Modification Of TiO2 Nanoparticles Research Articles

Photocatalytic Efficacy and Degradation Kinetics of Chitosan-Loaded Ce-TiO2 Nanocomposite towards for Rhodamine B Dye

The recent advancement in the production of nanomaterials with novel architectures and functionality has allowed for the effective treatment of industrial wastewaters and contaminated soil and, in that view, the current study aimed to investigate the catalytic efficacy of biopolymer-loaded titanium nanocomposite. Therefore, Cerium (Ce)-titanium dioxide (TiO2) loaded chitosan nanocomposite was formed and studied its catalytic efficacy towards the degradation of an industrial dye pollutant. For the production of Ce-TiO2/chitosan nanocomposite, we followed the hydrothermal synthesis route and the formed nanocomposite was thoroughly analyzed for the crystallinity (using powdered X-ray diffraction, XRD), surface bonding, and nature (using Fourier transform infrared, FTIR spectroscopy), morphology (scanning electron microscopy, SEM), elemental composition (electron diffraction analysis by X-rays, EDAX), porosity (Brunauer–Emmett–Teller, BET), and particles size in powdered form (transmission electron microscopy, TEM). Then the efficiency of synthesized nanocomposite was tested towards the photocatalytic degradation of Rhodamine B (Rh B) dye by applying various parameters such as the irradiation time, solution pH, catalyst dosage, and the dye concentration. Further, the Langmuir–Hinshelwood model was employed to investigate the kinetics of RhB degradation and provided a conceivable photocatalytic mechanism. It was indicated based on the catalyst mechanism that the modification of TiO2 nanoparticles with Ce and loading onto chitosan biopolymer may have accelerated the photocurrent transport due to an increase in the number of electrons and holes generated by the photon’s irradiation. In this way, the study has witnessed the excellent photocatalytic performance of Ce-TiO2/chitosan with 95% Rh B degradation as against the pure TiO2 nanoparticles thus stressing the importance of developing novel composite photocatalysts.

Preparation of TiO2 Superhydrophobic Composite Coating and Studies on Corrosion Resistance.

The superhydrophobic coatings with excellent performance are prepared on the brass substrate to improve its application limitations in real production. In this article, the superhydrophobicity was obtained by the modification of TiO2 nanoparticles, and the FAS/STA-TiO2 superhydrophobic coating of the composite structure was obtained by modification of 1, 1, 2H, 2H-perfluoroquine trimethyl silane (FAS). By using scanning electron microscopes (SEMs), X-ray spectrometers (EDSs), and Fourier transform infrared (FTIR) spectrometers, the surface morphology, chemical composition, and functional group structure of the samples were analyzed in turn. Experiments show that the water contact angle of the FAS-modified STA-TiO2 coating reaches 161.3°, and the sliding angle is close to 1.2°. Based on the chalk dust containment, it has enabled noticeable self-cleaning properties. The composite superhydrophobic coating also presents enhanced adhesive strength compared with the single coating by the tape peeling experiment. Moreover, the composite coating has a corrosion current density as low as 8.41 × 10-7 A/cm2, and the largest |Z| in low frequency in a 3.5% NaCl solution to achieve better protection of the brass substrate. It is also not difficult to see that FAS/STA-TiO2 coating can not only improve the corrosion resistance of brass substrates but also be applied to other metal substrates.

Preparation of smart brush-type cation-exchange adsorbents grafted nanosurface via SI-ATRP for dye removal

Application of brush-type cation-exchange adsorbents is attractive for efficient treatment of wastewater. But one of the great challenges in this field is the fabrication of adsorbents with high adsorption efficiency and stability under different pHs and temperatures as well as reusability. Here, promising organic-inorganic hybrid adsorbents were employed to remove organic dyes from water which are fast, reusable, and efficient. Poly(glycidyl methacrylate) p(GMA) was attached to the surface of TiO2 nanoparticles (NPs) via the SI-ATRP. Primarily, hydroxyl groups of the surface of TiO2 NPs were functionalized using aminopropyltriethoxysilane (APTES) followed by alpha- bromoisobutyryl bromide (BIBB) for covalent attachment of the ATRP initiator (0.3 mmol Br/g of nanoparticles) onto the surface. Decreasing the surface area after modification of TiO2 nanoparticles (NPs) with BIBB was observed from 59.25 m2/g for TiO2 to 51.46 m2/g for TiO2-Br macroinitiator. Then grafting of p(GMA) brushes on the surface of the macroinitiator was performed via the SI-ATRP method. The surface area was decreased to 5.06 m2/g and TiO2-p(GMA) polymer brushes with a grafting density of 1.12 chains/nm2 were formed. The cation-exchange adsorbent was formed through modification of epoxide groups of the grafted p(GMA) to sulfonate (SO3-) groups. The adsorption capacity of the prepared adsorbent for methylene blue (MB) was investigated under different pHs, adsorbent dosages, salt concentrations, and temperatures. Decreasing the dye removal efficiency to 57.4% was found after increasing the concentration of salt to 0.8 M. The maximum adsorption capacity for MB was 91.49 mg/g. Adsorption isotherm of Freundlich and pseudo-second-order kinetic model have exactly matched with experimental data of MB adsorption. The dye removal efficiency of the adsorbent did not decrease significantly after six cycles of adsorption.

Visible-Light Active Titanium Dioxide Nanomaterials with Bactericidal Properties.

This article provides an overview of current research into the development, synthesis, photocatalytic bacterial activity, biocompatibility and cytotoxic properties of various visible-light active titanium dioxide (TiO2) nanoparticles (NPs) and their nanocomposites. To achieve antibacterial inactivation under visible light, TiO2 NPs are doped with metal and non-metal elements, modified with carbonaceous nanomaterials, and coupled with other metal oxide semiconductors. Transition metals introduce a localized d-electron state just below the conduction band of TiO2 NPs, thereby narrowing the bandgap and causing a red shift of the optical absorption edge into the visible region. Silver nanoparticles of doped TiO2 NPs experience surface plasmon resonance under visible light excitation, leading to the injection of hot electrons into the conduction band of TiO2 NPs to generate reactive oxygen species (ROS) for bacterial killing. The modification of TiO2 NPs with carbon nanotubes and graphene sheets also achieve the efficient creation of ROS under visible light irradiation. Furthermore, titanium-based alloy implants in orthopedics with enhanced antibacterial activity and biocompatibility can be achieved by forming a surface layer of Ag-doped titania nanotubes. By incorporating TiO2 NPs and Cu-doped TiO2 NPs into chitosan or the textile matrix, the resulting polymer nanocomposites exhibit excellent antimicrobial properties that can have applications as fruit/food wrapping films, self-cleaning fabrics, medical scaffolds and wound dressings. Considering the possible use of visible-light active TiO2 nanomaterials for various applications, their toxicity impact on the environment and public health is also addressed.

Synthesis and Bioactivity of TiO2/PPy Micelle with Pachyrhizus erosus Extract as UV Absorbent Material

Indonesia is a tropical country with high intensity and duration of sunlight throughout over year. The condition causes the average UV index in Indonesia is at the level of 9 up to 11+ so that the power of the sun is extreme invade the human body. This condition makes Indonesia one of the countries with the highest UV index in the world. UV rays exposure can be harmful to humans and become one of the most significant factors causing the existing of skin cancer. Researchers have studied many efforts. Unfortunately, the use of oxidic nanoparticles combined with natural products is not yet explored comprehensively. TiO2 nanoparticles are materials that have excellent absorbability of UV light. In this study the TiO2 nanoparticles as core and combined with Polypyrrole polymer as shell form a micelle structure. The modification of TiO2 nanoparticles with Polypyrrole aims to enhance its UV protection, biocompatibility, and nontoxicity on the body. The addition of Pachyrhizus erosus extract as an enhancer of the efficacy of micelle as UV absorbent agent because it has the phenolic to skin softening properties. The synthesis of micelle TiO2/PPy was performed using in situ method, followed by stirring and sonication process to mix the Pachyrhizus erosus extract with micelle. The XRD analysis of Micelle synthesis shows that the addition of polypyrrole polymer does not affect the crystallinity of TiO2 nanoparticles. The results of testing the antibacterial properties of sunblock samples showed a clear zone with glycerine solvent.

Modification of TiO2 with graphene oxide and reduced graphene oxide; enhancing photocatalytic activity of TiO2 for removal of remazol Black B

Modified titanium dioxide (TiO2) nanoparticles with graphene oxide (GO) and reduced graphene oxide (rGO) were prepared using the chemisorption process. The characterization was carried out by IR, X‐ray diffraction spectra, scanning electron microscopy, energy dispersive X‐ray spectroscopy, and DRS techniques. The photocatalytic activity of GO/TiO2 and rGO/TiO2 nanocomposites was evaluated in photodegradation of Remazol Black B (RBB). The effects of various parameters, such as pH, adsorbent dosage, dye concentration, and contact time, were studied in a batch system. The results showed that GO/TiO2 and rGO/TiO2 nanocomposites can extend the absorption of light to the visible region and makes the photocatalysts active under visible‐light irradiation. Photocatalytic activity clearly showed that the modification of TiO2 nanoparticles by GO and rGO enhanced the degradation of RBB from the aqueous solution (99.9% dye removal). Photodegradation processes fitted well with the pseudo‐first‐order kinetic model (R2 > 0.99). POLYM. COMPOS., 40:210–216, 2019. © 2017 Society of Plastics Engineers

WITHDRAWN: Functionalization and surface modification of TiO2 nanoparticles for proton exchange membrane fuel cell

The fuel cell performance of sulfonated polyethersulfone (SPES) membrane was investigated with modified TiO2 nanoparticles. TiO2 nanoparticles were modified by sulfonation (STiO2) and surface modification with PANI (STiO2-PANI). The presence of the functional groups in the modified TiO2 was confirmed by Fourier transform infrared spectroscopy (FTIR) and XRD. The presence of sulfonic group in PES backbone was confirmed by 1HNMR spectroscopy. The SPES proton exchange membranes (PEM) were prepared by incorporating STiO2 and STiO2-PANI individually at 0.5% and 1% in the presence of N-methyl-2-pyrrolidone (NMP). The properties of the synthesized membrane were characterized by FTIR, XRD, Field Emission Scanning Electron Microscopy (FESEM). The performance of the membranes in terms of water uptake, swelling ratio, methanol uptake, ion exchange capacity were evaluated. Chemical stability, thermal properties and proton conductivity for the composite membranes were also determined. The highest proton conductivity is 1.07 × 10-3 S/cm exhibited by SPES/STiO2-PANI (0.5%) composite membrane. The ability of the membrane to hold more water molecules, presence of hydrophilic sulfonic acid groups and amine group of PANI were the main factors for the highest conductivity value. Surface modified STiO2 by PANI i.e., STiO2-PANI composite membrane exhibited excellent water uptake, ion exchange capacity, chemical and thermal properties with acceptable proton conductivity. The results represent that the composite membrane impregnated with STiO2-PANI to be a promising proton conducting material for fuel cell application.

Enhanced antibacterial activity of TiO2 nanoparticle surface modified with Garcinia zeylanica extract

BackgroundThe antibacterial activity of 21 nm TiO2 nanoparticles (NPs) and particles modified with Garcinia zeylanica (G. zeylanica) against Methicillin resistant Staphylococcus aureus was investigated in the presence and absence of light.ResultsSurface modification of TiO2 NPs with the adsorption of G. zeylanica extract, causes to shift the absorption edge of TiO2 NPs to higher wavelength. TiO2 NPs, G. zeylanica pericarp extract showed significant bactericidal activity which was further enhanced in contact with the TiO2 modified G. zeylanica extract.ConclusionsThe antimicrobial activity was enhanced in the presence of TiO2 NPs modified with G. zeylanica and with longer contact time.

Creeping Discharge Characteristics of Nanofluid-Impregnated Pressboards Under AC Stress

This paper presents experimental research on creeping discharge characteristics of TiO2 nanofluid-impregnated pressboards (NPs) under sustained ac voltage. It was found that NPs possess higher resistance to creeping discharge than that of pure oil-impregnated pressboard. The results of permittivity and surface charge accumulation and decay characteristics reveal that the modification of nanoparticles can not only make the electric field more uniformly distributed at the interface of nanofluid/pressboard due to a better matching in permittivity but also significantly increase the surface charge decay rate via a trapping and detrapping process in shallower traps. Thus, the creeping discharge characteristics of NPs are greatly improved by the modification of TiO2 nanoparticles.

Modification of TiO2 nanoparticles by HZSM-5 for the enhancement in photodegradation of Acid Green 25

A great approach for the preparation of TiO2 supported on HZSM-5 photocatalyst was employed by an energy efficient microwave assisted technique. Titanium tetraisopropoxide (TTIP) was used as a titanium precursor and medium pore size HZSM-5 with high thermal and chemical resistance used as a support. The amount of TTIP was varied in order to obtain different TiO2 loading of 20, 30 and 40 wt% on HZSM-5. The obtained nanomaterials were studied by a set of complementary characterization techniques including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform-infrared spectroscopy, surface area measurement (BET) and diffuse reflectance spectroscopy. The present research is mainly focused on the enhancement of surface area of TiO2 nanoparticles by using HZSM-5 as a support. The obtained nanomaterials were tested for the degradation of Acid Green 25 under UV light (365 nm). A maximum 96 % photodegradation of dye was achieved by utilizing most efficient TiO2(30 %)/HZSM-5 at 0.1 g/dm3 catalyst within 60 min under UV light.

Modification of TiO2 nanoparticles through lanthanum doping and peg templating

Pure and lanthanum doped titania nanopowders were synthesized through a room temperature sol-gel method using a template of polyethylene glycol (PEG). The progress of the synthesis in terms of phase formation and size of nanoparticles was monitored by X-ray diffraction, FTIR spectroscopy and SEM analysis. After calcination at 450?C in air, the results have shown the presence of small particles crystallized predominantly in the form of anatase phase, with significant agglomeration. Nitrogen adsorption-desorption measurements confirmed that all prepared powders are mesoporous with an average pore diameter in range 3.1-3.8 nm. The addition of lanthanum ions leads to the nanopowders with the highest specific surface (BET) area (203m2/g). The obtained powders were compared to TiO2 prepared without a template.

Development and Application of TiO2Nanoparticles Coupled with Silver Halide

Titanium dioxide (TiO2) is proposed to be effective photocatalyst for wastewater treatment, air purification, and self-cleaning ability, because of its strong oxidation and superhydrophilicity. In order to conquer the limits of TiO2, a variety of methods have been used. This paper presents a critical review of novel research and achievements in the modification of TiO2nanoparticles with silver halide (AgX,X=Cl, Br, I), which aims at enhancing the visible light absorption and photosensitivity. Herein we study the synthesis, physical and chemical properties, and the mechanism of this composite photocatalyst.

The influence of the size and surface modification of TiO2 nanoparticles on the rheological properties of alkyd resin

Spherical TiO2 particles of different size were dispersed in alkyd resin based on soybean oil. Four samples of TiO2 particles were used, three commercial and one obtained by acid catalyzed hydrolysis of titanium tetraisopropoxide. The size of the synthesized nanoparticles was determined by transmission electron microscopy. Surface modification of TiO2 nanoparticles was performed with propyl gallate and lauryl gallate. The influence of the size of TiO2 nanoparticles, their concentration and type of the surface modification on the rheological properties of alkyd resin was investigated. The obtained results have shown that the viscosity of the prepared dispersions was higher than viscosity of the pure resin, it increases with decreasing particle diameter and decreases with frequency increase. Surface modified particles showed higher influence on the viscosity of alkyd resin than unmodified, because their hydrodynamic volume is higher due to the presence of the adsorbed gallates, leading to the increase of effective volume fraction of particles in dispersion. For the lowest TiO2 concentration, the viscosity was higher for sample modified with lauryl gallate, due to the higher thickness of the adsorbed layer. The increase of concentration, because of less dispersion stability of the particles modified with propyl gallate, leads to particles agglomeration. The presence of agglomerates, which was confirmed by a change in the slope of the functional dependence of storage modulus on loss modulus, leads to a rapid increase in viscosity.

Enhancement of methyl violet removal by modification of TiO2 nanoparticles with AgI

Nanostructured AgI/TiO2 was synthesized by deposition–precipitation method. The AgI/TiO2 nanoparticles with different size were characterized using XRD and TEM methods. In order to compare the activity of these nanoparticles for removal of environmental pollutants, the adsorption of methyl violet by particles was studied. The equilibrium adsorption data were fitted to the different isotherms. The equilibrium data show that the modification of TiO2 nanoparticles with AgI, leads to the higher adsorption capacity (more than twice) for methyl violet. The kinetic data for adsorption of methyl violet indicates that modification of TiO2 with AgI leads to a stable adsorption.

Structure and photocatalytic performance of magnetically separable titania photocatalysts for the degradation of propachlor

A magnetic photocatalyst was prepared by modification of TiO2 nanoparticles (Degussa P25) with nanocrystalline γ-Fe2O3 nanoparticles through a protective lining made up of two oppositely charged polyelectrolytes. As-prepared magnetically separable photocatalysts differing in γ-Fe2O3 loading (3, 8, 13, 20 and 30wt.%) were characterized by XRD, TEM, thermal analysis, Mössbauer and magnetic measurements. The photocatalytic efficiency of the nanocomposite catalysts was evaluated using a chloroacetanilide herbicide (propachlor) in water as model compound. The primary degradation of propachlor followed pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. Generally, all magnetic photocatalysts exhibit good catalytic activity towards organic pollutants, do not suffer from photodissolution and can be reused several times without any decrease in their photocatalytic activity.

Effect of TiO2 Nanoparticles on the Improved Performances on Electrochemically Prepared Surface-Enhanced Raman Scattering-Active Silver Substrates

In this work, we use electrochemical oxidation−reduction cycles (ORC) methods to prepare surface-enhanced Raman scattering (SERS)-active silver substrates modified with TiO2 nanoparticles to improve the corresponding SERS performances. On the basis of the modified substrates, the SERS of Rhodamine 6G (R6G) exhibits a higher intensity by 4-fold of magnitude, as compared with that of R6G adsorbed on a SERS-active Ag substrate without the modification of TiO2 nanoparticles. Moreover, the SERS enhancement capabilities of the modified and the unmodified Ag substrates are seriously destroyed at temperatures higher than 200 and 125 °C, respectively. These results indicate that the modification of TiO2 nanoparticles can improve the thermal stability of SERS-active substrates. More interestingly, the SERS intensity of R6G was significantly increased by 9-fold of magnitude, as the temperature of the modified Ag substrate was raised from 25 to 125 °C. The aging in SERS intensity is also depressed on this modified Ag...

Influence of nanoparticle surface modification on the electrical behaviour of polyethylenenanocomposites

In this study, we present the results of the influence of surface modification ofTiO2 nanoparticles on the short-term breakdown strength and space chargedistribution of low-density polyethylene (LDPE). A polar silane coupling agentN-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPS) was used for thenanoparticle surface modification. Despite agglomeration and a poor interfacecompared to untreated nanoparticles, it was found that the incorporation of polargroups onto the nanoparticle surface improved both the dielectric breakdownstrength and space charge distribution as compared to samples filled with untreatednanoparticles. Microstructure studies showed that the presence of polar groups on theTiO2 nanoparticle surface did not evidently affect the degree of crystallinity, crystallinemorphology (except for internal spherulitic order), and chemical structure of the polymermatrix. The improved dielectric breakdown strength was therefore concluded to be directlydue to beneficial effects related to the variation of the electrical features at theparticle surface due to introduction of polar groups. For the same reason, with theuse of surface modified nanoparticles, formation of space charge was suppressed.