Oxidation Titanium Research Articles

Quantification of phenol degradation using hydrodynamic cavitation‐based packed bed reactor based on glass balls

AbstractThe current study presents a novel and effective cavitation technique for the degradation of phenol using a hydrodynamic cavitation‐based packed bed reactor (HCPBR). Several operational parameters, including fluid velocity, hydrogen peroxide (H2O2) generation (18.06 μM of H2O2 in 60 min), and initial phenol concentration, have been studied using a HCPBR. The effective parameters for phenol degradation were found to be a fluid velocity of 85.15 m/s and an initial phenol concentration of 20 ppm. It was also noted that the presence of a glass marble‐bed (15.35%) in the cavitation reactor exhibits a substantial effect on the degradation of phenol compared to the absence of a glass marble‐bed (2.91%). The investigation also examined the effect of combining hydrodynamic cavitation with chemical oxidation processes, specifically H2O2, persulfate (Na2S2O8 and K2S2O8), and titanium dioxide, on the extent of phenol degradation. Persulfate was shown to have a significant effect on phenol degradation at 1 g/L. To clarify if free radical attack is the driving force behind degradation, the impact of radical scavengers such as n‐butanol has also been examined. Toxicological assessments revealed that, for lentil meristematic cells, the therapy was quite cytotoxic, but it needs to be improved to eliminate its genotoxic side effects. Overall, the experiment clearly demonstrated the effectiveness of the HCPBR for phenol degradation.

Probing the Corrosion Rates of Novel Titanium Substrates in a Simulated PEM Fuel Cell Environment

Metallic bipolar plates are often used in proton exchange membrane fuel cells (PEMFCs) due to their facile manufacturing process, high electrical and thermal conductivity, and mechanical strength. [1] Titanium is particularly popular due to its corrosion-resistive properties which come from a naturally occurring passive oxide layer on its surface. However, the naturally occurring passive film cannot fully withstand the acidic environment of an operating PEMFC. And inherently, without this protective layer; corrosion will inevitably occur. [2] Thicker oxide layers can be formed on the surface by exposing the titanium to elevated temperatures in the presence of oxygenIn this study, the corrosion resistance of commercially pure titanium with thermally grown oxidation layers and titanium directly coated with a commercial sub-oxide coating was investigated. The corrosion resistance of the various samples was examined with potentiostatic and potentiodynamic tests in sulfuric acid solution at various temperatures to simulate PEMFC conditions. The samples were also subjected to a novel accelerated stress test to evaluate long term durability under fuel cell vehicle startup and shutdown conditions.

Hydrogen Peroxide Measurement Can Be Used to Monitor Plant Oxidative Stress Rapidly Using Modified Ferrous Oxidation Xylenol Orange and Titanium Sulfate Assay Correlation

Various methodologies, sensitivities, and types of interference affect the quantification of plant hydrogen peroxide (H2O2) concentration. Modified ferrous oxidation xylenol orange (eFOX) assay and titanium sulfate (Ti(SO4)2 assay are relatively accessible methods. However, their correlation is unknown, for example whether we can get the same results for different species in different environments. Leaf samples of Ambrosia trifida, Solidago altissima, Artemisia princeps, and Sicyos angulatus were collected from a riparian vegetation zone on sunny days. The H2O2 concentration in the plant leaves was evaluated in two groups. Nonfrozen leaf samples were prepared for analysis soon after arriving at the laboratory, and frozen leaf samples were stored at −80 °C for 25 days and prepared afterwards. The eFOX assay can measure even lower fluctuations in H2O2 concentration than the Ti(SO4)2 assay. A substantial correlation was observed between nonfrozen and frozen samples in the eFOX (r = 0.879, p < 0.001) and Ti(SO4)2 assays (r = 0.837, p < 0.001). Sample weight did not affect H2O2 quantification. Each species showed a substantial correlation between the eFOX and Ti(SO4)2 assays in nonfrozen conditions (Ambrosia trifida (r = 0.767, p < 0.001), Solidago altissima (r = 0.583, p < 0.001), Artemisia princeps (r = 0.672, p < 0.001), and Sicyos angulatus (r = 0.828, p < 0.001)). Therefore, both methods can be utilized easily and rapidly to quantify oxidative stress using H2O2.

An Experimental Anodized and Low-Pressure Oxygen Plasma-Treated Titanium Dental Implant Surface-Preliminary Report.

Chemical composition and physical parameters of the implant surface, such as roughness, regulate the cellular response leading to implant bone osseointegration. Possible implant surface modifications include anodization or the plasma electrolytic oxidation (PEO) treatment process that produces a thick and dense oxide coating superior to normal anodic oxidation. Experimental modifications with Plasma Electrolytic Oxidation (PEO) titanium and titanium alloy Ti6Al4V plates and PEO additionally treated with low-pressure oxygen plasma (PEO-S) were used in this study to evaluate their physical and chemical properties. Cytotoxicity of experimental titanium samples as well as cell adhesion to their surface were assessed using normal human dermal fibroblasts (NHDF) or L929 cell line. Moreover, the surface roughness, fractal dimension analysis, and texture analysis were calculated. Samples after surface treatment have substantially improved properties compared to the reference SLA (sandblasted and acid-etched) surface. The surface roughness (Sa) was 0.59-2.38 µm, and none of the tested surfaces had cytotoxic effect on NHDF and L929 cell lines. A greater cell growth of NHDF was observed on the tested PEO and PEO-S samples compared to reference SLA sample titanium.

Surface Modification of Titanium by Micro-Arc Oxidation in Promoting Schwann Cell Proliferation and Secretion of Neurotrophic Factors

Titanium and its alloys have been widely used in the field of oral implants over the past few decades. However, the effect of micro-arc oxidation modified titanium surface on Schwann cells has not been studied, which is of great significance for nerve regeneration around implants and improvement of osseoperception. In this study, the characterization of the titanium surface modified by micro-arc oxidation (MAO) was detected by scanning electron microscope (SEM), XPS and a contact angle measurement system. Schwann cells (SCs) were cultured on titanium surfaces of micro-arc oxidation (MAO) and pure titanium (Ti). At different time points, the morphology and adhesion of SCs on the titanium surfaces were observed by SEM. Cell proliferation activity was detected by the CCK-8 method. The expression levels of mRNA and proteins of nerve growth factor (NGF) and glial-derived neurotrophic factor (GDNF) were detected by RT-PCR, immunofluorescence and western blot. The results of this in vitro study revealed that micro-arc-oxidation-modified titanium surfaces promoted Schwann cell proliferation and secretion of neurotrophic factors compared with pure titanium. CCK-8 results showed that the number of Schwann cells on MAO surfaces was significantly higher than that of the Ti group on day 7. The mRNA expressions of Ngf and Gdnf were up-regulated in both groups from day 1 to day 7. On day 3 and day 7, the gene expression of Ngf in the MAO group was significantly higher than that of the Ti group. On day 7, the MAO group appeared significantly up-regulated in gene expression level of Gdnf. The results of western blot were consistent. Micro-arc oxidation modification provides an accurate and effective method for promoting nerve regeneration of titanium microtopography coatings, which have potential significance for promoting patients’ osseoperception ability in clinical practice.

Covalent-Bonding Oxidation Group and Titanium Cluster to Synthesize a Porous Crystalline Catalyst for Selective Photo-Oxidation Biomass Valorization.

The selective photo-oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is important due to its substitute-role in polyester-fabrication. Here, a titanium-cluster based metal-covalent organic framework nanosheet has been synthesized through the covalent-coupling between Ti6 -NH2 and benzotrithiophene tricarbaldehyde (BTT). The integration of them endows the nanosheet with a visible-light-adsorption region, effective electron-hole separation-efficiency and suitable photo-oxidation ability. Specifically, its photo-selectivity for HMF-to-FDCA can be >95 % with ≈100 % conversion, which is more than 2, 5, and 10 times higher than MOF-901 (43 %), Ti6 -NH2 (19 %) and under-darkness (9 %), respectively. Notably, an O2 -based mechanism is proposed and the vital roles of Ti6 -NH2 and BTT are verified by DFT calculations. This work might facilitate the exploration of porous-crystalline-catalysts for selective biomass-valorization.

Covalent‐Bonding Oxidation Group and Titanium Cluster to Synthesize a Porous Crystalline Catalyst for Selective Photo‐Oxidation Biomass Valorization

AbstractThe selective photo‐oxidation of biomass‐derived 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) is important due to its substitute‐role in polyester‐fabrication. Here, a titanium‐cluster based metal‐covalent organic framework nanosheet has been synthesized through the covalent‐coupling between Ti6‐NH2 and benzotrithiophene tricarbaldehyde (BTT). The integration of them endows the nanosheet with a visible‐light‐adsorption region, effective electron‐hole separation‐efficiency and suitable photo‐oxidation ability. Specifically, its photo‐selectivity for HMF‐to‐FDCA can be >95 % with ≈100 % conversion, which is more than 2, 5, and 10 times higher than MOF‐901 (43 %), Ti6‐NH2 (19 %) and under‐darkness (9 %), respectively. Notably, an O2‐based mechanism is proposed and the vital roles of Ti6‐NH2 and BTT are verified by DFT calculations. This work might facilitate the exploration of porous‐crystalline‐catalysts for selective biomass‐valorization.

Local anodic oxidation of silicon for create crossbar architecture

Paper present possibility of creation a neuromatrix in the form crossbar architecture on a silicon substrate is shown. Crossbar architecture in the form of a set of nanosized conductors, between which there is a layer of titanium oxide, capable of changing its conductivity under the action of the applied voltage, it is proposed to form using the method of local anodic oxidation. The results is present of the study technological parameters of the method of local anodic oxidation silicon and titanium for the implementation of the elements of this neuromatrix in the form of a memristor structures. Keywords: Silicon, titanium, local anodic oxidation, neuromatrix, crossbar.

Локальное анодное окисление кремния для создания кроссбар-архитектуры

Paper present possibility of creation a neuromatrix in the form crossbar architecture on a silicon substrate is shown. Crossbar architecture in the form of a set of nanosized conductors, between which there is a layer of titanium oxide, capable of changing its conductivity under the action of the applied voltage, it is proposed to form using the method of local anodic oxidation. The results is present of the study technological parameters of the method of local anodic oxidation silicon and titanium for the implementation of the elements of this neuromatrix in the form of a memristor structures.

Effect of Novel Micro-Arc Oxidation Implant Material on Preventing Peri-Implantitis

Dental implants occasionally fail for many reasons, especially peri-implantitis. The adhesion of bacteria to the surface of titanium is the initial factor in peri-implantitis. Therefore, the aim of this study was to assess the effect of a novel micro-arc oxidation (MAO) titanium on bacteria inhibition and regulation through periodontitis, and on a healthy saliva-derived biofilm, in vitro. MAO, sandblasting and acid etching (SLA), machined titanium and plasma-sprayed hydroxyapatite (HA) were selected for further study. The metabolic activity and biomass accumulation were tested using MTT (3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) and crystal violet assay after 24 h of anaerobic incubation. The structure was determined by scanning electron microscopy (SEM) and live/dead staining. Moreover, 16S rDNA sequencing was used to assess the microbial community. The results showed that biofilms on MAO were thinner compared to HA and SLA. In the periodontitis group, the biofilm accumulation and metabolic activity reached the highest levels in the HA group (p < 0.05); MAO titanium had the smallest biofilm accumulation and higher live/dead ratio; and the relative abundance of Lactobacillus in the SLA, HA and MAO groups increased significantly compared to the machined group (p < 0.05). In the healthy group, the relative abundance of Lactobacillus in the MAO group increased significantly compared to the other three groups (p < 0.05); the amount and metabolism activity of bacteria in the MAO group was lower (p < 0.05); MAO titanium had the least biofilm accumulation and a higher live/dead ratio. In conclusion, the novel MAO titanium had the ability to combat peri-implantitis by inhibiting the biofilm and regulating the microbial ecosystem to healthier conditions.

Bonding Evaluation Between Nanotube by Anodic Oxidation and Machined Dental Titanium Implant in Beagle Dog.

This study is to evaluate the bonding test between nanotube surface and machined dental titanium implant during the clinical procedure in beagle dog. A total of 24 screw-shaped implants (4 mm in diameter and 8.5 mm in length) were used. The implants were classified into 2 groups (n = 12): machined surface (M group) and nano surface which is nanotube formation on the machined surface (MA group). Anodic oxidation was performed at a 20 V for 10 min with 1 M H₃PO₄ and 1.5 wt% HF solutions. The implant were installed on beagle dog's humerus. After 4 and 12 weeks later, the beagle dog is sacrificed and the implant were removed with torque force. The removed implant was evaluated by SEM and EDX to observe the implant surface and nanotube's deformation. By investigating removed implant surfaces using SEM and EDX, M group was partially covered with bone, and MA groups were completely covered with bone. Nanotube was not shown any deformity. It indicated that nanotube showed good bonding stability with dental titanium implant.

Analysis of influence of ultra-hydrophilicity of oxidation titanium surface on blood compatibility based on density functional theory

Based on the density functional theory, it adopts the first-principles method to calculate the ultra-hydrophilicity of oxidation titanium surface under different oxygen vacancy concentrations. The calculation results show that under the practically feasible oxygen vacancy concentration range, with the increase of the oxygen vacancy concentration, the ultra-hydrophilicity of oxidation titanium surface is increased, and the semiconductor type of the oxidation titanium is transformed from p type to n type. When the oxidation titanium surface is in contact with blood, the n-type semiconductor and the features of the electron state occupying the bottom of conduction band of the oxidation titanium surface can suppress the transfer of charge from the fibrinogen in the blood to the oxidation titanium surface so to suppress the aggregation and activation of blood platelet, thus improve the ultra-hydrophilicity of oxidation titanium surface on blood compatibility.

Analysis of influence of ultra-hydrophilicity of oxidation titanium surface on blood compatibility based on density functional theory

Based on the density functional theory, it adopts the first-principles method to calculate the ultra-hydrophilicity of oxidation titanium surface under different oxygen vacancy concentrations. The calculation results show that under the practically feasible oxygen vacancy concentration range, with the increase of the oxygen vacancy concentration, the ultra-hydrophilicity of oxidation titanium surface is increased, and the semiconductor type of the oxidation titanium is transformed from p type to n type. When the oxidation titanium surface is in contact with blood, the n-type semiconductor and the features of the electron state occupying the bottom of conduction band of the oxidation titanium surface can suppress the transfer of charge from the fibrinogen in the blood to the oxidation titanium surface so to suppress the aggregation and activation of blood platelet, thus improve the ultra-hydrophilicity of oxidation titanium surface on blood compatibility.

Application of EDXRF in Detection of Impurity Elements in Anodic Oxide Layer of Surgical Implants

This paper established a qualitative and semi-quantitative analysis detection method of the micro-arc oxidation titanium and titanium alloy layer of Na, Si, P, S and other impurity elements by X-ray fluorescence. At the same time, from the angle of technological process, we analyzed the impurity element types and sources, and verify the reliability of this method. The locking plates superficial layer contained P element, the average was 1.01%. The occipital plate superficial layer contained Si element, the average was 1.39%. The advantages of this detection method were convenient and fast, and the sample without pretreatment and so forth. So this detection method was the ideal method of qualitative and semi-quantitative analysis to the micro-arc oxidation of surgical implants.

Photocatalytic efficiency of Fe2O3/TiO2 for the degradation of typical dyes in textile industries: Effects of calcination temperature and UV-assisted thermal synthesis

The inadequate management practices in industrial textile effluents have a considerable negative impact on the environment and human health due to the indiscriminate release of dyes. Photocatalysis is one of the diverse advance oxidation processes (AOPs) and titanium dioxide (TiO2) is recognized for its high oxidation and reduction power. A composite photocatalyst of Fe2O3/TiO2 is synthesized using different mass ratios of Fe:TiO2 to improve its photoactivity. The composite photocatalyst is calcined at 300–900 °C. Their photocatalytic activity for the degradation of Congo red (CR) and methyl orange (MO) is investigated by total organic carbon (TOC) analysis. The formation and characterization of the as-prepared composite are studied by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The effect of calcination temperature on the composite Fe2O3/TiO2 photocatalyst is investigated using Fourier transform infrared spectroscopy (FTIR). The photocatalytic activity and the phase conversion are studied by X-ray diffraction (XRD). The specific surface area of photocatalysts at different calcination temperatures is investigated based on Brunauer-Emmett-Teller (BET) surface area analysis. Results show that at an optimum calcination temperature of 300 °C for the photocatalyst preparation, the specific surface area is maximum and the photocatalyst has the highest photoactivity. Thus, the degradation of organic materials reaches 62.0% for MO and 46.8% for CR in the presence of Fe2O3/TiO2 (0.01 w:w Fe:TiO2) calcined at 300 °C with the highest specific surface area (98.73 m2/g). The transformation of TiO2 from anatase to rutile is facilitated by high temperature and high concentration of iron while high crystallization and particle size increase occur. An optimum calcination temperature of 300 °C is found at which the degradation of typical dyes in textile industries is maximum.

The Effects of Different Wavelength UV Photofunctionalization on Micro-Arc Oxidized Titanium

Many challenges exist in improving early osseointegration, one of the most critical factors in the long-term clinical success of dental implants. Recently, ultraviolet (UV) light-mediated photofunctionalization of titanium as a new potential surface treatment has aroused great interest. This study examines the bioactivity of titanium surfaces treated with UV light of different wavelengths and the underlying associated mechanism. Micro-arc oxidation (MAO) titanium samples were pretreated with UVA light (peak wavelength of 360 nm) or UVC light (peak wavelength of 250 nm) for up to 24 h. UVC treatment promoted the attachment, spread, proliferation and differentiation of MG-63 osteoblast-like cells on the titanium surface, as well as the capacity for apatite formation in simulated body fluid (SBF). These biological influences were not observed after UVA treatment, apart from a weaker effect on apatite formation. The enhanced bioactivity was substantially correlated with the amount of Ti-OH groups, which play an important role in improving the hydrophilicity, along with the removal of hydrocarbons on the titanium surface. Our results showed that both UVA and UVC irradiation altered the chemical properties of the titanium surface without sacrificing its excellent physical characteristics, suggesting that this technology has extensive potential applications and merits further investigation.

Construct Scaffold-like delivery system with poly (lactic-co-glycolic) microspheres on micro-arc oxidation titanium

In this paper, we present the first report about constructing a scaffold-like delivery system with poly (lactic-co-glycolic) (PLGA) microspheres on micro-arc oxidation titanium (MAO-Ti). The results show that this system could be stable on the porous MAO-Ti surface up for 6 weeks. Not only the system could control the release of model protein BSA, but also the MAO film could regulate the pH value of the solution which would decrease by the degradation of PLGA microspheres. In addition, compared to MAO-Ti, this system loaded with BSA could improve the proliferation of HBMSCs after 3 or 7 days culture.

Nanoporous anodic oxidation titanium enhances cell proliferation and differentiation of immortalized mouse embryonic cells

Biological integration of dental implants into the surrounding tissue determines clinical success and the attraction of bone cells. Titanium and its alloys are widely used biomaterials with high mechanical strength and excellent biocompatibility; nanotopographies are currently under investigation for efficiency in promoting cell functions. The purpose of this study was to carry out nanoporous anodic oxidation (NAO) surface treatment on titanium and to observe the responses of immortalized mouse embryonic (ME) cells. The titanium surface was modified in two ways; by NAO via hydrofluoric acid and by microporous anodic oxidation (MAO). The ME cells were solely obtained from mesenchymal mouse (embryonic day 14.5) molar tissue (tooth germ). Field emission scanning electron microscopy was used to visualize the titanium surface morphology as well as the attachment and morphological features of the ME cells. Cytotoxicity, cell proliferation, and alkaline phosphatase activity were assayed as well. The nano- and microporous structures of the modified titanium surfaces were well formed, with diameters of 100nm and 1–3μm, respectively. ME cells were well attached to the NAO and MAO treated surfaces, resulting in no cytotoxicity to ME cells. Cell proliferation was significantly higher for the cells at the NAO treated surface than cells at the MAO treated surface. Alkaline phosphatase activity on the NAO treated surface increased from 1 to 3weeks. Hence it was concluded that NAO treated surfaces provide an attractive substrate for ME cell adhesion, proliferation, and differentiation, and may serve as useful materials for the construction of dental implants.

Effects of irradiation on osteoblast‐like cells on different titanium surfaces in vitro

The aim of this study was to investigate the effects of irradiation on adhesion ability, proliferation, and differentiation of MC3T3-E1 cells on microarc oxidation (MAO) titanium surfaces and polished titanium (PT) surfaces. MC3T3-E1 cells were exposed to a single dose at 2, 4, 6, 8, or 10 Gy using a (60) Co source, with tissue culture polystyrene plates chosen as controls. On all surfaces, irradiation resulted in a dose-dependent decrease in cellular proliferation. At 4 Gy dose, the cell proliferation of cells decreased by 17.8% on MAO and 18.6% on PT surfaces, respectively, compared with nonirradiated controls. Cells exposed to 8 Gy dose showed significant inhibition in collagen secretion and osteogenesis-related genes expression (OSX, COL-Iα1, and OCN). In contrast, irradiation increased cell adhesion to three surfaces dose dependently. It was also demonstrated that cells on MAO surface showed higher adhesion and collagen secretion than on PT surface at different radiation doses. This study revealed the effects of irradiation on osteoblasts in vitro on two titanium surfaces. MAO surface could be used in dental implants in irradiated bone due to enhanced adhesion ability and collagen secretion in osteoblasts.

Mineralized and osteoid tissue from dental pulp stem cells on micro-arc oxidation titanium in vitro

The presence of insufficient bone volume affects the implant healing and success. The aim of this study was to evaluate osteogenic capacity of dental pulp stem cells (DPSCs) on micro-arc oxidation (MAO) titanium surface. DPSCs were challenged at MAO and smooth titanium surface separately for different durations, and the bone marrow mesenchymal stem cells (BMSCs) served as the positive controls. The osteogenic capacity of DPSCs on MAO titanium surface was assessed by using scanning electron microscopy, energy dispersive spectroscopy, biochemical tests and real-time quantitative PCR. Data showed that DPSCs differentiated into osteoblasts and expressed bone morphogenetic genes on MAO titanium surface. The results of this study revealed that DPSCs had good potential to generate mineralized tissue on MAO titanium plates. The differential potential of DPSCs may be regulated by MAO titanium surface. The osteogenesis potential of DPSCs on the MAO titanium was similar with BMSCs.