TiO2 Content Research Articles

Geochemistry of Neoproterozoic arenites from the Murwara area, Katni District, Madhya Pradesh: Implications for provenance, weathering and Tectonic Setting

Geochemical analysis in terms of major, trace and rare earth elements of the Neo-Proterozoic arenites of Rewa and Bhander Groups of the Vindhyan Supergroup from Murwara, Katni district, M.P., has been carried out to determine the provenance, weathering and tectonic setting. The arenites are rich in SiO2 content but less in Na2O, K2O and CaO contents, suggesting the dominance of quartz and less amount of feldspars and rock fragments. Geochemically, these rocks are classified as quartz arenites to sub litharenite to sub-arkose. The CIA (75-98) and PIA values for these arenites and A-CN-K diagram indicates a high intensity of weathering in the source area. High LREE/HREE ratios, negative Eu anomaly and La/Sc, Th/Sc, Th/Co and Cr/Th ratio values suggest felsic source of these arenites. The discriminant diagram for these arenites indicates a quartzose sedimentary provenance. Ni vs TiO2 and Th/Sc vs Sc bivariate plots indicate that the felsic rocks have been the source rock for these arenites. The discrimination diagrams based on log (K2O+Na2O) vs SiO2 and Fe2O3+MgO vs TiO2 contents show a passive margin setting. Whereas the results of new discriminant function multi-dimensional diagram for the high silica arenites reveals a change from collision to continental rift setting

Identification of carbonated eclogitic source for Cenozoic intraplate alkaline basalts from western Central Asia and its geodynamic implication

Carbonated eclogite has been identified as a significant component in the formation of intraplate alkaline basalts, typically attributed to stagnated subducted oceanic slabs, such as the Pacific plate beneath eastern China. However, it is unclear whether this component exists in other tectonic settings. Here, we present new zircon UPb geochronology, mineral chemistry, and geochemical analyses of Cenozoic Tuoyun basanites and alkaline basalts from western Central Asia, where stagnated subducted oceanic slabs are absent, to elucidate the source properties and associated geodynamic processes. Olivine compositions (e.g., moderate Ni concentrations, low Mn/Fe and Ni/(Mg/Fe) ratios) and whole-rock chemistry (e.g., high Fe/Mn, Ca/Al, and Zr/Hf ratios, TiO2 contents, and weak anomalies of Zr-Hf-Ti) suggest a carbonated eclogite in the mantle source of the Tuoyun basanites. Trace elements (positive NbTa anomalies and absence of positive Eu anomaly) and depleted to slightly enriched Sr-Nd-Hf isotopic compositions indicate that the basanites originated from mantle sources composed of variable proportions of altered oceanic crust (AOC) and carbonates. Synthesizing regional geochemical, geophysical studies and tectonic history, we propose that the continuous India-Eurasia collision triggered mantle upwelling, leading to the formation of a widespread carbonated eclogitic mantle source beneath western Central Asia. Our findings suggest that carbonate-rich mantle sources may also be present in areas without stagnated subduction slabs.

Mineralogy and Geochemistry of Titaniferous Iron Ores in El-Baroud Layered Gabbros: Fe-Ti Ore Genesis and Tectono-Metallogenetic Setting

The Neoproterozoic pyroxene gabbros and gabbronorites in the El-Baroud mafic intrusion in the Northern Eastern Desert (NED) of Egypt host Fe-Ti oxide ore deposits. This study discusses the major and trace elements of both titaniferous iron ores and their host rocks, along with the mineral chemistry (major and in situ trace elements) of interstitial clinopyroxene (Cpx), to gain a deeper understanding of the Fe-Ti oxide genesis. These ores occur as disseminated (55–60 vol.% of Fe-Ti oxides) and massive types (85–95 vol.%) in the form of the dyke, layer, and lens. They are composed of titanomagnetite (80–87 vol.%) with subordinate ilmenite (10–15 vol.%) and magnetite (3–5 vol.%), in accordance with their high Fe2O3 (75.66 wt.% on average) and TiO2 contents (16.30–17.60 wt.%). The Cpx in the investigated ores is diopside composition (Mg#; 0.72–0.83) and exhibits a nearly convex upward REE pattern, similar to Cpxs in the ferropicrite that originated from the primitive mantle. Melts in equilibrium with this Cpx resemble Greenstone ferropicrite melts; the parent melt of El-Baroud gabbros is possibly a ferropicritic melt that was derived from the lithospheric mantle during plume interaction. The El-Baroud gabbroic rocks were generated during the arc rifting and crystallized under a high oxygen fugacity at a temperature of 800–1000 °C and a pressure of 3 kbar with a depth of 12 km. The Fe-Ti oxide ores have been formed from ferropicritic parent melts by two processes, including in situ crystallization that leads to the formation of disseminated Fe-Ti oxides in the iron-rich gabbros at the bottom and liquid immiscibility that is responsible for the formation of thick Fe-Ti ore lenses and layers at the top of the gabbroic intrusion. Initially, titanomagnetite crystallized from the primary Ti-rich oxide melt. As cooling progressed, some of the excess titanium in this melt was exsolved in the form of the exsolution ilmenite lamellae within the titanomagnetite. The Fe-Ti oxide layers in the NED follow the trend of NW-SE (Najd trend), where their distribution is possibly controlled by the composition of parent melts (rich in Ti and Fe), high oxygen fugacity, and the structure related to the Najd fault system. The distribution of Fe-Ti oxide ores increases from the NED to the Southern Eastern Desert (SED), suggesting the dominant mantle plumes and/or shear zones in the SED relative to the NED.

Experimental evaluation of radiation shielding characteristics of borate-based-glass system reinforced with titanium oxide

In this work, the attenuation capability of new Borate-based-glass system reinforced with titanium oxide containing PbO, CaO, TiO2 and B2O3 with different percentages was determined. Four different glass samples were synthesized by experimental technique using high pure germanium detector at different gamma ray sources using narrow beam method. The experimental method was verified by XCOM software. The values of the two methods were close and the relative deviation was satisfactory (less than 5 %) for all gamma energies (0.060, 0.662, 1.173 and 1.333 MeV). The highest linear attenuation coefficient (LAC) values achieved at low radiation energy of 0.0595 MeV. The Highest LAC values were 13.64, 13.97, 14.32 and 14.67 cm−1 for samples PCBT-1, PCBT-2, PCBT-3 and PCBT-4 in the same order, respectively. Conversely, the lowest LAC values in the examined energy range were found at 1.333 MeV. The lowest LAC values were 0.259, 0.266, 0.272 and 0.279 cm−1 for the aforementioned glasses, respectively. At 0.662 MeV, the transmission factor (TF) values decreases as 64.18, 63.54, 62.88 and 62.19 % as TiO2 content increases as 5, 10, 15 and 20 mol % in the same order, respectively. The decreases in TF values was linked to an observable increase in the radiation protection efficiency (RPE). The increase in RPE with the increase of TiO2 content confirms that the addition of TiO2 leads to an improvement in the radiation shielding performance for the prepared glasses.

Impact of current density, TiO2 NPs, and ultrasonic waves on the physical and friction properties of Ni–Zn–TiO₂

In the present study, a nickel-zinc (Ni–Zn) alloy coating has been selected as the foundational coating, and the formation of a composite Ni–Zn-titanium dioxide (Ni–Zn–TiO2) coating, along with the factors influencing its development, has been thoroughly examined. The influential factors explored in this research encompass applying ultrasonic waves, current density, and incorporating varying concentrations of TiO2 nanoparticles (NPs). X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy, and a wear test apparatus were utilized to assess the characteristics of these coatings. The findings indicate that the concentration of TiO₂ NPs in the plating bath profoundly impacts the morphology and coating properties. An increased TiO₂ concentration in the plating bath led to a finer morphology. Applying ultrasonic waves during the plating process enhanced the dispersion and finer distribution of NPs within the coating, resulting in improved wear resistance due to the confinement of irregularities. Applying ultrasonic waves up to 60 W improved the properties; however, a reduction in elemental levels was observed when the ultrasonic waves were increased to 120 W. This decrease in elemental levels can be attributed to the high-intensity ultrasonic waves, resulting in diminished wear resistance.

Petrogenesis of the pyroxenitic Moho transition zone in the Zedong ophiolite, Southeastern Tibet

Understanding the petrological and geochemical processes shaping the Moho transition zone (MTZ) is crucial for advancing our knowledge of thermal and chemical exchanges between the oceanic crust and the residual upper mantle. In this study, we systematically investigate the MTZ outcropped within the Zedong ophiolite, located in the eastern part of the Yarlung-Tsangpo Suture Zone (YTSZ), with the aim of at reconstructing the magmatic processes responsible for generating the petrological Moho. The Zedong MTZ comprises a sequence of dunite, wehrlite, pyroxenite, and gabbro, with frequent occurrences of clinopyroxene-rich lithologies. Cyclicity within the MTZ sequences is characterized by the recurrence of olivine-rich intervals and the presence of zig-zag patterns in both major and trace elements of clinopyroxenes. Zircon UPb dating on the Zedong gabbros supports the coeval formation of the Zedong ophiolite with other YTSZ ophiolites. Clinopyroxene in the Zedong MTZ follows a differentiation sequence characterized by an increase in contents of Al2O3 and TiO2, coupled with a decrease in Mg#. This differentiation sequence along with frequent occurrences of amphibole suggest the evolution of a primitive hydrous melt depleted in Al2O3, TiO2, and Na2O. The depleted NdHf isotopes and rare earth element patterns of the MTZ rocks indicate that their parental magmas originated from fluid-enhanced re-melting of a previously depleted mantle. Additionally, we proposed that the initiation of a new subduction zone results in the re-melting of the mantle peridotite, leading to the formation of primitive hydrous basaltic melts. The variable lithologies observed in the Zedong MTZ arise from fractional crystallization and repeated replenishment of hydrous melts.

Postmortem analysis of MgO–C bricks used in smelting furnace for fabricating TiC-bearing slag

The process of “high temperature carbonization and low temperature chlorination”, considered as one of the most promising technologies, can extract over 60% titanium from blast furnace slag containing TiO2 at a concentration of 20%–25%. The primary equipment for high temperature carbonization is an electric furnace lined with MgO–C bricks. In this study, post-mortem analysis was conducted to investigate the corrosion and failure mechanisms of MgO–C refractory bricks taken from different areas of a circular electric furnace after 1200 cycles of service. Through XRD, SEM-EDS, and thermodynamic calculation analysis, the reaction and corrosion mechanism between MgO–C bricks and the slag were analyzed. The results demonstrated that the gradual corrosion of the brick was primarily attributed to the alternating effects of carbon oxidation and MgO dissolution. Moreover, an increase in temperature led to a higher corrosion rate of the refractories. At temperatures exceeding 1560 °C, the pre-formed barrier layer composed of MgAl2O4 and MgTi2O4 melted into the slag. And as TiO2 content decreased and TiC content increased, there was a gradual decline in the erosive impact of the slag. Furthermore, the failure mechanisms of refractory bricks in different areas varied due to the distinctive structure of the electric furnace. The bricks at the slag line area were mainly destroyed by slag corrosion, oxidation and thermal shock spalling, which had the shortest service life.

Durable ceramic-reinforced fluoropolymer nanocomposite corrosion protective coatings

In this study, inorganic-organic coatings composed of titanium dioxide (TiO2) as the ceramic component and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as the polymer matrix, hybridized with nano-TiO2 particles, were developed for protecting mild steel (MS) from corrosion. Prior to TiO2 coating deposition, the MS substrates were pretreated with a bioinspired sub-layer of polydopamine to improve the surface coating adhesion, followed by uniform co-deposition of PVDF-HFP with varying concentrations of embedded nano-TiO2. The inclusion of nano-TiO2 further reinforces and densifies PVDF-HFP, providing added corrosion protection. The fabricated coatings were characterized by microscopy, spectroscopy, and diffraction technique, while the corrosion protection properties were evaluated by impedance, potentiodynamic polarization, salt spray, and cyclic corrosion tests. Results showed that both the PVDF-HFP matrix and TiO2 contents had substantial effects on the coatings’ thermal stability, hydrophobicity, and surface mechanical properties. The coatings also exhibited satisfactory corrosion resistance, with increased impedance modulus to roughly sixteen orders of magnitude for the TiO2-PVDF-HFP coating containing 0.5 g/L TiO2, relative to the untreated MS substrate. This result can be attributed to the low surface energy of PVDF-HFP, coupled with the dense structure and added physical barrier of nano-TiO2. Overall, these hybrid polymer/ceramic coatings are poised to help design other highly resilient and hydrophobic surface coatings with durable protection against corrosion.

Differences in bulk Fe content and density between type I and type II ordinary chondrite chondrules: Implications for parent body heterogeneities in oxidation state and O‐isotopic composition

AbstractType II chondrules have higher oxidation states than type I chondrules; in ordinary chondrites (OC), type II chondrules tend to be larger, richer in bulk Fe, and have higher densities than type I chondrules. Magnesian type IA chondrules tend to be richer in 16O than type II chondrules. Because the aerodynamic behavior of a particle is a function of the product of its size and density, type I and type II chondrules (or their precursors) were partly separated in the ordinary chondrite zone of the solar nebula prior to the accretion of OC parent asteroids. LL chondrites acquired a chondrule population with the highest type II/type I ratios, L chondrites acquired chondrules with an intermediate ratio, and H chondrites acquired chondrules with the lowest type II/type I ratios. This contributed to the observed differences among OC groups in oxidation state and O‐isotopic composition: in going from H to L to LL, mean oxidation state increases and mean Δ17O values increase. Higher oxidation is marked by increases in the FeO contents of olivine, low‐Ca pyroxene, chromite, and ilmenite; increases in the TiO2 content of chromite; and increases in the Co content of kamacite.

Compositional signatures of clinopyroxenes from the mafic rocks of the Nagaland ophiolite (NE India): Inferences for melting of diverse source regions in a transitional arc-type setting

The Nagaland-Manipur ophiolite belt (NMOB) represents remnants of the Neo-Tethyan Ocean that evolved during the accretion of the Indian and Myanmar lithospheric plates. We studied clinopyroxenes of cumulate gabbro and basalt rocks from the northern section of the belt to decode the mechanism that controlled their petrogenesis and geotectonic setting. Clinopyroxenes (augite-diopside) exhibit compositional zoning and significant variations in their major and trace element contents. Zoned clinopyroxene from a single volcanic rock sample (2d-3-6-11) show higher concentrations of TiO2 (1.44 to 5.13 wt%) and Al (0.128–0.359 apfu) and lower Si (1.658–1.889 apfu) compared to clinopyroxenes from the other mafic rocks. The mg# [100 × Mg/(Mg + Fe2+)] values of clinopyroxenes range between 60.1 and 85.7. The trace element contents and the chondrite-normalised REE patterns of clinopyroxenes imply diverse geochemical affinities of both depleted mantle typical of tholeiite rocks and a less depleted LREE-enriched melt for the Nagaland mafic rocks. Pressure and temperature of crystallisation were estimated using single clinopyroxene geothermobarometry and were found to vary between 1–8 kbar and 840–1179 °C, respectively. In discrimination diagrams, the zoned clinopyroxenes show an alkaline composition consistent with a within-plate environment. On the other hand, clinopyroxenes from the rest of the mafic samples show a sub-alkaline composition typical of magmas produced in arc-related settings. Our study indicates the existence of diverse magma sources in an island arc-to-back arc setting during the formation of magmatic rocks in the NMOB.

Novel photocatalysis-assisted mechanical polishing of laser cladding cobalt-based alloy using TiO2 nanoparticles

This paper presents a novel photocatalysis-assisted mechanical polishing method for cobalt-based alloy cladding layers using TiO2 nanoparticles. By leveraging the active oxygen species generated by the photocatalyst under illuminated conditions, surface oxidation reactions on cobalt-based alloys are initiated, thereby enhancing material removal efficiency. The underlying principles of photocatalytic oxidation are elucidated, particularly the promotion of oxidation by •OH when it interacts with the metal surface, leading to the formation of a CoO oxide film on the cladding layer surface and a subsequent reduction in surface hardness. An experimental platform was established, and research findings identified an etching time of 60 min and a TiO2 concentration of 10 wt% as optimal process parameters. Comparative analysis with pure mechanical polishing and chemical mechanical polishing revealed that photocatalysis-assisted mechanical polishing yielded superior surface roughness of 60 nm and a material removal rate of 63.8 μm/min.

Empirical correlation to analyze performance of shell and tube heat exchanger using TiO2 Nanofluid-DI water in solar water heater

Recent studies have examined the thermal stability and reliability of TiO2 nanofluid-based heat exchangers under long-term operation in solar water heating systems. This includes assessing nanoparticle sedimentation, agglomeration, and degradation over time, as well as their impact on heat transfer performance and system reliability. In this study heat transfer and fluid flow characteristics of TiO2-DI-H2O (deionized water) nanofluid used in a shell and tube exchanger with different baffle angles under turbulent regimes were numerically explored. The proposed setup was run with nanoparticle concentration of 0 %–0.2 % and Reynolds numbers (Re) from 5000 to 15,000. Baffle angles of 10°, 20°, and 30° were chosen for turbulence analysis. It was observed that nanoparticle concentration strongly impacted the thermophysical properties. The results indicated that adding modest concentrations of TiO2 to DI-H2O significantly improves heat transfer and the Nu. At the Re of 5000 and 30° baffles, the Nu was 58; however, at the Re of 15,000, the Nu value was 88. The improvement in heat transfer of 62.85 %, 70.64 %, and 75.06 % was recorded for baffle angles of 10°, 20°, and 30° respectively, Furthermore, a notable increase in friction factor of 13.6 % at Re 15,000 was observed. However, the ideal baffle angle for maximum thermal performance is 30°. Finally, with shell temperature, it was established that 30° baffle orientation could provide the best h and Nu values and improve the overall performance of the heat exchanger. The obtained Nu was also compared with the existing correlations of literature in the turbulent regime with the aid of nanoparticles and presented for case applications.

Effects of TiO2 on the mechanical and physical properties of Fe2O3-Doped Yttria-Stabilized Zirconia for electrolyte of Solid Oxide Fuel Cells

Yttria-Stabilized Zirconia (YSZ) based electrolytes of Solid Oxide Fuel Cell (SOFC) are widely used due to their higher ionic conductivity, stability, and availability. The present study focuses on improving the performance of YSZ-based electrolytes particularly by doping other particles into YSZ. TiO2 was doped into Fe2O3-8YSZ composite and the effects of TiO2 on the mechanical and physical properties of the composites were observed. The concentrations of TiO2 were varied by 0 wt%, 1 wt%, 3 wt%, and 5 wt% for different compositions of the composites. The samples were fabricated by the solid-state reaction method by pressing the powders at 250 MPa for 3 min and were sintered at 1250 °C for 4 h. The sintered samples were then undergone through characterization tests in terms of percentage of volume shrinkage, density, porosity, Diametral Tensile Strength (DTS), and microhardness. The highest values of volume shrinkage (34.83%), relative density (97.83%), DTS (36.58 MPa), hardness (965 HV), and the lowest porosity (2.17%) were found for 5 wt% TiO2 addition. Besides, the lowest values of volume shrinkage (28.44%), relative density (87.94%), DTS (3.24 MPa), microhardness (340 HV), and the highest porosity (12.06%) were found for Fe2O3-8YSZ composites without (0 wt%) TiO2 addition.

An antimicrobial acrylic polyurethane coating with TiO2-Ag hybrid nanoparticles

Abstract The purpose of this work is to fabricate the advanced organic antibacterial coating containing the strong photocatalytic nanomaterials. For this purpose, firstly the TiO2–Ag hybrid nanoparticles are synthesized by chemical reduction method. Then, the antibacterial coating based on acrylic polyol, polyisocyanate, and these TiO2–Ag hybrid nanoparticles has been prepared. Mechanical properties show that the optimal content of TiO2–Ag hybrid nanoparticles in the coating matrix is 2 wt%, with its abrasion resistance of 166.2 L/mil; impact strength of 195 kg cm; adhesion of size #1 and relative hardness of 0.78. In addition, FE-SEM analysis shows that the nanocomposite coating has a tight structure with homogeneous dispersion of TiO2–Ag nanoparticles in the polymer matrix. The paint film has good antibacterial activity and has great application prospects. Data from the antibacterial test indicates that in the presence of an acrylic polyurethane coating containing 2 wt% TiO2–Ag, the number of viable Escherichia coli decreased from 3.4 × 105 CFU/ml to 1.5 × 102 CFU/ml after 24 h of culture.

Influence of TiO2 Nanoparticles on Enhancing the Properties Activity of Organic Polymeric Materials for Industrial Applications

Novel composite (MC/TiO2) films consisting of titanium dioxide nanoparticles (TiO2NPs) and organic polymer methylcellulose (MC), were synthesized for applied in photocatalysis and industrial sectors. The preparation of the nanocomposites MC/TiO2 films were verified successfully by EDX technique, which demonstrated the uniform distribution of TiO2 in the MC. Moreover, in frequency of 20 Hz to 5.5 MHz, the dielectric properties of MC as a function of TiO2 concentration were determined. The conductivity improved from 5.8 × 10−8 S.cm−1 for MC to 3.8 × 10−6 S.cm−1 for the composite MC/TiO2, and the dielectric constant ε′ has risen from 87 for MC to 179 for the composite MC/TiO2. In addition, the energy density increases from 3.86 × 10−4 J m−3 for MC to 7.94 × 10−4 J m−3 for MC/TiO2, and the relaxation time τr dropped from 11.5 × 10−5 sec to 2.58 × 10−5. In summary, the data investigated that the dielectric characteristics of MC/TiO2 were modified for usage in different applications as wastewater treatment and energy storage devices.

Effect of Titanium Dioxide on Cure Characteristics and Physico Mechanical Properties of High-Temperature Vulcanizing Silicone Rubber Composites

Silicone rubber (SiR), a vital elastomer, is extensively used in producing various engineering and general products, owing to its distinctive properties. Despite the remarkable properties, SiR-based products require anti-microbial agents such as titanium dioxide, TiO2 to negate black mold issues. Still, adding this agent alters the composites' processability and physical and mechanical properties. This study examined the impact of adding different TiO2 content as fillers on silicone rubber composites' processability, physical properties, and mechanical properties. Raw materials of 20-hardness high-temperature-vulcanization (HTV) SiR- reinforced with various TiO2 contents at 0.0, 0.3, 0.6 and 1.2 wt% were prepared using a two-roll mill. The results indicated SiR composites reinforced with 0.3 wt% TiO2 exhibited the best performance with a tensile strength of 1.49 MPa, elongation at break of 340.87%, modulus 100% of 0.664 MPa, modulus 300% of 0.822 MPa, and modulus 500% of 0.954 MPa. This performance can be attributed to the efficient crosslink density and the effective interactions between the TiO2 and silicone rubber particles at this concentration. Structural and morphological analyses further corroborated the results. Consequently, it can be inferred that silicone rubber reinforced with 0.3 wt% titanium dioxide holds the potential for formulating silicone rubber compounds that necessitate anti-microbial properties.

Study of Chlorella vulgaris from Different Growth Phases as Biosensor for Detection of Titanium and Silver Nanoparticles in Water

The increased use of metallic nanoparticles has led to concern for environmental contamination and disruption in water quality. Therefore, effective screening of metallic nanoparticles is important for detecting metallic nanoparticles in aquatic environments. Biosensors offer several advantages, including high sensitivity to pollutants, short response time, energy efficiency, and low waste generation. In this study, a whole-cell biosensor was developed using microalga Chlorella vulgaris as a recognition element, and its fluorescence response was used as a measuring parameter for detecting the presence of titanium dioxide (TiO2) and silver (Ag) nanoparticles in water. The responses of C. vulgaris at the lag, exponential, and stationary phases to different concentrations of TiO2 and Ag nanoparticles were studied. The results showed that in TiO2 and Ag nanoparticles exposures, the highest fluorescence change (50-150%) was observed at the lag phase, whereas the lowest fluorescence change (40-75%) was observed at the stationary phase. A significant fluorescence change was observed in 15 min. The immobilized C. vulgaris under TiO2 and Ag nanoparticles exposures showed 30-180% higher fluorescence change than the negative control, indicating the potential of C. vulgaris as a biosensor for rapid detection of TiO2 and Ag nanoparticles in water. The mathematical modeling of the responses of C. vulgaris to TiO2 and Ag nanoparticles at 15 min of exposure with high R2 indicated that this biosensor is sensitive to the concentration tested (0.010–10.000 mg.L-1). Taken together, these results reveal that, for the first time, it is possible to detect TiO2 and Ag nanoparticles in water within a very short time using a microalgae-based biosensor. Moreover, no genetic engineering requirement makes this biosensor simple, economical, and free from the restriction on genetically modified microorganisms for environmental applications.

Electrodeposition of Zn/TiO2 coatings on Ti6Al4V produced by selective laser melting, the characterization and corrosion resistance

Recently, additive manufacturing techniques have begun to be implemented extensively in the production of implants. Ti6Al4V alloy is a material of choice for implants due to its low density and high biocompatibility. Recent research, however, has demonstrated that Ti6Al4V alloy emits long-term ions (such as Al and V) that are hazardous to health. Surface modifications, including coating, are therefore required for implants. The electrodeposition method was utilized to deposit Zn-doped TiO2 onto the surfaces of Ti6Al4V samples, which were manufactured via the selective laser melting method. The effects of processing time, amount of TiO2 addition, microstructure of anode materials, and resistance to wear and corrosion were investigated. The coating hardness and thickness increased with increasing processing time and TiO2 concentration. It has been observed that the addition of TiO2 to zinc anode coatings results in an increase in wear and a decrease in corrosion rate. It was noted that the specimens exhibiting the most significant wear also possessed the highest hardness value. The specimens were generated utilizing a graphite anode, underwent a 30-min processing time, and comprised 10 g l−1 of TiO2.

Atrazine degradation through a heterogeneous dual-effect process using Fe–TiO2-allophane catalysts under sunlight

This study investigated the novel application of Fe–TiO2-allophane catalysts with 6.0 % w/w of iron oxide and two TiO2 proportions (10 % and 30 % w/w) for degrading atrazine (ATZ) using the heterogeneous dual-effect (HDE) process under sunlight. Comparative analyses with Fe-allophane and TiO2-allophane catalysts were conducted in both photocatalysis (PC) and HDE processes. FTIR spectra reveal the unique hydrous feldspathoids structure of allophane, showing evidence of new bond formation between Si–O groups of allophane clays and iron hydroxyl species, as well as Si–O–Ti bonds that intensified with higher TiO2 content. The catalysts exhibited an anatase structure. In Fe–TiO2-allophane catalysts, iron oxide was incorporated through the substitution of Ti4+ by Fe3+ in the anatase crystal lattice and precipitation on the surface of allophane clays, forming small iron oxide particles. Allophane clays reduced the agglomeration and particle size of TiO2, resulting in an enhanced specific surface area and pore volume for all catalysts. Iron oxide incorporation decreased the band gap, broadening the photoresponse to visible light. In the PC process, TiO2-allophane achieves 90 % ATZ degradation, attributed to radical species from the UV component of sunlight. In the HDE process, Fe–TiO2-allophane catalysts exhibit synergistic effects, particularly with 30 % w/w TiO2, achieving 100 % ATZ degradation and 85 % COD removal, with shorter reaction time as TiO2 percentage increased. The HDE process was performed under less acidic conditions, achieving complete ATZ degradation after 6 h without iron leaching. Consequently, Fe–TiO2-allophane catalysts are proposed as a promising alternative for degrading emerging pollutants under environmentally friendly conditions.

Kinetic study of adsorption and photocatalytic degradation of methylene blue dye using TiO2 nanoparticles with activated carbon

Activated carbon (AC) exhibits limited adsorption capacity for pollutants. Conversely, titanium dioxide (TiO2) demonstrates excellent photocatalytic performance, making it a popular choice for pollutant removal. This study investigates the removal of methylene blue (MB) dye from wastewater using AC, TiO2@AC-2, and TiO2@AC-10 samples via adsorption and photocatalysis. The Energy Dispersive analysis of x-rays (EDAX) has confirmed the presence of Ti, C and O in the prepared samples without any impurities. All the diffraction peaks in x-ray diffractograms indicated the presence of pure anatase TiO2 (tetragonal phase) with no evidence of any other phase. Fourier transform infrared spectroscopy (FTIR) analysis identified a peak around 545 cm−1 in the TiO2@AC-2 sample, indicative of O-Ti-O stretching vibrations. This peak shifted to 602 cm−1 in the TiO2@AC-10 sample. Raman spectroscopy confirmed the presence of carbon (D and G bands) at 1310–1347 cm−1 and 1582–1597 cm−1. Additionally, characteristic Raman active bands for anatase TiO2 were observed at 154 cm−1 (Eg), 204 cm−1 (Eg), 398 cm−1 (B1g), 508 cm−1 (A1g), and 628 cm−1 (Eg). N2 adsorption–desorption isotherms revealed a mesoporous structure for all samples (AC, TiO2@AC-2, and TiO2@AC-10) with hysteresis loops, indicating pores ranging from 2 nm to 50 nm in diameter. Reflectance spectra of TiO2@AC-2 and TiO2@AC-10 displayed absorption edges at 368 nm and 385 nm, respectively, corresponding to a direct band gap of approximately 3.22 eV. Subsequently, these prepared samples were effectively employed for the removal of methylene blue (MB) dye from wastewater utilizing both adsorption and photocatalysis method. Under dark conditions, 20 mg L−1 doses of TiO2@AC-2 and TiO2@AC-10 resulted in 60% and 36% dye adsorption within 60 min respectively. In the presence of UV radiation, the degradation of dye was observed to be 74% and 95% by TiO2@AC-2 and TiO2@AC-10 respectively. This observation indicates that TiO2 nanoparticles along with AC leads to enhanced photocatalytic activity. The Langmuir–Hinshelwood model reveals lower rate constants for AC compared to the composite samples. This is likely because AC lacks inherent catalytic activity, requiring UV light to trigger adsorption. Conversely, TiO2@AC-10 exhibits the highest rate constants (K1 = 24.25 × 10−3 min−1 and K2 = 82.71 × 10−3 min−1), aligning with its higher TiO2 content confirmed by EDAX analysis. This suggests a significantly faster photocatalytic rate and superior degradation efficiency, even at a low sample concentration (20 mg L−1).