Development Of Nonmetal-Doped Tio2 Nanotube Photocatalyst For Decolorization Of Methyl Orange

Tiubnano (TN) TiO2 telah menarik perhatian dalam bidang fotopemangkinan. Walaupun TiO2 adalah fotopemangkin yang digunakan secara meluas, kebolehannya untuk menyerap cahaya nampak adalah lemah dan rekombinasi pembawa cas menjadi satu cabaran yang besar. Oleh itu, matlamat kajianini adalah untuk membentukTN TiO2 terdop karbon (C)dan fosforus (P) untuk penyahwarnaanmetil oren (MO). Penghasilan TN C-TiO2 melalui penganodan telah berjaya dihasilkan di dalam elektrolit organik yang berfluorin. Gliserol dan glikol etilena (EG) pH neutral telah diguna sebagai elektrolit organik.Morfologi dan struktur bagi TN beroksida yang terbentuk telah dikaji.Melalui penganodan, faktor-faktor utama yang mempengaruhi struktur TN adalah jenis-jenis elektrolit, komposisi elektrolit, voltan penganodan dan masa penganodan.TN C-TiO2 telah berjaya dihasilkan dengan pantas dalam EG yang mengandungi 0.89 wt% air (H2O) dan 0.66 wt% ammonium fluorida (NH4F). Kadar pembentukan dalam elektrolit tersebut adalah 308 nm / min. C yang terdop di dalam TN TiO2mewujudkan satuaras tenaga baru di atas jalur valens (VB), yang terhasil daripadakarbon celahan C 2p serta satu lagi di bawah jalur konduksi (CB) yang berkaitan dengan anti ikatan, C - O yang berasal daripada pembentukan kekosongan oksigen. TN C-TiO2 disepuh lindap pada 500 ° C dengan purata saiz liang 95 nm, ketebalan dinding 18 nm dan panjang 18.5 m dengan nisbah aspek tinggi (141.2) dan luas permukaan (1025.6 m2g-1) menunjukkan kadar penyahwarnaanMO sebanyak39%dengan kadar tetap k = 5.9 x 10-3 min-1 berbanding 11% kadar penyahwarnaan oleh partikel nano TiO2 bersaiz 25 nm. Dalam usaha untuk meningkatkan aktiviti fotopemangkinan TN C-TiO2, P didop ke dalam TN C-TiO2 melalui penganodan Ti dalam EG mengandungi 1 M asid fosforik (H3PO4) dan kaedah rendamandi dalam H3PO4. Kajian menunjukkan bahawa TN C-TiO2direndam dalam 0.02 M H3PO4selama 90 minit pada 40 ° C dan disepuh lindap pada suhu 500 °C menunjukkan 45% penyahwarnaan dengan kadar tetap k = 8.1 x 10-3 min-1. P yang didop ke dalam TN C-TiO2 didapati mempunyai keadaan pengoksidaan pentavalen yang bakal menggantikan kekisi Ti4+ dan membentuk ikatan Ti-O-P lalu meningkatkan responsif TiO2terhadap cahaya nampak. ________________________________________________________________________________________________________________________ Well aligned TiO2nanotubes (NT) arrays have attracted substantial attention in the area of photocatalysis (PC). Although TiO2 is a widely used catalyst support, its poor visible light absorption and high recombination of charge carriers remains a major challenge for its application. Hence, this work aims to develop carbon (C) incorporated TiO2 NT and carbon phosphorus (CP)incorporated TiO2 NT for photocatalytic decolorization of methyl orange (MO) dye. The formation of C-TiO2 NT by anodization was successful in fluorinated organic electrolyte. Glycerol and ethylene glycol (EG) were the organic electrolyte with their neutral pH. The properties including morphology and structural of the nanotubular oxide formed were investigated. During anodization, the main factors effecting nanotubular structures are types of electrolyte, its composition, anodization voltage applied to anode and anodization time.C-TiO2 NT arrays were rapidly grown in EG containing 0.89 wt% of water (H2O) and 0.66 wt% of ammonium fluoride (NH4F). The optimized rate of formation was 308 nm/min. The incorporation of C into TiO2 NT induced the formation of a new state above valence band (VB), which is attributed to the C 2p state of the interstitial carbon, as well as new state below the conduction band (CB), corresponding to antibonding C–O state produced due to the formation of oxygen vacancies.C-TiO2 NT arrays annealed at 500 °C with average pore size of 95 nm, wall thickness of 18 nm and length of 18.5 m, with high aspect ratio (141.2) and surface area (1025.6 m2g-1) exhibited decolorization of about 39% under visible light illumination with rate constant of k = 5.9 x 10-3 min-1as compared to TiO2 nanoparticle of 25 nm which possessed 11% decolorization. In order to improve further the photocatalytic activity of C-TiO2 NT, incorporation of P into C-TiO2 NT was done via anodization of Ti in EG containing 1 M phosphoric acid (H3PO4) and wet impregnation in H3PO4. It was found that C-TiO2 NT impregnated in 0.02 M H3PO4 for 90 min at 40 °C and annealed at 500 °C exhibited 45% decolorization with rate constant of k = 8.1 x 10-3 min-1. It was found that the doped phosphorus existed in a pentavalent oxidation state, replacing part of Ti4+ in the anatase lattice in the form of Ti-O-P bonds, thus extended the spectral response of TiO2 NT to the visible region

Factor Affecting Geometry of TiO2 Nanotube Arrays (TNAs) in Aqueous and Organic Electrolyte

TiO2 nanotube arrays (TNA) have attracted scientific interest due to the combination of functional material properties with controllable nanostructure. Superior properties of TNA, including vectorial pathway of e− transport, minimized e− recombination, and high specific surface area render them as the most promising candidate for environment remediation, energy conversion and biocompatibility applications. The superior properties and efficacy of the TNA in various applications influenced by structural characteristics such as pore size, length and wall thickness. Therefore in this chapter the effect of various electrochemical parameters such as applied voltage, anodization time, electrolyte composition on the formation of controlled dimension of TNA in aqueous and organic electrolytes are reviewed

Surface Modification and Bioactivity of Anodic Ti6Al4V Alloy

The present study deals with surface modification of Ti6Al4V alloy via anodization technique. The morphology, structure, adhesion and bioactivity of Ti6Al4V alloy after anodization process were investigated in detail. The influence of fluoride content and direct circuit (DC) applied voltage during anodization of Ti6Al4V alloy in a bath with electrolytes composed of ethylene glycol (EG) and ammonium fluoride (NH4F) were considered. It was found that the average pore sizes and length of nanoporous or nanotubes were increasing with the fluoride content and applied voltage. A minimum of 3 wt% of NH4F is required to grow a self-organized nanotube arrays. As the fluoride content was increased to 5 wt%, TiO2 nanotubes with average diameter of 110 nm and 3.4 microm lengths were successfully synthesized. It is noteworthy to point out that the rate of the nanotube formation was increasing up to 9 microm thick bioactive TiO2 nanotubes layer as anodization time was increased to 3 h. Based on the results obtained, the PA6 cells cultured on anodic Ti6Al4V alloy showed highest level of cell viability and greater cell adhesion compared to the flat Ti6Al4V foil substrate. In fact, highly ordered nanotubes structure on Ti6Al4V alloy can provide beneficial effects for PA6 cells in attachment and proliferation

DEVELOPMENT OF TiO2 NANOTUBES VIA ANODIZATION FOR DEGRADATION OF METHYL ORANGE

TiO2 nanotubes were prepared by anodization of titanium foil (Ti) in an electrochemical bath consisiting fluorinated ethylene glycol/glycerol organic solvents. The pH of the bath was kept constant at pH~7 and the anodization time was varied (1, 15, 20, 30 and 60 min) to study the formation of well ordered TiO2 nanotubes. The crystal structure was studied by X-Ray Diffraction (XRD) analysis, and the morphology was observed via Field Emission Scanning Electron Microscopy (FESEM). The average tube diameter and tube length was found to be increase with increasing anodization time. Crystallization of the nanotubes to anatase phase occurred at 300 °C while rutile formation occurred at 600 °C. Sintegration of the nanotube arrays was observed at 700 °C. Photocatalytic activity of the nanotubes produced in different annealing temperature was also evaluated by the degradation of methyl orange. The detail of the observation is discussed thoroughly in this paper

Formation of high aspect ratio TiO2 nanotube arrays by anodization of Ti foil in organic solution

Titanium oxide (TiO2) nanotubes were successfully formed by anodization of pure titanium foil in a standard two-electrode bath consisting of ethylene glycol solution containing 5 wt% NH4F. The pH of the solution was ∼ 7 and the anodization voltage was 60 V. It was observed that such anodization condition results in ordered arrays of TiO2 nanotubes with smooth surface and a very high aspect ratio. It was observed that a minimum of 1 wt % water addition was required to form well ordered TiO2 nanotubes with length of approximately 18.5 μm. As-anodized sample, the self-organized TiO2 nanotubes have amorphous structure and annealing at 500oC of the nanotubes promote formation of anatase and rutile phase. Photocatalytic activity of well ordered TiO2 nanotubes with two different lengths was evaluated by measuring the degradation of methyl orange (MO). The elaboration of this observation is described in detail in this paper

Improved Adhesion of Nonfluorinated ZnO Nanotriangle Superhydrophobic Layer on Glass Surface by Spray-Coating Method

In this present work, a superhydrophobic glass surface comprising zinc oxide nanotriangles (ZnO-nt) and nontoxic silylating agent was developed via a cost-effective spray-coating technology. ZnO-nt was synthesized by a hydrothermal method. Poly(dimethylsiloxane) (PDMS) and dimethyldiethoxysilane (DMDEOS) were used as nontoxic (nonfluoro) silylating agents. The morphology and crystallinity of ZnO-nt were studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. ZnO-nt with polymeric silane (PDMS) exhibited maximum wettability as compared to nonpolymeric silane (DMDEOS). The water contact angle (WCA), sliding angle (SA), and surface roughness of ZnO-nt/PDMS-coated glass substrate under UV treatment were 165 ± 1°, 3 ± 1°, and 791 nm, respectively. The WCA of ZnO-nt/PDMS was higher (165°) than that of commercial ZnO/PDMS (ZnO-C/PDMS). ZnO-nt/PDMS was strongly attached to the glass substrate with good stability and adhesion. The reasons for improved hydrophobicity, adhesion, and mechanism of hierarchical microstructure formation on the glass substrate were explained in detail. PDMS was attached to the glass substrate via hydrogen bonds from solvated zinc acetate

Genome-nanosurface interaction of Titania Nanotube Arrays: evaluation of telomere, telomerase and NF-κB activities on epithelial cell model

Titanium Dioxide Nanotube Arrays (TNA) provides promising platform for medical implants and nanomedicine applications. The present cell-TNA study has provided profound understanding on protection of genome integrity via telomere, telomerase and NF-κB activities using epithelial cell model. It has been revealed in this study that cell-TNA interaction triggers the telomere shortening activity and inhibition of telomerase activity at mRNA and protein level. The present work supported that cell-TNA stimulus might involve controlled transcription and proliferative activities via NBN and TERF21P mechanisms. Moreover, inhibition of NF-κB may promote molecular sensitivity via senescence -associated secretory phenotype activities and might results in reduced inflammatory response which would be good for cell and nanosurface adaptation activities. Thus, this nanomaterial-molecular knowledge is beneficial for further nanomaterial characterization and advanced medical application

Bacteriostatic Activity of LLDPE Nanocomposite Embedded with Sol–Gel Synthesized TiO2/ZnO Coupled Oxides at Various Ratios

Metal oxide-polymer nanocomposite has been proven to have selective bactericidal effects against the main and common pathogens (Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli)) that can cause harmful infectious diseases. As such, this study looked into the prospect of using TiO2/ZnO with linear low-density polyethylene (LLDPE) to inactivate S. aureus and E. coli. The physical, structural, chemical, mechanical, and antibacterial properties of the nanocomposite were investigated in detail in this paper. The production of reactive species, such as hydroxyl radicals (•OH), holes (h+), superoxide anion radicals (O2•¯), and zinc ion (Zn2+), released from the nanocomposite were quantified to elucidate the underlying antibacterial mechanisms. LLDPE/25T75Z with TiO2/ZnO (1:3) nanocomposite displayed the best performance that inactivated S. aureus and E. coli by 95% and 100%, respectively. The dominant reactive active species and the zinc ion release toward the superior antibacterial effect of nanocomposite are discussed. This work does not only offer depiction of the effective element required for antimicrobial biomedical appliances, but also the essential structural characteristics to enhance water uptake to expedite photocatalytic activity of LLDPE/metal oxide nanocomposite for long term application