Anodization Method Research Articles

Lateral Spacing of TiO2 Nanotube Coatings Modulates In Vivo Early New Bone Formation

Due to the bio-inert nature of titanium (Ti) and subsequent accompanying chronic inflammatory response, an implant’s stability and function can be significantly affected, which is why various surface modifications have been employed, including the deposition of titanium oxide (TiO2) nanotubes (TNTs) onto the native surface through the anodic oxidation method. While the influence of nanotube diameter on cell behaviour and osteogenesis is very well documented, information regarding the effects of nanotube lateral spacing on the in vivo new bone formation process is insufficient and hard to find. Considering this, the present study’s aim was to evaluate the mechanical properties and the osteogenic ability of two types of TNTs-based pins with different lateral spacing, e.g., 25 nm (TNTs) and 92 nm (spTNTs). The mechanical properties of the TNT-coated implants were characterised from a morphological point of view (tube diameter, spacing, and tube length) using scanning electron microscopy (SEM). In addition, the chemical composition of the implants was evaluated using X-ray photoelectron spectroscopy, while surface roughness and topography were characterised using atomic force microscopy (AFM). Finally, the implants’ hardness and elastic modulus were investigated using nanoindentation measurements. The in vivo new bone formation was histologically evaluated (haematoxylin and eosin—HE staining) at 6 and 30 days post-implantation in a rat model. Mechanical characterisation revealed that the two morphologies presented a similar chemical composition and mechanical strength, but, in terms of surface roughness, the spTNTs exhibited a higher average roughness. The microscopic examination at 1 month post-implantation revealed that spTNTs pins (57.21 ± 34.93) were capable of promoting early new bone tissue formation to a greater extent than the TNTs-coated implants (24.37 ± 6.5), with a difference in the average thickness of the newly formed bone tissue of ~32.84 µm, thus highlighting the importance of this parameter when designing future dental/orthopaedic implants.

Review on TiO2 nanotubes in dye-sensitized solar cells: electrochemical anodization and hydrothermal method

Review on TiO2 nanotubes in dye-sensitized solar cells: electrochemical anodization and hydrothermal method

Enhancing Titanium Dioxide Nanotube Array Stability on Dental Implants through Laser Lithography-Assisted Microline Patterning.

Titanium dioxide nanotube arrays (TNTs) generated in situ on the surface of dental implants have been shown to enhance bone integration for load-bearing support while managing load distribution and energy dissipation to prevent bone resorption from overload. However, their inadequate stability limits the clinical use of conventional TNTs. This study introduces an innovative approach to improve the mechanical stability of TNTs while maintaining their bone-integration efficiency. The method involved creating microline patterns on TNTs (L-TNTs), where the TNTs were embedded within grooves for enhanced protection. This was achieved through a combination of laser lithography-assisted microline patterning and anodization. Incorporation of microline patterns significantly increased the mechanical stability of the TNTs. This improvement was evidenced by multiple tests: peeling tests demonstrated the maximum adhesive strength of the L-TNTs increased by at least 50%; friction-wear tests revealed narrower, shallower abrasion patterns and lower average friction coefficients; and ex vivo screw implant insertion and removal tests showed post-insertion, the nanotube structures in the TNTs peeled, whereas those in the L-TNTs remained intact. The L-TNTs also maintained their efficacy in promoting bone integration both in vitro and in vivo, establishing a robust platform for multifunctional implant investigation and advancing the practical application of TNTs. STATEMENT OF SIGNIFICANCE: This study presents a novel laser lithography-assisted micropatterning and anodization method for creating micro-lined titanium dioxide nanotube arrays (L-TNTs) on dental implants. Compared to conventional TNTs, L-TNTs enhanced adhesive strength and wear resistance while maintaining efficacy in promoting bone integration. This method enhances the mechanical stability of TNTs, facilitating its practical application in multifunctional dental implants.

Study on Differential Pulse Anodic Stripping Voltammetry Method for Simultaneous Determination of Trace amount of Zn, Cd, Pb, Cu in some Cough Syrups in Vietnam

The optimal measurement parameters of differential pulse anodic stripping voltammetry method (DP-ASV) to simultaneously determine the trace amount of the four elements Zn, Cd, Pb, Cu have been studied, including the sweep rate, pulse amplitude, drop size of mercury, initial purge, equilibration time. The analytical procedure was applied to determine Zn, Cd, Pb, Cu in 12 cough syrup samples in Viet Nam, including 6 functional food samples and 6 medicinal samples. The quantitative echnique used was standard addition and the applicability of quantitative elements in self - made samples was studied. Cough syrup analysis samples were digested using the wet ashing method in microwave oven. Research results show that there are no regular differences in elements content between medicinal cough syrup samples and functional food samples, except for functional food samples TP08 which has Pb content and the syrup medicine sample TH03 which has Cu content many times higher than other types. However, the content of the studied elements is within the allowable limits according to curent regulations (QCVN 8-2:2011/BYT; 46/2007/QĐ-BYT, WHO). The method has low detection limits and limit of quantification with ppb level, the relative standard deviations (% RSD) of repeated measurements are less than 3%, and recovery reflects the accuracy of the analytical method for elements ranging from 61.0 % to 87.5 %, which meets AOAC requirements for trace.

Cathode-mediated electrochemical conversion of phenol to benzoquinone in wastewater: High yield rate and low energy consumption.

Selective conversion of organic pollutants in wastewater into value-added chemicals is a promising strategy for sustainable water management. Electrochemical processes offer attractive features of precise control over reaction pathway to achieve desired products, however, the traditional anode-mediated processes still face challenges of over-oxidation by the inevitably formed of hydroxyl radical (HO•). Herein, we proposed a new cathode-mediated approach for selective conversion of phenol to p-benzoquinone (p-BQ) through peroxymonosulfate (PMS) activation. A core-shell layered mesoporous spherical iron-based carbon catalyst (denoted Fe/C-MS) was rationally designed to initiate the reactions, where the first shell layer composed of mesoporous carbon provided a confined environment to enrich PMS and phenols, and the electronic configuration of encapsulated Fe species favored the formation of high-valent ion-oxo species (FeIV=O) during PMS activation. Notably, the electrochemical process with Fe/C-MS and PMS (denoted Fe/C-MS-E/PMS) achieved a high yield of p-BQ at 80.2 % and a selectivity of 93.7 % within 5 min, resulting in an ultra-low energy consumption (0.07 KWh/mol phenol). The p-BQ production rate reached an impressive value of 1002.5 %/h, 30-500 times higher than the traditional chemical and anodic oxidation methods. The applicability of this cathode-mediated process was further validated by its successful treatment of real coking wastewater, underscoring the potential as a sustainable strategy for selective conversion of phenol to desired products with high yield and low energy consumption. All the findings available in this study drive us to image that the long-neglected cathode-mediated process, if rationally designed, may serve as an attractive strategy for more sustainable resource recovery during wastewater treatment.

Constructing AgO/Ag2O Electrocatalysts with Highly Exposed and Tightly Contacted Active Facets for Efficient Oxygen Evolution.

The development of efficient electrocatalysts for the oxygen evolution reaction (OER) and the elucidation of their underlying mechanisms are crucial for overcoming the low efficiency of hydrogen production through the electrolysis of water. Utilizing the electrochemical anodic oxidation method, a series of silver-based electrocatalysts (Ag-x, where x signifies the applied direct current (DC) voltage, x = 0, 5, 10, 15) were prepared employing metallic silver wire as the anode under DC voltages. The resulting silver-based electrodes have been oxidized and reconstructed, yielding AgO/Ag2O composite on the surface. Notably, the Ag-10 electrode exhibited the lowest overpotential (399 mV at 50 mA cm-2 and 456 mV at 100 mA cm-2), along with good stability. The superior OER performance of Ag-10 is not only attributed to the high exposure and tight interface of the AgO (-111) and Ag2O (111) crystal phases, as well as the higher prevalence of Ag-O-O-Ag species on its surface, but also its larger electrochemical active surface area (ECSA). This work provides insight for the synthesis of metal oxide-based electrocatalysts and understanding the electrocatalytic mechanism.

Vanadium-doped nanoporous structure on stainless steel substrate for high-performance flexible supercapacitor

Ferric oxide nanopores on stainless steel substrates offer a promising cathode structure for flexible supercapacitors, but their capacitance and cycling stability remain insufficient for practical use. In this study, we develop vanadium-doped nanoporous structures on stainless steel foil using a simple, cost-effective in-situ anodic oxidation method, optimizing the doping concentration. The resulting electrode exhibits a specific capacitance of 320.9 mF cm⁻2 at a current density of 1 mA cm⁻2, a 3.17-fold increase over the undoped counterpart, with 88.4 % capacitance retention after 8000 cycles. To demonstrate practical viability, we assemble a flexible hybrid supercapacitor by pairing the vanadium-doped cathode with a typical activated carbon-coated carbon cloth anode. The device exhibits a wide operating potential window of 1.8 V, a high energy density of 58.83 mWh·cm⁻³, and a power density of 0.5 W cm⁻³, alongside robust bending tolerance. The enhanced performance is attributed to an increased number of redox reaction sites and reduced internal resistance, as confirmed through both experimental and theoretical analysis. These findings highlight the potential of vanadium-doped nanoporous structures for use in high-performance, flexible, and cost-effective supercapacitors.

Effect of Chemical Polishing on the Formation of TiO2 Nanotube Arrays Using Ti Mesh as a Raw Material.

As a unique form of TiO2, TiO2 nanotube arrays (TiO2NTAs) have been widely used. TiO2NTAs are usually prepared by Ti foil, with little research reporting its preparation by Ti mesh. In this paper, TiO2NTAs are prepared on a Ti mesh surface via an anodic oxidation method in the F-containing electrolyte. The optimal parameters for the synthesis of TiO2NTAs are as follows: the solvent is ethylene glycol and water; the electrolyte is NH4F (0.175 mol/L); the voltage is 20 V; and the anodic oxidation time is 40 min without chemical polishing. However, there is a strange phenomenon where the nanotube arrays grow only at the intersection of Ti wires, which may be caused by chemical polishing, and the other areas, where TiO2NTAs cannot be observed on the surface of Ti mesh, are covered by a dense TiO2 film. New impurities (the hydrate of TiO2 or other products) introduced by chemical polishing and attaching to the surface of the Ti mesh reduce the current of anodic oxidation and further inhibit the growth of TiO2 nanotubes. Hence, under laboratory conditions, for commercially well-preserved Ti mesh, there is no necessity for chemical polishing. The formation of TiO2NTAs includes growth and crystallization processes. For the growth process, F- ions corrode the dense TiO2 film on the surface of Ti mesh to form soluble complexes ([TiF6]2-), and the tiny pores remain on the surface of Ti mesh. Given the basic photoelectrochemical measurements, TiO2NTAs without chemical polishing have better properties.

Enhancing the heterointerface stability of Al2O3/Ba0.5Sr0.5TiO3/Al2O3 composite thin films by adaptive anodizing method under high electric field

Enhancing the heterointerface stability of Al2O3/Ba0.5Sr0.5TiO3/Al2O3 composite thin films by adaptive anodizing method under high electric field

Fabrication of Patterned TiO2 Nanotube Layers Utilizing 3D Printer Platform and Their Electrochromic Properties

An anodization method can easily fabricate nanostructured oxide layers by controlling electrochemical parameters such as the types of electrolyte solutions, the electrolyte composition, applied voltage/current, temperature and pH. In the anodization process, it is common to form an oxide on the surface of a metal substrate with an area of several to several hundred cm2. However, several approaches have been attempted to form oxide layers on a local area or manufacture a certain oxide layer pattern using the anodization process. For this purpose, partial oxidation can be achieved through the masks and patterned metal substrates can be employed for local anodization. However, these methods are disadvantageous in process-complexity and time-consumption. Therefore, this study realizes complicated patterns composed of anodized TiO2 nanostructures using a 3D printer and apply them to the electrochromic displays. A commercial 3D printer was modified to enable a direct anodization and TiO2 nanotube was anodized on the Ti substrate with the desired pattern designed by a digital code (G-code). High speed anodization was performed at a speed of 1 mm/s. Furthermore, the surface of the patterned TiO2 nanotube was modified by adsorption of the viologen molecules and the electrochromic properties of the viologen-anchored TiO2 (V-TiO2) nanotube layers were investigated.

Mn Oxide / IrO2 / Ti Anodes Prepared By Calcination for Oxygen Evolution in Seawater Electrolysis

INTRODUCTIONIn the future, hydrogen production will be performed by direct electrolysis of seawater. However, every time hydrogen is produced, it is necessary to avoid generating chlorine because it has a negative impact on the ecosystem. We have been developing an oxygen evolution anode for seawater electrolysis that produces only oxygen without chlorine. It has been found that anodically deposited g-MnO2-type Mn1-xMoxSnyO2+xanodes showed the oxygen evolution efficiency for more than 4000 hours in the electrolysis of 0.5 M NaCl [1]. The anodic deposition method has required many steps and further cleaning of the electrolytic diaphragm. For these reasons, in order to commercialize oxygen evolution anodes for seawater electrolysis, it is essential to establish a simple manufacturing method. We are considering fabricating Mn oxide as an active material on an IrO2 intermediate layer formed on a titanium substrate using calcination method.In this study, Mn oxide electrodes were fabricated by coating various concentrations of manganese nitrate butanol solutions on the IrO2intermediate layer and at various calcination temperatures. We have investigated the crystal structure and Mn oxide weight that would have the highest activity for oxygen evolution efficiency.EXPERIMENTALTitanium metal substrates were immersed to roughen enhancing the anchor effect of the substrate on the electrocatalyst layer in concentrated H2SO4. IrO2 intermediate layer was formed by coating on one side of the titanium substrate in 0.26 M Chloroiridic acid with a brush, dried at 363 K for 10 min in air. The other side was coated in the same procedure and dried. And then these substrates was calcined at 723 K for 10 min in air. This procedure was repeated three times but the final calcination of the specimen was continued for 60 min at 723 K in air for calcination. Mn oxide electrocatalyst for oxygen evolution was formed by coating on the IrO2 / Ti in 0.073～0.52 M Mn(NO3)2 butanolsolution with a brush and drying at 353 K for 90 min in the same way as when forming the IrO2 intermediate layer. Calcination was performed at 473, 573, and 723 K. Impurities formed without becoming manganese oxides were electrolytically cleaned in 0.5 M NaCl until no dissolution of the impurities was observed.The performance of the electrode was examined by electrolysis of 0.5 M NaCl solution at 1000Am-2. The oxygen evolution efficiency was estimated by the difference between the total charge passed during electrolysis and the formation charge of chlorine analyzed by iodometric titration. Polarization curves were measured galvanostatically. Correction for IR drop was made with the electrochemical impedance spectroscopy (EIS) method.The characterization of the electrode was carried out by XRD and EPMA.RESULTS AND DISCUSSIONXRD diffraction clarified that Mn₂O₃ were consisted at 723 K, Ramsdellite-type MnO₂ at 673 K, and IrO2 at 573 K.Figure 1 shows the relationship between Mn oxide weight and oxygen evolution efficiency. The oxygen evolution efficiency of the anode consisted of only IrO2 was about 8%. It found that the oxygen evolution efficiency was different due to the difference in calcination temperature, that is, the difference in crystal structure to Mn oxide weight of about 2.5 mgcm-2. The oxygen evolution efficiency of the anode with Ramsdellite-type MnO₂ formed at 573 K was about 57 % at 1.8 mgcm-2. The oxygen evolution efficiency of anodes formed at 473 and 723 K with the equivalent weight was about 52 and 32 % respectively. Previous research has shown that anodes containing the γ-MnO2 formed by anodic deposition have high catalytic activity for oxygen evolution [2]. The γ-MnO2 contains stacking faults in which β-MnO2 is mixed into the ramsdellite-MnO2[3]. The electrode with 4.5 mgcm-2 of Mn₂O₃ at 723 K shows the maximum oxygen generation efficiency, which is about 83%.A future challenge is to add substances such as molybdenum as additional elements to obtain higher oxygen evolution efficiency. In conventional electrode fabrication using anodic deposition, the addition of molybdenum significantly has improved oxygen generation efficiency.REFERENSE[1]Z. Kato, J. Bhattarai , N. Kumagai, K. Izumiya, and K. Hashimoto, Applied. Surface. Science. 257 (2011) 8230.[2] A. A. El-Moneim, N. Kumagai, K. Asami, and K. Hashimoto , Materials Transactions, Vol. 46, No. 2 (2005) pp. 309[3] Jian-Bao LI, K. Koumoto and H. Yanagida, Journal of the Ceramic Society of Japan, 96 [1] (1988)74 Figure 1

Fabrication of Tubular Alumina through-Hole Membranes by Anodization of Al Wires

Membrane filters with uniformly sized pores have attracted considerable attention because they are useful for filtering a variety of particulates. Among them, anodic porous alumina, obtained by the anodization of Al in an electrolyte, has been studied as a membrane filter for microfiltration because it can form a nanohole array structure with regularly arranged pores of uniform size. We previously reported that a two-layer anodization method using concentrated sulfuric acid can form highly ordered alumina through-hole membranes with high throughput [1]. Using this method, it was possible to form not only flat membrane filters but also tubular membrane filters [2]. Tubular alumina membrane filters have potential applications in filter modules for space savings and efficient microfiltration. To achieve efficient filtration in filter modules consisting of tubular membrane filters, it is necessary to increase the density of the filter packed in the module, which requires the fabrication of tubular filters with small diameters. However, it is difficult to form tubular alumina membrane filters thinner than 1 cm in diameter using a previously reported method. In this report, we describe the results of a new method based on a two-layer anodization process using concentrated sulfuric acid to form tubular membrane filters with millimeter diameters. Electropolished Al wire was anodized in 0.3 M oxalic acid at 40 V to form anodic porous alumina. The sample was then re-anodized in 12M sulfuric acid at 40V to form a highly soluble alumina layer at the bottom of the previously formed anodic porous alumina. After anodization, the sample was immersed in a mixed solution of chromic acid and phosphoric acid to selectively dissolve the alumina layer formed in concentrated sulfuric acid, thereby exposing the Al substrate at the bottom of the pores. Tubular alumina membrane filters were obtained by selectively dissolving the Al substrate through nanopores in an iodine-methanol solution. In this study, Al wires with diameters ranging from 2 to 5 mm were used as the starting materials, and in all cases, it was possible to form tubular alumina membrane filters without cracks. SEM observations of the obtained samples showed that the tubular alumina membrane filter was uniformly sized through the holes. The tubular alumina membrane filter obtained in this study is expected to be useful in a variety of applications.

Slow-Scan anodization of copper in alkaline Solution: Synthesis, performance Evolution, and theoretical analysis of Cu(OH)2 nanowires for High-Performance supercapacitors

In this work, a binder-free Cu/Cu(OH)2 NwBs electrode was fabricated using a simple potentiodynamic anodization method. The effect of anodization scan rates of 3, 0.5, and 0.1 mV/s on the structural, morphological, and supercapacitive properties was thoroughly investigated. An areal capacitance of 22.5 mF/cm2 at 1 mA/cm2 was achieved at scan rate of anodization 0.1 mV/s. The Cu/Cu(OH)2 electrode demonstrates excellent retention cyclic stability of 120 % after 10,000 cycles. Post-cycling analysis revealed a phase transformation from Cu(OH)2 to CuO, accompanied by significant morphological changes. A theoretical model based on Fick’s law was employed, which aligned well with the experimental data. The diffusion coefficient values were calculated from charge/discharge data, and the results indicated that higher diffusion coefficients corresponded to higher specific capacitance, demonstrating improved supercapacitor performance.

Electrochemical synthesis and carbon doping of nanostructured iron fluorides from the selection of metal current collectors in lithium-ion batteries

The use of materials that rely on conversion reactions as electrodes in lithium-ion batteries is extensively investigated due to their potential for enhanced capacity compared to traditional electrode materials. Iron fluorides, in particular, present a promising alternative in terms of specific capacity. However, these materials often face challenges related to low intrinsic conductivity. This issue is typically addressed in the literature by doping the active material with carbon particles and reducing the particle size of the active material. This study explores the feasibility of directly integrating conductive carbon from the substrate into the fluoride-based active material during the synthesis process. The synthesis employs a simple anodic method conducted directly on the chosen metallic substrate, which then functions as the current collector in the devices. This approach simplifies the synthesis process, reduces processing time, and eliminates the need for additives and binders at the conventional active material-current collector interface. Two FeF3 layers were electrochemically synthesized on steel substrates with different carbon contents. These layers were evaluated as cathode-active materials for rechargeable lithium-ion batteries. The influence of carbon on the conductivity of the conversion layer was assessed using Electrochemical Impedance Spectroscopy (EIS) with a model based on conductive porous electrodes. Morphological and thickness analyses of the layers showed a strong correlation between increased pore size and layer thickness and the carbon content in the metallic substrate. The optimal performance was observed with the layer on the substrate with higher carbon content. The electrochemical performance of the active material was further evaluated using electrochemical impedance spectroscopy and galvanostatic tests in pouch cells. The conversion layers derived from carbon steel exhibited reduced resistivity and enhanced specific capacitance and cyclability compared to layers formed on pure iron.

Facile Preparation of High-Performance Polythiophene Derivative and Effect of Torsion Angle Between Thiophene Rings on Electrochromic Color Change.

The electrochromic phenomenon of conducting polymer is mainly dominated by the π-π* band transition. The π conjugation is influenced by the coplanarity between polymer units, deviations from which can lead to an increased ionization potential and band gap values. In order to investigate the effect of plane distortion angle on electrochromic color in the main chain structure of polymerization, high-performance poly(3,3'-dimethyl-2,2'-bithiophene) (PDMeBTh) with a large plane distortion angle is successfully synthesized in boron trifluoride diethyl etherate (BFEE) by the electrochemical anodic oxidation method. The electrochemical and thermal properties of PDMeBTh prepared from BFEE and ACN/TBATFB are compared. The electrochromic properties of PDMeBTh are systematically investigated. The PDMeBTh shows a different color change (orange-yellow in the neutral state) compared to poly (3-methylthiophene) (light-red in the neutral state) due to the large torsion angle between thiophene rings of the main polymer chain. The optical contrast, response time, and coloring efficiency (CE) of the prepared PDMeBTh are also studied, which shows good electrochromic properties. For practical applications, an electrochromic device is fabricated by the PDMeBTh and PEDOT. The color of the device can be reversibly changed between orange-yellow and dark blue. The light contrast of the device is 27% at 433 nm and 61% at 634 nm. The CE value of the device is 403 cm2 C-1 at 433 nm and 577 cm2 C-1 at 634 nm. The constructed device also has good open circuit memory and electrochromic stability, showing good potential for practical applications.

Synthesis of pure ZnO and carbon nanoparticle/ZnO nanostructures for highly efficient glucose sensors

ABSTRACT This work presents a promising method to prepare pure zinc oxide (ZnO) films and carbon nanoparticles (CNPs) decorated ZnO (CNP/ZnO) nanostructured films as glucose sensors. ZnO nanostructure film was grown on Zn foil via the anodisation method, whereas the carbon nanoparticles were synthesised by the hydrothermal method, the decoration process of carbon nanoparticles on ZnO film nanocomposites was conducted using the ultrasonication method. Numerous experiments were conducted, such as microstructure observation, crystallinity analysis, and electrochemical property research. The nanostructures were ascertained by energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), UV-vis spectroscopy, photoluminescence (PL) measurements, and X-ray diffraction (XRD). ZnO NPs displayed a structure with an average crystallite size of 5.12–13.47 nm, and the PL emission spectra were found to be in the 387 nm range, ZnO films were created by annealing ZnO samples at 200°C for 2 h, and FE-SEM presented nanoparticle-like shapes with a particle size range of (20–50 nm) for voltage anodisation (6 v). This led to an elevation of the energy gap to 3.20 eV. The electrochemical characterisation of the CNPs/ZnO nanostructures refines remarkably the sensitivity to glucose via pure zinc oxide nanostructures. The CNP/ZnO nanostructures demonstrated improved glucose-sensing ability with a sensitivity value of 2827 µA. m M − 1 . The low detection limit is 0.8 mm with a linear range from (0.3 mm to 1 mm). The sensitivity and repeatability of the biosensors were assessed by measuring and analysing their I–V characteristics at different glucose concentrations. Based on a straightforward, affordable, and innovative sensor design, this result validates the sensor’s significant potential as a high-performance nonenzymatic glucose sensor. It was observed that when zinc oxide films were decorated with carbon nanoparticles, there was an increase in the sensitivity of glucose detection. This is due to an increase in charge transfer and conductivity, as well as an increase in the oxidation and reduction process.

Efficient biosorption of Zn(II), Cd(II), and Pb(II) by Aspergillus brasiliensis in industrial wastewater coupled with electrochemical monitoring via sensor enhanced with modified silver nanoparticles.

This work investigates the use of Aspergillus brasiliensis, this particular species of Aspergillus, as a biosorbent for the first time. It is employed to biosorption Zn(II), Cd(II), and Pb(II) and combines the biosorption experiments with electrochemical measurements for in situ analysis. For the experiments, a batch system was employed with the dead biomass. In order to determine the biosorption capacity, the impact of several operational parameters was examined, including pH, temperature, agitation speed, contact time, and initial metal concentration, and the optimum values were 5, 30°C, 150rpm, 2h, and 150ppm, respectively. Using 0.2g biomass in 100mL solution, the maximal uptake of Zn(II), Cd(II), and Pb(II) at ideal conditions was determined to be 33.67, 24.51, and 36.76, respectively. The Langmuir and Freundlich isotherm model was studied for the biosorption process. An electrochemical sensor using nanomaterials is designed and constructed to monitor the concentration of these metals. The silver nanoparticles functionalized with thiosemicarbazide and 6-mercaptohexanoic acid (mercaptohexanoylhydrazinecarbothioamide-coated silver nanoparticles, MHHC-AgNPs) linked to the carboxylated multi-walled carbon nanotubes (MWCNTs) were utilized for glassy carbon electrode modification (MHHC-AgNPs/MWCNTs/GCE). The concentration range of Zn(II) is 0.7-173µg/L, Cd(II) is 1.18-293µg/L, and Pb(II) is 2.17-540µg/L. The detection limits for Zn(II), Cd(II), and Pb(II) are 0.036µg/L, 0.15µg/L, and 0.16µg/L, respectively. Under optimized conditions, these results were obtained using the differential pulse anodic stripping voltammetry method (DPASV). The successful detection of Zn(II), Cd(II), and Pb(II) was achieved by effectively preventing interference from other common ions. It was effectively employed for measuring ions in industrial wastewater, and the results obtained aligned with those acquired from an atomic absorption spectrometer (AAS). Thus, Aspergillus brasiliensis species, along with this electrochemical sensor, can be used to remediate and monitor environmental pollution, Zn(II), Cd(II), and Pb(II), successfully.

Nanotube formation and coating of hydroxyapatite-polyvinyl alcohol-collagen composite on Ti-6Al-4V metal alloy

Abstract Ti-6Al-4V metal is widely used as an implantable material due to its biocompatibility and corrosion resistance; however, it has low bioactive properties. The formation of nanotubes and a hydroxyapatite-polyvinyl alcohol-collagen composite coating on Ti-6Al-4V metal aims to enhance its biocompatibility and bioactivity. The nanotube oxide layer Ti-6Al-4V was formed by the anodization method. The composite’s infrared spectrum showed characteristic absorption bands from Hydroxyapatite (HAp), polyvinyl alcohol, and collagen. The composite-coated Ti-6Al-4V metal, both non-nanotube, and nanotube, showed a typical diffraction pattern of HAp and titanium element. The electron microscope image showed the uniform granular form of HAp. The corrosion test results showed that composite-coated nanotube Ti-6Al-4V metal could not improve corrosion resistance. It is also relevant to the in vitro test in a lactate ringer solution that showed the higher Ca2+ ion of nanotube Ti-6Al-4V metal than that of non-nanotube Ti-6Al-4V metal.

Novel Anodic TiO2 Synthesis Method with Embedded Graphene Quantum Dots for Improved Photocatalytic Activity

Photocatalytic degradation of pollutants have a high potential for sustainable and renewable uses. TiO2 is a widely studied photocatalyst due to its high chemical and photochemical stability and wide range of applications. However, the wide band gap and low capacity of photo-induced charge separation provide lower catalytic activity; thus, improvement of these properties must be found. The doping of TiO2 with other elements, such as carbon nanoparticles (CNP) in a quantum dot form, offers a promising pathway to improve the aforementioned properties. In addition, in situ doping methods should be investigated for practical scalability, as they offer the advantage of integrating dopants directly during material synthesis, ensuring a more uniform distribution and better interaction between the dopant and the host material, in turn leading to more consistent photocatalytic properties. Current technologies primarily involve nanoparticle combinations. This work focuses on the development of a novel in situ synthesis methodology by the introduction of three different graphene-based quantum nanodots into anodic TiO2 and the following investigation of structural, morphological, and photocatalytic properties. Results indicate that the introduction of CNP allows for the shift of a set of parameters, such as the optical band gap, increased photo-induced charge carrier density of TiO2/CNP composite, and, most importantly, the change of crystalline phase composition depending on added CNP material. Research indicates that not only a higher concentration of added CNP enhances higher photocatalytic activity as tested by the degradation of methylene blue dye, but also the type of CNP determines final crystalline phase. For the first time brookite and rutile phases were obtained in anodic titania synthesized in inorganic electrolyte by introducing hydrothermally treated exfoliated graphene.

The X-Direction Scanning of Atomic Force Microscopy to Analyze Porous Silicon P-Type Si(100) Fabricated by Electrochemical Anodization Method

This work only investigated the x-direction scanning of atomic force microscopy, which can accurately measure porous silicon's width, depth, and roughness. Pores on p-type Si (100) surfaces fabricated by electrochemical anodization method with the variation of resistivity and current density, i.e., 0.001-0.005 Ω.cm (high dopant) and 1-10 Ω.cm (low dopant), and 4, 6, 8, and 10 mA/cm2, respectively. Macroporous silicon was obtained for both high and low dopants. Pore width, pore depth, and roughness of silicon increase with increasing the current density. Characteristics of porous silicon for high dopants are smaller than that for low dopants. It indicates that large amounts of dopant in silicon can slow the etching process.