocatalyst with a wide band gap, which limited its application. Ion doping and formulating a high-quality screen-printing paste enhance its features. However, the printability of objects for advanced application seems essential nowadays. In this research, the Sn-doped TiO2 nanoparticles were prepared through a sol-gel method followed by calcination at various temperatures of 450 °C, 550 °C, 650 °C, 750 °C, and 850 °C. Screen-printing pastes were prepared with 18 wt% of the synthesized Sn-doped TiO2 nanoparticles to evaluate photocatalytic activity. Finally, the prepared paste with optimum nanoparticle concentration was screen printed onto the microscope glass slides at various printing times (1, 3, and 5 runs) and annealed at 500 °C temperature to investigate the thickness of printed Sn-doped TiO2 nanoparticles effect. The photocatalytic activity and crystal structure of nano Sn-doped-TiO2 were characterized using photoluminescence (PL) spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) and scanning electron microscope (SEM) analyses were conducted to investigate the size and morphology of the prepared nanoparticles, respectively. The highest photocatalytic activity for the degradation of methylene blue was obtained at the calcination temperature of 450 °C.

ALD coated polypropylene hernia meshes for prevention of mesh-related post-surgery complications: an experimental study in animals

In this work, thermal atomic layer deposition (ALD) was used to synthesize vanadium (V)-doped TiO₂thin nanofilm on polypropylene (PP) hernia meshes. Multiple layers of (Al₂O₃+ TiVO_x) nano-films were coated on the PP hernia mesh surface to provide a layer with a total thickness of 38 nm to improve its antibacterial properties, thereby, prevent mesh-related post-surgery complications. Highly conformal V-doped TiO₂nanofilm were deposited on PP mesh at a temperature of 85 °C. Rats and rabbits have been used to evaluate the tissue reaction on coated PP hernia meshes and biomechanical testing of the healed tissue. Five rabbits and ten rats have been implanted with ALD coated and uncoated (control) PP meshes into the back of rats and abdominal wall of rabbits. Histology of the mesh-adjacent tissues and electron microscopy of the explanted mesh surface were performed to characterize host tissue response to the implanted PP meshes. The effect of V-doped TiO₂coating on a living organism and fibroblast functions and bacterial activities were studied. The present results indicated that ALD coating improves adhesion properties and exhibited enhanced antibacterial activity compared to uncoated PP mesh. It was shown that V-doped TiO₂coatings were highly effective in inhibitingS. aureusandE. coliadhesion and exhibited excellent antibacterial activity. We found that V-doping of TiO₂, unlike bare TiO₂, allows generated and further procured strong redox reactions which effectively kills bacteria under visible light. We have reported comparative analysis of the use of undoped (bare) TiO₂and V-doped TiO₂as a coating for PP meshes and their action in biological environment and preventing biofilms formation compared with uncoated PP meshes. The PP meshes coated with V-doped TiO₂showed significantly lower shrinkage rates compared with an identical PP mesh without a coating. We have shown that ALD coatings provide non-adhesive and functional (antibacterial) properties.

Titaniumdioxide mediated sonophotodynamic therapy against prostate cancer

In this study, we aimed to investigate of antitumor efficiency of titanium dioxide mediated photodynamic (PDT), sonodynamic (SDT), and sonophotodynamic (SPDT) therapies with a possible mechanism against the PC3 prostate cancer cell line. SPDT is a new approach to cancer treatment that combines sonodynamic and photodynamic therapies. On the other hand, Titanium dioxide (TiO₂) has been used in many applications in pharmaceutical products and cosmetics, industrial products, and medicines. TiO₂ nanoparticles will be useful for the treatment of cancer with PDT and SDT as the sensitizers in medicine. In this study, TiO₂ nanoparticles were used for an in vitro comparison between the PDT, SDT, SPDT damages on prostate cancer cell lines. For this purpose, the cells were incubated in RPMI-1640 media with various concentrations of TiO₂ and subjected to 0,5 W/cm² ultrasound and/or 0,5 mJ/cm² light irradiation. The prostate cancer cells were irradiated with light and exposed with the US and both for SPDT in the presence and/or absence of TiO₂. Cell viability was measured using by MTT test after treatments. Investigate to apoptosis mechanism, Propidium iodide and Hoechst 33342 staining were used and the results showed that apoptotic cell bodies were increased compared with other groups. According to western blot analyses, caspase-3, caspase-8, PARP, and Bax levels were decreased after treatments, whereas the expression levels of caspase-9 were increased. Biochemical results showed that after treatments MDA levels were increased while SOD, CAT, GSH levels were decreased. In conclusion, TiO₂-mediated SPDT may provide a promising approach for prostate cancer therapy and might play a key role in the apoptotic mechanism of these treatments.

Synergetic effect of Sn doped ZnO nanoparticles synthesized via ultrasonication technique and its photocatalytic and antibacterial activity

The current work reports the photocatalytic and antibacterial performance of tin (Sn) doped zinc oxide (ZnO) nanoparticles synthesized via ultrasonic aided co-precipitation technique. The increase of Sn concentration decreased the lattice parameter and increased the crystallite size without changing the ZnO structure. The hexagonal shaped particles and sheets obtained for 3% and 5% Sn substituted ZnO, respectively. The increase of dopant concentration reduced the reflectance and optical band gap energy of Sn doped ZnO. The vibrational band present at 1443 cm^-1 confirmed the successful bond formation of Sn-O-Zn. The 5% Sn doped ZnO nanoparticles exhibited greater dye elimination rate of methylene blue compared to 3% Sn. The antibacterial activity of Sn doped ZnO showed the higher zone of inhibition about 14 mm against different pathogens. The 5% Sn doped ZnO photocatalyst improve the transfer rate of photo excite carrier and decrease the rate of recombination which greatly influence on the photocatalytic and antibacterial performance.

Scalable Synthesis of Mesoporous TiO2 for Environmental Photocatalytic Applications

Increasing environmental concern, related to pollution and clean energy demand, have urged the development of new smart solutions profiting from nanotechnology, including the renowned nanomaterial-assisted photocatalytic degradation of pollutants. In this framework, increasing efforts are devoted to the development of TiO2-based nanomaterials with improved photocatalytic activity. A plethora of synthesis routes to obtain high quality TiO2-based nanomaterials is currently available. Nonetheless, large-scale production and the application of nanosized TiO2 is still hampered by technological issues and the high cost related to the capability to obtain TiO2 nanoparticles with high reaction yield and adequate morphological and structural control. The present review aims at providing a selection of synthetic approaches suitable for large-scale production of mesoporous TiO2-based photocatalysts due to its unique features including high specific surface area, improved ultraviolet (UV) radiation absorption, high density of surface hydroxyl groups, and significant ability for further surface functionalization The overviewed synthetic strategies have been selected and classified according to the following criteria (i) high reaction yield, (ii) reliable synthesis scale-up and (iii) adequate control over morphological, structural and textural features. Potential environmental applications of such nanostructures including water remediation and air purification are also discussed.

Scalable Synthesis of Mesoporous TiO2 for Environmental Photocatalytic Applications

Increasing environmental concern, related to pollution and clean energy demand, have urged the development of new smart solutions profiting from nanotechnology, including the renowned nanomaterial-assisted photocatalytic degradation of pollutants. In this framework, increasing efforts are devoted to the development of TiO2-based nanomaterials with improved photocatalytic activity. A plethora of synthesis routes to obtain high quality TiO2-based nanomaterials is currently available. Nonetheless, large-scale production and the application of nanosized TiO2 is still hampered by technological issues and the high cost related to the capability to obtain TiO2 nanoparticles with high reaction yield and adequate morphological and structural control. The present review aims at providing a selection of synthetic approaches suitable for large-scale production of mesoporous TiO2-based photocatalysts due to its unique features including high specific surface area, improved ultraviolet (UV) radiation absorption, high density of surface hydroxyl groups, and significant ability for further surface functionalization The overviewed synthetic strategies have been selected and classified according to the following criteria (i) high reaction yield, (ii) reliable synthesis scale-up and (iii) adequate control over morphological, structural and textural features. Potential environmental applications of such nanostructures including water remediation and air purification are also discussed.

Aqueous photocatalytic degradation of selected micropollutants by Pd-modified titanium dioxide in three photoreactor types

The goals of the present study were to synthesise highly efficient Pd-TiO₂ photocatalyst, to characterise its performance in slurry in smaller scale and to investigate its performance in the aqueous photocatalytic oxidation of three antibiotics: doxycycline, sulphamethizole and amoxicillin. The performance of the photocatalyst was evaluated in an open batch slurry reactor equipped with a fluorescent long-wavelength ultraviolet (UVA) lamp (0.2 L). With the fastest degrading doxycycline, experimental research was continued in a fixed-bed continuous flow photoreactor (0.13 L), with the Pd-TiO₂ photocatalyst attached to a glass plate, and a medium laboratory-scale three-phase fluidised-bed reactor (2 L) equipped with four fluorescent UVA lamps, with the photocatalyst attached to the surface of expanded clay granules employed as the bed material. While showing very high activity in the batch slurry reactor, far surpassing P25 Aeroxide, the performance of Pd-TiO₂ with doxycycline was comparable to P25 in the semi-continuous reactors.

Visible light-driven decomposition of gaseous benzene on robust Sn2+-doped anatase TiO2 nanoparticles

The Sn²⁺-doped TiO₂ nanoparticles are excellent and promising visible-light photocatalysts for the decomposition of benzene with robust photostability.

Nano-/microstructure improved photocatalytic activities of semiconductors

Photocatalysis has emerged as a promising technique owing to its valuable applications in environmental purification. With the demand of building effective photocatalyst materials, semiconductor investigation experienced a developing process from simple chemical modification to complicated morphology design. In this review, the general relationship between morphology structures and photocatalytic properties is mainly discussed. Various nano-/microsized structures from zero- to three-dimensional are discussed, and the photocatalytic efficiency correspon- ding to the structures is analysed. The results showed that simple structures can be easily obtained and can facilitate chemical modification, whereas one- or three-dimensional structures can provide structure-enhanced properties such as surface area increase, multiple reflections of UV light, etc. Those principles of structure-related photocatalytic properties will afford basic ideology in designing new photocatalytic materials with more effective catalytic properties.

Clinical and histomorphometrical study on titanium dioxide-coated external fixation pins

Background:

Pin site infection is the most common and significant complication of external fixation. In this work, the efficacy of pins coated with titanium dioxide (TiO₂) for inhibition of infection was compared with that of stainless steel control pins in an in vivo study.

Methods:

Pins contaminated with an identifiable Staphylococcus aureus strain were inserted into femoral bone in a rat model and exposed to ultraviolet A light for 30 minutes. On day 14, the animals were sacrificed and the bone and soft tissue around the pin were retrieved. The clinical findings and histological findings were evaluated in 60 samples.

Results:

Clinical signs of infection were present in 76.7% of untreated pins, but in only 36.7% of TiO₂-coated pins. The histological bone infection score and planimetric rate of occupation for bacterial colonies and neutrophils in the TiO₂-coated pin group were lower than those in the control group. The bone-implant contact ratio of the TiO₂-coated pin group was significantly higher (71.4%) than in the control pin group (58.2%). The TiO₂ was successful in decreasing infection both clinically and histomorphometrically.

Conclusion:

The photocatalytic bactericidal effect of TiO₂ is thought to be useful for inhibiting pin site infection after external fixation.

Aqueous photocatalytic oxidation of sulfamethizole

Aqueous photocatalytic oxidation (PCO) of a non-biodegradable sulphonamide antibiotic sulfamethizole was studied. The impacts of photocatalyst dose, initial pH, and substrate concentration in the range from 1 to 100 mg L(-1) were examined with a number of organic and inorganic by-products determined, suggesting the initial break-up of the SMZ molecule at the sulphonamide bond. The experiments were carried out under artificial near-UV and visible light, and solar radiation using Degussa P25 and less efficient visible light-sensitive C-doped titanium dioxide as photocatalysts.

Preparation and application of visible-light-responsive Ni-doped and SnO2-coupled TiO2 nanocomposite photocatalysts

A new series of visible-light-driven TiO2 photocatalysts constituting lattice-doped Ni and surface-coupled SnO2 nanocomposites, xNi-TiO2-SnO2 (x=0.1, 0.3, 0.5), were synthesized. TiO2 and xNi-TiO2 were prepared by a sol-gel method while the SnO2 was coupled to these via a ligand exchange reaction and finally the catalysts were thermally treated. The presence of Ni ions in the lattice of the photocatalysts was indirectly confirmed by a red shift in DRS spectra. XRD showed crystalline peaks only assignable to TiO2 anatase phase. XPS analysis confirmed that Sn is present on the surface of the catalysts as SnO2 while Ni(2)O(3) is absent. The xNi-TiO2-SnO2 nanocomposites showed a promising visible-light-responsive photocatalytic activity and were found superior to TiO2, xNi-TiO2 and TiO2-SnO2 for the degradation of toluene in air.

Sonochemical and sonophotocatalytic degradation of malachite green: the effect of carbon tetrachloride on reaction rates

A comparative study between the sonolytic, photocatalytic and sonophotocatalytic oxidation processes of aqueous solutions of malachite green was carried out in the presence of carbon tetrachloride, under a low power ultrasonic field (<15 W) and using titanium dioxide as a photocatalyst. The effect of a number of parameters such as ultrasonic intensity, TiO2 crystalline structure and the presence of CCl4 were studied using an inexpensive reactor. Enhanced rates of sonolytic degradation of malachite green in the presence of CCl4 were demonstrated. On the other hand, the simultaneous use of sonolysis and photocatalysis in the presence of CCl4 does not improve the degradation rate of malachite green in comparison with the one obtained using only sonolysis, but it makes possible a faster oxidative degradation of some reaction intermediaries. Finally, in air saturated solutions both processes, the sonolytic and the photocatalytic one, follow a first-order rate law.