Boric Acid Reclamation System (BARS)

International Nuclear Information System (INIS)

Kniazewycz, B.G.; Markind, J.

1986-03-01

KLM Technologies' personnel have identified a Boric Acid Reclamation System (BARS) utilizing reverse osmosis and ultrafiltration to produce a recyclable grade of otherwise waste boric acid at PWRs, thus reducing a major source of low-level radwaste. The design of a prototype BARS as a compact volume reduction system was the result of KLM's Phase 1 Program, and based upon a preliminary feasibility program, which assessed the applicability of membrane technology to refurbish and recycle waste boric acid from floor and equipment drain streams. The analysis of the overall program indicated a substantial savings regarding off-site disposal costs. Today's economic scenario indicates that optimization of volume reduction operation procedures could significantly reduce waste management costs, especially where burial penalties have become more severe. As a reaction to the economic burden imposed by final disposal, many nuclear plants are currently modifying their design and operating philosophies concerning liquid radwaste processing systems to meet stricter environmental regulations, and to derive potential economic benefits by reducing the ever-increasing volumes of wastes that are produced. To effect these changes, innovative practices in waste management and more efficient processing technologies are being successfully implemented

Zinc-Nickel Codeposition in Sulfate Solution Combined Effect of Cadmium and Boric Acid

Directory of Open Access Journals (Sweden)

Y. Addi

2011-01-01

Full Text Available The combined effect of cadmium and boric acid on the electrodeposition of zinc-nickel from a sulfate has been investigated. The presence of cadmium ion decreases zinc in the deposit. In solution, cadmium inhibits the zinc ion deposition and suppresses it when deposition potential value is more negative than −1.2 V. Low concentration of CdSO4 reduces the anomalous nature of Zn-Ni deposit. Boric acid decreases current density and shifts potential discharge of nickel and hydrogen to more negative potential. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. Boric acid and cadmium.

Boric acid corrosion of low alloy steel

Energy Technology Data Exchange (ETDEWEB)

Jones, R.; White, G.; Collin, J.; Marks, C. [Dominion Engineering, Inc., Reston, Virginia (United States); Reid, R.; Crooker, P. [Electric Power Research Inst., Palo Alto, California (United States)

2010-07-01

In the last decade, the industry has been aware of a potential loss of coolant accident (LOCA) per the following scenario: primary water stress corrosion cracking (PWSCC) of a primary system component or weld leads to a coolant leak, the coolant corrodes a low alloy steel structural component (e.g., the reactor vessel (RV) or the reactor vessel head (RVH)), and corrosion degrades the pressure boundary leading to a loss of coolant accident. The industry has taken several steps to address this concern, including replacement of the most susceptible components (RVH replacement), enhanced inspection (both NDE of components and visual inspections for boric acid deposits), and safety analyses to determine appropriate inspection intervals. Although these measures are generally thought to have adequately addressed this issue, there have been some uncertainties in the safety analyses which the industry has sought to address in order to quantify the extent of conservatism in the safety analyses. Specifically, there has been some uncertainty regarding the rate of boric acid corrosion under various conditions which might arise due to a PWSCC leak and the extent to which boric acid deposits are retained near the leak under various geometries. This paper reviews the results of the Electric Power Research Institute (EPRI) Materials Reliability Program (MRP) boric acid corrosion (BAC) test programs conducted over the last 8 years, focusing on the most recent results of full-scale mockup testing of CRDM nozzle and bottom mounted nozzle (BMN) configurations. The main purpose of this presentation is to provide an overview of the latest understanding of the risk of boric acid corrosion as it is informed by the results of the testing conducted over the last eight years. The rate of boric acid corrosion has been found to be a function of many factors, including initial chemistry, the extent of concentration due to boiling, the temperature at which concentration takes place, the velocity

General corrosion of metallic materials in boric acid environments

International Nuclear Information System (INIS)

Gras, J.M.

1994-05-01

Certain low-alloy steel components in PWR primary circuit were corroded by leaking water containing boric acid. A number of studies have been performed by manufacturers in the USA and by EDF in France to determine the rate of general corrosion for low-alloy steels in media containing varying concentrations of boric acid. The first part of this paper summarizes the studies performed and indicates how far work has advanced to date in establishing the resistance of stainless steels to general corrosion in concentrated boric acid solutions. The second part of the paper discusses the mechanism of corrosion and proposes a model. Carbon steels and low-alloy steels - carbon steels and low-alloy steels in deaerated diluted boric acid solutions (pH > 4) corrode very slowly ( -1 . (author). 31 refs., 12 figs., 13 tabs

Ion exchange separation of low boric acid concentrations from water

International Nuclear Information System (INIS)

Kysela, J.; Brabec, J.; Peterka, F.

1975-01-01

Boric acid poisoning of the moderator of the TR-O experimental heavy water reactor was studied. The possibility is discussed of removing boric acid from heavy water by means of a strong basic anion exchanger, below the residual concentration of 0.01 mg B/l. Measurements of the usable capacities of the strong basic anion exchanger Zerollit FF showed that the penetration of boric acid during the sorption period does not exceed the value of 0.015 mg B/l. The dependence was found of capacity on the boric acid concentration in the solution. Analytical methods used to determine B in water are also described. (author)

Boric Acid Corrosion of Concrete Rebar

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Yang L.

2013-07-01

Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure and compromise the integrity of the structure. Because corrosion rate of carbon steel in concrete in the presence of boric acid is lacking in published literature and available data are equivocal on the effect of boric acid on rebar corrosion, corrosion rate measurements were conducted in this study using several test methods. Rebar corrosion rates were measured in (i borated water flowing in a simulated concrete crack, (ii borated water flowing over a concrete surface, (iii borated water that has reacted with concrete, and (iv 2,400 ppm boric acid solutions with pH adjusted to a range of 6.0 to 7.7. The corrosion rates were measured using coupled multielectrode array sensor (CMAS and linear polarization resistance (LPR probes, both made using carbon steel. The results indicate that rebar corrosion rates are low (~1 μm/yr or lesswhen the solution pH is ~7.1 or higher. Below pH ~7.1, the corrosion rate increases with decreasing pH and can reach ~100 μm/yr in solutions with pH less than ~6.7. The threshold pH for carbon steel corrosion in borated solution is between 6.8 and 7.3.

Boric Acid Reclamation System (BARS)

International Nuclear Information System (INIS)

Kniazewycz, B.G.; Markind, J.

1986-01-01

KLM Technologies was recently awarded a contract by the Department of Energy for a Phase II demonstration of an optimized full-scale prototype membrane system including performance evaluation under plant operating conditions. The program will serve as the catalyst for developing technology to augment the industry's incentive toward innovative and compact volume reduction alternatives for PWRs. The development and demonstration of the KLM Boric Acid Reclamation System, which is readily retrofitted into existing PWR facilities, will provide a positive means of reducing PWR waste volumes without requiring the $25-50 million equipment and support facility expenditures associated with most liquid waste volume reduction systems. This new application for membrane separation technology can reduce waste by upward of 50 percent for two-thirds of the operating nuclear plants in the U.S. The use of membrane technology has demonstrated significant process potential in radwaste and related applications. Reverse Osmosis (RO) and Ultrafiltration (UF) can provide selective filtration capability and concentrate contaminants without the need of filter aids, thus minimizing the requirements of chemical regeneration, costly resins, and major process equipment with large auxiliary heat supplies. KLM Technologies' personnel have identified a Boric Acid Reclamation System (BARS) utilizing RO and UF to produce a recyclable grade of otherwise waste boric acid at PWRs, thus reducing a major source of low-level radwaste. The design of a prototype BARS as a compact volume reduction system was the result of KLM's Phase I Program, and based upon a preliminary feasibility program, which assessed the applicability of membrane technology to refurbish and recycle waste boric acid from floor and equipment drain streams. The analysis of the overall program indicated a substantial savings regarding off-site disposal costs

Characterisation of boric acid aerosol behaviour and interactions with stainless steel

International Nuclear Information System (INIS)

Anderson, A.B.; Beard, A.M.; Bennett, P.J.; Benson, C.G.

1991-03-01

Experiments have been conducted to determine the physical characteristics of boric acid aerosol. Aqueous solutions of boric acid (either 200 or 2000 ppm boron) were injected at a controlled rate onto a 304 stainless steel cone held at 1000 o C. The transport and deposition of the resulting aerosol was studied through a system including pipework and a dilution chamber. Work was also undertaken to characterise the interaction between boric acid and stainless steel. Boric acid was vaporized in steam-argon atmospheres at 300 o C and passed over 304 stainless steel coupons held at temperatures between 400 and 1000 o C. (author)

Antimicrobial activity of eumelanin-based hybrids: The role of TiO2 in modulating the structure and biological performance

International Nuclear Information System (INIS)

Vitiello, Giuseppe; Pezzella, Alessandro; Zanfardino, Anna; Silvestri, Brigida; Giudicianni, Paola; Costantini, Aniello; Varcamonti, Mario; Branda, Francesco; Luciani, Giuseppina

2017-01-01

Eco-friendly hybrid Eumelanin-TiO 2 nanostructures, recently obtained through in situ methodology based on hydrothermal route, have shown a striking antimicrobial activity, after exposure to oxidative environment, even under visible light induction condition. Nevertheless, the role of each component in defining the efficacy of these biological properties is far from being clearly defined. Furthermore, the effect of oxidative step on hybrids structure has not yet addressed. This study aims at elucidating the role of the ratio between eumelanin precursor, 5,6-dihydroxyindole-2-carboxylic acid (DHICA), and TiO 2 , for its polymerization in defining morphology and structural organization of TiO 2 -melanin nanostructures. Furthermore, tests on a Gram-negative Escherichia coli DH5α strain under UV irradiation and even visible light allowed to assess the contribution of each component, as well as of the TiO 2 –DHICA charge transfer complex to overall biological performance. Finally, results of biocide characterization were combined with spectroscopic evidences to prove that oxidative treatment induces a marked structural modification in melanin thus enhancing overall antimicrobial efficacy. - Highlights: • Eco-friendly hybrid Eumelanin-TiO 2 nanostructures shows striking antimicrobial activity under visible light. • TiO 2 catalyzes 5,6-dihydroxyindole-2-carboxylic acid (DHICA) polymerization to eumelanin. • Eumelanin precursor/catalyst ratio modulates physico-chemical and structural properties of hybrid nanostructures. • Oxidative treatment increases the reticulation grade of the polymeric chains within the nanoparticles. • Additional oxidative process of the eumelanin pigment strongly improves the antimicrobial activity of hybrids.

Boric acid solubility in the presence of alkali metal nitrides

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Tsekhanskij, R S; Molodkin, A K; Sadetdinov, Sh V [Chuvashskij Gosudarstvennyj Univ., Cheboksary (USSR); Universitet Druzhby Narodov, Moscow (USSR))

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodium, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion. Boric acid is salted out from solutions containing lithium and sodium cations with increase of nitrate ion.

Boric acid solubility in the presence of alkali metal nitrides

International Nuclear Information System (INIS)

Skvortsov, V.G.; Tsekhanskij, R.S.; Molodkin, A.K.; Sadetdinov, Sh.V.

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodiUm, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion Boric acid is salted out form solutions containing lithium and sodium cations with increase of nitrate ion

Preparation of Transparent Bulk TiO2/PMMA Hybrids with Improved Refractive Indices via an in Situ Polymerization Process Using TiO2 Nanoparticles Bearing PMMA Chains Grown by Surface-Initiated Atom Transfer Radical Polymerization.

Science.gov (United States)

Maeda, Satoshi; Fujita, Masato; Idota, Naokazu; Matsukawa, Kimihiro; Sugahara, Yoshiyuki

2016-12-21

Transparent TiO 2 /PMMA hybrids with a thickness of 5 mm and improved refractive indices were prepared by in situ polymerization of methyl methacrylate (MMA) in the presence of TiO 2 nanoparticles bearing poly(methyl methacrylate) (PMMA) chains grown using surface-initiated atom transfer radical polymerization (SI-ATRP), and the effect of the chain length of modified PMMA on the dispersibility of modified TiO 2 nanoparticles in the bulk hybrids was investigated. The surfaces of TiO 2 nanoparticles were modified with both m-(chloromethyl)phenylmethanoyloxymethylphosphonic acid bearing a terminal ATRP initiator and isodecyl phosphate with a high affinity for common organic solvents, leading to sufficient dispersibility of the surface-modified particles in toluene. Subsequently, SI-ATRP of MMA was achieved from the modified surfaces of the TiO 2 nanoparticles without aggregation of the nanoparticles in toluene. The molecular weights of the PMMA chains cleaved from the modified TiO 2 nanoparticles increased with increases in the prolonging of the polymerization period, and these exhibited a narrow distribution, indicating chain growth controlled by SI-ATRP. The nanoparticles bearing PMMA chains were well-dispersed in MMA regardless of the polymerization period. Bulk PMMA hybrids containing modified TiO 2 nanoparticles with a thickness of 5 mm were prepared by in situ polymerization of the MMA dispersion. The transparency of the hybrids depended significantly on the chain length of the modified PMMA on the nanoparticles, because the modified PMMA of low molecular weight induced aggregation of the TiO 2 nanoparticles during the in situ polymerization process. The refractive indices of the bulk hybrids could be controlled by adjusting the TiO 2 content and could be increased up to 1.566 for 6.3 vol % TiO 2 content (1.492 for pristine PMMA).

Lubrication from mixture of boric acid with oils and greases

Science.gov (United States)

Erdemir, Ali

1995-01-01

Lubricating compositions including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

High production of D-tagatose by the addition of boric acid.

Science.gov (United States)

Lim, Byung-Chul; Kim, Hye-Jung; Oh, Deok-Kun

2007-01-01

An L-arabinose isomerase mutant enzyme from Geobacillus thermodenitrificans was used to catalyze the isomerization of D-galactose to D-tagatose with boric acid. Maximum production of D-tagatose occurred at pH 8.5-9.0, 60 degrees C, and 0.4 molar ratio of boric acid to D-galactose, and the production increased with increasing enzyme concentration. Under the optimum conditions, the enzyme (10.8 units/mL) converted 300 g/L D-galactose to 230 g/L D-tagatose for 20 h with a yield of 77% (w/w); the production and conversion yield with boric acid were 1.5-fold and 24% higher than without boric acid, respectively. In 24 h, the enzyme produced 370 g/L D-tagatose from 500 g/L D-galactose with boric acid, corresponding to a conversion yield of 74% (w/w) and a production rate of 15.4 g/L.h. The production and yield of D-tagatose obtained in this study are unprecedented.

The development of precisely analytical method for the concentrated boric acid solution in the NPP systems

Energy Technology Data Exchange (ETDEWEB)

Sung, G. B.; Jung, K. H.; Kang, D. W. [KEPRI, Taejon (Korea, Republic of); Park, C. S. [KEPCO, Taejon (Korea, Republic of)

1999-05-01

Boric acid is used for reactivity control in nuclear reactors, which frequently results in leftover boric acid. This extra boric acid is stored in boric acid storage tank after the concentration process by boric acid evaporator. Apart from this excess, highly concentrated boric acid is stored in safety-related boric acid storage tank. Accordingly, proper maintenance of these boric acid is one of the greatest safety concerns. The solubility of boric acid decreases with decreasing temperature resulting in its precipitation. Consequently, the temperature of boric acid storage tanks is maintained at high temperature. The following analysis should be also performed at the similar temperature to prevent the formation of boric acid precipitation, which is difficult to achieve affecting the accuracy of analytical results. This paper presents a new sampling and measuring technique that makes up for the difficulties mentioned above and shows several advantages including improved reliability and short analysis time. This method is based on gravimetry and dilution method and is expected to be widely used in field application.

Synthesis of hybrid cellulose nanocomposite bonded with dopamine SiO2/TiO2 and its antimicrobial activity

Science.gov (United States)

Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Jaehwan; Kim, Joo-Hyung

2015-04-01

Organic-inorganic hybrid material based cellulose was synthesized by the sol-gel approach. The explosion of activity in this area in the past decade has made tremendous progress in industry or academic both fundamental understanding of sol-gel process and applications of new functionalized hybrid materials. In this present research work, we focused on cellulose-dopamine functionalized SiO2/TiO2 hybrid nanocomposite by sol-gel process. The cellulose-dopamine hybrid nanocomposite was synthesized via γ-aminopropyltriethoxysilane (γ-APTES) coupling agent by in-situ sol-gel process. The chemical structure of cellulose-amine functionalized dopamine bonding to cellulose structure with covalent cross linking hybrids was confirmed by FTIR spectral analysis. The morphological analysis of cellulose-dopamine nanoSiO2/TiO2 hybrid nanocomposite materials was characterized by XRD, SEM and TEM. From this different analysis results indicate that the optical transparency, thermal stability, control morphology of cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite. Furthermore cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite was tested against pathogenic bacteria for antimicrobial activity.

Modification of Titanium Dioxide Nanoparticles With Copper Oxide Co-Catalyst for Photo catalytic Degradation of 2,4-Dichlorophenoxyacetic Acid

International Nuclear Information System (INIS)

Leny Yuliati; Siah, W.R.; Nur Azmina Roslan; Mustaffa Shamsuddin

2016-01-01

2,4-dichlorophenoxyacetic acid (2,4-D) is a common herbicide that has been used widely. Due to its excessive usage, the 2,4-D herbicides can cause contamination over agricultural land and water bodies. In the present work, a simple impregnation method was used to modify the commercial titanium dioxide (P25 TiO_2) nanoparticles with the copper oxide. The prepared samples were characterized by X-ray Diffraction (XRD), reflectance UV-visible and fluorescence spectroscopies. It was observed that the incorporation of copper oxide did not significantly affect the crystal structure of P25 TiO_2. On the other hand, the presence of copper oxide was confirmed by reflectance UV-visible and fluorescence spectroscopies. The activity of the prepared sample was evaluated for photo catalytic removal of the 2,4-D. The photo catalytic activity of the TiO_2 increased with the increase of copper oxide loading up to 0.5 mol %. Unfortunately, the higher loading amount of copper oxide resulted in the lower photo catalytic activity. This study suggested that the higher photo catalytic activities obtained on the low loading samples were due to the lower electron-hole recombination. (author)

Experimental Study and Reactive Transport Modeling of Boric Acid Leaching of Concrete

Directory of Open Access Journals (Sweden)

Chiang K.-T. K.

2013-07-01

Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure, compromise the integrity of the structure, or cause unmonitored releases of contaminated water to the environment. Experimental data indicate that pH is a critical parameter that determines the corrosion susceptibility of rebar in borated water and the degree of concrete degradation by boric acid leaching. In this study, reactive transport modeling of concrete leaching by borated water was performed to provide information on the solution pH in the concrete crack or matrix and the degree of concrete degradation at different locations of an SFP concrete structure exposed to borated water. Simulations up to 100 years were performed using different boric acid concentrations, crack apertures, and solution flow rates. Concrete cylinders were immersed in boric acid solutions for several months and the mineralogical changes and boric acid penetration in the concrete cylinder were evaluated as a function of time. The depths of concrete leaching by boric acid solution derived from the reactive transport simulations were compared with the measured boric acid penetration depth.

Boric acid - ammonium rhodanide (nitrate, sulfate) - water system at 25 deg C

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Molodkin, A K; Tsekhanskij, R S; Sadetdinov, Sh V; Nikonov, F V [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (USSR); Universitet Druzhby Narodov, Moscow (USSR))

1985-03-01

Methods of isothermal solubility and refractometry have been used to establish that boric acid-ammonium rhodanite (nitrate, sulfate) - water systems are of a simple eutonic type. Rhodanide salts out boric acid, while nitrate and sulfate salt it in. The lyotropic effect referred to the volumetric share of both anion and cation increases in the series SCN/sup -/ < NO/sub 3//sup -/ < SO/sub 4//sup 2 -/.

CEC mechanism in electrochemical oxidation of nitrocatechol-boric acid complexes

International Nuclear Information System (INIS)

Rafiee, Mohammad; Nematollahi, Davood; Salehzadeh, Hamid

2011-01-01

Graphical abstract: Display Omitted Highlights: → Nitrochetechol and its anionic form undergo complex reaction with boric acid. → The electron transfer of complex is coupled with both proceeding and following chemical reactions. → Electrochemical behavior of complex is resolved by diagnostic criteria and digital simulation. - Abstract: The electrochemical behavior of nitrocatechols-boric acid complexes in aqueous solution has been studied using cyclic voltammetry. The results indicate that nitrocatechol-boric acid complex derivatives are involved in the CEC mechanism. In this work, the impact of empirical parameters on the shape of the voltammograms is examined based on a CEC mechanism. In addition, homogeneous rate constants of both the preceding and the following reactions were estimated by comparing the experimental cyclic voltammograms with the digitally simulated results. The calculated dissociation constants for the complexes (K d ) and for ring cleavage of nitroquinone (k f2 ) were found to vary in the following order: 4-nitrocatechol > 3-methylnitrocatechol > 3-metoxynitrocatechol.

The boric acid - ammonium rhodanide (nitrate, sulfate) - water system at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Molodkin, A.K.; Tsekhanskij, R.S.; Sadetdinov, Sh.V.; Nikonov, F.V.

1985-01-01

Methods of isothermal solubility and refractometry have been used to establish that boric acid-ammonium rhodanite (nitrate, sulfate) - water systems are of a simple eutonic type. Rhodanide salts out boric acid, while nitrate and sulfate salt it in. The lyotropic effect referred to the volumetric share of both anion and cation increases in the series SCN - 3 - 4 2-

The Effects of Doping Copper and Mesoporous Structure on Photocatalytic Properties of TiO2

Directory of Open Access Journals (Sweden)

Yang Wang

2014-01-01

Full Text Available This paper describes a system for the synthesis of Cu-doped mesoporous TiO2 nanoparticles by a hydrothermal method at relatively low temperatures. The technique used is to dope the as-prepared mesoporous TiO2 system with copper. In this method, the copper species with the form of Cu1+, which was attributed to the reduction effect of dehydroxylation and evidenced by X-ray photoelectron spectroscopy (XPS and X-ray diffraction (XRD, was well dispersed in the optimal concentration 1 wt.% Cu-doped mesoporous TiO2. In this as-prepared mesoporous TiO2 system, original particles with a size of approximately 20 nm are aggregated together to shapes of approximately 1100 nm, which resulted in the porous aggregate structure. More importantly, the enhancement of the photocatalytic activity was discussed as effects due to the formation of stable Cu(I and the mesoporous structure in the Cu-doped mesoporous TiO2. Among them, Cu-doped mesoporous TiO2 shows the highest degradation rate of methyl orange (MO. In addition, the effects of initial solution pH on degradation of MO had also been investigated. As a result, the optimum values of initial solution pH were found to be 3.

Novel Flexible Transparent Conductive Films with Enhanced Chemical and Electromechanical Sustainability: TiO2 Nanosheet-Ag Nanowire Hybrid.

Science.gov (United States)

Sohn, Hiesang; Kim, Seyun; Shin, Weonho; Lee, Jong Min; Lee, Hyangsook; Yun, Dong-Jin; Moon, Kyoung-Seok; Han, In Taek; Kwak, Chan; Hwang, Seong-Ju

2018-01-24

Flexible transparent conductive films (TCFs) of TiO 2 nanosheet (TiO 2 NS) and silver nanowire (Ag NW) network hybrid were prepared through a simple and scalable solution-based process. The as-formed TiO 2 NS-Ag NW hybrid TCF shows a high optical transmittance (TT: 97% (90.2% including plastic substrate)) and low sheet resistance (R s : 40 Ω/sq). In addition, the TiO 2 NS-Ag NW hybrid TCF exhibits a long-time chemical/aging and electromechanical stability. As for the chemical/aging stability, the hybrid TCF of Ag NW and TiO 2 NS reveals a retained initial conductivity (ΔR s /R s 4000%) or RuO 2 NS-Ag NW hybrid (ΔR s /R s > 200%). As corroborated by the density functional theory simulation, the superb chemical stability of TiO 2 NS-Ag NW hybrid is attributable to the unique role of TiO 2 NS as a barrier, which prevents Ag NW's chemical corrosion via the attenuated adsorption of sulfidation molecules (H 2 S) on TiO 2 NS. With respect to the electromechanical stability, in contrast to Ag NWs (ΔR/R 0 ∼ 152.9%), our hybrid TCF shows a limited increment of fractional resistivity (ΔR/R 0 ∼ 14.4%) after 200 000 cycles of the 1R bending test (strain: 6.7%) owing to mechanically welded Ag NW networks by TiO 2 NS. Overall, our unique hybrid of TiO 2 NS and Ag NW exhibits excellent electrical/optical properties and reliable chemical/electromechanical stabilities.

Liquid Superlubricity of Polyethylene Glycol Aqueous Solution Achieved with Boric Acid Additive.

Science.gov (United States)

Ge, Xiangyu; Li, Jinjin; Zhang, Chenhui; Luo, Jianbin

2018-03-27

Boric acid is a weak acid and has been used as a lubrication additive because of its special structure. In this study, we report that boric acid could achieve a robust superlubricity (μ friction coefficient of approximately 0.004-0.006 could be achieved with boric acid under neutral conditions (pH of approximately 6.4), which is different from the acidic conditions leading to superlubricity. The influence of various factors, including boric acid concentration, sliding speed, applied load, PEG molecular weight, and the volume of lubricant on the superlubricity, were investigated. The results reveal that the PEG aqueous solution with the boric acid additive could achieve superlubricity under a wide range of conditions. The surface composition analysis shows that the synergy effect between boric acid and PEG provides sufficient H + ions to realize the running-in process. Moreover, a composite tribochemical film composed of silica and ammonia-containing compounds were formed on the ball surface, contributing to the superlubricity. The film thickness calculation shows that superlubricity was achieved in a mixed lubrication region, and therefore, the superlubricity state was dominated by both the composite tribochemical film formed via the tribochemical reaction on the contact surfaces and the hydrodynamic lubricating film between the contact surfaces. Such a liquid superlubricity achieved under neutral conditions is of importance for both scientific understanding and engineering applications.

Fabrication of TiO_2 nanorod assembly grafted rGO (rGO@TiO_2-NR) hybridized flake-like photocatalyst

International Nuclear Information System (INIS)

Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

2017-01-01

Highlights: • TiO_2 nanorod assembly grafted with GO hybrid was successfully fabricated. • TiO_2 nanorods can reduce the aggregation of TiO_2 nanoparticles on graphene. • This unique structure facilitates the injection of electron from TiO_2 to graphene. - Abstract: To efficiently separate the photo-generated electron–hole pairs of TiO_2 hybrid, anatase TiO_2 nanorod assembly grafted reduced graphene oxides (rGO@TiO_2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO_2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO_2 microsphere assembly is obtained from TiO_2 nanorods. The presence of GO results in the formation of a flake-like TiO_2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO_2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min"−"1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO_2 sample (0.012 min"−"1). The enhanced photocatalytic activity of the rGO@TiO_2-NR hybrid was attributed to the strong interaction between TiO_2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO_2–rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO_2 to graphene, thus retarding the recombination of electron–hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity

Experimental observations of boric acid precipitation scenarios

Energy Technology Data Exchange (ETDEWEB)

Vaghetto, R., E-mail: r.vaghetto@tamu.edu; Childs, M., E-mail: masonchilds@tamu.edu; Jones, P., E-mail: pgjones87@tamu.edu; Lee, S., E-mail: sayalee@tamu.edu; Kee, E., E-mail: erniekee@gmail.com; Hassan, Y.A., E-mail: y-hassan@tamu.edu

2017-02-15

During a Loss of Coolant Accident (LOCA) in Light Water Reactors (LWR), borated water is injected into the core through the safety injection system. The continuous vaporization of the water from the core may increase the concentration of boric acid in the core that, under certain conditions may reach the solubility limit and precipitate. This includes scenarios where the liquid water supply to the core is affected by possible blockages due to debris accumulation. Questions have been raised on the effects of the precipitate in the core on the flow behavior, including the possibility of additional blockages produced by precipitate accumulation. A simple experimental facility was constructed to perform experimental observations of the behavior of borated water under the combined effects of the boiling and the boric acid precipitation (BAP). The facility consists of a transparent polycarbonate vertical pipe where forty-five heated rods have been installed to supply the power to the water to reach the saturation temperature, and maintain a desired boil-off rate. The layout and geometry of the experimental apparatus were conceived to emulate a simplified core of a Pressurized Water Reactor (PWR). Experimental observations have been conducted under two different conditions. Preliminary tests were conducted to observe the behavior of the water and the boric acid precipitate during a boil-off scenario without borated water addition (decreasing water level). During the main test runs, borated water was constantly injected from the top of the test section to maintain a constant mixture level in the test section. Both tests assumed no flow from the bottom of the test section which may be the case of PWR LOCA scenarios in presence of debris-generated core blockage. The observations performed with a set of cameras installed around the test section showed interesting effects of the vapor bubbles on the boric acid precipitate migration and accumulation in the test section. The

Esterification of microcrystalline cellulose by binary mixture of pyromellitic dianhydride and boric acid

International Nuclear Information System (INIS)

Arslanov, Sh.S.; Petropavlovskij, G.A.

1996-01-01

The reaction between microcrystalline cellulose and boric acid in the medium of dimethyl-sulfoxide (DMSO) and in solid phase has been studied. By the methods of IR and 1 H NMR spectroscopy it has been shown that the triatment of cellulose with boric acid solution in DMSO, while the latter is removed under vacuum conditions and cellulose is heated up to 170 deg C, gives rise to formation of unstable esters of cellulose and boric acid. Pyromellitate-borates of cellulose are formed in the course of cellulose reaction with a mixture of boric acid and pyromellite dianhydride. 9 refs., 3 figs., 1 tab

Chloride stress corrosion cracking of Alloy 600 in boric acid solutions

International Nuclear Information System (INIS)

Berge, Ph.; Noel, D.; Gras, J.M.; Prieux, B.

1997-10-01

The high nickel austenitic alloys are generally considered to have good resistance to chloride stress corrosion cracking. In the standard boiling magnesium chloride solution tests, alloys with more than 40% nickel are immune. Nevertheless, more recent data show that cracking can occur in both Alloys 600 and 690 if the solution is acidified. In other low pH media, such as boric acid solution at 100 deg C, transgranular and intergranular cracking are observed in Alloy 600 in the presence of minor concentrations of sodium chloride (2g/I). In concentrated boric acid at higher temperatures (250 and 290 deg C), intergranular cracking also occurs, either when the chloride concentration is high, or at low chloride contents and high oxygen levels. The role of pH and a possible specific action of boric acid are discussed, together with the influence of electrochemical potential. (author)

The Usability of Boric Acid as an Alternative Foaming Agent on the Fabrication of Al/Al2O3 Composite Foams

Science.gov (United States)

Yaman, Bilge; Onuklu, Eren; Korpe, Nese O.

2017-09-01

Pure Al and alumina (2, 5, 10 wt.% Al2O3)-added Al composite foams were fabricated through powder metallurgy technique, where boric acid (H3BO3) is employed as a new alternative foaming agent. It is aimed to determine the effects of boric acid on the foaming behavior and cellular structure and also purposed to develop the mechanical properties of Al foams by addition of Al2O3. Al and Al composite foams with porosity fraction in the range of 46-53% were achieved by sintering at 620 °C for 2 h. Cell morphology was characterized using a combination of stereomicroscope equipped with image analyzer and scanning electron microscopy. Microhardness values were measured via using Vickers indentation technique. Quasi-static compression tests were performed at strain rate of 10-3 s-1. Compressive strength and energy absorption of the composite foams enhanced not only by the increasing weight fraction of alumina, but also by the usage of boric acid which leads to formation of boron oxide (B2O3) acting as a binder in obtaining dense cell walls. The results revealed that the boric acid has outstanding potential as foaming agent in the fabrication of Al and Al composite foams by providing improved mechanical properties.

Linear and nonlinear optical studies of bare and copper doped TiO2 nanoparticles via sol gel technique

Science.gov (United States)

Rajamannan, B.; Mugundan, S.; Viruthagiri, G.; Praveen, P.; Shanmugam, N.

2014-01-01

In general, the nanoparticles of TiO2 may exist in the phases of anatase, rutile and brookite. In the present work, we used titanium terta iso propoxide and 2-propanol as a common starting material to prepare the precursors of bare and copper doped nanosized TiO2. Then the synthesized products were calcinated at 500 °C and after calcination the pure TiO2 nanoparticles in anatase phase were harvested. The crystallite sizes of bare and copper doped TiO2 nanoparticles were calculated from X-ray diffraction analysis. The existence of functional groups of the samples was identified by Fourier transform infrared spectroscopy. The optical properties of bare and doped samples were carried out using UV-DRS and photoluminescence measurements. The surface morphology and the element constitution of the copper doped TiO2 nanoparticles were studied by scanning electron microscope fitted with energy dispersive X-ray spectrometer arrangement. The nonlinear optical properties of the products were confirmed by Kurtz second harmonic generation (SHG) test and the output power generated by the nanoparticle was compared with that of potassium di hydrogen phosphate (KDP).

TiO2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity

International Nuclear Information System (INIS)

Tian Lihong; Ye Liqun; Deng Kejian; Zan Ling

2011-01-01

MWCNT/TiO 2 hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO 2 nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO 2 was 20%, MWCNT/TiO 2 hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO 2 nanostructures at 400 deg. C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue. - Graphical abstract: MWCNT/TiO 2 nanostructures have been prepared by solvothermal method, which exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. The carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs enhanced the photoabsorbance of the hybrid materials in the visible light region. Highlights: → Anatase TiO 2 nanoparticles were anchored on CNTs surface uniformly via solvothermal method → The morphology facilitated the electron transfer between CNTs and TiO 2 → Ti-C bonds extended the absorption of MWCNT/TiO 2 to the whole visible light region. → The hybrid nanostructures showed enhanced visible-light induced photocatalytic activity.

Preliminary Evaluation Of DWPF Impacts Of Boric Acid Use In Cesium Strip FOR SWPF And MCU

International Nuclear Information System (INIS)

Stone, M.

2010-01-01

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the current dilute nitric acid strip solution with boric acid. To support this effort, the impact of using 0.01M, 0.1M, 0.25M and 0.5M boric acid in place of 0.001M nitric acid was evaluated for impacts on the DWPF facility. The evaluation only covered the impacts of boric acid in the strip effluent and does not address the other changes in solvents (i.e., the new extractant, called MaxCalix, or the new suppressor, guanidine). Boric acid additions may lead to increased hydrogen generation during the SRAT and SME cycles as well as change the rheological properties of the feed. The boron in the strip effluent will impact glass composition and could require each SME batch to be trimmed with boric acid to account for any changes in the boron from strip effluent additions. Addition of boron with the strip effluent will require changes in the frit composition and could lead to changes in melt behavior. The severity of the impacts from the boric acid additions is dependent on the amount of boric acid added by the strip effluent. The use of 0.1M or higher concentrations of boric acid in the strip effluent was found to significantly impact DWPF operations while the impact of 0.01M boric acid is expected to be relatively minor. Experimental testing is required to resolve the issues identified during the preliminary evaluation. The issues to be addressed by the testing are: (1) Impact on SRAT acid addition and hydrogen generation; (2) Impact on melter feed rheology; (3) Impact on glass composition control; (4) Impact on frit production; and (5) Impact on melter offgas. A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system includes the option to replace the

Experimental and modeling study of Portland cement paste degradation in boric acid

International Nuclear Information System (INIS)

Benakli, A.; Chomat, L.; Le Bescop, P.; Wall, J.

2015-01-01

In the framework of Spent Fuel Pools (SFP) lifetime studies, an investigation of the Portland cement degradation in boric acid has been requested by the Electric Power Research Institute. The main goal of this study is to identify the physico-chemical degradation mechanisms involved in boric acid media. Both experimental and modeling approaches are considered. Concerning degradation experiments, sample of cement paste are immersed during three and nine months in a boric acid solution at 2400 ppm that is periodically renewed. Boric acid concentration has been chosen to be representative of SFP solution. Results will be confronted with reactive transport numerical calculations performed by the reactive transport code HYTEC associated with a dedicated extended database called Thermoddem. The analysis of degradation solution revealed a main ions release mechanism driven by diffusion especially for calcium, nitrate, sodium and sulfate. Leaching behavior of magnesium seems to be more complex. Decalcification is the major degradation process involved, even if a non-negligible contribution of further cations (Mg 2+ , Na + ) and anions (SO 4 2- ) has been noticed. Analysis of degradation soution also revealed that kinetic of Portland cement paste degradation in boric acid is higher than in pure water, regarding the degraded depths measured and calcium leaching rate. This observation has been confirmed by solid characterization. Microstructure analysis of degraded Portland cement paste showed a global porosity increase in the degraded zone that might be mainly attributed to Portlandite dissolution. An Ettringite reprecipitation in the degraded zone has been suspected but could also be Ettringite-like phases containing boron. The analysis techniques used did not allow us to differentiate it, and no others specific mineral phases containing boron has been identified. Profile pattern by XRD analysis allowed us to identify four zones composing the degraded Portland cement paste

Study of structural, surface and hydrogen storage properties of boric acid mediated metal (sodium)-organic frameworks

Science.gov (United States)

Ozer, Demet; Köse, Dursun A.; Sahin, Onur; Oztas, Nursen A.

2018-04-01

Three boric acid mediated metal organic frameworks were synthesized by solution method with using succinic acid, fumaric acid and acetylene dicarboxylic acid as a ligand source and sodium as a metal source. The complexes were characterized by FT-IR, powder XRD, elemental analyses and single crystal measurements. The complexes with the formula, C4H18B2Na2O14, C4H16B2Na2O14 and C4H14B2Na2O14 were successfully obtained. BET surface area of complexes were calculated and found as 13.474 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-succinato)-di-sodium boric acid solvate), 1.692 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-fumarato)-di-sodium boric acid solvate) and 5.600 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-acetylenedicarboxylato)-di-sodium boric acid solvate). Hydrogen storage capacities of the complexes were also studied at 77 K 1 bar pressure and found as 0.108%, 0.033%, 0.021% by mass. When different ligands were used, the pore volume, pore width and surface area of the obtained complexes were changed. As a consequence, hydrogen storage capacities also changed.

One-step synthesis of hierarchically porous hybrid TiO2 hollow spheres with high photocatalytic activity

Science.gov (United States)

Liu, Ruiping; Ren, Feng; Yang, Jinlin; Su, Weiming; Sun, Zhiming; Zhang, Lei; Wang, Chang-an

2016-03-01

Hierarchically porous hybrid TiO2 hollow spheres were solvothermally synthesized successfully by using tetrabutyl titanate as titanium precursor and hydrated metal sulfates as soft templates. The as-prepared TiO2 spheres with hierarchically pore structures and high specific surface area and pore volume consisted of highly crystallized anatase TiO2 nanocrystals hybridized with a small amount of metal oxide from the hydrated sulfate. The proposed hydrated-sulfate assisted solvothermal (HAS) synthesis strategy was demonstrated to be widely applicable to various systems. Evaluation of the hybrid TiO2 hollow spheres for the photo-decomposition of methyl orange (MO) under visible-light irradiation revealed that they exhibited excellent photocatalytic activity and durability.

Surface interactions of cesium and boric acid with stainless steel

International Nuclear Information System (INIS)

Grossman-Canfield, N.

1995-08-01

In this report, the effects of cesium hydroxide and boric acid on oxidized stainless steel surfaces at high temperatures and near one atmosphere of pressure are investigated. This is the first experimental investigation of this chemical system. The experimental investigations were performed using a mass spectrometer and a mass electrobalance. Surfaces from the different experiments were examined using a scanning electron microscope to identify the presence of deposited species, and electron spectroscopy for chemical analysis to identify the species deposited on the surface. A better understanding of the equilibrium thermodynamics, the kinetics of the steam-accelerated volatilizations, and the release kinetics are gained by these experiments. The release rate is characterized by bulk vaporization/gas-phase mass transfer data. The analysis couples vaporization, deposition, and desorption of the compounds formed by cesium hydroxide and boric acid under conditions similar to what is expected during certain nuclear reactor accidents. This study shows that cesium deposits on an oxidized stainless steel surface at temperatures between 1000 and 1200 Kelvin. Cesium also deposits on stainless steel surfaces coated with boric oxide in the same temperature ranges. The mechanism for cesium deposition onto the oxide layer was found to involve the chemical reaction between cesium and chromate. Some revaporization in the cesium hydroxide-boric acid system was observed. It has been found that under the conditions given, boric acid will react with cesium hydroxide to form cesium metaborate. A model is proposed for this chemical reaction

Fabrication of TiO2 nanorod assembly grafted rGO (rGO@TiO2-NR) hybridized flake-like photocatalyst

Science.gov (United States)

Lv, Kangle; Fang, Shun; Si, Lingling; Xia, Yang; Ho, Wingkei; Li, Mei

2017-01-01

To efficiently separate the photo-generated electron-hole pairs of TiO2 hybrid, anatase TiO2 nanorod assembly grafted reduced graphene oxides (rGO@TiO2-NR) hybrid was successfully fabricated using potassium titanium oxalate (PTO) and graphene oxides (GO) as starting materials and diethylene glycol (DEG) as reductant. The effect of GO content on the structure and photocatalytic activity of rGO@TiO2-NR composite was systematically studied. Results show that, in the absence of GO, only TiO2 microsphere assembly is obtained from TiO2 nanorods. The presence of GO results in the formation of a flake-like TiO2-nanorod-assembled grafted rGO hybrid. The photocatalytic activity of rGO@TiO2-NR composite increases first and then decreases with increase in the amount of GO from 0 wt.% to 10 wt.%. The hybridized S4 sample prepared with 4 wt.% GO possesses the highest photocatalytic activity with a constant rate of 0.039 min-1 in the photocataytic degradation of Brilliant X-3B dye (X3B); this sample was enhanced more than three times when compared with pure TiO2 sample (0.012 min-1). The enhanced photocatalytic activity of the rGO@TiO2-NR hybrid was attributed to the strong interaction between TiO2 nanorods and rGO. The unique hierarchical structure of 1D nanorod assembly TiO2-rGO flakes facilitates the injection and transfer of photo-generated electrons from TiO2 to graphene, thus retarding the recombination of electron-hole pairs and enhancing the photocatalytic activity. The enlarged BET surface areas, not only increasing the number of active sites, but also facilitating the adsorption of the dye, and improved light-harvesting ability also contribute to the enhanced photoreactivity of rGO@TiO2-NR hybrid.

Studies on CO2-laser Hybrid-Welding of Copper

DEFF Research Database (Denmark)

Nielsen, Jakob Skov; Olsen, Flemming Ove; Bagger, Claus

2005-01-01

CO2-laser welding of copper is known to be difficult due to the high heat conductivity of the material and the high reflectivity of copper at the wavelength of the CO2-laser light. THis paper presents a study of laser welding of copper, applying laser hybrid welding. Welding was performed as a hy...

Inhibition studies of soybean (Glycine max) urease with heavy metals, sodium salts of mineral acids, boric acid, and boronic acids.

Science.gov (United States)

Kumar, Sandeep; Kayastha, Arvind M

2010-10-01

Various inhibitors were tested for their inhibitory effects on soybean urease. The K(i) values for boric acid, 4-bromophenylboronic acid, butylboronic acid, and phenylboronic acid were 0.20 +/- 0.05 mM, 0.22 +/- 0.04 mM, 1.50 +/- 0.10 mM, and 2.00 +/- 0.11 mM, respectively. The inhibition was competitive type with boric acid and boronic acids. Heavy metal ions including Ag(+), Hg(2+), and Cu(2+) showed strong inhibition on soybean urease, with the silver ion being a potent inhibitor (IC(50) = 2.3 x 10(-8) mM). Time-dependent inhibition studies exhibited biphasic kinetics with all heavy metal ions. Furthermore, inhibition studies with sodium salts of mineral acids (NaF, NaCl, NaNO(3), and Na(2)SO(4)) showed that only F(-) inhibited soybean urease significantly (IC(50) = 2.9 mM). Competitive type of inhibition was observed for this anion with a K(i) value of 1.30 mM.

CoFe2O4-TiO2 Hybrid Nanomaterials: Synthesis Approaches Based on the Oil-in-Water Microemulsion Reaction Method

Directory of Open Access Journals (Sweden)

Arturo Adrián Rodríguez-Rodríguez

2017-01-01

Full Text Available CoFe2O4 nanoparticles decorated and wrapped with TiO2 nanoparticles have been prepared by mixing well-dispersed CoFe2O4 with amorphous TiO2 (impregnation approach and growing amorphous TiO2 over the magnetic core (seed approach, respectively, followed by thermal treatment to achieve TiO2 crystallinity. Synthesis strategies were based on the oil-in-water microemulsion reaction method. Thermally treated nanomaterials were characterized in terms of structure, morphology, and composition, to confirm hybrid nanoparticles formation and relate with the synthesis approaches; textural, optical, and magnetic properties were evaluated. X-ray diffraction revealed coexistence of cubic spinel-type CoFe2O4 and tetragonal anatase TiO2. Electron microscopy images depicted crystalline nanoparticles (sizes below 25 nm, with homogeneous Ti distribution for the hybrid nanoparticles synthesized by seed approach. EDX microanalysis and ICP-AES corroborated established chemical composition. XPS evidenced chemical states, as well as TiO2 predominance over CoFe2O4 surface. According to BET measurements, the hybrid nanoparticles were mesoporous. UV-Vis spectroscopy showed optical response along the UV-visible light region. Magnetic properties suggested the breaking order of magnetic domains due to modification with TiO2, especially for mediated seed approach sample. The properties of the obtained hybrid nanoparticles were different in comparison with its individual components. The results highlight the usefulness of designed microemulsion approaches for the straightforward synthesis of CoFe2O4-TiO2 nanostructured hybrids.

Microwave-assisted synthesis and characterization of poly(acrylic)/SiO2-TiO2 core-shell nanoparticle hybrid thin films

International Nuclear Information System (INIS)

Chien, Wen-Chen; Yu, Yang-Yen; Chen, Po-Kan; Yu, Hui-Huan

2011-01-01

In this study, poly(acrylic)/SiO 2 -TiO 2 core-shell nanoparticle hybrid thin films were successfully synthesized by microwave-assisted polymerization. The coupling agent 3-(trimethoxysilyl) propyl methacrylate (MSMA) was hydrolyzed with colloidal SiO 2 -TiO 2 core-shell nanoparticles, and then polymerized with two acrylic monomers and initiator to form a precursor solution. The results of this study showed that the spin-coated hybrid films had relatively good surface planarity, high thermal stability, a tunable refractive index (1.525 2 -TiO 2 core-shell nanoparticle hybrid thin films, for potential use in optical applications.

Boric acid - trilon B (glycine, acetylurea) - water systems at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Rodionov, N.S.; Molodkin, A.K.; Fedorov, Yu.A.; Tsekhanskij, R.S.

1985-01-01

Boric acid-trilon B (glycine, acetylurea)-water systems are studied at 25 deg C by the methods of isothermal solubility densi- and refractometry. It is ascertained that all of them are of a simple eutonic type with a small salting-out effect of organic components on boric acid

Boric acid - trilon B (glycine, acetylurea) - water systems at 25 deg C

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Rodionov, N S; Molodkin, A K; Fedorov, Yu A; Tsekhanskij, R S

1985-07-01

Boric acid-trilon B (glycine, acetylurea)-water systems are studied at 25 deg C by the methods of isothermal solubility densi- and refractometry. It is ascertained that all of them are of a simple eutonic type with a small salting-out effect of organic components on boric acid.

Crystallization behaviour of nanostructured hybrid SiO2-TiO2 gel glasses to nanocomposites.

Science.gov (United States)

Tsvetelina, Gerganova; Yordanka, Ivanova; Yuliya, Vueva; Miranda, Salvado Isabel M; Helena, Fernandes Maria

2010-04-01

The crystallization behaviour of hybrid SiO2-TiO2 nanocomposites derived from titanosiloxanes by sol-gel method has been investigated depending on the type of siloxane precursor and the pirolysis temperature. The resulting hybrid titanosiloxanes, crosslinked with trimethylsilil isocyanate (nitrogen-modified) or methyltrietoxisilane (carbon-modified), were pirolyzed in an inert atmosphere in the temperature range between 600 to 1100 degrees C in order to form C-(N)-Si-O-TiO2 nanocomposites. By means of XRD, FTIR, 29Si NMR, SEM, TEM and AFM investigations have been established that the transformation of the nanostructured SiO2-TiO2 hybrid materials into nanocomposites as well as the crystalline size depend on the titanium content and the type of cross-linking agents used in the synthesizes.

Enhanced photovoltaic properties of perovskite solar cells by TiO2 homogeneous hybrid structure.

Science.gov (United States)

Su, Pengyu; Fu, Wuyou; Yao, Huizhen; Liu, Li; Ding, Dong; Feng, Fei; Feng, Shuang; Xue, Yebin; Liu, Xizhe; Yang, Haibin

2017-10-01

In this paper, we fabricated a TiO 2 homogeneous hybrid structure for application in perovskite solar cells (PSCs) under ambient conditions. Under the standard air mass 1.5 global (AM 1.5G) illumination, PSCs based on homogeneous hybrid structure present a maximum power conversion efficiency of 5.39% which is higher than that of pure TiO 2 nanosheets. The enhanced properties can be explained by the better contact of TiO 2 nanosheets/nanoparticles with CH 3 NH 3 PbI 3 and fewer pinholes in electron transport materials. The advent of such unique structure opens up new avenues for the future development of high-efficiency photovoltaic cells.

Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

DEFF Research Database (Denmark)

Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter

2016-01-01

TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM...

Electrodialysis recovery of boric acid and potassium hydroxide from eluates of SWC facilities at NPP with VVER

International Nuclear Information System (INIS)

Dudnik, S.N.; Virich, P.M.; Kramskikh, E.Y.; Masanov, O.L.; Turovsky, I.P.

1993-01-01

To extract boric acid and potassium hydroxide from regenerates of SWC-2-46 facilities, an electrodialysis-sorption process has been devised consisting of the following operations: separation of boron-alkaline regenerate solution into desorbate and wash water; filling of desalination and concentration chambers, respectively, with desorbate and was water of electrodialysis equipment; production of boric acid and potassium hydroxide from desorbate by electrodialysis; removal of chloride-ion from boric acid solution on ion-exchange filter AB-17-18. The flow-sheet was tested and boron containing alkaline regeneration solutions were recovered from Novovoronezh NPP

Effect of nano-silver and boric acid on extending the vase life of cut rose (Rosa hybrida L.).

Science.gov (United States)

Hashemabadi, Davood; Liavali, Mahbanoo Hoseinzadeh; Kaviani, Behzad; Mousavi, Meysam; Keyghobadi, Saghi; Zahiri, Samaneh

2014-09-01

Silver nano-particles (2-5 nm diam.), as antimicrobial agent and boric acid, as ethylene production inhibitor are used for enhancing the quality and vase life of cut flowers. In the present study the effects of a preservative solution containing nano-silver and boric acid on some traits of cut rose (Rosa hybrida L. cv. Yellow Island) including vase life, ethylene production, dry weight percentage, chlorophyll content, flower opening index, beta-carotene of petals and the number of basal stem end bacteria were investigated. The results showed that the effect of nano-silver and boric acid as either solitary or in combination with each other were significant (p rose treated with 100 mg l(-1) boric acid along with 5 mg l(-1) nano-silver. The lowest number of bacteria in the end of stem was calculated in cut flowers treated with the highest concentrations of boric acid (300 mg l(-1)) and nano-silver (20 mg l(-1)).

Hybrid selective noncatalytic reduction (SNCR)/selective catalytic reduction (SCR) for NOx removal using low-temperature SCR with Mn-V2O5/TiO2 catalyst.

Science.gov (United States)

Choi, Sung-Woo; Choi, Sang-Ki; Bae, Hun-Kyun

2015-04-01

cause of acid rain and ozone hole. A technology, so-called hybrid SNCR/SCR process, was tested using Mn-V2O5/TiO2 monolithic catalyst for NOx reduction, and the method is promising. The results of this study would provide some ideas to parties such as policy makers, environmental engineers, and so on.

Solution-Processed Ultrathin TiO2 Compact Layer Hybridized with Mesoporous TiO2 for High-Performance Perovskite Solar Cells.

Science.gov (United States)

Jeong, Inyoung; Park, Yun Hee; Bae, Seunghwan; Park, Minwoo; Jeong, Hansol; Lee, Phillip; Ko, Min Jae

2017-10-25

The electron transport layer (ETL) is a key component of perovskite solar cells (PSCs) and must provide efficient electron extraction and collection while minimizing the charge recombination at interfaces in order to ensure high performance. Conventional bilayered TiO 2 ETLs fabricated by depositing compact TiO 2 (c-TiO 2 ) and mesoporous TiO 2 (mp-TiO 2 ) in sequence exhibit resistive losses due to the contact resistance at the c-TiO 2 /mp-TiO 2 interface and the series resistance arising from the intrinsically low conductivity of TiO 2 . Herein, to minimize such resistive losses, we developed a novel ETL consisting of an ultrathin c-TiO 2 layer hybridized with mp-TiO 2 , which is fabricated by performing one-step spin-coating of a mp-TiO 2 solution containing a small amount of titanium diisopropoxide bis(acetylacetonate) (TAA). By using electron microscopies and elemental mapping analysis, we establish that the optimal concentration of TAA produces an ultrathin blocking layer with a thickness of ∼3 nm and ensures that the mp-TiO 2 layer has a suitable porosity for efficient perovskite infiltration. We compare PSCs based on mesoscopic ETLs with and without compact layers to determine the role of the hole-blocking layer in their performances. The hybrid ETLs exhibit enhanced electron extraction and reduced charge recombination, resulting in better photovoltaic performances and reduced hysteresis of PSCs compared to those with conventional bilayered ETLs.

Impacts of impregnation with boric acid and borax on the red colour ...

African Journals Online (AJOL)

Impacts of impregnation with boric acid and borax on the red colour tone of some hardwoods and varnishes. H Keskin, M Atar, A Ketizmen. Abstract. This study was performed to determine the impacts of impregnation with boric acid and borax on the red colour tone of some hardwoods and varnishes. For this purpose, the ...

Towards the development of a novel bioinspired functional material: synthesis and characterization of hybrid TiO2/DHICA-melanin nanoparticles.

Science.gov (United States)

Pezzella, Alessandro; Capelli, Luigia; Costantini, Aniello; Luciani, Giuseppina; Tescione, Fabiana; Silvestri, Brigida; Vitiello, Giuseppe; Branda, Francesco

2013-01-01

A large number of recent literature data focus on modification/modulation of surface chemistry of inorganic materials in order to improve their functional properties. Melanins, a wide class of natural pigments, are recently emerging as a powerful organic component for developing bioinspired active material for a large number of applications from organoelectronics to bioactive compounds. Here we report the use of the approach referred as "chimie douce", involving in situ formation of the hybrids through reactions of precursors under mild conditions, to prepare novel hybrid functional architectures based on eumelanin like 5,6 dihydroxyindole-2-carboxylic acid (DHICA) polymer and TiO2. Two synthesis procedures were carried out to get DHICA-melanin coated TiO2 nanoparticles as well as mixed DHICA/TiO2 hybrid nanostructures. Such systems were characterized through EPR, FT-IR and fluorescence spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and TEM microscopy in order to assess the effect of synthesis path as well as of DHICA content on structural, morphological and optical properties of TiO2 nanostructures. In particular, EPR, FT-IR spectra and TGA analysis confirmed the presence of DHICA-melanin in these samples. TEM measurements indicated the formation of the nanoparticles having relatively narrow size distribution with average particle size of about 10nm. DHICA-melanin does act as a morphological agent affecting morphology of hybrid nanostructures. XRD analysis proved that TiO2 hybrid nanoparticles kept anatase structures for DHICA-melanin contents within the range of investigated compositions, i.e. up to 50% wt/wt. Copyright © 2012 Elsevier B.V. All rights reserved.

40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride... its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

Effect of boric acid on intergranular corrosion in tube support plate crevices

International Nuclear Information System (INIS)

Brunet, J.P.; Campan, J.L.

1993-10-01

Intergranular attack on steam generator tubing is one important phenomenon involved in availability of Pressurized Water Reactors. Boric acid appears to be a possible candidate for inhibiting the corrosion process. The program performed in Cadarache was supposed to give statistical informations on the boric acid effect. It was based on a large number of samples initially attacked during a program performed by BABCOCK ampersand WILCOX. These samples were sleeved onto Alloy 690 tubes, in order to prevent premature cracking. Unfortunately it was not possible to find chemical conditions able to produce significant additional corrosion; we postulated mainly due to a drastic reduction of the thermal flux resulting from the increase of the tube wall thickness under the tube support plates (TSP). The tests demonstrate that such sleeve could be a possible remedy of the corrosion when introduced under the TSP. The tests show indications of a possible beneficial effect of the boric acid, a large variability of the heats sensitivity to the IGA and a predominant effect of Na 2 CO 3 on IGA production

Removal of Aqueous Boron by Using Complexation of Boric Acid with Polyols: A Raman Spectroscopic Study

Energy Technology Data Exchange (ETDEWEB)

Eom, Ki Heon; Jeong, Hui Cheol; An, Hye Young; Lim, Jun-Heok; Lee, Jea-Keun; Won, Yong Sun [Pukyong National University, Busan (Korea, Republic of)

2015-12-15

Boron is difficult to be removed from seawater by simple RO (reverse osmosis) membrane process, because the size of boric acid (B(OH){sub 3}), the major form of aqueous boron, is as small as the nominal pore size of RO membrane. Thus, the complexation of boric acid with polyols was suggested as an alternative way to increase the size of aqueous boron compounds and the complexation behavior was investigated with Raman spectroscopy. As a reference, the Raman peak for symmetric B-O stretching vibrational mode both in boric acid and borate ion (B(OH){sub 4}{sup -}) was selected. A Raman peak shift (877 cm{sup -1} →730 cm{sup -1}) was observed to confirm that boric acid in water is converted to borate ion as the pH increases, which is also correctly predicted by frequency calculation. Meanwhile, the Raman peak of borate ion (730 cm{sup -1}) did not appear as the pH increased when polyols were applied into aqueous solution of boric acid, suggesting that the boric acid forms complexing compounds by combining with polyols.

Enriched boric acid as an optimized neutron absorber in the EPR primary coolant

International Nuclear Information System (INIS)

Cosse, Christelle; Jolivel, Fabienne; Berger, Martial

2012-09-01

This paper focuses on one of the most important EPR PWR reactor design optimizations, through primary coolant conditioning by enriched boric acid (EBA). On PWRs throughout the world, boric acid has already been implemented in primary coolant and associated auxiliary systems for criticality control, due to its high Boron 10 neutron absorption cross section. Boric acid also allows primary coolant pH 300C control in combination with lithium hydroxide in many PWRs. The boric acid employed in the majority of existing PWRs is the 'natural' one, with a typical isotopic atomic abundance in Boron 10 about 19.8 at.%. However, EPR requirements for neutron management are more important, due to its fully optimized design compared to older PWRs. From the boron point of view, it means that criticality could be controlled either by increased 'natural' Boron concentrations or by using EBA. Comparatively to 'natural' boric acid, EBA allows for: - the use of smaller storage volumes for an identical total Boron concentration, or lower total Boron concentration if the tank volumes are kept identical. The latter also reduces the risks of boric acid crystallization, in spite of increased neutron-absorbing properties - the application of an evolutionary chemistry operating regime called Advanced pH Control, making it possible to maintain a constant pH 300C value at 7.2 in the primary coolant at nominal conditions throughout entire cycles. This optimized stability of pH 300C will contribute to reduce the consequences of contamination of the reactor coolant system by corrosion products, and consequently, all related issues - the reduction of borated liquid wastes, thanks to maximal recycling resulting from EPR design. The increased design costs associated with EBA are consequently compensated by a reduced total consumption of this chemical. Therefore, the basic design choice for the EPR is the use of EBA. For the Flamanville 3 EPR, according to the above

Effect of boric acid mass transfer on the accumulation thereof in a fuel core under emergency modes at NPPs with WMR

Science.gov (United States)

Morozov, A. V.; Sorokin, A. P.; Ragulin, S. V.; Pityk, A. V.; Sahipgareev, A. R.; Soshkina, A. S.; Shlepkin, A. S.

2017-07-01

Boric acid mass transfer processes in the reactor facilities with WMR are considered for the case of an emergency with breaking of the main circulation pipeline (MCP) and the operation of the passive safety systems, such as first-, second-, and third-stage accumulator tank systems, and a passive heat removal system (PHRS). Calculation results are presented for a change in the boric acid concentration in the fuel core (FC) of a water-moderated reactor (WMR) in the case of an emergency process. The calculations have been performed for different values of drop entrainment of boric acid from the reactor (0, 0.2, 2%). A substantial excess of the maximum concentration of boric acid has been found to occur 24 hours after an emergency event with a break of MCP. It is shown that increasing the droplet entrainment of boric acid causes the crystallization and accumulation thereof in the FC to become slower. The mass of boric acid deposits on the elements of internals is determined depending on the values of drop entrainment. These results allow one to draw a conclusion concerning the possibility of accumulation and crystallization of boric acid in the FC, because the latter event could lead to a blocking of the flow cross section and disturbance in the heat removal from fuel elements. A review of available literature data concerning the thermal properties of boric acid solution (density, viscosity, thermal conductivity) is presented. It is found that the available data are of quite a general character, but it does not cover the entire range of parameters (temperature, pressure, acid concentrations) inherent in a possible emergency situation at nuclear power plants with WMR. It is demonstrated that experimental study of boric acid drop entrainment at the parameters inherent in the emergency mode of WMR operation, as well as the studies of boric acid thermal properties in a wide range of concentrations, are required.

TiO2 micro-nano-hybrid surface to alleviate biological aging of UV-photofunctionalized titanium.

Science.gov (United States)

Iwasa, Fuminori; Tsukimura, Naoki; Sugita, Yoshihiko; Kanuru, Rajita Kodali; Kubo, Katsutoshi; Hasnain, Hafiz; Att, Wael; Ogawa, Takahiro

2011-01-01

Bioactivity and osteoconductivity of titanium degrade over time after surface processing. This time-dependent degradation is substantial and defined as the biological aging of titanium. UV treatment has shown to reactivate the aged surfaces, a process known as photofunctionalization. This study determined whether there is a difference in the behavior of biological aging for titanium with micro-nano-hybrid topography and titanium with microtopography alone, following functionalization. Titanium disks were acid etched to create micropits on the surface. Micro-nano-hybrid surfaces were created by depositioning 300-nm diameter TiO(2) nodules onto the micropits using a previously established self-assembly protocol. These disks were stored for 8 weeks in the dark to allow sufficient aging, then treated with UV light for 48 hours. Rat bone marrow-derived osteoblasts were cultured on fresh disks (immediately after UV treatment), 3-day-old disks (disks stored for 3 days after UV treatment), and 7-day- old disks. The rates of cell attachment, spread, proliferation, and levels of alkaline phosphatase activity, and calcium deposition were reduced by 30%-50% on micropit surfaces, depending on the age of the titanium. In contrast, 7-day-old hybrid surfaces maintained equivalent levels of bioactivity compared with the fresh surfaces. Both micropit and micro-nano-hybrid surfaces were superhydrophilic immediately after UV treatment. However, after 7 days, the micro-nano- hybrid surfaces became hydrorepellent, while the micropit surfaces remained hydrophilic. The sustained bioactivity levels of the micro-nano-hybrid surfaces were nullified by treating these surfaces with Cl(-)anions. A thin TiO(2) coating on the micropit surface without the formation of nanonodules did not result in the prevention or alleviation of the time-dependent decrease in biological activity. In conclusion, the micro-nano-hybrid titanium surfaces may slow the rate of time-dependent degradation of titanium

Photovoltaic characterization of hybrid solar cells using surface modified TiO2 nanoparticles and poly(3-hexyl)thiophene

International Nuclear Information System (INIS)

Guenes, Serap; Marjanovic, Nenad; Nedeljkovic, Jovan M; Sariciftci, Niyazi Serdar

2008-01-01

We report on the photovoltaic performance of bulk heterojunction solar cells using novel nanoparticles of 6-palmitate ascorbic acid surface modified TiO 2 as an electron acceptor embedded into the donor poly(3-hexyl)thiophene (P3HT) matrix. Devices were fabricated by using P3HT with varying amounts of red TiO 2 nanoparticles (1:1, 1:2, 1:3 w-w ratio). The devices were characterized by measuring current-voltage characteristics under simulated AM 1.5 conditions. Incident photon to current efficiency (IPCE) was spectrally resolved. The nanoscale morphology of such organic/inorganic hybrid blends was also investigated using atomic force microscopy (AFM).

KLM's boric acid reclamation system (BARS). An update

International Nuclear Information System (INIS)

Schuelke, D.; Kniazewycz, B.G.; Markind, J.; Brossart, M.A.; Choi, R.C.

1987-01-01

KLM Technologies has implemented its Department of Energy Phase II Small Business Innovative Research (SBIR) demonstration program for a radioactive waste Boric Acid Reclamation System (BARS). Preliminary performance indicates enhanced treatment by the BARS technique over state of the art process methods for selective removal of silica and other impurities from borated water matrices. At optimal system recovery of 96-97 percent. BARS removes nominal levels of boric acid while achieving significant rejection for soluble silica and selective radioisotopes. This is indicative of superior performance compared to existing data governing standard boric acid process treatment in the presence of silica and other contaminants. Conventional technologies have also proven to be relatively expensive, utilizing costly chemically treated disposable resins for primary waste removal. The overall BARS program indicates substantial savings regarding off-site disposal costs based on reduced waste generation. Optimization of the BARS technology could have potential impact on conventional process technologies that are essentially non-selective in removal capacities. Within the scope of the project, a variety of contaminated process stream and mixed radwaste sources have been evaluated at Northern States Power's Prairie Island Nuclear Generating Station. The design of an advanced prototype BARS as an optimized process alternative was the result of KLM's initial Phase 1 SBIR program with the DOE in 1984 and 1985

Determination of contaminants in boric acid used as neutron moderator by means of ion chromatography and selective electrodes

International Nuclear Information System (INIS)

Pires, M.A.F.; Abrao, A.

1988-07-01

The boric acid used as neutron moderator in reactors must observe restrictions about the concentration of some impurities. According to Westinghouse (1) specification, the highest limits for sodium, sulphate, phosphate, fluoride, and chlorine are: Na + - 0,003%; SO 4 -2 - 0,0006%; PO 4 -3 - 0,003%; F - - 0,00002%; Cl - - 0,00004%. This paper describes the determination of ions above mentioned directly in the boric acid solution. The sample is dissolved in water or in an appropriate eluent and is injected in the ion chromatograph. Na + and F - are determined by means of selective electrodes. The determination limits found for F - (0,0002%) and Cl - (0,0002%) are not sufficiently low to attent the specifications. The determination limits found for SO 4 -2 (0,0005%), PO 4 -3 (0,0003%) and Na + (0,0005%) are good enough for nuclear pure boric acid analysis. In some samples nitrate (detection limit 0,0015%) was found as well. Boric acid from different suppliers were analysed. (author) [pt

Evaluation of ultrasonic technique to characterize the concentration of boric acid in liquid medium

International Nuclear Information System (INIS)

Kohara, Richard Yuzo Ramida

2015-01-01

This dissertation is to analyze the viability of using ultrasonic technique to characterize the concentration of boric acid in liquid medium non-invasively, therefore, ultrasonic tests were performed relating different boric acid concentrations with the travel time of the ultrasonic wave, also were evaluated factors able to mask the characterization of these concentrations by ultrasonic technique. The results showed that the ultrasonic technique allows the characterization of boric acid concentrations in liquid medium in very simple terms by the ultrasonic wave travel time, requiring further studies in complex conditions. (author)

Mechanism of Early Stage Corrosion for Boric-sulfuric Acid Anodized 2A97 Al-Cu-Li Alloy Under Tropical Marine Atmosphere

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LUO Chen

2016-09-01

Full Text Available Optical microscopy(OM, scanning electron microscopy(SEM, EDX and EIS combined with ultramicrotomy were employed to investigate the micro morphology, chemical composition and electrochemical properties of anodized 2A97 Al-Cu-Li alloy before and after atmospheric corrosion. The results show that when electrolytes containing combinations of tartaric-sulfuric or boric-sulfuric acid are used to grow the films at different temperatures, boric acid addition and higher temperature allow for higher current density that speeds up the film growth. The pore geometry and structure is similar for different electrolytes. Dispersive dark rusty spots composed of O, Al, Cl, Cu are present on the boric-sulfuric acid anodized specimen after exposure in tropical marine atmosphere for 1 month. Deposition of white corrosion product is found on the specimen surface as well. Severe pitting occurs and develops deeply into the alloy substrate after elongated outdoor exposure. Corrosion propagation is associated with θ-phase particles.

Device for regulating light water nuclear reactors by changing the boric acid concentration in the cooling water circuit

International Nuclear Information System (INIS)

Brown, W.W.; Van der Schoot, M.R.

1980-01-01

Small changes in boric acid concentration can be carried out quickly by a combination of an ion exchanger with temperature-dependent capacity and an evaporator. No boric acid need be extracted from the circuit or added to it. However, if large changes of concentration are required, boric acid has to be added. The evaporator is then used to separate distilled water and concentrated boric acid when the cooling water is diluted. (DG) [de

Boric acid reduces axonal and myelin damage in experimental sciatic nerve injury

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Zahir Kizilay

2016-01-01

Full Text Available The aim of this study was to investigate the effects of boric acid in experimental acute sciatic nerve injury. Twenty-eight adult male rats were randomly divided into four equal groups (n = 7: control (C, boric acid (BA, sciatic nerve injury (I , and sciatic nerve injury + boric acid treatment (BAI. Sciatic nerve injury was generated using a Yasargil aneurysm clip in the groups I and BAI. Boric acid was given four times at 100 mg/kg to rats in the groups BA and BAI after injury (by gavage at 0, 24, 48 and 72 hours but no injury was made in the group BA. In vivo electrophysiological tests were performed at the end of the day 4 and sciatic nerve tissue samples were taken for histopathological examination. The amplitude of compound action potential, the nerve conduction velocity and the number of axons were significantly lower and the myelin structure was found to be broken in group I compared with those in groups C and BA. However, the amplitude of the compound action potential, the nerve conduction velocity and the number of axons were significantly greater in group BAI than in group I. Moreover, myelin injury was significantly milder and the intensity of nuclear factor kappa B immunostaining was significantly weaker in group BAI than in group I. The results of this study show that administration of boric acid at 100 mg/kg after sciatic nerve injury in rats markedly reduces myelin and axonal injury and improves the electrophysiological function of injured sciatic nerve possibly through alleviating oxidative stress reactions.

Combined effects of adsorption and photocatalysis by hybrid TiO2/ZnO-calcium alginate beads for the removal of copper

Institute of Scientific and Technical Information of China (English)

Devagi Kanakaraju; Shantini Ravichandar; Ying Chin Lim

2017-01-01

The use of nanosized titanium dioxide (TiO2) and zinc oxide (ZnO) in the suspension form during treatment makes the recovering and recycling of photocatalysts difficult.Hence,supported photocatalysts are preferred for practical water treatment applications.This study was conducted to investigate the efficiency of calcium alginate (CaAlg) beads that were immobilized with hybrid photocatalysts,TiO2/ZnO to form TiO2/ZnO-CaAlg.Theseimmobilized beads,with three different mass ratios of TiO2:ZnO (1∶1,1∶2,and 2∶1) were used to remove Cu(Ⅱ) in aqueous solutions in the presence of ultraviolet light.These beads were subjected to three cycles of photocatalytic treatment with different initial Cu(Ⅱ) concentrations (10-80 ppm).EDX spectra have confirmed the inclusion of Ti and Zn on the surface of the CaAlg beads.Meanwhile,the surface morphology of the beads as determined using SEM,has indicated differences of before and after the photocatalytic treatment of Cu(Ⅱ).Among all three,the equivalent mass ratio TiO2/ZnO-CaAlg beads have shown the best performance in removing Cu(Ⅱ) during all three recycling experiments.Those TiO2/ZnO-CaAlg beads have also shown consistent removal of Cu,ranging from 7.14-62.0 ppm (first cycle) for initial concentrations of 10-80 ppm.In comparison,bare CaAlg was only able to remove 6.9-48 ppm of similar initial Cu concentrations.Thus,the potential use of TiO2/ZnO-CaAlg beads as environmentally friendly composite material can be further extended for heavy metal removal from contaminated water.

Preparation of Oleyl Phosphate-Modified TiO2/Poly(methyl methacrylate Hybrid Thin Films for Investigation of Their Optical Properties

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Masato Fujita

2015-01-01

Full Text Available TiO2 nanoparticles (NPs modified with oleyl phosphate were synthesized through stable Ti–O–P bonds and were utilized to prepare poly(methyl methacrylate- (PMMA- based hybrid thin films via the ex situ route for investigation of their optical properties. After surface modification of TiO2 NPs with oleyl phosphate, IR and 13C CP/MAS NMR spectroscopy showed the presence of oleyl groups. The solid-state 31P MAS NMR spectrum of the product revealed that the signal due to oleyl phosphate (OP shifted upon reaction, indicating formation of covalent Ti–O–P bonds. The modified TiO2 NPs could be homogeneously dispersed in toluene, and the median size was 16.1 nm, which is likely to be sufficient to suppress Rayleigh scattering effectively. The TEM images of TiO2/PMMA hybrid thin films also showed a homogeneous dispersion of TiO2 NPs, and they exhibited excellent optical transparency even though the TiO2 content was 20 vol%. The refractive indices of the OP-modified TiO2/PMMA hybrid thin films changed higher with increases in TiO2 volume fraction, and the hybrid thin film with 20 vol% of TiO2 showed the highest refractive index (n = 1.86.

The characterisation of molecular boric acid by mass spectrometry and matrix isolation-infrared spectroscopy

International Nuclear Information System (INIS)

Ogden, J.S.; Young, N.A.; Bowsher, B.R.

1987-10-01

Boric acid (H 3 BO 3 ) is used as a soluble neutron absorber in the coolant of pressurised water reactors and will be an important species in defining the fission product chemistry of severe reactor accidents. Mass spectrometry and matrix isolation-infrared spectroscopy have been used to characterise boric acid in the vapour phase and hence assess the implications of any chemical interactions. Crystalline orthoboric acid vaporises to yield molecular H 3 BO 3 when heated in vacuum to approximately 40 0 C. The infrared spectrum of the vapour species isolated in low-temperature nitrogen matrices shows characteristic absorptions at 3668.5 (E'), 1426.2 (E'), 1009.9 (E'), 675.0 (A''), 513.8 (A'') and 448.9 (E') cm -1 , consistent with C 3h symmetry. These spectral assignments are supported by extensive isotope labelling, and by a partial normal co-ordinate analysis. These data will be used to quantify specific thermodynamic functions and hence assist in determining the magnitude of reactions such as boric acid with caesium iodide. (author)

Characterization and improved solar light activity of vanadium doped TiO2/diatomite hybrid catalysts.

Science.gov (United States)

Wang, Bin; Zhang, Guangxin; Leng, Xue; Sun, Zhiming; Zheng, Shuilin

2015-03-21

V-doped TiO2/diatomite composite photocatalysts with different vanadium concentrations were synthesized by a modified sol-gel method. The diatomite was responsible for the well dispersion of TiO2 nanoparticles on the matrix and consequently inhibited the agglomeration. V-TiO2/diatomite hybrids showed red shift in TiO2 absorption edge with enhanced absorption intensity. Most importantly, the dopant energy levels were formed in the TiO2 bandgap due to V(4+) ions substituted to Ti(4+) sites. The 0.5% V-TiO2/diatomite photocatalyst displayed narrower bandgap (2.95 eV) compared to undoped sample (3.13 eV) and other doped samples (3.05 eV) with higher doping concentration. The photocatalytic activities of V doped TiO2/diatomite samples for the degradation of Rhodamine B under stimulated solar light illumination were significantly improved compared with the undoped sample. In our case, V(4+) ions incorporated in TiO2 lattice were responsible for increased visible-light absorption and electron transfer to oxygen molecules adsorbed on the surface of TiO2 to produce superoxide radicals ˙O2(-), while V(5+) species presented on the surface of TiO2 particles in the form of V2O5 contributed to e(-)-h(+) separation. In addition, due to the combination of diatomite as support, this hybrid photocatalyst could be separated from solution quickly by natural settlement and exhibited good reusability. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis and Mechanical Properties Investigation of Nano TiO2/Glass/Epoxy Hybrid Nanocomposite

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Hamid Reza Salehi

2015-10-01

Full Text Available Mechanical properties of epoxy and glass/epoxy filled with 0.25, 0.5 and 1 vol% of TiO2 nanoparticles have been studied using tensile and three-point bending tests. For the TiO2/epoxy nanocomposites, the results showed that the strength and stiffness were improved, though the strain at ultimate strength point and breaking strain decreased. Moreover, the hybrid nanocomposites composed of 4 layers of woven E-glass fabric and TiO2/epoxy matrix were fabricated and cut onaxis and 45° off-axis by water jet. The results of tensile and three-point bending tests indicated a remarkable improvement in the strength and stiffness that could not be related to the mechanical improvement of the matrix. The samples containing 1 vol% nano TiO2 were improved relative to samples without the nanoparticles. The tensile strength of the on-axis and off-axis samples containing 1 vol% TiO2 increased by about 25.9% and 17.9%, in the order given, compared to that of the glass/epoxy specimens. In three-point bending test, the strength of the on-axis and off-axis specimens was improved 26% and 23.2%, respectively. In addition, the tensile stiffness of the onaxis and off-axis samples containing 1 vol% TiO2 increased, respectively, by about 14.4% and 17.5% compared to that of the glass/epoxy specimens. Also for the same on-axis and off-axis samples the three-point bending stiffness increased about 19.8% and 14.6%, respectively. The whole investigation on the microstructure of the hybrid nanocomposites illustrated that stronger interfaces between the fiber and TiO2/epoxy matrix were formed and improvement was noticed on mechanical properties of ternary composite compared to those of the fiber/epoxy composites. The analysis of damage zones of hybrid nanocomposites showed that the surface area of the damaged zone declined considerably due to the brittle behavior of TiO2-filled specimens but the area below the stress-strain curve, showing energy absorption during the test

Characterization and improved solar light activity of vanadium doped TiO2/diatomite hybrid catalysts

International Nuclear Information System (INIS)

Wang, Bin; Zhang, Guangxin; Leng, Xue; Sun, Zhiming; Zheng, Shuilin

2015-01-01

Highlights: • V-doped TiO 2 /diatomite composite photocatalyst was synthesized. • The physiochemical property and solar light photoactivity were characterized. • The presence and influence of V ions in TiO 2 matrix was systematically analyzed. • The photocatalysis for Rhodamine B were studied under solar light illumination. - Abstract: V-doped TiO 2 /diatomite composite photocatalysts with different vanadium concentrations were synthesized by a modified sol–gel method. The diatomite was responsible for the well dispersion of TiO 2 nanoparticles on the matrix and consequently inhibited the agglomeration. V-TiO 2 /diatomite hybrids showed red shift in TiO 2 absorption edge with enhanced absorption intensity. Most importantly, the dopant energy levels were formed in the TiO 2 bandgap due to V 4+ ions substituted to Ti 4+ sites. The 0.5% V-TiO 2 /diatomite photocatalyst displayed narrower bandgap (2.95 eV) compared to undoped sample (3.13 eV) and other doped samples (3.05 eV) with higher doping concentration. The photocatalytic activities of V doped TiO 2 /diatomite samples for the degradation of Rhodamine B under stimulated solar light illumination were significantly improved compared with the undoped sample. In our case, V 4+ ions incorporated in TiO 2 lattice were responsible for increased visible-light absorption and electron transfer to oxygen molecules adsorbed on the surface of TiO 2 to produce superoxide radicals ·O 2 – , while V 5+ species presented on the surface of TiO 2 particles in the form of V 2 O 5 contributed to e – –h + separation. In addition, due to the combination of diatomite as support, this hybrid photocatalyst could be separated from solution quickly by natural settlement and exhibited good reusability

Determination of uranium in boric acid samples at Paks Nuclear Power Plant by ICP-MS method

International Nuclear Information System (INIS)

Komlosi, E.Zs.; Menyhart, A.; Varju, I.

2005-01-01

Measurement of uranium became necessary in 2003, after the incident of unit 2 in April, when the fission products, uranium and transuranium isotopes got into the cooling water. The measurement of uranium with ICP-MS method was initiated in January 2004. Apparatus type Agilent 7500a was used. Uranium concentration and uranium isotope ratio were measured in samples with different - but known - boric acid concentration. Internal standard was used for the elimination of the matrix effect. The samples have high boric acid concentration (in few samples over 20 g/litres). Two methods were used for the reduction of the boric acid concentration: dilution and evaporation with ethyl alcohol. Both methods were found successful and exact. The limit of detection is 0.1 ng/litres for the Uranium-238. (N.T.)

Tuning TiO2 nanoparticle morphology in graphene-TiO2 hybrids by graphene surface modification

Science.gov (United States)

Sordello, Fabrizio; Zeb, Gul; Hu, Kaiwen; Calza, Paola; Minero, Claudio; Szkopek, Thomas; Cerruti, Marta

2014-05-01

We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production.We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted

Ingested boric acid effect on the venom chemistry of Solenopsis invicta Buren (Hymenoptera: Formicidae)

Science.gov (United States)

During a field evaluation of a boric acid bait against the red imported fire ant, Solenopsis invicta Buren, it was observed that workers of intoxicated colonies produced stings with less toxic effects compared to workers from healthy colonies. In this study, the effect of boric acid on the levels o...

PERIODS OF VERTEBRAL COLUMN SENSITIVITY TO BORIC ACID TREATMENT IN CD-1 MICE IN UTERO

Science.gov (United States)

Periods of vertebral column sensitivity to boric acid treatment in CD-1 mice in utero.Cherrington JW, Chernoff N.Department of Toxicology, North Carolina State University, Raleigh, NC 27695, USA. jana_cherrington@hotmail.comBoric acid (BA) has many uses as...

Copper doping enhanced the oxidative stress-mediated cytotoxicity of TiO2 nanoparticles in A549 cells.

Science.gov (United States)

Ahmad, J; Siddiqui, M A; Akhtar, M J; Alhadlaq, H A; Alshamsan, A; Khan, S T; Wahab, R; Al-Khedhairy, A A; Al-Salim, A; Musarrat, J; Saquib, Q; Fareed, M; Ahamed, M

2018-05-01

Physicochemical properties of titanium dioxide nanoparticles (TiO 2 NPs) can be tuned by doping with metals or nonmetals. Copper (Cu) doping improved the photocatalytic behavior of TiO 2 NPs that can be applied in various fields such as environmental remediation and nanomedicine. However, interaction of Cu-doped TiO 2 NPs with human cells is scarce. This study was designed to explore the role of Cu doping in cytotoxic response of TiO 2 NPs in human lung epithelial (A549) cells. Characterization data demonstrated the presence of both TiO 2 and Cu in Cu-doped TiO 2 NPs with high-quality lattice fringes without any distortion. The size of Cu-doped TiO 2 NPs (24 nm) was lower than pure TiO 2 NPs (30 nm). Biological results showed that both pure and Cu-doped TiO 2 NPs induced cytotoxicity and oxidative stress in a dose-dependent manner. Low mitochondrial membrane potential and higher caspase-3 enzyme (apoptotic markers) activity were also observed in A549 cells exposed to pure and Cu-doped TiO 2 NPs. We further observed that cytotoxicity caused by Cu-doped TiO 2 NPs was higher than pure TiO 2 NPs. Moreover, antioxidant N-acetyl cysteine effectively prevented the reactive oxygen species generation, glutathione depletion, and cell viability reduction caused by Cu-doped TiO 2 NPs. This is the first report showing that Cu-doped TiO 2 NPs induced cytotoxicity and oxidative stress in A549 cells. This study warranted further research to explore the role of Cu doping in toxicity mechanisms of TiO 2 NPs.

Electron Injection from Copper Diimine Sensitizers into TiO ₂ : Structural Effects and Their Implications for Solar Energy Conversion Devices

Energy Technology Data Exchange (ETDEWEB)

Mara, Michael W. [Department; Bowman, David N. [Department; Buyukcakir, Onur [Graduate; Shelby, Megan L. [Department; Haldrup, Kristoffer [Centre; Huang, Jier; Harpham, Michael R.; Stickrath, Andrew B.; Zhang, Xiaoyi; Stoddart, J. Fraser [Department; Coskun, Ali [Graduate; Jakubikova, Elena [Department; Chen, Lin X. [Department

2015-07-21

Copper(I) diimine complexes have emerged as low cost replacements for ruthenium complexes as light sensitizers and electron donors, but their shorter metal-to-ligand-charge-transfer (MLCT) states lifetimes and lability of transient Cu(II) species impede their intended functions. Two carboxylated Cu(I) bis-2,9-diphenylphenanthroline (dpp) complexes [Cu(I)(dpp-O(CH2CH2O)(5))(dpp-(COOH)(2))](+) and [Cu(I)(dpp-O(CH2CH2O)(5))(dpp-(F-COOH)(2))](+) (F = tolyl) with different linker lengths were synthesized in which the MLCT-state solvent quenching pathways are effectively blocked, the lifetime of the singlet MLCT state is prolonged, and the transient Cu(II) ligands are stabilized. Aiming at understanding the mechanisms of structural influence to the interfacial charge transfer in the dye-sensitized solar cell mimics, electronic and geometric structures as well as dynamics for the MLCT state of these complexes and their hybrid with TiO2 nanoparticles were investigated using optical transient spectroscopy, X-ray transient absorption spectroscopy, time-dependent density functional theory, and quantum dynamics simulations. The combined results show that these complexes exhibit strong absorption throughout the visible spectrum due to the severely flattened ground state, and a long-lived charge-separated Cu(II) has been achieved via ultrafast electron injection (<300 fs) from the 1MLCT state into TiO2 nanoparticles. The results also indicate that the TiO2-phen distance in these systems does not have significant effect on the efficiency of the interfacial electron-transfer process. The mechanisms for electron transfer in these systems are discussed and used to develop new strategies in optimizing copper(I) diimine complexes in solar energy conversion devices.

Interactions of aqueous NOM with nanoscale TiO2: implications for ceramic membrane filtration-ozonation hybrid process.

Science.gov (United States)

Kim, Jeonghwan; Shan, Wenqian; Davies, Simon H R; Baumann, Melissa J; Masten, Susan J; Tarabara, Volodymyr V

2009-07-15

The combined effect of pH and calcium on the interactions of nonozonated and ozonated natural organic matter (NOM) with nanoscale TiO2 was investigated. The approach included characterization of TiO2 nanoparticles and NOM, extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) modeling of NOM-TiO2 and NOM-NOM interactions, batch study on the NOM adsorption onto TiO2 surface, and bench-scale study on the treatment of NOM-containing feed waters using a hybrid process that combines ozonation and ultrafiltration with a 5 kDa ceramic (TiO2 surface) membrane. It was demonstrated that depending on pH and TiO2 loading, the adsorption of NOM species is controlled by either the availability of divalent cations or by preozonation of NOM. XDLVO surface energy analysis predicts NOM adsorption onto TiO2 in the ozone-controlled regime but not in the calcium-controlled regime. In both regimes, short-range NOM-NOM and NOM-TiO2 interactions were governed by acid-base and van der Waals forces, whereas the role of electrostatic forces was relatively insignificant. Ozonation increased the surface energy of NOM, contributing to the hydrophilic repulsion component of the NOM-NOM and NOM-TiO2 interactions. In the calcium-controlled regime, neither NOM-TiO2 nor NOM-NOM interaction controlled adsorption. Non-XDLVO interactions such as intermolecular bridging by calcium were hypothesized to be responsible for the observed adsorption behavior. Adsorption data proved to be highly predictive of the permeate flux performance.

Synthesis of PBAD-lipiodol nanoparticles for combination treatment with boric acid in boron neutron capture therapy for hepatoma in-vitro

International Nuclear Information System (INIS)

Chou, F.I.; Chung, H.P.; Liu, H.M.; Wen, H.W.; Chi, C.W.; Lin, Shanyang; Lui, W.Y.; Kai, J.J.

2006-01-01

This study attempted to increase BNCT efficiency for hepatoma by a combined treatment of phenylboric acid derivative entrapped lipiodol nanoparticles (PBAD-L nanoparticles) with boric acid. The size of PBAD-L nanoparticles were 400-750 nm at the boron concentrations of 0.3-2.7 mg/ml. After 24 hours the boron concentration in PBAD-L nanoparticles treated human hepatoma HepG2 cells was 112 ppm, while that in rat liver Clone 9 cells was 52 ppm. With the use of 25 μg B/ml boric acid, after 6 hours the boron concentration in HepG2 and Clone 9 cells were 75 ppm and 40 ppm, respectively. In a combined treatment, boron concentration in HepG2 cells which were treated with PBAD-L nanoparticles for 18 hours and then combined with boric acid for 6 hours was 158 ppm. After neutron irradiation, the surviving fraction of HepG2 cells treated with PBAD-L nanoparticles was 12.6%, while that in the ones with a combined treatment was 1.3%. In conclusion, the combined treatment provided a higher boron concentration in HepG2 cells than treatments with either PBAD-L nanoparticles or boric acid, resulting in a higher therapeutic efficacy of BNCT in hepatoma cells. (author)

Cattaneo-Christov based study of {TiO}_2 -CuO/EG Casson hybrid nanofluid flow over a stretching surface with entropy generation

Science.gov (United States)

Jamshed, Wasim; Aziz, Asim

2018-06-01

In the present research, a simplified mathematical model is presented to study the heat transfer and entropy generation analysis of thermal system containing hybrid nanofluid. Nanofluid occupies the space over an infinite horizontal surface and the flow is induced by the non-linear stretching of surface. A uniform transverse magnetic field, Cattaneo-Christov heat flux model and thermal radiation effects are also included in the present study. The similarity technique is employed to reduce the governing non-linear partial differential equations to a set of ordinary differential equation. Keller Box numerical scheme is then used to approximate the solutions for the thermal analysis. Results are presented for conventional copper oxide-ethylene glycol (CuO-EG) and hybrid titanium-copper oxide/ethylene glycol ({TiO}_2 -CuO/EG) nanofluids. The spherical, hexahedron, tetrahedron, cylindrical, and lamina-shaped nanoparticles are considered in the present analysis. The significant findings of the study is the enhanced heat transfer capability of hybrid nanofluids over the conventional nanofluids, greatest heat transfer rate for the smallest value of the shape factor parameter and the increase in Reynolds number and Brinkman number increases the overall entropy of the system.

Preparation of Sb2S3 nanocrystals modified TiO2 dendritic structure with nanotubes for hybrid solar cell

Science.gov (United States)

Li, Yingpin; Wei, Yanan; Feng, Kangning; Hao, Yanzhong; Pei, Juan; Sun, Bao

2018-06-01

Array of TiO2 dendritic structure with nanotubes was constructed on transparent conductive fluorine-doped tin oxide glass (FTO) with titanium potassium oxalate as titanium source. Sb2S3 nanocrystals were successfully deposited on the TiO2 substrate via spin-coating method. Furthermore, TiO2/Sb2S3/P3HT/PEDOT:PSS composite film was prepared by successively spin-coating P3HT and PEDOT:PSS on TiO2/Sb2S3. It was demonstrated that the modification of TiO2 dendritic structure with Sb2S3 could enhance the light absorption in the visible region. The champion hybrid solar cell assembled by TiO2/Sb2S3/P3HT/PEDOT:PSS composite film achieved a power conversion efficiency (PCE) of 1.56%.

Effects of an inorganic insecticide (boric acid) against Blattella ...

African Journals Online (AJOL)

ufuoma

2013-05-01

May 1, 2013 ... Data on ovarian .... The overall data suggested an interference of boric acid with the ... solutions as baits for management of German cockroaches .... Comp. Biochem. Physiol. 135C:257-267. Tine S, Aribi N, Soltani N (2011).

Effect of boric acid on intergranular corrosion and on hideout return efficiency of sodium in the tube support plate crevices

International Nuclear Information System (INIS)

Paine, J.P.N.; Shoemaker, C.E.; Campan, J.L.; Brunet, J.P.; Schindler, P.; Stutzmann, A.

1995-01-01

Sodium hydroxide is one of the main causes of intergranular attack/stress corrosion cracking (IGA/SCC) of alloy 600 steam generator (S.G.) tubes. Boric acid appears to be one of the possible remedies for intergranular corrosion process inhibition. In order to obtain data on boric acid injection efficiency, an experimental program was performed on previously corroded tubes. To prevent premature tube wall cracking, samples were sleeved on alloy 690 tubes. The objective of the tests was to evaluate, on a statistically valid number of samples, the effectiveness of boric acid and tube sleeving as possible remedies for IGA/SCC extension. Another independent experimental program was initiated to determine the hideout return efficiency in the tube support plate (TSP) and tubesheet (TS) crevices after a significant duration (≤ 180 hours) of sodium hideout. The main objective of the first tests being a statistical evaluation of the efficiency of boric acid treatment, was not achieved. The tests did demonstrate that sleeving effectively reduces IGA/SCC growth. In an additional program, cracks were obtained on highly susceptible tubes when specimens were not sleeved. The companion tests performed in the same conditions but with an addition of boric acid did not show any IGA or cracks. These results seem to demonstrate the possible effect of boric acid in preventing the corrosion process. Results of the second tests did not demonstrate any difference in the amount of sodium piled up in the crevices before and after boric acid injection. They however showed an increase of the hideout return efficiency at the tube support plate level from 78 % without boric acid to 95 % when boric acid is present in the feed water

Hydrothermal synthesis spherical TiO2 and its photo-degradation property on salicylic acid

International Nuclear Information System (INIS)

Guo Wenlu; Liu Xiaolin; Huo Pengwei; Gao Xun; Wu Di; Lu Ziyang; Yan Yongsheng

2012-01-01

Anatase TiO 2 spheres have been prepared using hydrothermal synthesis. The prepared spheres were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). The TiO 2 consisted of well-defined spheres with size of 3-5 μm. The photocatalytic activity of spherical TiO 2 was determined by degradation of salicylic acid under visible light irradiation. It was revealed that the degradation rate of the spherical TiO 2 which was processed at 150 °C for 48 h could reach 81.758%. And the kinetics of photocatalytic degradation obeyed first-order kinetic, which the rate constant value was 0.01716 S -1 of the salicylic acid onto TiO 2 (temperature: 150, time: 48 h). The kinetics of adsorption followed the pseudo-second-order model and the rate constant was 1.2695 g mg -1 of the salicylic acid onto TiO 2 (temperature: 150, time: 48 h).

Silver Nanoparticles Influence on Photocatalytic Activity of Hybrid Materials Based on TiO2 P25

Directory of Open Access Journals (Sweden)

Tomkouani Kodom

2015-01-01

Full Text Available The aim of the present study consists in the obtaining of a hybrid material film, obtained using TiO2 P25 and silver nanoparticles (AgNPs. The film manufacturing process involved realization of physical mixtures of TiO2 P25 and AgNPs dispersions. The size distribution of the AgNPs proved to be a key factor determining the photodegradation activity of the materials measured using methyl orange. The best result was 33% degradation of methyl orange (MO after 150 min. The second approach was the generation of AgNPs on the surface of TiO2 P25. The obtained hybrid material presents photocatalytic activity of 45% MO degradation after 150 min. The developed materials were characterized by UV-VIS, SEM, and DLS analyses.

TiO2 micro-nano-hybrid surface to alleviate biological aging of UV-photofunctionalized titanium

Directory of Open Access Journals (Sweden)

Iwasa F

2011-06-01

Full Text Available Fuminori Iwasa1, Naoki Tsukimura1, Yoshihiko Sugita1, Rajita Kodali Kanuru1, Katsutoshi Kubo1, Hafiz Hasnain1, Wael Att1,2, Takahiro Ogawa11Laboratory of Bone and Implant Sciences (LBIS, The Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA; 2Department of Prosthodontics, Dental School, Albert-Ludwigs University, Freiburg, GermanyAbstract: Bioactivity and osteoconductivity of titanium degrade over time after surface processing. This time-dependent degradation is substantial and defined as the biological aging of titanium. UV treatment has shown to reactivate the aged surfaces, a process known as photofunctionalization. This study determined whether there is a difference in the behavior of biological aging for titanium with micro-nano-hybrid topography and titanium with microtopography alone, following functionalization. Titanium disks were acid etched to create micropits on the surface. Micro-nano-hybrid surfaces were created by depositioning 300-nm diameter TiO2 nodules onto the micropits using a previously established self-assembly protocol. These disks were stored for 8 weeks in the dark to allow sufficient aging, then treated with UV light for 48 hours. Rat bone marrow–derived osteoblasts were cultured on fresh disks (immediately after UV treatment, 3-day-old disks (disks stored for 3 days after UV treatment, and 7-day-old disks. The rates of cell attachment, spread, proliferation, and levels of alkaline phosphatase activity, and calcium deposition were reduced by 30%–50% on micropit surfaces, depending on the age of the titanium. In contrast, 7-day-old hybrid surfaces maintained equivalent levels of bioactivity compared with the fresh surfaces. Both micropit and micro-nano-hybrid surfaces were superhydrophilic immediately after UV treatment. However, after 7 days, the micro-nano-hybrid surfaces became hydrorepellent

Preparation and solar-light photocatalytic activity of TiO2 composites: TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite

Science.gov (United States)

Li, Y.; Li, S. G.; Wang, J.; Li, Y.; Ma, C. H.; Zhang, L.

2014-12-01

Three TiO2 loaded composites, TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite, were prepared in order to improve the solar-light photocatalytic activity of TiO2. The results showed that the photocatalytic activity could obviously be enhanced by loading appropriate amount of inorganic mineral materials. Meanwhile, TiO2 content, heat-treatment temperature and heat-treatment time on the photocatalytic activity were reviewed. Otherwise, the effect of solar light irradiation time and dye concentration on the photocatalytic degradation of Acid Red B was investigated. Furthermore, the degradation mechanism and adsorption process were also discussed.

Is Boric Acid Toxic to Reproduction in Humans? Assessment of the Animal Reproductive Toxicity Data and Epidemiological Study Results.

Science.gov (United States)

Duydu, Yalçın; Başaran, Nurşen; Ustündağ, Aylin; Aydın, Sevtap; Undeğer, Ulkü; Ataman, Osman Yavuz; Aydos, Kaan; Düker, Yalçın; Ickstadt, Katja; Waltrup, Brita Schulze; Golka, Klaus; Bolt, Hermann Maximilian

2016-01-01

Boric acid and sodium borates are classified as toxic to reproduction in the CLP Regulation under "Category 1B" with the hazard statement of "H360FD". This classification is based on the reprotoxic effects of boric acid and sodium borates in animal experiments at high doses. However, boron mediated reprotoxic effects have not been proven in epidemiological studies so far. The epidemiological study performed in Bandırma boric acid production plant is the most comprehensive published study in this field with 204 voluntarily participated male workers. Sperm quality parameters (sperm morphology, concentration and motility parameters), FSH, LH and testosterone levels were determined in all participated employees as the reproductive toxicity biomarkers of males. However, boron mediated unfavorable effects on reproduction in male workers have not been determined even in the workers under very high daily boron exposure (0.21 mg B/kg-bw/day) conditions. The NOAEL for rat reproductive toxicity is equivalent to a blood boron level of 2020 ng/g. This level is higher than the mean blood boron concentration (223.89 ± 69.49 ng/g) of the high exposure group workers in Bandırma boric acid production plant (Turkey) by a factor of 9. Accordingly, classifying boric acid and sodium borates under "Category 1B" as "presumed reproductive human toxicant in the CLP regulation seems scientifically not reasonable. The results of the epidemiological studies (including the study performed in China) support for a down-classification of boric acid from the category 1B, H360FD to category 2, H361d, (suspected of damaging the unborn child).

Boric acid as a mild and efficient catalyst for one-pot synthesis of 1

Indian Academy of Sciences (India)

Abstract. An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

Management of Azole-Refractory Candida Species Using Boric Acid

African Journals Online (AJOL)

Mgina

commonly used drugs in the country, the best performance of boric acid envisage the need to update the national ... drugs especially with the azole antifungal groups and are ... Other factors include extensive use of broad spectrum ..... influence not only prescription tendency but .... pharmacokinetics, and antifungal therapy.

Non-aqueous hybrid supercapacitors fabricated with mesoporous TiO2 microspheres and activated carbon electrodes with superior performance

Science.gov (United States)

Cai, Yong; Zhao, Bote; Wang, Jie; Shao, Zongping

2014-05-01

Mesoporous TiO2 microspheres, synthesized by a facile template-free solvothermal method and subsequent heat treatment, are exploited as the electrode for hybrid supercapacitors. The effects of the calcination temperature on the phase composition, particulate microstructure and morphology are characterized by XRD, Raman, FE-SEM and N2 adsorption/desorption measurements. Hybrid supercapacitors utilizing the as-prepared TiO2 mesoporous microspheres as the negative electrode and activated carbon (AC) as the positive electrode in a non-aqueous electrolyte are fabricated. The electrochemical performance of these hybrid supercapacitors is studied by galvanostatic charge-discharge and cyclic voltammetry (CV). The hybrid supercapacitor built from TiO2 microspheres calcined at 400 °C shows the best performance, delivering an energy density of 79.3 Wh kg-1 at a power density of 178.1 W kg-1. Even at a power density of 9.45 kW kg-1, an energy density of 31.5 Wh kg-1 is reached. These values are much higher than the AC-AC symmetric supercapacitor. In addition, the hybrid supercapacitor exhibits excellent cycling performance, retaining 98% of the initial energy density after 1000 cycles. Such outstanding electrochemical performance of the hybrid supercapacitor is attributed to the matched reaction kinetics between the two electrodes with different energy storage mechanisms.

Carbon nanotube TiO2 hybrid films for detecting traces of O2

Science.gov (United States)

Llobet, E.; Espinosa, E. H.; Sotter, E.; Ionescu, R.; Vilanova, X.; Torres, J.; Felten, A.; Pireaux, J. J.; Ke, X.; Van Tendeloo, G.; Renaux, F.; Paint, Y.; Hecq, M.; Bittencourt, C.

2008-09-01

Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO2 films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. beverage industry.

Application of Lime Additive on Cementation of Concentrated Low Activities Liquid Radwaste Containing Boric Acid

International Nuclear Information System (INIS)

Bahdir-Johan

2000-01-01

The effect of lime additive on the waste form containing boric acid and the activity 1 μCi/ml have been studied. The studying parameter was the optimum lime additive in concentrate. The sample was made by cement slurry containing boric acid. The cement slurry composition are water/cement ratio (W/C) was 0.35, sand/cement ratio (S/C) was 0.75 and boric (B) was 15000 ppm. On this condition into cement slurry was added the lime additive (K/C) 0.05 -0.8 by weigh. The quality test included density, compressive strength and leaching rate. The density was determination by weighing and measuring sample volume, compressive strength determination using Paul Weber apparatus and leaching rate tested using aquadest. The result of this research are the lime/cement ratio (K/C) 0.30; the density (ρ) 2.449 ± 0.008 g.cm -3 , the compressive strength (Γ) 44.005 ± 0.012 N.mm -2 and the leaching rate (Rn) 7.20x10 -4 -0.90x10 -4 g.cm -2 day -1 . According to this research the quality of the waste form has been complied the IAEA quality standard. (author)

Quasiparticle interfacial level alignment of highly hybridized frontier levels: H2O on TiO2(110).

Science.gov (United States)

Migani, Annapaola; Mowbray, Duncan J; Zhao, Jin; Petek, Hrvoje

2015-01-13

Knowledge of the frontier levels' alignment prior to photoirradiation is necessary to achieve a complete quantitative description of H2O photocatalysis on TiO2(110). Although H2O on rutile TiO2(110) has been thoroughly studied both experimentally and theoretically, a quantitative value for the energy of the highest H2O occupied levels is still lacking. For experiment, this is due to the H2O levels being obscured by hybridization with TiO2(110) levels in the difference spectra obtained via ultraviolet photoemission spectroscopy (UPS). For theory, this is due to inherent difficulties in properly describing many-body effects at the H2O-TiO2(110) interface. Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G0W0, we disentangle the adsorbate and surface contributions to the complex UPS spectra of H2O on TiO2(110). We perform this separation as a function of H2O coverage and dissociation on stoichiometric and reduced surfaces. Due to hybridization with the TiO2(110) surface, the H2O 3a1 and 1b1 levels are broadened into several peaks between 5 and 1 eV below the TiO2(110) valence band maximum (VBM). These peaks have both intermolecular and interfacial bonding and antibonding character. We find the highest occupied levels of H2O adsorbed intact and dissociated on stoichiometric TiO2(110) are 1.1 and 0.9 eV below the VBM. We also find a similar energy of 1.1 eV for the highest occupied levels of H2O when adsorbed dissociatively on a bridging O vacancy of the reduced surface. In both cases, these energies are significantly higher (by 0.6 to 2.6 eV) than those estimated from UPS difference spectra, which are inconclusive in this energy region. Finally, we apply self-consistent QPGW (scQPGW1) to obtain the ionization potential of the H2O-TiO2(110) interface.

Breaking Bad Delirium: Methamphetamine and Boric Acid Toxicity with Hallucinations and Pseudosepsis.

Science.gov (United States)

Johnson, Kayla; Stollings, Joanna L; Ely, E Wesley

2017-02-01

A 30-year-old patient presented with hallucinations and profound shock. He was initially misdiagnosed as having severe sepsis; once ingestions were considered, he was diagnosed as potentially having arsenic toxicity. The clinical story reveals many instructional lessons that could aid in the evaluation and management of future patients. This man presented with large amounts of blue crystals around his nose and lips from inhaling and eating boric acid (an ant poison) so he could, as he put it, kill the ants "pouring into my mouth and nose and up into my brain." His profound pseudosepsis and sustained delirium were induced by co-ingestion of methamphetamine and a large quantity of boric acid. Delirium is a form of acute brain dysfunction that often is multifactorial in critical illness and, when seen in septic shock, is associated with prolonged mechanical ventilation, increased length of hospital stay, medical costs, higher mortality, and long-term cognitive impairment resembling dementia. Pseudosepsis is a noninfectious condition most commonly seen with ingestions such as salicylate (aspirin) toxicity. This report emphasizes the need to recognize agents that contain boric acid as an etiology of unexplained delirium and profound shock.

Pilot-plant evaluation of TiO2 and TiO2-based hybrid photocatalysts for solar treatment of polluted water.

Science.gov (United States)

Andronic, Luminita; Isac, Luminita; Miralles-Cuevas, Sara; Visa, Maria; Oller, Isabel; Duta, Anca; Malato, Sixto

2016-12-15

Materials with photocatalytic and adsorption properties for advanced wastewater treatment targeting reuse were studied. Making use of TiO 2 as a well-known photocatalyst, Cu 2 S as a Vis-active semiconductor, and fly ash as a good adsorbent, dispersed mixtures/composites were prepared to remove pollutants from wastewater. X-ray diffraction, scanning electron microscopy, energy-dispersive X-Ray spectroscopy, atomic force microscopy, band gap energy, point of zero charge (pH pzc ) and BET porosity were used to characterize the substrates. Phenol, imidacloprid and dichloroacetic acid were used as pollutants for photocatalytic activity of the new photocatalysts. Experiments using the new dispersed powders were carried out at laboratory scale in two solar simulators and under natural solar irradiation at the Plataforma Solar de Almería, in a Compound Parabolic Collector (CPC) for a comparative analysis of pollutants removal and mineralization efficiencies, and to identify features that could facilitate photocatalyst separation and reuse. The results show that radiation intensity significantly affects the phenol degradation rate. The composite mixture of TiO 2 and fly ash is 2-3 times less active than sol-gel TiO 2 . Photodegradation kinetic data on the highly active TiO 2 are compared for pollutants elimination. Photodegradation of dichloroacetic acid was fast and complete after 90min in the CPC, while after 150min imidacloprid and phenol removal was 90% and 56% respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Pilot-plant evaluation of TiO_2 and TiO_2-based hybrid photocatalysts for solar treatment of polluted water

International Nuclear Information System (INIS)

Andronic, Luminita; Isac, Luminita; Miralles-Cuevas, Sara; Visa, Maria; Oller, Isabel; Duta, Anca; Malato, Sixto

2016-01-01

Materials with photocatalytic and adsorption properties for advanced wastewater treatment targeting reuse were studied. Making use of TiO_2 as a well-known photocatalyst, Cu_2S as a Vis-active semiconductor, and fly ash as a good adsorbent, dispersed mixtures/composites were prepared to remove pollutants from wastewater. X-ray diffraction, scanning electron microscopy, energy-dispersive X-Ray spectroscopy, atomic force microscopy, band gap energy, point of zero charge (pH_p_z_c) and BET porosity were used to characterize the substrates. Phenol, imidacloprid and dichloroacetic acid were used as pollutants for photocatalytic activity of the new photocatalysts. Experiments using the new dispersed powders were carried out at laboratory scale in two solar simulators and under natural solar irradiation at the Plataforma Solar de Almería, in a Compound Parabolic Collector (CPC) for a comparative analysis of pollutants removal and mineralization efficiencies, and to identify features that could facilitate photocatalyst separation and reuse. The results show that radiation intensity significantly affects the phenol degradation rate. The composite mixture of TiO_2 and fly ash is 2-3 times less active than sol-gel TiO_2. Photodegradation kinetic data on the highly active TiO_2 are compared for pollutants elimination. Photodegradation of dichloroacetic acid was fast and complete after 90 min in the CPC, while after 150 min imidacloprid and phenol removal was 90% and 56% respectively.

Effect of Silica Sol on Boric-sulfuric Acid Anodic Oxidation of LY12CZ Aluminum Alloy

Directory of Open Access Journals (Sweden)

LIU Hui-cong

2016-07-01

Full Text Available Aluminum alloy anodizing coatings were prepared for LY12CZ in the boric-sulfuric acid solution (45g/L sulfuric acid,8g/L boric acid with the addition of 10%,20%,30% (volume fractionsilica sol,with the gradient voltage of 15V. The current and voltage transients of the anodizing process were collected by data collection instrument. The surface morphologies,microstructure and chemical composition of the anodic coatings were characterized by scanning electron microscopy (SEM. The corrosion resistance was examined by neutral salt spray,electrochemical impedance spectroscopy (EIS test and titrating test. The results show that the different concentration of silica sol addition can influence the forming and dissolution of anodizing coatings,improve the compactness smoothness and corrosion resistance during the anodizing process in the boric-sulfuric acid solution.

Synergy of boric acid and added salts in the catalytic dehydration of hexoses to 5-hydroxymethylfurfural in water

DEFF Research Database (Denmark)

Hansen, Thomas Steen; Mielby, Jerrik Jørgen; Riisager, Anders

2011-01-01

Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural.......Boric acid and salts showed a synergistic effect on the dehydration of concentrated aqueous sugar solutions to yield 5-hydroxymethylfurfural....

TiO2 activation using acid-treated vermiculite as a support: Characteristics and photoreactivity

International Nuclear Information System (INIS)

Jin Ling; Dai Bin

2012-01-01

Vermiculite was treated by sulfuric or nitric acid aqueous solutions with different concentration. These modified materials as the promising supports, were used to immobilize TiO 2 . TiO 2 was prepared by the precursor, which was obtained by substituting partly isopropyl alcohol with Cl - in titanium chloride {[Ti(IV)(OR) n Cl m ] (n = 2-3, m = 4 - n)}. The TiO 2 /vermiculite composites were characterized by X-ray diffraction, scanning electron microscopy, and the nitrogen absorption. Their photocatalytic activity was evaluated by removal of methylene blue (MB). The pure anatase type crystalline phase was well deposited on the supports. The concentrations of acid for treatment had a significant influence on pore sizes and surface area of vermiculite. The treatment process changed microstructure of vermiculite, modified its characteristics, and farther improved the catalytic activity and absorption capacity of TiO 2 /vermiculite composites. The treatment effect of nitric acid was superior to that of sulfuric acid.

Hybrid TiO2: polymer photovoltaic cells made from a titanium oxide precursor

NARCIS (Netherlands)

Slooff, L.H.; Wienk, M.M.; Kroon, J.M.

2004-01-01

Hybrid TiO2:polymer photovoltaic cells were made from mixtures of titanium(IV) isopropoxide and poly[2-methoxy-5-(3',7'-dimethyloctyl)-p-phenylene vinylene] (MDMO-PPV) or poly(3-octyl thiophene) (P3OT) via hydrolysis in air. Cells were made with varying titanium(IV) isopropoxide:polymer ratios.

Mitochondrial dysfunction is involved in the toxic activity of boric acid against Saprolegnia.

Directory of Open Access Journals (Sweden)

Shimaa E Ali

Full Text Available There has been a significant increase in the incidence of Saprolegnia infections over the past decades, especially after the banning of malachite green. Very often these infections are associated with high economic losses in salmonid farms and hatcheries. The use of boric acid to control the disease has been investigated recently both under in vitro and in vivo conditions, however its possible mode of action against fish pathogenic Saprolegnia is not known. In this study, we have explored the transformation in Saprolegnia spores/hyphae after exposure to boric acid (1 g/L over a period 4-24 h post treatment. Using transmission electron microscopy (TEM, early changes in Saprolegnia spores were detected. Mitochondrial degeneration was the most obvious sign observed following 4 h treatment in about 20% of randomly selected spores. We also investigated the effect of the treatment on nuclear division, mitochondrial activity and function using confocal laser scanning microscopy (CLSM. Fluorescence microscopy was also used to test the effect of treatment on mitochondrial membrane potential and formation of reactive oxygen species. Additionally, the viability and proliferation of treated spores that correlated to mitochondrial enzymatic activity were tested using an MTS assay. All obtained data pointed towards changes in the mitochondrial structure, membrane potential and enzymatic activity following treatment. We have found that boric acid has no effect on the integrity of membranes of Saprolegnia spores at concentrations tested. It is therefore likely that mitochondrial dysfunction is involved in the toxic activity of boric acid against Saprolegnia spp.

Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

Science.gov (United States)

Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

2018-03-01

The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

A Ag synchronously deposited and doped TiO2 hybrid as an ultrasensitive SERS substrate: a multifunctional platform for SERS detection and photocatalytic degradation.

Science.gov (United States)

Yang, Libin; Sang, Qinqin; Du, Juan; Yang, Ming; Li, Xiuling; Shen, Yu; Han, Xiaoxia; Jiang, Xin; Zhao, Bing

2018-06-06

Ag simultaneously deposited and doped TiO2 (Ag-TiO2) hybrid nanoparticles (NPs) were prepared via a sol-hydrothermal method, as both a sensitive surface-enhanced Raman scattering (SERS) substrate and a superior photocatalyst for the first time. Ag-TiO2 hybrid NPs exhibit excellent SERS performance for several probe molecules and the enhancement factor is calculated to be 1.86 × 105. The detection limit of the 4-mercaptobenzoic acid (4-MBA) probe on the Ag-TiO2 substrate is 1 × 10-9 mol L-1, which is four orders of magnitude lower than that on pure TiO2 as a consequence of the synergistic effects of TiO2 and Ag. This is the highest SERS sensitivity among the reported semiconductor substrates and even comparable to noble metal substrates, and a SERS enhancement mechanism from the synergistic contribution of the semiconductor and noble metal was proposed. And importantly, the Ag-TiO2 hybrid shows excellent photocatalytic degradation activity for the detected species under UV light irradiation at lower concentration conditions, even for the hard to degrade 4-MBA molecule. This makes the Ag-TiO2 hybrid promising as a dual-function platform for both highly sensitive SERS detection and photocatalytic degradation of a pollutant system. Moreover, it also proves that the Ag-TiO2 hybrid can serve as a promising recyclable SERS-active substrate by virtue of its photocatalytic self-cleaning properties for some specific applications, for instance comparative studies of different species on the same SERS platform, in addition to the economic benefit.

Activity of boric acid on German cockroaches: Analysis of residues ...

African Journals Online (AJOL)

STORAGESEVER

2009-02-18

Feb 18, 2009 ... Full Length Research Paper. Activity of ... In a previous study, we have shown that boric ... ing 300 µl of curcumin solution (12.5 mg curcumin, 10 ml acetic acid) ..... Schal C, Chiang AS, Burns EL, Gadot M, Cooper RA (1993).

Synthesis of highly ordered TiO2 nanotube in malonic acid solution by anodization.

Science.gov (United States)

Ryu, Won Hee; Park, Chan Jin; Kwon, Hyuk Sang

2008-10-01

We synthesized TiO2 nanotube array by anodizing in a solution of malonic acid (HOOCCH2COOH) and NH4F, and analyzed the morphology of the nanotube using scanning electron microscopy (SEM). The morphology of TiO2 nanotube was largely affected by anodizing time, anodizing voltage, and malonic acid concentration. With increasing the anodizing voltage from 5 V to 20 V, the diameter of TiO2 nanotube was increased from about 20 nm to 110 nm and its length from about 10 nm to 700 nm. In addition, the length of TiO2 nanotube was increased with increasing anodizing time up to 6 h at 20 V. We obtained the longest and the most highly ordered nanotube structure when anodizing Ti in a solution of 0.5 wt% NH4F and 1 M malonic acid at 20 V for 6 h.

Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution

International Nuclear Information System (INIS)

Kim, Dong Jin; Kim, Hong Pyo; Kim, Joung Soo; Machonald, Digby D.

2005-01-01

This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000∼10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

Microwave-assisted synthesis of C-doped TiO2 and ZnO hybrid nanostructured materials as quantum-dots sensitized solar cells

Science.gov (United States)

Rangel-Mendez, Jose R.; Matos, Juan; Cházaro-Ruiz, Luis F.; González-Castillo, Ana C.; Barrios-Yáñez, Guillermo

2018-03-01

The microwave-assisted solvothermal synthesis of C-doped TiO2 and ZnO hybrid materials was performed. Saccharose, titanium isopropoxide and zinc acetate were used as organic and inorganic sources for the synthesis. The influence of temperature and reaction time on the textural and optoelectronic properties of the hybrid materials was verified. Carbon quantum-dots of TiO2 and ZnO nanostructured spheres were obtained in a second pot by controlled calcination steps of the precursor hybrid materials. A carefully characterization by adsorption-desorption N2 isotherms, XRD, XPS, SEM, UV-vis/DR and electro- and photo-electrochemistry properties of the carbon quantum-dots TiO2 and ZnO spheres was performed. The photoelectrochemical activity of TiO2-C and ZnO-C films proved to be dependent on the conditions of synthesis. It was found a red-shift in the energy band gap of the semiconductors with values of 3.02 eV and 3.13 eV for the TiO2-C and ZnO-C, respectively, clearly lower than those on bare semiconductors, which is associated with the C-doping effect. From the photo-electrochemistry characterization of C-doped TiO2 and ZnO films can be concluded that the present materials have potential applications as photoelectrodes for quantum-dots sensitized solar cells.

Fabrication of Li{sub 2}TiO{sub 3} pebbles using PVA–boric acid reaction for solid breeding materials

Energy Technology Data Exchange (ETDEWEB)

Park, Yi-Hyun, E-mail: yhpark@nfri.re.kr; Cho, Seungyon; Ahn, Mu-Young

2014-12-15

Highlights: • Li{sub 2}TiO{sub 3} pebbles were successfully fabricated by the slurry droplet wetting method. • Boron was used as hardening agent of PVA and completely removed during sintering. • Microstructure of fabricated Li{sub 2}TiO{sub 3} pebble was exceptionally homogeneous. • Suitable process conditions for high-quality Li{sub 2}TiO{sub 3} pebble were summarized. - Abstract: Lithium metatitanate (Li{sub 2}TiO{sub 3}) is a candidate breeding material of the Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM). The breeding material is used in pebble-bed form to reduce the uncertainty of the interface thermal conductance. In this study, Li{sub 2}TiO{sub 3} pebbles were successfully fabricated by the slurry droplet wetting method using the cross-linking reaction between polyvinyl alcohol (PVA) and boric acid. The effects of fabrication parameters on the shaping of Li{sub 2}TiO{sub 3} green body were investigated. In addition, the basic characteristics of the sintered pebble were also evaluated. The shape of Li{sub 2}TiO{sub 3} green bodies was affected by slurry viscosity, PVA content and boric acid content. The grain size and average crush load of sintered Li{sub 2}TiO{sub 3} pebble were controlled by the sintering time. The boron was completely removed during the final sintering process.

Determination of Optimum Duration and Concentration of Stevia (Stevia rebaudiana Bert.) Seed Priming with Boric Acid (H3BO3)

OpenAIRE

SHAHVERDI, Mehdi Aghighi; OMIDI, Heshmat; TABATABAEI, Seyed Jalal

2017-01-01

In order to determine optimal duration and concentration of Stevia seed priming with boric acid for improving germination, an experimental factorial completely randomized design with three replications was conducted in the laboratory of Seed Science and Technology, Shahed University of Tehran in 2015. The first factor was different concentrations of boric acid (0, 0.5, 1.0, 1.5 and 2.0 percent) and the second factor was priming duration (0, 8, 16, 24 and 32 hours). Effects of concentration an...

Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: Prospective matrix for satellite cell adhesion and cultivation

International Nuclear Information System (INIS)

Amna, Touseef; Hassan, M. Shamshi; Van Ba, Hoa; Khil, Myung-Seob; Lee, Hak-Kyo; Hwang, I.H.

2013-01-01

We report the fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe 3 O 4 /TiO 2 hybrid nanofibers were prepared by facile sol–gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe 3 O 4 /TiO 2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe 3 O 4 /TiO 2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe 3 O 4 /TiO 2 composite nanofibers after being cultured. We observed that Fe 3 O 4 –TiO 2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe 3 O 4 /TiO 2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine. Highlights: ► We report fabrication of novel Fe 3 O 4 /TiO 2 hybrid nanofibers by facile electrospinning. ► The utilized satellite cells were isolated from native Korean Hanwoo cattle. ► Fe 3 O 4 /TiO 2 composite with small diameters (∼ 200 nm) can mimic the natural ECM well. ► Fe 3 O 4 /TiO 2

Enhanced activity of Anticarsia gemmatalis Hüb. (Lepidoptera: Noctuidae) nuclear polyhedrosis virus by boric acid in the laboratory

OpenAIRE

Morales, Lauro; Moscardi, Flávio; Sosa-Gómez, Daniel R.; Paro, Fábio E.; Soldorio, Ivanilda L.

1997-01-01

Boric acid concentrations (0.02,0.03,0.045,0.067 and 0.101 g/100 ml of diet) were evaluated in combination with the Anticarsia gemmatalis Hüb. nuclear polyhedrosis virus (AgNPV) for enhanced virali activity against the insect. Seven days after inoculation, the median lethal concentration (LC50) was 1.52 x 10(5) for the AgNPV alone and 7.95 x 10² for the NPV mixed with 0.045g of boric acid/100 ml of diet. At subsequent evaluation dates (9,11 and 14 days after inoculation) LC50's for NPV+boric ...

Algae decorated TiO2/Ag hybrid nanofiber membrane with enhanced photocatalytic activity for Cr(VI) removal under visible light

OpenAIRE

Wang, L; Zhang, C; Gao, F; Mailhot, G; Pan, G

2017-01-01

Algae as an abundant natural biomass, more attention has been paid to explore its potential application in environmental pollutants treatment. This work prepared the algae-TiO2/Ag bionano hybrid material by loading algae cells on the ultrafine TiO2/Ag chitosan hybrid nanofiber mat. For the first time, the synergistic photocatalytic effect of fresh algae and TiO2/Ag nanomaterial was investigated by removal of Cr(VI). The addition of algae significantly improved the photo-removal of Cr(VI) in t...

Limitations when use chloramphenicol-bcyclodextrins complexes in ophtalmic solutions buffered with boric acid/borax system

Directory of Open Access Journals (Sweden)

Todoran Nicoleta

2014-12-01

Full Text Available Chloramphenicol eye drops are commonly prescribed in concentrations of 0.5-1% in the treatment of infectious conjunctivitis. In terms of ophthalmic solution preparation, the major disadvantage of chloramphenicol consists in its low solubility in water. The solubility is increased by substances that form chloramphenicol-complexes, for example: boric acid/borax or cyclodextrins. Objective: Experimental studies aimed to evaluate the potential advantages of enhancing the solubility and stability of chloramphenicol (API by molecular encapsulation in b-cyclodextrin (CD, in formulation of ophthalmic solutions buffered with boric acid/borax system. Methods and Results: We prepared four APIb- CD complexes, using two methods (kneading and co-precipitation and two molar ratio of API/b-cyclodextrin (1:1 and 1:2. The formation of complexes was proved by differential scanning calorimetry (DSC and the in vitro dissolution tests. Using these compounds, we prepared eight ophthalmic solutions, formulated in two variants of chloramphenicol concentrations (0.4% and 0.5%. Each solution was analyzed, by the official methods, at preparation and periodically during three months of storing in different temperature conditions (4°C, 20°C and 30°C. Conclusions: Inclusion of chloramphenicol in b-cyclodextrin only partially solves the difficulties due to the low solubility of chloramphenicol. The protection of chloramphenicol molecules is not completely ensured when the ophthalmic solutions are buffered with the boric acid/borax system.

Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

KAUST Repository

Mahmood, Khalid; Swain, Bhabani Sankar; Amassian, Aram

2015-01-01

A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

KAUST Repository

Mahmood, Khalid

2015-03-23

A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

Investigation of TiO2 photocatalyst performance for decolorization in the presence of hydrodynamic cavitation as hybrid AOP.

Science.gov (United States)

Bethi, Bhaskar; Sonawane, S H; Rohit, G S; Holkar, C R; Pinjari, D V; Bhanvase, B A; Pandit, A B

2016-01-01

In this article, an acoustic cavitation engineered novel approach for the synthesis of TiO2, cerium and Fe doped TiO2 nanophotocatalysts is reported. The prepared TiO2, cerium and Fe doped TiO2 nanophotocatalysts were characterized by XRD and TEM analysis to evaluate its structure and morphology. Photo catalytic performance of undoped TiO2 catalyst was investigated for the decolorization of crystal violet dye in aqueous solution at pH of 6.5 in the presence of hydro dynamic cavitation. Effect of catalyst doping with Fe and Ce was also studied for the decolorization of crystal violet dye. The results shows that, 0.8% of Fe-doped TiO2 exhibits maximum photocatalytic activity in the decolorization study of crystal violet dye due to the presence of Fe in the TiO2 and it may acts as a fenton reagent. Kinetic studies have also been reported for the hybrid AOP (HAOP) that followed the pseudo first-order reaction kinetics. Copyright © 2015 Elsevier B.V. All rights reserved.

Hybrid TiO2 -Ruthenium Nano-photosensitizer Synergistically Produces Reactive Oxygen Species in both Hypoxic and Normoxic Conditions.

Science.gov (United States)

Gilson, Rebecca C; Black, Kvar C L; Lane, Daniel D; Achilefu, Samuel

2017-08-28

Photodynamic therapy (PDT) is widely used to treat diverse diseases, but its dependence on oxygen to produce cytotoxic reactive oxygen species (ROS) diminishes the therapeutic effect in a hypoxic environment, such as solid tumors. Herein, we developed a ROS-producing hybrid nanoparticle-based photosensitizer capable of maintaining high levels of ROS under both normoxic and hypoxic conditions. Conjugation of a ruthenium complex (N3) to a TiO 2 nanoparticle afforded TiO 2 -N3. Upon exposure of TiO 2 -N3 to light, the N3 injected electrons into TiO 2 to produce three- and four-fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO 2 at 160 mmHg. TiO 2 -N3 maintained three-fold higher hydroxyl radicals than TiO 2 under hypoxic conditions via N3-facilitated electron-hole reduction of adsorbed water molecules. The incorporation of N3 transformed TiO 2 from a dual type I and II PDT agent to a predominantly type I photosensitizer, irrespective of the oxygen content. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct access to highly crystalline mesoporous nano TiO2 using sterically bulky organic acid templates

Science.gov (United States)

Bakre, Pratibha V.; Tilve, S. G.

2018-05-01

Sterically bulky monocarboxylic acid templates pivalic acid and phenoxyacetic acid are reported for the first time as organic templates in the sol-gel synthesis of TiO2. Mesoporous nanoparticulates of pure anatase phase and of well defined size were synthesized. The characterization of the materials prepared was done by various methods such as XRD, SEM, TEM, FTIR, UV-DRS, BET, etc. The prepared TiO2 samples were evaluated for the day light photodegradation of methylene blue by comparing with Degussa P25 and templates free synthesized TiO2 and were found to be more efficient.

Effectiveness of 3 per cent boric acid in 70 per cent alcohol versus 1 per cent clotrimazole solution in otomycosis patients: a randomised, controlled trial.

Science.gov (United States)

Romsaithong, S; Tomanakan, K; Tangsawad, W; Thanaviratananich, S

2016-09-01

To compare the clinical effectiveness and adverse events for 3 per cent boric acid in 70 per cent alcohol versus 1 per cent clotrimazole solution in the treatment of otomycosis. A total of 120 otomycosis patients were randomly assigned to receive either 1 per cent clotrimazole solution (intervention group) or 3 per cent boric acid in 70 per cent alcohol (control group) at the Khon Kaen Hospital ENT out-patient department. Treatment effectiveness was determined based on the otomicroscopic absence of fungus one week after therapy, following a single application of treatment. After 1 week of treatment, there were data for 109 participants, 54 in the clotrimazole group and 55 in the boric acid group. The absolute difference in cure rates between 1 per cent clotrimazole solution and 3 per cent boric acid in 70 per cent alcohol was 17.9 per cent (95 per cent confidence interval, 2.3 to 33.5; p = 0.028) and the number needed to treat was 6 (95 per cent confidence interval, 3.0 to 43.4). Adverse events for the two agents were comparable. One per cent clotrimazole solution is more effective than 3 per cent boric acid in 70 per cent alcohol for otomycosis treatment.

Facile Preparation of TiO2 Nanobranch/Nanoparticle Hybrid Architecture with Enhanced Light Harvesting Properties for Dye-Sensitized Solar Cells

Directory of Open Access Journals (Sweden)

Ju Seong Kim

2015-01-01

Full Text Available We report TiO2 nanobranches/nanoparticles (NBN hybrid architectures that can be synthesized by a facile solution phase method. The hybrid architecture simultaneously improves light harvesting and charge collection performances for a dye-sensitized solar cell. First, TiO2 nanorods with a trunk length of 2 μm were grown on a fluorine-doped tin oxide (FTO/glass substrate, and then nanobranches and nanoparticles were deposited on the nanorods’ trunks through a solution method using an aqueous TiCl3 solution at 80°C. The relative amount of nanobranches and nanoparticles can be controlled by multiplying the number of TiCl3 treatments to maximize the amount of surface area. We found that the resultant TiO2 NBN hybrid architecture greatly improves the amount of dye adsorption (five times compared to bare nanorods due to the enhanced surface area, while maintaining a fast charge collection, leading to a three times higher current density and thus tripling the maximum power conversion efficiency for a dye-sensitized solar cell.

The electrical conductivity and energy band gap of ‘bunga belimbing buluh’/tio2 nanocrystals as hybrid solar cell

Science.gov (United States)

Kamarulzaman, N. H.; Salleh, H.; Ghazali, M. S. M.; Ghazali, S. M.; Ahmad, Z.

2018-05-01

This research intends to explore the effect of thickness of inorganic titania nanocrystals (TiO2 NCs) materials and Averrhoe bilimbi’s flower towards the electrical conductivity. Averrhoe bilimbi’s flower or also known as ‘bunga belimbing buluh’ was used for the first time as a natural dye in hybrid solar cells. The performance of electrical conductivity can be improved in bilayer heterojunction hybrid solar cell (HCS). The TiO2 NCs was deposited on the ITO substrate using Electrochemistry method at room temperature. The dye extracted from Averrhoe bilimbi’s flower was deposited on the top of TiO2 NCs layered using the same method. The electrical conductivity can be recorded using Four Point Probe (FPP) under dark and light radiation (range of 0 Wm-2 to 200Wm-2). From the results, electrical conductivity was increased by the increment light intensity and suitable for further solar cell fabrications.

FTIR study of formic acid interaction with TiO2 and TiO2 doped with Pd and Cu in photocatalytic processes

International Nuclear Information System (INIS)

Arana, J.; Garriga i Cabo, C.; Dona-Rodriguez, J.M.; Gonzalez-Diaz, O.; Herrera-Melian, J.A.; Perez-Pena, J.

2004-01-01

In this study the different processes occurring on the TiO 2 and Pd and Cu doped TiO 2 surfaces during the photocatalytic formic acid degradation in the presence or absence of S 2 O 8 2- or H 2 O 2 have been investigated. FTIR studies have shown the relevance of the H-bounded hydroxyl groups. It has been observed that formate molecules interact simultaneously with the dopants and surfacial Ti atoms yielding an intermediate species which plays an important role in the phototacatalytic degradation mechanism. Also, it has been determined that Pd or Cu oxides may act as receptors or transmitters of the TiO 2 photogenerated electrons and thus modify the degradation mechanism. Different redox reactions have been proposed according to the obtained results

Heteropoly acid promoted V2O5/TiO2 catalysts for NO abatement with ammonia in alkali containing flue gases

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders

2011-01-01

V2O5/TiO2 and heteropoly acid promoted V2O5/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD and NH3-TPD. The influence of the calcination temperature from 400 to 700 1C on crystallinity and acidic properties was studied and compared with the activity for the selective...... catalytic reduction (SCR) of NO with ammonia. The SCR activity of heteropoly acid promoted catalysts was found to be much higher than for unpromoted catalysts. The stability of heteropoly acid promoted catalysts is dependent on calcination temperature and there is a gradual decrease in SCR activity...... and acidity with increase in calcination temperatures. Furthermore, the heteropoly acid promoted V2O5/TiO2 catalysts showed excellent alkali deactivation resistance and might therefore be alternative deNOx catalysts in biomass fired power plants....

Influence of temperature, hydrogen and boric acid concentration on IGSCC susceptibility of unsensitized 316 stainless steel

Energy Technology Data Exchange (ETDEWEB)

Arioka, Koji [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2002-09-01

IGSCC susceptibility of unsensitized 316SS under PWR primary water was studied as a function of solution temperature, dissolved hydrogen, and boric acid concentration by SSRT test using specimens with cold deformed hump. IGSCC growth rate was dependent on temperature and the obtained activation energy was 21.6K cal/mol. Regarding the influence of dissolved hydrogen, there was a simple monotonic increase in crack growth rate with the increasing hydrogen concentration within the PWR primary water chemistry specifications. Also, there was a remarkable difference in IGSCC susceptibility with regard to the effect to boric acid concentration. Within the tested concentration, the IGSCC susceptibility under high concentrated boric acid solution (2300ppm B) was inhibited in comparison with that under 500ppm B. These temperature and dissolved hydrogen dependencies of IGSCC susceptibility were similar to the literature on published data on irradiated 316SS. Although further study is required to clarify the mechanism, however the similarity of the dependencies suggests that the rate-limited IGSCC process of un-irradiated 316SS is related to that of IASCC. (author)

Further investigation on boric acid catalytic graphitization of polyacrylonitrile carbon fibers: Mechanism and mechanical properties

International Nuclear Information System (INIS)

Wen, Ya; Lu, Yonggen; Xiao, Hao; Qin, Xianying

2012-01-01

Highlights: ► The modulus of carbon fiber was improved by boric acid at the temperature range of 1500–2900 °C. ► 2300 °C is a key temperature degree from which the boron began to benefit fiber strength. ► The fiber strength was affected by the boron reaction and related to the boron states. -- Abstract: Catalytic graphitization of polyacrylonitrile based carbon fibers by boric acid doping was studied and the dependence of fiber tensile strength on the boron content and temperature was discussed. It was found that there existed a key temperature point for the boron to take effect. When the fibers were modified with 7.0 wt.% boric acid solution, with increasing temperature, the tensile strength was lower than that of the unmodified ones below 2300 °C, but a reverse thing happened above 2300 °C. Moreover, when being heated at 2500 °C, the modified fibers showed an increasing tensile modulus and strength with increasing boron content till maximums of 404 GPa and 2.46 GPa, 26% and 16% higher than those of unmodified ones. The mechanical properties of the fibers were affected by the interaction of carbon and boron, and also related with boron states. The decomposition of boron acid and its interaction with carbon brought defects on fiber surface, degrading the mechanical properties below 1300 °C. With further heat treatment, the boron diffused into the fibers and divided into two states: substitutional and interstitial. At a temperature over 2300 °C with an appreciate boron content, the substitutional would be formed predominantly, which removed the structural defects and relaxed the distortions, so as to benefit the mechanical properties.

Boric acid inhibits embryonic histone deacetylases: A suggested mechanism to explain boric acid-related teratogenicity

International Nuclear Information System (INIS)

Di Renzo, Francesca; Cappelletti, Graziella; Broccia, Maria L.; Giavini, Erminio; Menegola, Elena

2007-01-01

Histone deacetylases (HDAC) control gene expression by changing histonic as well as non histonic protein conformation. HDAC inhibitors (HDACi) are considered to be among the most promising drugs for epigenetic treatment for cancer. Recently a strict relationship between histone hyperacetylation in specific tissues of mouse embryos exposed to two HDACi (valproic acid and trichostatin A) and specific axial skeleton malformations has been demonstrated. The aim of this study is to verify if boric acid (BA), that induces in rodents malformations similar to those valproic acid and trichostatin A-related, acts through similar mechanisms: HDAC inhibition and histone hyperacetylation. Pregnant mice were treated intraperitoneally with a teratogenic dose of BA (1000 mg/kg, day 8 of gestation). Western blot analysis and immunostaining were performed with anti hyperacetylated histone 4 (H4) antibody on embryos explanted 1, 3 or 4 h after treatment and revealed H4 hyperacetylation at the level of somites. HDAC enzyme assay was performed on embryonic nuclear extracts. A significant HDAC inhibition activity (compatible with a mixed type partial inhibition mechanism) was evident with BA. Kinetic analyses indicate that BA modifies substrate affinity by a factor α = 0.51 and maximum velocity by a factor β = 0.70. This work provides the first evidence for HDAC inhibition by BA and suggests such a molecular mechanism for the induction of BA-related malformations

Copper doped TiO2 nanoparticles characterized by X-ray absorption spectroscopy, total scattering, and powder diffraction--a benchmark structure-property study.

Science.gov (United States)

Lock, Nina; Jensen, Ellen M L; Mi, Jianli; Mamakhel, Aref; Norén, Katarina; Qingbo, Meng; Iversen, Bo B

2013-07-14

Metal functionalized nanoparticles potentially have improved properties e.g. in catalytic applications, but their precise structures are often very challenging to determine. Here we report a structural benchmark study based on tetragonal anatase TiO2 nanoparticles containing 0-2 wt% copper. The particles were synthesized by continuous flow synthesis under supercritical water-isopropanol conditions. Size determination using synchrotron PXRD, TEM, and X-ray total scattering reveals 5-7 nm monodisperse particles. The precise dopant structure and thermal stability of the highly crystalline powders were characterized by X-ray absorption spectroscopy and multi-temperature synchrotron PXRD (300-1000 K). The combined evidence reveals that copper is present as a dopant on the particle surfaces, most likely in an amorphous oxide or hydroxide shell. UV-VIS spectroscopy shows that copper presence at concentrations higher than 0.3 wt% lowers the band gap energy. The particles are unaffected by heating to 600 K, while growth and partial transformation to rutile TiO2 occur at higher temperatures. Anisotropic unit cell behavior of anatase is observed as a consequence of the particle growth (a decreases and c increases).

Improved thermal conductivity of TiO2-SiO2 hybrid nanofluid in ethylene glycol and water mixture

Science.gov (United States)

Hamid, K. A.; Azmi, W. H.; Nabil, M. F.; Mamat, R.

2017-10-01

The need to study hybrid nanofluid properties such as thermal conductivity has increased recently in order to provide better understanding on nanofluid thermal properties and behaviour. Due to its ability to improve heat transfer compared to conventional heat transfer fluids, nanofluids as a new coolant fluid are widely investigated. This paper presents the thermal conductivity of TiO2-SiO2 nanoparticles dispersed in ethylene glycol (EG)-water. The TiO2-SiO2 hybrid nanofluids is measured for its thermal conductivity using KD2 Pro Thermal Properties Analyzer for concentration ranging from 0.5% to 3.0% and temperature of 30, 50 and 70°C. The results show that the increasing in concentration and temperature lead to enhancement in thermal conductivity at range of concentration studied. The maximum enhancement is found to be 22.1% at concentration 3.0% and temperature 70°C. A new equation is proposed based on the experiment data and found to be in good agreement where the average deviation (AD), standard deviation (SD) and maximum deviation (MD) are 1.67%, 1.66% and 5.13%, respectively.

Improvement of epoxy resin properties by incorporation of TiO2 nanoparticles surface modified with gallic acid esters

International Nuclear Information System (INIS)

Radoman, Tijana S.; Džunuzović, Jasna V.; Jeremić, Katarina B.; Grgur, Branimir N.; Miličević, Dejan S.; Popović, Ivanka G.; Džunuzović, Enis S.

2014-01-01

Highlights: • Nanocomposites of epoxy resin and TiO 2 nanoparticles surface modified with gallates. • The T g of epoxy resin was increased by incorporation of surface modified TiO 2 . • WVTR of epoxy resin decreased in the presence of surface modified TiO 2 nanoparticles. • WVTR of nanocomposites was reduced with increasing gallates hydrophobic chain length. • Modified TiO 2 nanoparticles react as oxygen scavengers, inhibiting steel corrosion. - Abstract: Epoxy resin/titanium dioxide (epoxy/TiO 2 ) nanocomposites were obtained by incorporation of TiO 2 nanoparticles surface modified with gallic acid esters in epoxy resin. TiO 2 nanoparticles were obtained by acid catalyzed hydrolysis of titanium isopropoxide and their structural characterization was performed by X-ray diffraction and transmission electron microscopy. Three gallic acid esters, having different hydrophobic part, were used for surface modification of the synthesized TiO 2 nanoparticles: propyl, hexyl and lauryl gallate. The gallate chemisorption onto surface of TiO 2 nanoparticles was confirmed by Fourier transform infrared and ultraviolet–visible spectroscopy, while the amount of surface-bonded gallates was determined using thermogravimetric analysis. The influence of the surface modified TiO 2 nanoparticles, as well as the length of hydrophobic part of the gallate used for surface modification of TiO 2 nanoparticles, on glass transition temperature, barrier, dielectric and anticorrosive properties of epoxy resin was investigated by differential scanning calorimetry, water vapor transmission test, dielectric spectroscopy, electrochemical impedance spectroscopy and polarization measurements. Incorporation of surface modified TiO 2 nanoparticles in epoxy resin caused increase of glass transition temperature and decrease of the water vapor permeability of epoxy resin. The water vapor transmission rate of epoxy/TiO 2 nanocomposites was reduced with increasing hydrophobic part chain length of

Three-dimensional observation of TiO2 nanostructures by electron tomography

KAUST Repository

Suh, Young Joon

2013-03-01

Three-dimensional nanostructures of TiO2 related materials including nanotubes, electron acceptor materials in hybrid polymer solar cells, and working electrodes of dye sensitized solar cells (DSSCs) were visualized by electron tomography as well as TEM micrographs. The regions on the wall of TiO2 nanotubes where the streptavidins were attached were elucidated by electron tomogram analysis. The coverage of TiO2 nanotubes by streptavidin was also investigated. The TiO2 nanostructures in hybrid polymer solar cells made by sol-gel and atomic layer deposition (ALD) methods and the morphologies of pores between TiO2 particles in DSSCs were also observed by reconstructed three-dimensional images made by electron tomography. © 2012 Elsevier Ltd.

Boric Acid Catalyzed Convenient Synthesis of Benzimidazoles in Aqueous Media

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Mohammad Reza Poor Heravi

2013-01-01

Full Text Available Synthesis of benzimidazoles has been developed by the o-phenylenediamine with aldehydes using boric acid an efficient catalyst under mild reaction conditions in aqueous media. The product is applicable to aryl and heteroaryl aldehydes. This reaction led to the formation of benzimidazoles new derivatives in good yields. The FT-IR, 19F-NMR, 1H-NMR, 13C-NMR spectra and elemental analysis confirm the structure of compounds.

Boric Acid Catalyzed Convenient Synthesis of Benzimidazoles in Aqueous Media

OpenAIRE

Poor Heravi, Mohammad Reza; Ashori, Marjan

2013-01-01

Synthesis of benzimidazoles has been developed by the o-phenylenediamine with aldehydes using boric acid an efficient catalyst under mild reaction conditions in aqueous media. The product is applicable to aryl and heteroaryl aldehydes. This reaction led to the formation of benzimidazoles new derivatives in good yields. The FT-IR, 19F-NMR, 1H-NMR, 13C-NMR spectra and elemental analysis confirm the structure of compounds.

Surface modification of calcium–copper hydroxyapatites using polyaspartic acid

International Nuclear Information System (INIS)

Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen; Debbabi, Mongi

2013-01-01

Highlights: ► The reaction of polyaspartic acid with calcium hydroxyapatite and mixed calcium–copper hydroxyapatite is tested. ► Chemical analysis shows that the presence of copper in the apatitic structure increases the reactivity of the apatite surface. ► X-ray powder analysis shows the conservation of unique crystalline phase of hydroxyapatite after copper incorporation and/or PASP acid reacting. ► IR spectra show the formation of the formation of organometallic bond M-O-C (M=Ca or Cu) on the apatitic surface. ► Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) indicated that the texture surface was changed by the grafting. - Abstract: Mixed calcium–copper hydroxyapatite (Ca–CuHAp), with general formula Ca (10−x) Cu x (PO 4 ) 6 (OH) 2 , where 0 ≤ x ≤ 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca–CuHAp–PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (P-OH) band of (HPO 4 ) 2− groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay.

Science.gov (United States)

Gülsoy, Nagihan; Yavas, Cüneyd; Mutlu, Özal

2015-01-01

The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P borax-induced genotoxicity in fish.

Model for conductometric detection of carbohydrates and alcohols as complexes with boric acid and borate ion in high-performance liquid chromatography

International Nuclear Information System (INIS)

Bertrand, G.L.; Armstrong, D.W.

1989-01-01

In recent articles, Okada has demonstrated the utility of indirect conductometric detection of electrically neutral sugars and alcohols through their complexes in boric acid solution. The use of a boric acid eluent provides a highly sensitive means of detection for monosaccharides, lactose, and sugar alcohols but not for polysaccharides (other than lactose) and simple alcohols. Addition of sorbitol, mannitol, or fructose to the boric acid eluent allows detection of the polysaccharides and simple alcohols, as well as lactose, glucose, fructose, and presumably other monosaccharides and sugar alcohols. These results were interpreted in terms of the ability of an analyte to form either dissociated or undissociated complexes with boric acid. This interpretation was quantified with a mathematical description of the complexation equilibria and the conductivity due to ionic species. Unfortunately, the mathematical model contains some incorrect assumptions that severely limit the utility of the derived equations and may prevent optimization of this potentially important technique. We present here a more general mathematical model that does not suffer from these limitations

Determination of boron as boric acid by automatic potentiometric titration

International Nuclear Information System (INIS)

Midgley, D.

1988-06-01

Boron in PWR primary coolant and related waters may be determined as boric acid by titration with sodium hydroxide, using a glass electrode as a pH indicator. With a modern automatic titrator, the analysis is quick, convenient, accurate and precise. In the titration of 8 mg B (e.g. 4 ml of 2000 mg 1 -1 solution), no significant bias was observed and relative standard deviations were about 0.25%. With 0.8 g B, a bias of about 2% appears, although this could be reduced by restandardizing the titrant, but the relative standard deviation was still -1 B, depending on the stage of the fuel cycle. (author)

Accurate quantification of tio2 nanoparticles collected on air filters using a microwave-assisted acid digestion method

Science.gov (United States)

Mudunkotuwa, Imali A.; Anthony, T. Renée; Grassian, Vicki H.; Peters, Thomas M.

2016-01-01

Titanium dioxide (TiO2) particles, including nanoparticles with diameters smaller than 100 nm, are used extensively in consumer products. In a 2011 current intelligence bulletin, the National Institute of Occupational Safety and Health (NIOSH) recommended methods to assess worker exposures to fine and ultrafine TiO2 particles and associated occupational exposure limits for these particles. However, there are several challenges and problems encountered with these recommended exposure assessment methods involving the accurate quantitation of titanium dioxide collected on air filters using acid digestion followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Specifically, recommended digestion methods include the use of chemicals, such as perchloric acid, which are typically unavailable in most accredited industrial hygiene laboratories due to highly corrosive and oxidizing properties. Other alternative methods that are used typically involve the use of nitric acid or combination of nitric acid and sulfuric acid, which yield very poor recoveries for titanium dioxide. Therefore, given the current state of the science, it is clear that a new method is needed for exposure assessment. In this current study, a microwave-assisted acid digestion method has been specifically designed to improve the recovery of titanium in TiO2 nanoparticles for quantitative analysis using ICP-OES. The optimum digestion conditions were determined by changing several variables including the acids used, digestion time, and temperature. Consequently, the optimized digestion temperature of 210°C with concentrated sulfuric and nitric acid (2:1 v/v) resulted in a recovery of >90% for TiO2. The method is expected to provide for a more accurate quantification of airborne TiO2 particles in the workplace environment. PMID:26181824

Synthesis of 1-amidoalkyl-2-naphthols based on a three-component reaction catalyzed by boric acid as a solid heterogeneous catalyst under solvent-free conditions

Directory of Open Access Journals (Sweden)

Zahed Karimi-Jaberi

2012-12-01

Full Text Available An efficient method for the preparation of 1-amidoalkyl-2-naphthols has been described using a multi-component, one-pot condensation reaction of 2-naphthol, aldehydes and amides in the presence of boric acid under solvent-free conditions.DOI: http://dx.doi.org/10.4314/bcse.v26i3.18

Surface modification of calcium-copper hydroxyapatites using polyaspartic acid

Science.gov (United States)

Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen; Debbabi, Mongi

2013-01-01

Mixed calcium-copper hydroxyapatite (Ca-CuHAp), with general formula Ca(10-x)Cux(PO4)6(OH)2, where 0 ≤ x ≤ 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca-CuHAp-PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (Psbnd OH) band of (HPO4)2- groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

Effect of complexing reagents on the ionization constant of boric acid and its relation to isotopic exchange separation factor

International Nuclear Information System (INIS)

Sharma, B.K.; Subramanian, R.; Mathur, P.K.

1991-01-01

The effect of change in concentration of complexing reagents having two or more hydroxyl groups, viz., ethylene glycol, propylene glycol, dextrose and mannitol on the ionization constant of boric acid has been studied by pH-metric titration method. The effect of increase in ionization constant of boric acid on isotopic exchange separation factor for the separation of isotopes of boron by ion exchange chromatography has been studied by the batch method. (author). 9 refs

The Effects of Anchor Groups on (1) TiO2-Catalyzed Photooxidation and (2) Linker-Assisted Assembly on TiO2

Science.gov (United States)

Anderson, Ian Mark

Quantum dot-sensitized solar cells (QDSSCs) are a popular target for research due to their potential for highly efficient, easily tuned absorption. Typically, light is absorbed by quantum dots attached to a semiconductor substrate, such as TiO2, via bifunctional linker molecules. This research aims to create a patterned monolayer of linker molecules on a TiO2 film, which would in turn allow the attachment of a patterned layer of quantum dots. One method for the creation of a patterned monolayer is the functionalization of a TiO2 film with a linker molecule, followed by illumination with a laser at 355 nm. This initiates a TiO 2-catalyzed oxidation reaction, causing loss of surface coverage. A second linker molecule can then be adsorbed onto the TiO2 surface in the illuminated area. Towards that end, the behaviors of carboxylic and phosphonic acids adsorbed on TiO2 have been studied. TiO2 films were functionalized by immersion in solutions a single adsorbate and surface coverage was determined by IR spectroscopy. It is shown that phosphonic acids attain higher surface coverage than carboxylic acids, and will displace them from TiO2 when in a polar solvent. Alkyl chain lengths, which can influence stabilities of monolayers, are shown not to have an effect on this relationship. Equilibrium binding data for the adsorption of n-hexadecanoic acid to TiO2 from a THF solution are presented. It is shown that solvent polarity can affect monolayer stability; carboxylates and phosphonates undergo more desorption into polar solvents than nonpolar. Through illumination, it was possible to remove nearly all adsorbed linkers from TiO2. However, the illuminated areas were found not to be receptive to attachment by a second adsorbate. A possible reason for this behavior is presented. I also report on the synthesis and characterization of a straight-chain, thiol-terminated phosphonic acid. Initial experiments involving monolayer formation and quantum dot attachment are presented

Catalysis of a Nanometre Solid Super Acid of SO42-/TiO2 on the Thermal Decomposition of Ammonium Nitrate

OpenAIRE

Song, Xiaolan; Wang, Yi; Song, Dan; An, Chongwei; Wang, Jingyu

2016-01-01

Raw TiO2 nanoparticles were prepared using the hydroly‐ sis of TiCl4. The nanoparticles were subjected to a surface treatment in diluted sulphuric acid and, subsequently, calcined at different temperatures. Then, a type of super solid acid (SO42-/TiO2) with particle sizes of 20∼30 nm was fabricated. The catalysis of SO42-/TiO2 on the thermolysis of ammonium nitrate (AN) was probed using thermal analysis. For SO42-/TiO2 (AN doped with 3%SO42-/TiO2), the onset temperature decreased by 19°C and ...

Gel electrolytes based on poly(acrylonitrile)/sulpholane with hybrid TiO2/SiO2 filler for advanced lithium polymer batteries

International Nuclear Information System (INIS)

Kurc, Beata

2014-01-01

Highlights: • Paper describes properties of gel electrolyte based on PAN with TMS and TiO 2 -SiO 2 . • The TiO 2 -SiO 2 oxide composite was precipitated in the emulsion system and used as the fillers. • The capacity of the graphite anode depends on the current rate and the amount of TiO 2 -SiO 2 . • For PE3 electrolyte was obtained practical capacity more than 90% of the theoretical capacity. - Abstract: This paper describes the synthesis and properties of a new type of ceramic fillers for composite polymer gel electrolytes. Hybrid TiO 2 -SiO 2 ceramic powders have been obtained by co-precipitation from titanium(IV) sulfate solution using sodium silicate as the precipitating agent. The resulting submicron-size powders have been applied as fillers for composite polymer gel electrolytes for Li-ion batteries based on polyacrylonitrile (PAN) membranes. The powders and gel electrolytes have been examined structurally and electrochemically, showing favorable properties in terms of electrolyte uptake and electrochemical characteristics in Li-ion cells

Electrospun Fe3O4/TiO2 hybrid nanofibers and their in vitro biocompatibility: prospective matrix for satellite cell adhesion and cultivation.

Science.gov (United States)

Amna, Touseef; Hassan, M Shamshi; Van Ba, Hoa; Khil, Myung-Seob; Lee, Hak-Kyo; Hwang, I H

2013-03-01

We report the fabrication of novel Fe3O4/TiO2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe3O4/TiO2 hybrid nanofibers were prepared by facile sol-gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe3O4/TiO2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe3O4/TiO2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe3O4/TiO2 composite nanofibers after being cultured. We observed that Fe3O4-TiO2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe3O4/TiO2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine. Copyright © 2012 Elsevier B.V. All rights reserved.

Estimation of influence of a solution of a boric acid and temperatures on a isolation material from basalt fibers

International Nuclear Information System (INIS)

Pyshnova, V.V.; Skobelkina, T.N.; Yurchenko, V.G.; Knot'ko, A.V.; Putlyaev, V.I.

2006-01-01

Paper presents the results of investigation into long-term simultaneous effect of a medium (boric acid solution) and temperature on a thermal-insulating basalt fiber material. The basalt fiber clothes used at the NPP were tested. When evaluating simultaneous effect of boric acid solution and temperature one kept watch on density, compressibility, elasticity and diameter of fiber. According to the results of 30 day tests, the basic technical parameters of the thermal-insulating material have changed insignificantly [ru

Fabrication of TiO2@Yeast-Carbon Hybrid Composites with the Raspberry-Like Structure and Their Synergistic Adsorption-Photocatalysis Performance

Directory of Open Access Journals (Sweden)

Dang Yu

2013-01-01

Full Text Available In the present work, we report the preparation and photocatalytic properties of TiO2@yeast-carbon with raspberry-like structure using a pyrolysis method. The products are characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermal gravimetric and differential thermal analysis (TGA-DTA, Fourier transformed infrared spectroscopy (FT-IR, and ultraviolet visible spectroscopy (UV-VIS, respectively. The results show that the hybrid TiO2@yeast-carbon microspheres have ordered elliptic shapes of uniform size (length = 3.5±0.3 μm; width = 2.5±0.5 μm. UV-VIS ascertains that the as-prepared microspheres possess an obvious light response in a wide range of 250–400 nm. In the decomposition of typical model pollutants including methylene blue and congo red, the hybrid composites exhibited excellent photocatalytic activity for the methylene blue due to the enhanced adsorption ability. Further investigation reveals that the combined effect of adsorption from the yeast-carbon core and photocatalytic degradation from the attached TiO2 nanoparticles were responsible for the improvement of the photocatalytic activities. Hereby, the raspberry-like TiO2@yeast-carbon has promising applications in water purification.

Activity and deactivation of sulphated TiO2- and ZrO2-based V, Cu, and Fe oxide catalysts for NO abatement in alkali containing flue gases

DEFF Research Database (Denmark)

Kustov, Arkadii; Rasmussen, Søren Birk; Fehrmann, Rasmus

2007-01-01

Vanadia, copper and iron oxide catalysts supported on conventional TiO2, ZrO2, and sulphated-TiO2 and ZrO2 have been prepared. These catalysts were characterized by elemental analysis, N-2-BET, XRD, and NH3-TPD methods. The influence of potassium oxide additives on the acidity and activity...... of the catalysts with potassium leads to a considerable decrease of their catalytic activity. In the case of the traditional carriers (TiO2, ZrO2), the poisoning of the catalyst with small amounts of potassium oxide (K/metal ratio...

Surface modification of calcium-copper hydroxyapatites using polyaspartic acid

Energy Technology Data Exchange (ETDEWEB)

Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Debbabi, Mongi, E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2013-01-01

Highlights: Black-Right-Pointing-Pointer The reaction of polyaspartic acid with calcium hydroxyapatite and mixed calcium-copper hydroxyapatite is tested. Black-Right-Pointing-Pointer Chemical analysis shows that the presence of copper in the apatitic structure increases the reactivity of the apatite surface. Black-Right-Pointing-Pointer X-ray powder analysis shows the conservation of unique crystalline phase of hydroxyapatite after copper incorporation and/or PASP acid reacting. Black-Right-Pointing-Pointer IR spectra show the formation of the formation of organometallic bond M-O-C (M=Ca or Cu) on the apatitic surface. Black-Right-Pointing-Pointer Transmission electron microscopy (TEM) micrographs and atomic force microscopy (AFM) indicated that the texture surface was changed by the grafting. - Abstract: Mixed calcium-copper hydroxyapatite (Ca-CuHAp), with general formula Ca{sub (10-x)}Cu{sub x}(PO{sub 4}){sub 6}(OH){sub 2}, where 0 {<=} x {<=} 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca-CuHAp-PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (P-OH) band of (HPO{sub 4}){sup 2-} groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

Stable Water Oxidation in Acid Using Manganese-Modified TiO2 Protective Coatings.

Science.gov (United States)

Siddiqi, Georges; Luo, Zhenya; Xie, Yujun; Pan, Zhenhua; Zhu, Qianhong; Röhr, Jason A; Cha, Judy J; Hu, Shu

2018-06-06

Accomplishing acid-stable water oxidation is a critical matter for achieving both long-lasting water-splitting devices and other fuel-forming electro- and photocatalytic processes. Because water oxidation releases protons into the local electrolytic environment, it becomes increasingly acidic during device operation, which leads to corrosion of the photoactive component and hence loss in device performance and lifetime. In this work, we show that thin films of manganese-modified titania, (Ti,Mn)O x , topped with an iridium catalyst, can be used in a coating stabilization scheme for acid-stable water oxidation. We achieved a device lifetime of more than 100 h in pH = 0 acid. We successfully grew (Ti,Mn)O x coatings with uniform elemental distributions over a wide range of manganese compositions using atomic layer deposition (ALD), and using X-ray photoelectron spectroscopy, we show that (Ti,Mn)O x films grown in this manner give rise to closer-to-valence-band Fermi levels, which can be further tuned with annealing. In contrast to the normally n-type or intrinsic TiO 2 coatings, annealed (Ti,Mn)O x films can make direct charge transfer to a Fe(CN) 6 3-/4- redox couple dissolved in aqueous electrolytes. Using the Fe(CN) 6 3-/4- redox, we further demonstrated anodic charge transfer through the (Ti,Mn)O x films to high work function metals, such as iridium and gold, which is not previously possible with ALD-grown TiO 2 . We correlated changes in the crystallinity (amorphous to rutile TiO 2 ) and oxidation state (2+ to 3+) of the annealed (Ti,Mn)O x films to their hole conductivity and electrochemical stability in acid. Finally, by combining (Ti,Mn)O x coatings with iridium, an acid-stable water-oxidation anode, using acid-sensitive conductive fluorine-doped tin oxides, was achieved.

Microporous TiO2-WO3/TiO2 films with visible-light photocatalytic activity synthesized by micro arc oxidation and DC magnetron sputtering

International Nuclear Information System (INIS)

Wu, Kee-Rong; Hung, Chung-Hsuang; Yeh, Chung-Wei; Wu, Jiing-Kae

2012-01-01

Highlights: ► A simple MAO is used to prepare porous WO 3 /TiO 2 layer on Ti sheet as a visible-light enabled catalyst. ► The photocatalytic activity of the WO 3 /TiO 2 is enhanced by sputtering over an N,C-TiO 2 layer. ► This is ascribed to the synergetic effect of hybrid sample prepared by two-step method. - Abstract: This study reports the preparation of microporous TiO 2 -WO 3 /TiO 2 films with a high surface area using a two-step approach. A porous WO 3 /TiO 2 template was synthesized by oxidizing a titanium sheet using a micro arc oxidation (MAO) process. This sheet was subsequently overlaid with a visible light (Vis)-enabled TiO 2 (N,C-TiO 2 ) film, which was deposited by codoping nitrogen (N) and carbon (C) ions into a TiO 2 lattice using direct current magnetron sputtering. The resulting microporous TiO 2 -WO 3 /TiO 2 film with a 0.38-μm-thick N,C-TiO 2 top-layer exhibited high photocatalytic activity in methylene blue (MB) degradation among samples under ultraviolet (UV) and Vis irradiation. This is attributable to the synergetic effect of two-step preparation method, which provides a highly porous microstructure and the well-crystallized N,C-TiO 2 top-layer. This is because a higher surface area with high crystallinity favors the adsorption of more MB molecules and more photocatalytic active areas. Thus, the microporous TiO 2 -WO 3 /TiO 2 film has promising applications in the photocatalytic degradation of dye solution under UV and Vis irradiation. These results imply that the microporous WO 3 /TiO 2 can be used as a template of hybrid electrode because it enables rapid fabrication.

Surface acidity scales: Experimental measurements of Brønsted acidities on anatase TiO2 and comparison with coinage metal surfaces

Science.gov (United States)

Silbaugh, Trent L.; Boaventura, Jaime S.; Barteau, Mark A.

2016-08-01

The first quantitative surface acidity scale for Brønsted acids on a solid surface is presented through the use of titration-displacement and equilibrium experiments on anatase TiO2. Surface acidities of species on TiO2 correlated with gas phase acidities, as was previously observed in qualitative studies of Brønsted acid displacement on Ag(110), Cu(110) and Au(111). A 90% compression of the surface acidity scale relative to the gas phase was observed due to compensation from the covalent component of the conjugate base - surface bond. Adsorbed conjugate bases need not be completely anionic for correlations with gas phase acidities to hold. Positive and negative substituent effects, such as substituted fluorine and hydrocarbon sidechain dispersion interactions with the surface, may modify the surface acidity scale, in agreement with previous experimental and theoretical work on Au(111).

Properties of TiO2 prepared by acid treatment of BaTiO3

International Nuclear Information System (INIS)

Okada, Kiyoshi; Yanagisawa, Tomoki; Kameshima, Yoshikazu; Nakajima, Akira

2007-01-01

TiO 3 powders were prepared by acid treatment of BaTiO 3 and their properties were investigated. The BaTiO 3 powder was subjected to HNO 3 in concentrations ranging from 10 -3 to 8 M at 90 deg. C for 0.5-6 h. Dissolution of BaTiO 3 and precipitation of TiO 2 occurred at acid concentrations of 2-5 M. BaTiO 3 dissolves completely to form a clear solution at reaction times of 0.5-1 h, but a rutile precipitate is formed after 2 h of acid treatment. By contrast, anatase is precipitated by adjusting the pH of the clear solution to 2-3 using NaOH or NH 4 OH solution. The rutile crystals were small and rod-shaped, consisting of many small coherent domains connected by grain boundaries with small inclination angles and edge dislocations, giving them a high specific surface area (S BET ). With increasing HNO 3 concentration, the S BET value increased from 100 to 170 m 2 /g while the crystallite size decreased from 25 to 11 nm. The anatase crystals obtained here were very small equi-axial particles with a smaller crystallite size than the rutile and S BET values of about 270 m 2 /g (higher than the rutile samples). The photocatalytic activity of these TiO 2 was determined from the decomposition rate of Methylene Blue under ultraviolet irradiation. Higher decomposition rates were obtained with larger crystallite sizes resulting from heat treatment. The maximum decomposition rates were obtained in samples heated at 500-600 deg. C. The photocatalytic activity of the TiO 2 was found to depend more strongly on the sample crystallite size than on S BET

Catalysis of a Nanometre Solid Super Acid of SO42-/TiO2 on the Thermal Decomposition of Ammonium Nitrate

Directory of Open Access Journals (Sweden)

Xiaolan Song

2016-03-01

Full Text Available Raw TiO2 nanoparticles were prepared using the hydroly‐ sis of TiCl4. The nanoparticles were subjected to a surface treatment in diluted sulphuric acid and, subsequently, calcined at different temperatures. Then, a type of super solid acid (SO42-/TiO2 with particle sizes of 20∼30 nm was fabricated. The catalysis of SO42-/TiO2 on the thermolysis of ammonium nitrate (AN was probed using thermal analysis. For SO42-/TiO2 (AN doped with 3%SO42-/TiO2, the onset temperature decreased by 19°C and the peak tem‐ perature decreased by 15.8°C. For TiO2 (AN doped with 3%TiO2, the peak temperature decreased by only 0.5°C. Using the DSC-IR technology, the gas products of the decomposition of 3%SO42-/TiO2-doped AN were detected. We found that the products were mainly N2O (g and a small amount of H2O (g, and that no NH3 (g or HNO3 (g was detected, which ascertained the decomposition reaction of NH4NO3→N2O(g+H2O(g. In addition, the catalysis mechanism of SO42-/TiO2 on the AN decomposi‐ tion was discussed in detail.

Synthesis of ascorbic acid enhanced TiO2 photocatalyst: its characterization and catalytic activity in CO2 photoreduction

Directory of Open Access Journals (Sweden)

Mohd Farid Bin Mohd Na'aim

2018-04-01

Full Text Available To date, the development of solar environmental remediation has shifted more emphasis on the green and simple synthesis of catalyst for CO2 photocatalysis process. Herein, TiO2 photocatalyst was successfully synthesized via hydrothermal method. The effects of the different molar ratio of ascorbic acid C6H8O6, (AA added during the preparation of TiO2 nanoparticles were comprehensively studied. The characterization of TiO2 nanocrystals was performed via XRD, XPS, DRUV-vis, and FTIR. The results show the AA loading into TiO2 nanoparticles significantly intensified the XRD spectra of anatase structure. In fact, this feature had signified a reactivity of the photocatalyst in the visible region. In an instance, BET surface area was also enhanced with the highest recorded value of 135.14 m2/g for 0.8AA. Meanwhile, the CO2 photoreduction over synthesized TiO2 had produced the highest amount of HCOOH at 39.3 μmol/g cat for 0.8AA within 6 hours of reaction time. Furthermore, the DRUV-vis analysis had illustrated better light absorption ability of 0.8AA. This profound finding is attributed to the correlation between large surface area, pure anatase phase, and high adsorbed water molecules. Therefore, this study had significantly demonstrated the potential of modified TiO2 with AA in CO2 photocatalysis area while simultaneously presents a green and simple method for TiO2 synthesis.

Metal‐Free Dehydration of Glucose to 5‐(Hydroxymethyl)furfural in Ionic Liquids with Boric Acid as a Promoter

DEFF Research Database (Denmark)

Ståhlberg, Tim; Rodriguez, Sergio; Fristrup, Peter

2011-01-01

The dehydration of glucose and other hexose carbohydrates to 5‐(hydroxymethyl)furfural (HMF) was investigated in imidazolium‐based ionic liquids with boric acid as a promoter. A yield of up to 42 % from glucose and as much as 66 % from sucrose was obtained. The yield of HMF decreased as the conce......The dehydration of glucose and other hexose carbohydrates to 5‐(hydroxymethyl)furfural (HMF) was investigated in imidazolium‐based ionic liquids with boric acid as a promoter. A yield of up to 42 % from glucose and as much as 66 % from sucrose was obtained. The yield of HMF decreased...

Graphitic-C(3)N(4)-hybridized TiO(2) nanosheets with reactive {001} facets to enhance the UV- and visible-light photocatalytic activity.

Science.gov (United States)

Gu, Liuan; Wang, Jingyu; Zou, Zhijuan; Han, Xijiang

2014-03-15

AnataseTiO(2)nanosheets with dominant {001} facets were hybridized with graphitic carbon nitride (g-C(3)N(4)) using a facile solvent evaporation method. On top of the superior photocatalytic performance of highly reactive {001} facets, the hybridization with g-C(3)N(4) is confirmed to further improve the reactivity through degrading a series of organic molecules under both UV- and visible-light irradiation. It is proposed that an effective charge separation between g-C(3)N(4) and TiO2 exists in the photocatalytic process, i.e., the transferring of photogenerated holes from the valence band (VB) of TiO(2) to the highest occupied molecular orbital (HOMO) of g-C(3)N(4), and the injecting of electrons from the lowest unoccupied molecular orbital (LUMO) of g-C(3)N(4) to the conduction band (CB) of TiO(2). Due to this synergistic effect, the enhancement of UV- and visible-light photoactivity over the hybrid is achieved. Furthermore, it has been revealed that holes were the main factor for the improved photoactivity under UV-light, while the OH radicals gained the predominance for degrading organic molecules under visible-light. Overall, this work would be significant for fabricating efficient UV-/visible-photocatalysts and providing deeper insight into the enhanced mechanisms of π-conjugated molecules hybridized semiconductors. Copyright © 2014 Elsevier B.V. All rights reserved.

TiO2 and Cu/TiO2 Thin Films Prepared by SPT

Directory of Open Access Journals (Sweden)

S. S. Roy

2015-12-01

Full Text Available Titanium oxide (TiO2 and copper (Cu doped titanium oxide (Cu/TiO2 thin films have been prepared by spray pyrolysis technique. Titanium chloride (TiCl4 and copper acetate (Cu(CH3COO2.H2O were used as source of Ti and Cu. The doping concentration of Cu was varied from 1-10 wt. %. The X-ray diffraction studies show that TiO2 thin films are tetragonal structure and Cu/TiO2 thin films implies CuO has present with monoclinic structure. The optical properties of the TiO2 thin films have been investigated as a function of Cu-doping level. The optical transmission of the thin films was found to increase from 88 % to 94 % with the addition of Cu up to 8 % and then decreases for higher percentage of Cu doping. The optical band gap (Eg for pure TiO2 thin film is found to be 3.40 eV. Due to Cu doping, the band gap is shifted to lower energies and then increases further with increasing the concentration of Cu. The refractive index of the TiO2 thin films is found to be 2.58 and the variation of refractive index is observed due to Cu doped. The room temperature resistivity of the films decreases with increasing Cu doping and is found to be 27.50 - 23.76 W·cm. It is evident from the present study that the Cu doping promoted the thin film morphology and thereby it is aspect for various applications.

Cover Picture: Metal‐Free Dehydration of Glucose to 5‐(Hydroxymethyl)furfural in Ionic Liquids with Boric Acid as a Promoter (Chem. Eur. J. 5/2011)

DEFF Research Database (Denmark)

Ståhlberg, Tim Johannes Bjarki; Rodriguez, Sergio; Fristrup, Peter

2011-01-01

Boric acid promotes the dehydration of glucose to 5-(hydroxy)methylfurfural in ionic liquids. Computational analyses by DFT calculations show a significant decrease in energy for the isomerization of glucose to fructose when the sugars are bound to boric acid and isotopic labeling NMR studies con...

Porous TiO2 Conformal Coating on Carbon Nanotubes as Energy Storage Materials

International Nuclear Information System (INIS)

Yan, Litao; Xu, Yun; Zhou, Meng; Chen, Gen; Deng, Shuguang; Smirnov, Sergei; Luo, Hongmei; Zou, Guifu

2015-01-01

The controllable synthesis of strongly coupled inorganic materials/carbon nanotubes (CNTs) hybrids represents a long-standing challenge for developing advanced catalysts and energy-storage materials. Here we report a simple sol-gel method for facile synthesis of TiO 2 /CNTs hybrid. The porous anatase TiO 2 nanoparticles are uniformly coated on the CNTs conducting network, which leads to remarkably improved electrochemical performances such as exceptional cycling stability, good high rate durability, and reduced resistance. This hybrid exhibits a reversible capacity as high as 200 mA·h g −1 at a current density of 0.1 A g −1 as an anode in lithium-ion battery (LIB). As a supercapacitor (SC), it shows a specific supercapacitance of 145 F g −1 in 0.5 M H 2 SO 4 electrolyte, higher than that of the previously reported TiO 2 based supercapacitors. Moreover, this hybrid also exhibits excellent durability after 1000 cycles for both LIBs and SCs. Such superior performance and cycling durability demonstrate the reinforced synergistic effects between the porous TiO 2 and interweaved CNTs network, indicating a great application potential for such hybrid materials in high power LIBs and SCs

Hybrid Processes Combining Photocatalysis and Ceramic Membrane Filtration for Degradation of Humic Acids in Saline Water

Directory of Open Access Journals (Sweden)

Lili Song

2016-03-01

Full Text Available This study explored the combined effects of photocatalysis with ceramic membrane filtration for the removal of humic acid in the presence of salt; to simulate saline wastewater conditions. The effects of operating parameters, such as salinity and TiO2 concentration on permeate fluxes, total organic carbon (TOC, and UV absorbance removal, were investigated. The interaction between the humic acids and TiO2 photocatalyst played an important role in the observed flux change during ceramic membrane filtration. The results for this hybrid system showed that the TOC removal was more than 70% for both without NaCl and with the 500 ppm NaCl concentration, and 62% and 66% for 1000 and 2000 ppm NaCl concentrations. The reduction in UV absorbance was more complete in the absence of NaCl compared to the presence of NaCl. The operation of the integrated photoreactor-ceramic membrane filter over five repeat cycles is described. It can be concluded that the overall removal performance of the hybrid system was influenced by the presence of salts, as salt leads to agglomeration of TiO2 particles by suppressing the stabilising effects of electrostatic repulsion and thereby reduces the effective surface contact between the pollutant and the photocatalyst.

The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication.

Science.gov (United States)

Hazman, Ömer; Bozkurt, Mehmet Fatih; Fidan, Abdurrahman Fatih; Uysal, Fadime Erkan; Çelik, Sefa

2018-03-02

The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.

Design of Test Facility to Evaluate Boric Acid Precipitation Following a LOCA

Energy Technology Data Exchange (ETDEWEB)

Suh, Jeong-Kwan; Song, Yong-Jae [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

The U.S.NRC has identified a concern that debris associated with generic safety issue (GSI) - 191 may affect the potential precipitation of boric acid due to one or more of the following phenomena: - Reducing mass transport (i.e. mixing) between the core and the lower plenum (should debris accumulate at the core inlet) - Reduced lower plenum volume (should debris settle in the lower plenum), and, - Increased potential for boric acid precipitation (BAP) in the core (should debris accumulate in suspension in the core) To address these BAP issues, KHNP is planning to conduct validation tests by constructing a BAP test facility. This paper describes the design of test facility to evaluate BAP following a LOCA. The design of BAP test facility has been developed by KHNP. To design the test facility, test requirements and success criteria were established, and scaling analysis of power-to-volume method, Ishii-Kataoka method, and hierarchical two-tiered method were investigated. The test section is composed of two fuel assemblies with half of full of prototypic FA height. All the fuel rods are heated by the electric power supplier. The BAP tests in the presence of debris, buffering agents, and boron will be performed following the test matrix.

Non-noble metal graphene oxide-copper (II) ions hybrid electrodes for electrocatalytic hydrogen evolution reaction

KAUST Repository

Muralikrishna, S.

2015-08-25

Non-noble metal and inexpensive graphene oxide-copper (II) ions (GO-Cu2+) hybrid catalysts have been explored for the hydrogen evolution reaction (HER). We were able to tune the binding abilities of GO toward the Cu2+ ions and hence their catalytic properties by altering the pH. We have utilized the oxygen functional moieties such as carboxylate, epoxide, and hydroxyl groups on the edge and basal planes of the GO for binding the Cu2+ ions through dative bonds. The GO-Cu2+ hybrid materials were characterized by cyclic voltammetry in sodium acetate buffer solution. The morphology of the hybrid GO-Cu2+ was characterized by atomic force microscopy. The GO-Cu2+ hybrid electrodes show good electrocatalytic activity for HER with low overpotential in acidic solution. The Tafel slope for the GO-Cu2+ hybrid electrode implies that the primary discharge step is the rate determining step and HER proceed with Volmer step. © 2015 American Institute of Chemical Engineers Environ Prog.

Self-assembled supramolecular system PDINH on TiO2 surface enhances hydrogen production.

Science.gov (United States)

Li, Xin; Lv, Xingshuai; Zhang, Qianqian; Huang, Baibiao; Wang, Peng; Qin, Xiaoyan; Zhang, Xiaoyang; Dai, Ying

2018-09-01

Constructing organic-inorganic hybrids is one of the hopeful strategies to improve photocatalyst performance. In this study, perylene-3,4,9,10-tetracarboxylic diimide (PDINH) and commercial TiO 2 P25 are chosen as raw materials to construct a PDINH/TiO 2 organic-inorganic hybrid, which has higher photocatalytic H 2 production activity and photocurrent intensity than pure PDINH and TiO 2 , respectively. The apparent quantum efficiency for H 2 production over 0.5%PDINH/TiO 2 reaches as high as 70.69% using irradiation at 365 nm. Moreover, XRD, DRS, HRTEM, FT-IR, and XPS are used to characterize the crystal structure, optical absorption, morphology, molecular structure, and chemical bonds, as well as the elemental and chemical states of PDINH/TiO 2 organic-inorganic hybrid. The interfaces between PDINH and TiO 2 , which largely determine photocatalytic performance, is also analyzed systematically. Furthermore, charge density difference (Δρ) is used to analyze the electron-ion interactions of PDINH and TiO 2 , and reveals that substantial charge transfer occurs from PDINH to TiO 2 . Copyright © 2018. Published by Elsevier Inc.

Evaluation of ultrasonic technique to characterize the concentration of boric acid in liquid medium; Avaliacao de tecnica ultrassonica para medida de concentracao de acido borico em meio liquido

Energy Technology Data Exchange (ETDEWEB)

Kohara, Richard Yuzo Ramida

2015-06-01

This dissertation is to analyze the viability of using ultrasonic technique to characterize the concentration of boric acid in liquid medium non-invasively, therefore, ultrasonic tests were performed relating different boric acid concentrations with the travel time of the ultrasonic wave, also were evaluated factors able to mask the characterization of these concentrations by ultrasonic technique. The results showed that the ultrasonic technique allows the characterization of boric acid concentrations in liquid medium in very simple terms by the ultrasonic wave travel time, requiring further studies in complex conditions. (author)

Enhanced photoelectrocatalytic degradation of 2,4-dichlorophenoxyacetic acid by CuInS2 nanoparticles deposition onto TiO2 nanotube arrays

International Nuclear Information System (INIS)

Liu Ronghua; Liu Yutang; Liu Chengbin; Luo Shenglian; Teng Yarong; Yang Lixia; Yang Renbin; Cai Qingyun

2011-01-01

Research highlights: → The photocatalytic application of CuInS 2 with a direct band gap of about 1.5 eV and a high absorption coefficient remains unknown. → We describe an impulse electrodeposition approach to deposit CuInS 2 nanoparticles in uniform size of about 20 nm onto the top surface of the highly oriented TiO 2 NT arrays while minimizing the clogging of the tube entrances. → The novel photocatalyst exhibits a highly visible-light photocatalytic degradation activity for the target organic pollutant. → Moreover, the stability of the modified TiO 2 NT is good. → Therefore, CuInS 2 nanoparticles modified TiO 2 NT photocatalysts have potential utility in practical purification of organic wastewater. - Abstract: Surface modification of TiO 2 nanotube (NT) arrays with CuInS 2 nanoparticles (NPs) for photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was reported. A pulse electrodeposition technique was used to prepare the CuInS 2 NPs, and the resulted CuInS 2 NPs, with a uniform size of about 20 nm, were found to deposit on the top surface of the highly oriented TiO 2 NT while without clogging the tube entrances. Compared with the unmodified TiO 2 NT, the CuInS 2 NPs modified TiO 2 NT (CuInS 2 -TiO 2 NT) showed significantly enhanced photocatalytic activity towards 2,4-D under visible light. After 160 min irradiation, the removal rate of 2,4-D is 100% by using CuInS 2 -TiO 2 NT, much higher than 65.2% by using the unmodified TiO 2 NT in photoelectrocatalytic process. The increased photodegradation efficiency mainly results from the improved photocurrent density as results of enhanced visible-light absorption and decreased hole-electron recombination due to the presence of narrow-band-gap p-type semiconductor CuInS 2 .

59Ni and 63Ni separation from boric acid concentrates produced at NPP

International Nuclear Information System (INIS)

Fisera, O.

2010-01-01

Procedure for direct separation of radionickel from boric acid concentrate was developed. Quantitative separation from 100 mL of real concentrate on the column filled with 3 mL of PAN-DMG composite material was achieved. PAN-DMG material (dimethylglyoxime in porous beads of polyacrylonitrile) was compared with Ni Resin and DMG-PAN material exhibited higher sorption capacity for nickel than Ni Resin. (author)

Visible light photoelectrocatalysis with salicylic acid-modified TiO2 nanotube array electrode for p-nitrophenol degradation

International Nuclear Information System (INIS)

Wang Xin; Zhao Huimin; Quan Xie; Zhao Yazhi; Chen Shuo

2009-01-01

This research focused on immersion method synthesis of visible light active salicylic acid (SA)-modified TiO 2 nanotube array electrode and its photoelectrocatalytic (PEC) activity. The SA-modified TiO 2 nanotube array electrode was synthesized by immersing in SA solution with an anodized TiO 2 nanotube array electrode. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), UV-vis diffuse reflectance spectrum (DRS), and Surface photovoltage (SPV) were used to characterize this electrode. It was found that SA-modified TiO 2 nanotube array electrode absorbed well into visible region and exhibited enhanced visible light PEC activity on the degradation of p-nitrophenol (PNP). The degradation efficiencies increased from 63 to 100% under UV light, and 79-100% under visible light (λ > 400 nm), compared with TiO 2 nanotube array electrode. The enhanced PEC activity of SA-modified TiO 2 nanotube array electrode was attributed to the amount of surface hydroxyl groups introduced by SA-modification and the extension of absorption wavelength range.

Photo-Catalytic Properties of TiO2 Supported on MWCNTs, SBA-15 and Silica-Coated MWCNTs Nanocomposites.

Science.gov (United States)

Ramoraswi, Nteseng O; Ndungu, Patrick G

2015-12-01

Mesoporous silica, specifically SBA-15, acid-treated multi-walled carbon nanotubes and a hybrid nanocomposite of SBA-15 coated onto the sidewalls acid-treated multi-walled carbon nanotubes (CNTs) were prepared and used as supports for anatase TiO2. Sol-gel methods were adapted for the synthesis of selected supports and for coating the materials with selected wt% loading of titania. Physical and chemical properties of the supports and catalyst composite materials were investigated by powder X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis, scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), UV-vis diffuse reflectance spectroscopy and fluorescence spectroscopy. The photo-activity of the catalyst composites were evaluated on the decolorisation of methylene blue as a model pollutant. Coating CNTs with SBA-15 improved the thermal stability and textural properties of the nanotubes. All supported titania composites had high surface areas (207-301 m(2)/g), altered band gap energies and reduced TiO2 crystallite sizes. The TiO2/SBA-CNT composite showed enhanced photo-catalytic properties and activity than the TiO2/SBA-15 and TiO2/CNT composites. In addition, an interesting observation was noted with the TiO2/SBA-15 nanocomposites, which had a significantly greater photo-catalytic activity than the TiO2/CNT nanocomposites in spite of the high electron-hole recombination phenomena observed with the photoluminescence results. Discussions in terms of morphological, textural and physical-chemical aspects to account for the result are presented.

Modified g-C3N4/TiO2 nanosheets/ZnO ternary facet coupled heterojunction for photocatalytic degradation of p-toluenesulfonic acid (p-TSA) under visible light

Science.gov (United States)

Jiang, Dong; Yu, Han; Yu, Hongbing

2017-01-01

Novel ternary nanocomposites with facet coupled structure were synthesized by using modified g-C3N4, TiO2 nanosheets and nano-ZnO. Nanosheet/nanosheet heterojunction structure was investigated by TEM, XPS and XRD. FT-IR and Nitrogen adsorption were illustrated for chemical/physical structure analyses. Solution of p-Toluenesulfonic acid (p-TSA) was chosen as target pollutant for visible light photodegradation and the excellent removal efficiency was achieved by this structurally modified g-C3N4/TiO2/ZnO hybrid. The visible light absorption improvement and quantum efficiency enhancement, which were testified by UV-vis DRS, PL and p-TSA photodegradation measurements, due to the facet coupled structure and appropriate quantity of modified g-C3N4 in the nanocomposites.

Sol–gel hybrid membranes loaded with meso/macroporous SiO2, TiO2–P2O5 and SiO2–TiO2–P2O5 materials with high proton conductivity

International Nuclear Information System (INIS)

Castro, Yolanda; Mosa, Jadra; Aparicio, Mario; Pérez-Carrillo, Lourdes A.; Vílchez, Susana; Esquena, Jordi; Durán, Alicia

2015-01-01

In this work, highly conductive hybrid organic–inorganic membranes loaded with SiO 2 , TiO 2 –P 2 O 5 and SiO 2 –TiO 2 –P 2 O 5 meso/macroporous particles were prepared via a sol–gel process. Meso/macroporous particles were incorporated to hybrid membranes, for improving water retention and enhancing electrochemical performance. These particles with a polymodal pore size distribution were prepared by templating in highly concentrated emulsions, the particles showed a specific surface area between 50 m 2 /g (TiO 2 –P 2 O 5 ) and 300 m 2 /g (SiO 2 –TiO 2 –P 2 O 5 ). The particles were dispersed in a hybrid silica sol and further sprayed onto glass paper. The films were polymerized and sintered; those loaded with meso/macroporous particles had a homogenous distribution. High temperature proton conductivity measurements confirmed a high water retention. Conductivity of these materials is higher than that of Nafion ® at higher temperatures (120 °C) (2·10 −2  S/cm). This study provides processing guideline to achieve hybrid electrolytes for efficient conduction of protons due to their high surface area and porous structure. - Highlights: • Hybrid electrolyte with meso/macroporous particles were synthesized by sol–gel. • Depositions of hybrid solutions by spraying onto glass substrates were performed. • Proton conductivity was evaluated as a function of composition and porous structure

Adsorption and oxidation of oxalic acid on anatase TiO2 (001) surface: A density functional theory study.

Science.gov (United States)

Sun, Tao; Wang, Yun; Zhang, Haimin; Liu, Porun; Zhao, Huijun

2015-09-15

Anatase TiO2 (001) surfaces have attracted great interest for photo-degradation of organic species recently due to their high reactivity. In this work, adsorption properties and oxidation mechanisms of oxalic acid on the anatase TiO2 (001) surface have been theoretically investigated using the first-principles density functional theory. Various possible adsorption configurations are considered by diversifying the connectivity of carboxylic groups with the surface. It is found that the adsorption of oxalic acid on the anatase (001) surface prefer the dissociative states. A novel double-bidentate configuration has been found due to the structural match between oxalic acid and the (001) surface. More charge is transferred from the adsorbed oxalic acid to the surface with the double-bidentate configuration when comparing with other adsorption structures. Thus, there is a positive correlation relationship between the transferred charge amount and the interfacial bond numbers when oxalic acid adsorbs on the anatase TiO2 (001) surface. The adsorption energies with dispersion corrections have demonstrated that the van der Waals interactions play an important role in the adsorption, especially when adsorbates are close to the surface. Copyright © 2015 Elsevier Inc. All rights reserved.

Structure, Morphology and Optical Properties of TiO2 Films Formed by Anodizing in a Mixed Solution of Citric Acid and Sulfamic Acid

Science.gov (United States)

Choudhary, R. K.; Sarkar, P.; Biswas, A.; Mishra, P.; Abraham, G. J.; Sastry, P. U.; Kain, V.

2017-08-01

TiO2 films of 50-180 nm thickness were formed at room temperature by anodization of titanium metal in a mixture of citric acid and sulfamic acid in the potential range of 5-30 V. The films so obtained were characterized for their crystal structure, surface morphology, chemical composition and optical properties. Grazing incidence x-ray diffraction and micro-laser Raman spectroscopy measurements of the anodic films confirmed the formation of brookite phase of TiO2 at anodizing potentials of 15, 20, 25 and 30 V and amorphous structure at 5 and 10 V. Field emission scanning electron microscopy revealed non-porous microstructure of the films. Spectroscopic ellipsometry measurements evaluated the band gap of TiO2 at around 3.3 eV, whereas the refractive index of the films was found to be in the range of 2-2.35, in the visible range of spectrum.

Superhydrophobicity construction with dye-sensitised TiO2 on fabric surface for both oil/water separation and water bulk contaminants purification

Science.gov (United States)

Yu, Linfeng; Zhang, Shengmiao; Zhang, Meng; Chen, Jianding

2017-12-01

For the promising material for both oil/water separation and water-soluble contaminants, the Dye@TiO2-TEOS/VTEO hybrid modified polyester fabric is developed by a simple dip-coating process, which combines Dye-sensitised TiO2 with silicon contained superhydrophobic coating to guarantee the long-term stability of Dye-sensitised TiO2 system as well as material's sustainability. The modified fabric possesses selective oil/water seperation properties towards water and oil, besides, mechanical, acid and alkali durability shows this material's appropriate performance on oil/water separation. UV-Vis absorption spectrum reveals the Dye 4-(2H-imidazol-2-ylazo) benzoic acid could sensitize the semiconductor TiO2 for visible light catalytic organic pollutant degradation that is also confirmed by methylene blue degradation experiment. Density Functional calculation (DFT) witnesses that HOMO, HOMO-1 of Dye contributed by oxygen bonding to TiO2 can insert into TiO2 band gap and result in low energy electron excitation. The ability of oil/water separation and water-soluble contaminants purification provides the material opportunity to practical applications in environmental restoration and human life.

Carbon Nanotube Fiber Pretreatments for Electrodeposition of Copper

OpenAIRE

Hannula, Pyry-Mikko; Junnila, Minttu; Janas, Dawid; Aromaa, Jari; Forsén, Olof; Lundström, Mari

2018-01-01

There is increasing interest towards developing carbon nanotube-copper (CNT-Cu) composites due to potentially improved properties. Carbon nanotube macroscopic materials typically exhibit high resistivity, low electrochemical reactivity, and the presence of impurities, which impede its use as a substrate for electrochemical deposition of metals. In this research, different CNT fiber pretreatment methods, such as heat treatment, immersion in Watts bath, anodization, and exposure to boric acid (...

Development of DNA biosensor based on TiO2 nanoparticles

Science.gov (United States)

Nadzirah, Sh.; Hashim, U.; Rusop, M.

2018-05-01

A novel technique of DNA hybridization on the TiO2 nanoparticles film was developed by dropping a single droplet of target DNA onto the surface of TiO2 for the study of various concentrations of target DNA. The surface of TiO2 nanoparticle film was functionalized with APTES and covalently immobilized with 1 µM probe DNA on the silanized TiO2 nanoparticles surface. The effect of silanization, immobilization and hybridization were quantitatively measured by the output current signal obtained using a picoammeter. The 1 µM target DNA was found to be the most effective target towards the 1 µM probe DNA as the output current signal was within range; while the output current signal of the 10 µM target DNA was observed to beyond the range of the probe DNA control due to the excessive concentration as compared to the probe DNA. This approach has several advantages such as rapid, simple, low cost, and sensitive current signal during detection of different target DNA concentrations.

Toxicity of nanoparticles of CuO, ZnO and TiO2 to microalgae Pseudokirchneriella subcapitata.

Science.gov (United States)

Aruoja, Villem; Dubourguier, Henri-Charles; Kasemets, Kaja; Kahru, Anne

2009-02-01

Toxicities of ZnO, TiO2 and CuO nanoparticles to Pseudokirchneriella subcapitata were determined using OECD 201 algal growth inhibition test taking in account potential shading of light. The results showed that the shading effect by nanoparticles was negligible. ZnO nanoparticles were most toxic followed by nano CuO and nano TiO2. The toxicities of bulk and nano ZnO particles were both similar to that of ZnSO4 (72 h EC50 approximately 0.04 mg Zn/l). Thus, in this low concentration range the toxicity was attributed solely to solubilized Zn2+ ions. Bulk TiO2 (EC50=35.9 mg Ti/l) and bulk CuO (EC50=11.55 mg Cu/l) were less toxic than their nano formulations (EC50=5.83 mg Ti/l and 0.71 mg Cu/l). NOEC (no-observed-effect-concentrations) that may be used for risk assessment purposes for bulk and nano ZnO did not differ (approximately 0.02 mg Zn/l). NOEC for nano CuO was 0.42 mg Cu/l and for bulk CuO 8.03 mg Cu/l. For nano TiO2 the NOEC was 0.98 mg Ti/l and for bulk TiO2 10.1 mg Ti/l. Nano TiO2 formed characteristic aggregates entrapping algal cells that may contribute to the toxic effect of nano TiO2 to algae. At 72 h EC50 values of nano CuO and CuO, 25% of copper from nano CuO was bioavailable and only 0.18% of copper from bulk CuO. Thus, according to recombinant bacterial and yeast Cu-sensors, copper from nano CuO was 141-fold more bioavailable than from bulk CuO. Also, toxic effects of Cu oxides to algae were due to bioavailable copper ions. To our knowledge, this is one of the first systematic studies on effects of metal oxide nanoparticles on algal growth and the first describing toxic effects of nano CuO towards algae.

Synthesis of stable TiO2 nanotubes: effect of hydrothermal treatment, acid washing and annealing temperature.

Science.gov (United States)

López Zavala, Miguel Ángel; Lozano Morales, Samuel Alejandro; Ávila-Santos, Manuel

2017-11-01

Effect of hydrothermal treatment, acid washing and annealing temperature on the structure and morphology of TiO 2 nanotubes during the formation process was assessed. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy analysis were conducted to describe the formation and characterization of the structure and morphology of nanotubes. Hydrothermal treatment of TiO 2 precursor nanoparticles and acid washing are fundamental to form and define the nanotubes structure. Hydrothermal treatment causes a change in the crystallinity of the precursor nanoparticles from anatase phase to a monoclinic phase, which characterizes the TiO 2 nanosheets structure. The acid washing promotes the formation of high purity nanotubes due to Na + is exchanged from the titanate structure to the hydrochloric acid (HCl) solution. The annealing temperature affects the dimensions, structure and the morphology of the nanotubes. Annealing temperatures in the range of 400 °C and 600 °C are optimum to maintain a highly stable tubular morphology of nanotubes. Additionally, nanotubes conserve the physicochemical properties of the precursor Degussa P25 nanoparticles. Temperatures greater than 600 °C alter the morphology of nanotubes from tubular to an irregular structure of nanoparticles, which are bigger than those of the precursor material, i.e., the crystallinity turn from anatase phase to rutile phase inducing the collapse of the nanotubes.

Enhanced photovoltaic performance of inverted hybrid bulk-heterojunction solar cells using TiO2/reduced graphene oxide films as electron transport layers

Science.gov (United States)

Morais, Andreia; Alves, João Paulo C.; Lima, Francisco Anderson S.; Lira-Cantu, Monica; Nogueira, Ana Flavia

2015-01-01

In this study, we investigated inverted hybrid bulk-heterojunction solar cells with the following configuration: fluorine-doped tin oxide (FTO) |TiO2/RGO|P3HT:PC61BM|V2O5 or PEDOT:PSS|Ag. The TiO2/GO dispersions were prepared by sol-gel method, employing titanium isopropoxide and graphene oxide (GO) as starting materials. The GO concentration was varied from 0.1 to 4.0 wt%. The corresponding dispersions were spin-coated onto FTO substrates and a thermal treatment was performed to remove organic materials and to reduce GO to reduced graphene oxide (RGO). The TiO2/RGO films were characterized by x-ray diffraction, Raman spectroscopy, and microscopy techniques. Atomic force microscopy (AFM) images showed that the addition of RGO significantly changes the morphology of the TiO2 films, with loss of uniformity and increase in surface roughness. Independent of the use of V2O5 or PEDOT: PSS films as the hole transport layer, the incorporation of 2.0 wt% of RGO into TiO2 films was the optimal concentration for the best organic photovoltaic performance. The solar cells based on TiO2/RGO (2.0 wt%) electrode exhibited a ˜22.3% and ˜28.9% short circuit current density (Jsc) and a power conversion efficiency enhancement, respectively, if compared with the devices based on pure TiO2 films. Kelvin probe force microscopy images suggest that the incorporation of RGO into TiO2 films can promote the appearance of regions with different charge dissipation capacities.

Interface actions between TiO2 and porous diatomite on the structure and photocatalytic activity of TiO2-diatomite

International Nuclear Information System (INIS)

Xia, Yue; Li, Fangfei; Jiang, Yinshan; Xia, Maosheng; Xue, Bing; Li, Yanjuan

2014-01-01

TiO 2 -diatomite photocatalysts were prepared by sol–gel process with various pre-modified diatomite. In order to obtain diatomite with different surface characteristics, two modification approaches including calcination and phosphoric acid treatment on the micro-structure of diatomite are introduced. The photocatalysts were characterized by XRD, XPS, nitrogen adsorption–desorption isotherms and micromorphology analysis. The results indicate that, compared with pure TiO 2 , the anatase-to-rutile phase transition temperature of TiO 2 loaded on diatomite carrier is significantly increased to nearly 900 °C, depending on the different pretreatment method of diatomite. The photocatalytic activities of different samples were evaluated by their degradation rate of methyl orange (MO) dye under UV and visible-light irradiation. The samples prepared by phosphoric acid pretreatment method exhibit the highest photocatalytic activity. After 90 min of UV irradiation, about 90% of MO is decomposed by the best effective photocatalyst. And after 8 h visible-light irradiation, nearly 60% of MO is decomposed by the same sample. Further mechanism investigation reveals that the H 3 PO 4 pretreatment process can obviously change the surface features of diatomite carrier, cause the formation of Si–O–Ti bond, increase the binding strength between TiO 2 and diatomite, restrain crystal growth of loaded TiO 2 , and thus form thermal-stable mesoporous structure at the granular spaces. It helps to build micro-, meso- and macro-porous hierarchical porous structure in TiO 2 -diatomite, and improves the charge and mass transfer efficiency during catalyzing process, resulting in the significantly increased photocatalytic activity of TiO 2 -diatomite pretreated by phosphoric acid.

Interface actions between TiO2 and porous diatomite on the structure and photocatalytic activity of TiO2-diatomite

Science.gov (United States)

Xia, Yue; Li, Fangfei; Jiang, Yinshan; Xia, Maosheng; Xue, Bing; Li, Yanjuan

2014-06-01

TiO2-diatomite photocatalysts were prepared by sol-gel process with various pre-modified diatomite. In order to obtain diatomite with different surface characteristics, two modification approaches including calcination and phosphoric acid treatment on the micro-structure of diatomite are introduced. The photocatalysts were characterized by XRD, XPS, nitrogen adsorption-desorption isotherms and micromorphology analysis. The results indicate that, compared with pure TiO2, the anatase-to-rutile phase transition temperature of TiO2 loaded on diatomite carrier is significantly increased to nearly 900 °C, depending on the different pretreatment method of diatomite. The photocatalytic activities of different samples were evaluated by their degradation rate of methyl orange (MO) dye under UV and visible-light irradiation. The samples prepared by phosphoric acid pretreatment method exhibit the highest photocatalytic activity. After 90 min of UV irradiation, about 90% of MO is decomposed by the best effective photocatalyst. And after 8 h visible-light irradiation, nearly 60% of MO is decomposed by the same sample. Further mechanism investigation reveals that the H3PO4 pretreatment process can obviously change the surface features of diatomite carrier, cause the formation of Si-O-Ti bond, increase the binding strength between TiO2 and diatomite, restrain crystal growth of loaded TiO2, and thus form thermal-stable mesoporous structure at the granular spaces. It helps to build micro-, meso- and macro-porous hierarchical porous structure in TiO2-diatomite, and improves the charge and mass transfer efficiency during catalyzing process, resulting in the significantly increased photocatalytic activity of TiO2-diatomite pretreated by phosphoric acid.

Titanium dioxide (TiO2) nanoparticles filled poly(d,l lactid acid) (PDLLA) matrix composites for bone tissue engineering

NARCIS (Netherlands)

Gerhardt, L.C.; Jell, G.M.R.; Boccaccini, A.R.

2007-01-01

Titanium dioxide (TiO2) nanoparticles were investigated for bone tissue engineering applications with regard to bioactivity and particle cytotoxicity. Composite films on the basis of poly(d,l lactid acid) (PDLLA) filled with 0, 5 and 30 wt% TiO2 nanoparticles were processed by solvent casting.

Fabrication of ridge waveguide structure from photosensitive TiO2/ormosil hybrid films by using an ultraviolet soft imprint technique

International Nuclear Information System (INIS)

Zhang, Xuehua; Que, Wenxiu; Chen, Jing; Gao, Tianxi; Hu, Jiaxing; Liu, Weiguo

2013-01-01

Photosensitive TiO 2 /organically modified silane hybrid films were prepared by combining a low-temperature sol–gel process with a spin-coating technique. Optical properties and photochemical activities of the as-prepared hybrid sol–gel films under different UV irradiation time were characterized and monitored by prism coupling technique, UV–visible spectroscopy, and Fourier transform infrared spectroscopy. Surface morphology of the hybrid films was also observed by an atomic force microscopy. Advantages for fabrication of ridge waveguide structure based on the photosensitive hybrid films were demonstrated by an ultraviolet soft imprint technique. Effects of imprint force, imprint time, and UV irradiation time on high replication fidelity of the ridge waveguide structure were also investigated. An altitude replication fidelity of 99.7% can be obtained when the imprint force of 2 MPa, imprint time of 30 min and UV irradiation time of 45 min were chosen. Scanning electron microscopy and surface profiler were used to characterize the morphological and surface profile properties of the as fabricated ridge waveguide structure. Results indicate that the as-prepared photosensitive hybrid materials have great applicability for the fabrication of micro-optical elements and advantage as the imprint layer under the ultraviolet soft imprint technique. - Highlights: ► Photosensitive TiO 2 /ormosil hybrid film is prepared by a sol–gel process. ► Optical properties of the films change a little with UV exposure time. ► Photo-chemical property of the film changes a lot with UV exposure time. ► The imprint force and time, and the UV exposure time affect the imprint fidelity. ► A fidelity value of 99.7% is obtained under an optimized condition

Chromate enhanced visible light driven TiO2 photocatalytic mechanism on Acid Orange 7 photodegradation

International Nuclear Information System (INIS)

Wang, Yeoung-Sheng; Shen, Jyun-Hong; Horng, Jao-Jia

2014-01-01

Highlights: • Photocatalysis of Cr(VI) and TiO 2 were studied by ESR analysis on DMPO-OH signals. • Mechanism of Cr(VI)-enhanced by visible light was different from that by UV. • O 2 adsorbed on TiO 2 surfaces could react with Cr(VI) to lower photoenergy needed. • Even by UV, no TiO 2 photocatalysis was observed without O 2 solution. • Visible light and Cr(VI) redox reaction could activate TiO 2 and would yield ·OH. - Abstract: When hexavalent chromium (Cr(VI)) is added to a TiO 2 photocatalytic reaction, the decolorization and mineralization efficiencies of azo dyes Acid Orange 7 (AO7) are enhanced even though the mechanism is unclear. This study used 5,5-dimethyl-L-pyrroline-N-oxide (DMPO) as the scavenger and the analysis of Electron Spin Resonance (ESR) to investigate this enhancement effect by observing the hydroxyl radical (·OH) generation of the Cr(VI)/TiO 2 system under UV and visible light (Vis) irradiation. With Cr(VI), the decolorization efficiencies were approximately 95% and 62% under UV and Vis, and those efficiencies were 25% less in the absence of Cr(VI). The phenomena of the DMPO-OH signals during the ESR analysis under Vis 405 and 550 nm irradiation were obviously the enhancement effects of Cr(VI) in aerobic conditions. In anoxic conditions, the catalytic effects of Cr(VI) could not be achieved due to the lack of a redox reaction between Cr(VI) and the adsorbed oxygen at the oxygen vacancy sites on the TiO 2 surfaces . The results suggest that by introducing the agents of redox reactions such as chromate ions, we could lower the photoenergy of TiO 2 needed and allow Vis irradiation to activate photocatalysis

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

Science.gov (United States)

DeAlba-Montero, I.; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene

2017-01-01

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. PMID:28286459

Hybridization and bond-orbital components in site-specific X-ray photoelectron spectra of rutile TiO2

International Nuclear Information System (INIS)

Woicik, J.C.; Nelson, E.J.; Kronik, Leeor; Jain, Manish; Chelikowsky, James R.; Heskett, D.; Berman, L.E.; Herman, G.S.

2002-01-01

We have determined the Ti and O components of the rutile TiO 2 valence band using the method of site-specific x-ray photoelectron spectroscopy. Comparisons with calculations based on pseudopotentials within the local density approximation reveal the hybridization of the Ti 3d, 4s, and 4p states, and the O 2s and 2p states on each site. These chemical effects are observed due to the large differences between the angular-momentum dependent matrix elements of the photoelectron process

The double peaks and symmetric path phenomena in the catalytic activity of Pd/Al2O3-TiO2 catalysts with different TiO2 contents

Science.gov (United States)

Zhang, Shen; Guo, Yuyu; Li, Xingying; Wu, Xu; Li, Zhe

2018-06-01

Physicochemical properties of Pd/Al2O3-TiO2 catalysts with different amounts of TiO2 contents were investigated by XRD, nitrogen adsorption-desorption, FTIR, NH3-TPD, H2-TPR and XPS techniques. Catalysts of different compositions were tested in the ethanol oxidation reaction to study the effects of TiO2 contents. Double peaks and symmetric path phenomena were observed at certain temperatures with the increase in TiO2 contents. The symmetric peak phenomena and the diverse activity fluctuations have been ascribed to the controlling factors such as temperature and compositions. With the increase in TiO2 content, the surface area, adsorbed oxygen contents and surface acid quantity decreased gradually. The large surface area and adsorbed oxygen contents were conducive to the performance, while increased acid amounts were not beneficial for ethanol oxidation. At 150 and 175 °C, Pd/AT(X1

Hierarchical porous photoanode based on acid boric catalyzed sol for dye sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Maleki, Khatereh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box: 14395-553, Tehran (Iran, Islamic Republic of); Abdizadeh, Hossein [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box: 14395-553, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Golobostanfard, Mohammad Reza, E-mail: Mohammadreza.Golbostanfard@gmail.com [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box: 14395-553, Tehran (Iran, Islamic Republic of); Adelfar, Razieh [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box: 14395-553, Tehran (Iran, Islamic Republic of)

2017-02-01

Highlights: • Acid boric can thoroughly leads to the hierarchical porous titania structure. • Boron is introduced into titania lattice which causes slight blueshift of bandgap. • The optimized sol parameters are H{sub 3}BO{sub 3}/TTiP = 0.45, DI/TTiP = 4.5, and 0.17 M. • Optimized paste parameters is not changed compared to conventional pastes. • The DSSC based on H{sub 3}BO{sub 3} catalyzed sol shows promising efficiency of 2.91%. - Abstract: The hierarchical porous photoanode of the dye sensitized solar cell (DSSC) is synthesized through non-aqueous sol-gel method based on H{sub 3}BO{sub 3} as an acid catalyst and the efficiencies of the fabricated DSSC based on these photoanodes are compared. The sol parameters of 0.17 M, water mole ratio of 4.5, acid mole ratio of 0.45, and solvent type of ethanol are introduced as optimum parameters for photoanode formation without any detectable cracks. The optimized hierarchical photoanode mainly contains anatase phase with slight shift toward higher angles, confirming the doping of boron into titania structure. Moreover, the porous structure involves two ranges of average pore sizes of 20 and 635 nm. The diffuse reflectance spectroscopy (DRS) shows the proper scattering and blueshift in band gap. The paste parameters of solid:liquid, TiO{sub 2}:ethyl cellulose, and terpineol:ethanol equal to 11:89, 3.5:7.5, and 25:64, respectively, are assigned as optimized parameters for this novel paste. The photovoltaic properties of short circuit current density, open circuit voltage, fill factor, and efficiency of 5.89 mA/cm{sup 2}, 703 mV, 0.7, and 2.91% are obtained for the optimized sample, respectively. The relatively higher short circuit current of the main sample compared to other samples is mainly due to higher dye adsorption in this sample corresponding to its higher surface area and presumably higher charge transfer confirmed by low R{sub S} and R{sub ct} in electrochemical impedance spectroscopy data. Boric acid as

Boric acid as cost-effective and recyclable catalyst for trimethylsilyl protection and deprotection of alcohols and phenols

Energy Technology Data Exchange (ETDEWEB)

Rostami, Amin; Akradi, Jamal; Ahmad-Jangi, Firoz, E-mail: a_rostami372@yahoo.co [University of Kurdistan, Sanandaj (Iran, Islamic Republic of). Faculty of Science. Dept. of Chemistry

2010-07-01

Boric acid has been used as a green, selective and recyclable catalyst for trimethysilylation of alcohols and phenols using hexamethyldisilazane in acetonitrile. Deprotection of trimethylsilyl ethers to their parent alcohols and phenols was also achieved using this catalyst in water at room temperature. The salient features of this methodology are cheap processing, mild acidity conditions, excellent yields of products and easy availability of the catalyst. (author)

An assessment of boric acid and borax using the IEHR Evaluative Process for Assessing Human Developmental and Reproductive Toxicity of Agents. Expert Scientific Committee.

Science.gov (United States)

Moore, J A

1997-01-01

Boron is a ubiquitous element widely distributed in nature in the form of borates at low concentrations in soils and rocks. Boron is released from these minerals by the natural weathering processes in the form of boric acid, which is water soluble and biologically available. High levels of boric acid are naturally found in sea water. Boric acid and borax are used in the greatest quantities and represent the major boron chemical exposures to humans and the environment. The principal use of boric acid and borax is in the manufacture of various types of glass products that do not result in exposure to the consumer. Boric acid and borax are also found in an array of consumer goods including fireproofing for fabrics and wood, insecticides, and in many cosmetics and personal care products as well. Boron may be an essential element for higher animals including humans. Boric acid and borax are considered to be completely absorbed by the oral route of exposure. Absorption through intact skin is considered negligible, although absorption can occur through denuded or irritated skin. Boron levels in the body do not persist upon cessation of exposure. People may be exposed to boron through three primary sources: 1) consumption of private, municipal, or commercial (bottled) sources of drinking water; 2) dietary consumption of crops and other foodstuffs (including dietary supplements for body building); and 3) inhalation of boron compounds during their mining, manufacturing, and other industrial processing. While boron has been detected in 81.8% of the municipal water systems, it is a minor source of boron in most parts of the U.S. The mean boron concentration is reported as 0.2 mg B/L. However, residents of California and other western states with boron-rich geologic deposits may be regularly exposed to higher levels in drinking water. Individuals who drink bottled mineral water may also increase their exposure to boron. An EPA health advisory, recommends boron concentrations in

Fiberboards treated with N’-N-(1, 8-Naphthalyl) hydroxylamine (NHA-Na), borax, and boric acid

Science.gov (United States)

Turgay Akbulut; S. Nami Kartal; Frederick Green

2004-01-01

This paper reports on the physical and mechanical properties and decay and termite resistance of fiberboard panels made from pine and beech treated with N’-N-(1, 8-Naphthalyl) hydroxylamine sodium salt(NHA-Na), borax, and boric acid at varying loadings. The panels were manufactured using 10 percent urea-formaldehyde resin and 1 percent NH4Cl. Mechanical and physical...

Improved visible-light photocatalytic activity of TiO2 co-doped with copper and iodine

Science.gov (United States)

Dorraj, Masoumeh; Goh, Boon Tong; Sairi, Nor Asrina; Woi, Pei Meng; Basirun, Wan Jefrey

2018-05-01

Cu-I-co-doped TiO2 photocatalysts active to visible light absorption were prepared by hydrothermal method and calcined at various temperatures (350 °C, 450 °C, and 550 °C). The co-doped powders at 350 °C displayed the highest experimental Brunauer-Emmett-Teller surface area and lowest photoluminescence intensity, which demonstrated that a decrease in electron-hole recombination process. The synthesis of co-doped TiO2 was performed at this optimized temperature. In the co-doped sample, the Cu2+ doped TiO2 lattice created a major "red-shift" in the absorption edge due to the presence of the 3d Cu states, whereas the amount of red-shift from the I5+ doping in the TiO2 lattice was minor. Interestingly, the presence of Cu2+ species also boosted the reduction of I5+ ions to the lower multi-valance state I- in the TiO2 lattice by trapping the photogenerated electrons, which resulted in effective separation of the photogenerated charges. The Cu-I-co-doped TiO2 was able to degrade methyl orange dye under visible-light irradiation with improved photocatalytic activity compared with the single metal-doped TiO2 and pure TiO2 because of the strong visible light absorption and effective separation of photogenerated charges caused by the synergistic effects of Cu and I co-dopants.

Electrocatalytic glucose oxidation via hybrid nanomaterial catalyst of multi-wall TiO2 nanotubes supported Ni(OH)2 nanoparticles: Optimization of the loading level

International Nuclear Information System (INIS)

Gu, Yingying; Liu, Yicheng; Yang, Haihong; Li, Benqiang; An, Yarui

2015-01-01

Highlights: • Multi-wall TiO 2 nanotube supported Ni(OH) 2 nanoparticles, Ni(OH) 2 /TNTs, was prepared and investigated as anode electro-catalysts for glucose oxidation. • Ni(OH) 2 -24.2%/TNTs obtains the best catalytic activity. • Compared with Ni(OH) 2, the current density of Ni(OH) 2 -24.2%/TNTs increased 5.9 times in 0.1 M NaOH solution. - Abstract: The novel hybrid nanomaterial catalyst of multi-wall TiO 2 nanotube supported Ni(OH) 2 nanoparticles (Ni(OH) 2 /TNTs) was prepared through hydrothermal method and investigated as anode electro-catalysts for glucose oxidation. The nanostructure was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermogravimetry-differential thermal analysis (TGA) and nitrogen adsorption-desorption (BET-BJH). The electrochemical performance was measured by a range of electrochemical measurements. Compared with Ni(OH) 2 , the current density of Ni(OH) 2 /TNTs modified GC electrode increased 5.9 times in 0.1 M NaOH solution. The results indicated that the synthesized nanoparticles exhibited good electro-catalytic activity and stability for glucose oxidation. Meanwhile, the hybrid nanomaterial of Ni(OH) 2 /TNTs may be a potential candidate catalyst for direct glucose fuel cell

Deposition of copper indium sulfide on TiO2 nanotube arrays and its application for photocatalytic decomposition of gaseous IPA

Directory of Open Access Journals (Sweden)

Young Ku

2016-09-01

Full Text Available TiO2 nanotube arrays (TNTs were modified with copper indium sulfide (Cu/In/S by successive ionic layer adsorption and reaction (SILAR method. The field-emission scanning electron microscopy and X-ray photoelectron spectroscopy analysis demonstrated the presence of copper indium sulfide nanoparticles on the surface of the modified TNTs. The Cu/In/S-modified TNTs exhibited higher photocurrent density and photocatalytic activity than plain TNTs. The concentration of sulfur precursor was found to be an important factor on the composition of modified Cu/In/S films by SILAR. Some composition deviations were observed on the stoichiometry of the Cu/In/S-modified TNTs, which evidently affected the electrochemical characteristics of the modified TNTs. Experiments using the modified TNTs of composition close to the stoichiometric ratio of CuInS2 usually delivered higher photocatalytic decomposition of gaseous isopropyl alcohol in air streams and exhibited better stability during operation.

Simultaneous pollutant removal and electricity generation in denitrifying microbial fuel cell with boric acid-borate buffer solution.

Science.gov (United States)

Chen, Gang; Zhang, Shaohui; Li, Meng; Wei, Yan

2015-01-01

A double-chamber denitrifying microbial fuel cell (MFC), using boric acid-borate buffer solution as an alternative to phosphate buffer solution, was set up to investigate the influence of buffer solution concentration, temperature and external resistance on electricity generation and pollutant removal efficiency. The result revealed that the denitrifying MFC with boric acid-borate buffer solution was successfully started up in 51 days, with a stable cell voltage of 205.1 ± 1.96 mV at an external resistance of 50 Ω. Higher concentration of buffer solution favored nitrogen removal and electricity generation. The maximum power density of 8.27 W/m(3) net cathodic chamber was obtained at a buffer solution concentration of 100 mmol/L. An increase in temperature benefitted electricity generation and nitrogen removal. A suitable temperature for this denitrifying MFC was suggested to be 25 °C. Decreasing the external resistance favored nitrogen removal and organic matter consumption by exoelectrogens.

In vivo percutaneous absorption of boric acid, borax, and disodium octaborate tetrahydrate in humans compared to in vitro absorption in human skin from infinite and finite doses.

Science.gov (United States)

Wester, R C; Hui, X; Hartway, T; Maibach, H I; Bell, K; Schell, M J; Northington, D J; Strong, P; Culver, B D

1998-09-01

Literature from the first half of this century report concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax, and disodium octaborate tetrahydrate (DOT) in biological matrices. This made it possible, in the presence of comparatively large natural dietary boron intakes for the in vivo segment of this study, to quantify the boron passing through skin. Human volunteers were dosed with 10B-enriched boric acid, 5.0%, borax, 5.0%, or disodium octaborate tetrahydrate, 10%, in aqueous solutions. Urinalysis, for boron and changes in boron isotope ratios, was used to measure absorption. Boric acid in vivo percutaneous absorption was 0.226 (SD = 0.125) mean percentage dose, with flux and permeability constant (Kp) calculated at 0.009 microgram/cm2/h and 1.9 x 10(-7) cm/h, respectively. Borax absorption was 0.210 (SD = 0.194) mean percentage of dose, with flux and Kp calculated at 0.009 microgram/cm2/h and 1.8 x 10(-7) cm/h, respectively. DOT absorption was 0.122 (SD = 0.108) mean percentage, with flux and Kp calculated at 0.01 microgram/cm2/h and 1.0 x 10(-7) cm/h, respectively. Pretreatment with the potential skin irritant 2% sodium lauryl sulfate had no effect on boron skin absorption. In vitro human skin percentage of doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 micrograms/cm2/h and permeability constants (Kp) of 5.0 x 10(-4), 1.2 x 10(-4), and 2.9 x 10(-4) cm/h for the 0.05, 0.5, and 5.0% solutions. The above in vitro doses were at infinite, 1000 microliters/cm2 volume. At 2 microliters/cm2 (the in vivo dosing volume), flux decreased some

Study on the enhanced adsorption properties of lysozyme on polyacrylic acid modified TiO2 nano-adsorbents

Science.gov (United States)

Liu, Yufeng; Jin, Zu; Meng, Hao; Zhang, Xia

2018-01-01

The adsorption and immobilization of enzymes onto solid carriers has been focused on due to their many advantages, such as improved stability against a thermal or organic solvent and a good cycle usability. TiO2 nanoparticles is one of excellent nano-adsorbents owing to its excellent biocompatibility, non-inflammatory, and abundant surface hydroxyl groups, which are convenient to be combined with various functional groups. In this paper polyacrylic acid (PAA) modified TiO2 nanoparticles were synthesized through an in situ light-induced polymerization of acrylic acid on the surface of TiO2 nanoparticles. The structure and surface physicochemical properties of the PAA/TiO2 nanoparticles were characterized by TEM, XRD, FT-IR, Zeta potential measurements and TG-DSC. The experimental results showed that the isoelectric point of PAA/TiO2 significantly reduced to 1.82 compared with that of pure TiO2 nanoparticles (6.08). In the adsorption tests of lysozyme (Lyz), the PAA/TiO2 nanoparticles displayed enhanced adsorption activity compared with pristine TiO2. The maximum adsorption capacity of PAA/TiO2 for Lyz was 225.9 mg g-1 under the optimum conditions where the initial concentration of Lyz was 300 mg ml-1, the addition amount of PAA/TiO2 was 6.4 mg, the adsorption time was 30 min and the pH value was 7.0. The sodium dodecyl sulfate (SDS, 0.5%) presented the best efficiency (76.86%) in the removal of adsorbed Lyz, and the PAA/TiO2 nanoparticles showed excellent adsorption stability based on five cyclic adsorption-desorption tests. The fitting calculation results of the adsorption isotherm and the thermodynamics indicated the adsorption was an exothermic, entropy increasing, spontaneous and monomolecular layer adsorption process.

Synthesis, characterization, and performance evaluation of multilayered photoanodes by introducing mesoporous carbon and TiO2 for humic acid adsorption

Science.gov (United States)

Hosseini, Soraya; Jahangirian, Hossein; Webster, Thomas J; Soltani, Salman Masoudi; Aroua, Mohamed Kheireddine

2016-01-01

Nanostructured photoanodes were prepared via a novel combination of titanium dioxide (TiO2) nanoparticles and mesoporous carbon (C). Four different photoanodes were synthesized by sol–gel spin coating onto a glassy substrate of fluorine-doped tin oxide. The photocatalytic activities of TiO2, TiO2/C/TiO2, TiO2/C/C/TiO2, and TiO2/C/TiO2/C/TiO2 photoanodes were evaluated by exposing the synthesized photoanodes to UV–visible light. The photocurrent density observed in these photoanodes confirmed that an additional layer of mesoporous carbon could successfully increase the photocurrent density. The highest photocurrent density of ~1.022 mA cm−2 at 1 V/saturated calomel electrode was achieved with TiO2/C/C/TiO2 under an illumination intensity of 100 mW cm−2 from a solar simulator. The highest value of surface roughness was measured for a TiO2/C/C/TiO2 combination owing to the presence of two continuous layers of mesoporous carbon. The resulting films had a thickness ranging from 1.605 µm to 5.165 µm after the calcination process. The presence of double-layer mesoporous carbon resulted in a 20% increase in the photocurrent density compared with the TiO2/C/TiO2 combination when only a single mesoporous carbon layer was employed. The improved performance of these photoanodes can be attributed to the enhanced porosity and increased void space due to the presence of mesoporous carbon. For the first time, it has been demonstrated here that the photoelectrochemical performance of TiO2 can be improved by integrating several layers of mesoporous carbon. Comparison of the rate of removal of humic acid by the prepared photoanodes showed that the highest performance from TiO2/C/C/TiO2 was due to the highest photocurrent density generated. Therefore, this study showed that optimizing the sequence of mesoporous carbon layers can be a viable and inexpensive method for enhanced humic acid removal. PMID:27574426

Few-Layer MoS2 Nanodomains Decorating TiO2 Nanoparticles: A Case Study for the Photodegradation of Carbamazepine

Directory of Open Access Journals (Sweden)

Sara Cravanzola

2018-03-01

Full Text Available S-doped TiO2 and hybrid MoS2/TiO2 systems have been synthesized, via the sulfidation with H2S of the bare TiO2 and of MoOx supported on TiO2 systems, with the aim of enhancing the photocatalytic properties of TiO2 for the degradation of carbamazepine, an anticonvulsant drug, whose residues and metabolites are usually inefficiently removed in wastewater treatment plants. The focus of this study is to find a relationship between the morphology/structure/surface properties and photoactivity. The full characterization of samples reveals the strong effects of the H2S action on the properties of TiO2, with the formation of defects at the surface, as shown by transmission electron microscopy (TEM and infrared spectroscopy (IR, while also the optical properties are strongly affected by the sulfidation treatment, with changes in the electronic states of TiO2. Meanwhile, the formation of small and thin few-layer MoS2 domains, decorating the TiO2 surface, is evidenced by both high-resolution transmission electron microscopy (HRTEM and UV-Vis/Raman spectroscopies, while Fourier-transform infrared (FTIR spectra give insights into the nature of Ti and Mo surface sites. The most interesting findings of our research are the enhanced photoactivity of the MoS2/TiO2 hybrid photocatalyst toward the carbamazepine mineralization. Surprisingly, the formation of hazardous compounds (i.e., acridine derivatives, usually obtained from carbamazepine, is precluded when treated with MoS2/TiO2 systems.

Photocatalytic degradation of clofibric acid, carbamazepine and iomeprol using conglomerated TiO2 and activated carbon in aqueous suspension.

Science.gov (United States)

Ziegmann, Markus; Frimmel, Fritz H

2010-01-01

The combination of powdered activated carbon (PAC) and TiO(2) has been tested for synergistic/antagonistic effects in the photocatalytic degradation of carbamazepine, clofibric acid and iomeprol. Synergistic effects are thought to be caused by rapid adsorption on the PAC surface followed by diffusion to the TiO(2) surface and photocatalytic degradation. The Freundlich constant K(F) was used for comparing the sorption properties of the three substances and it was found that K(F) for clofibric acid was 3 times lower than for carbamazepine and iomeprol, regardless of the kind of PAC used. A PAC with a distinct tendency to form conglomerates was selected so that a high percentage of the PAC surface was in direct proximity to the TiO(2) surface. The photocatalytic degradation of the pharmaceutically active compounds studied followed pseudo-first order kinetics. Synergistic effects only occurred for clofibric acid (factor 1.5) and an inverse relationship between adsorption affinity and synergistic effects was found. High affinity of the target substances to the PAC surface seemed to be counterproductive for the photocatalytic degradation.

Copper-Assisted Oxidative Trifluoromethylthiolation of 2,3-Allenoic Acids with AgSCF3.

Science.gov (United States)

Pan, Shen; Huang, Yangen; Xu, Xiu-Hua; Qing, Feng-Ling

2017-09-01

The oxidative trifluoromethylthiolation of 2,3-allenoic acids with AgSCF 3 in the presence of (NH 4 ) 2 S 2 O 8 and catalytic copper salt was investigated. A series of 4-aryl-2,3-allenoic acids underwent radical trifluoromethylthiolation/intramolecular cyclization to afford β-trifluoromethylthiolated butenolides, which were conveniently transformed into trifluoromethylthiolated furan derivatives. In contrast, 2-monosubstituted 2,3-allenoic acids were converted into the corresponding 3,4-bis(trifluoromethylthio)but-2-enoic-acids under similar reaction conditions.

Electrocatalytic activity of lithium polysulfides adsorbed into porous TiO2 coated MWCNTs hybrid structure for lithium-sulfur batteries

Science.gov (United States)

He, Xiulin; Hou, Huijie; Yuan, Xiqing; Huang, Long; Hu, Jingping; Liu, Bingchuan; Xu, Jingyi; Xie, Jia; Yang, Jiakuan; Liang, Sha; Wu, Xu

2017-01-01

Lithium-sulfur batteries have attracted great attention because of their high energy density, environmental friendliness, natural abundance and intrinsically low cost of sulfur. However, their commercial applications are greatly hindered by rapid capacity decay due to poor conductivity of electrode, fast dissolution of the intermediate polysulfides into the electrolyte, and the volume expansion of sulfur. Herein, we report a novel composite MWCNTs@TiO2-S nanostructure by grafting TiO2 onto the surface of MWCNTs, followed by incorporating sulfur into the composite. The inner MWCNTs improved the mechanical strength and conductivity of the electrode and the outer TiO2 provided the adsorption sites to immobilize polysulfides due to bonding interaction between TiO2 and polysulfides. The MWCNTs@TiO2-S composite with a mass ratio of 50% (MWCNTs in MWCNTs@TiO2) exhibited the highest electrochemistry performance among all compositing ratios of MWCNTs/TiO2. The performance improvement might be attributed to the downward shift of the apparent Fermi level to a more positive potential and electron rich space region at the interface of MWCNTs-TiO2 that facilitates the reduction of lithium polysulfide at a higher potential. Such a novel hybrid structure can be applicable for electrode design in other energy storage applications. PMID:28098167

TiO2/PCL hybrid materials synthesized via sol–gel technique for biomedical applications

International Nuclear Information System (INIS)

Catauro, M.; Bollino, F.; Papale, F.; Marciano, S.; Pacifico, S.

2015-01-01

The aim of the present work has been the synthesis of organic/inorganic hybrid materials based on titanium dioxide and poly(ε-caprolactone) (PCL) to be used in the biomedical field. Several materials have been synthesized using sol–gel methods by adding different amounts of polymer to the inorganic sol. The obtained gels have been characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The FT-IR data allowed us to hypothesize that the structure formed was that of an interpenetrating network, realized by hydrogen bonds between Ti-OH groups in the sol–gel intermediate species and carbonyl groups in the polymer repeating units. SEM and AFM analyses highlighted that the obtained materials were nanostructurated hybrids. To evaluate the biological properties of the hybrids, their bioactivity and cytotoxicity were investigated as a function of the PCL amount. The bioactivity of the synthesized systems was proven by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating human blood plasma (SBF). MTT cytotoxicity tests and Trypan Blue dye exclusion tests were carried out exposing NIH-3T3 mouse embryonic fibroblasts for 24 and 48 h to extracts from the investigated hybrid materials. The results showed that all the hybrids had a non-cytotoxic effect on target cells. - Highlights: • TiO 2 /PCL hybrids were obtained by the sol–gel process for biomedical applications. • Synthesized materials were found to be first-class hybrid nanocomposites. • Hybrids appear to be bioactive, a fundamental characteristic for osseointegration. • MTT and Trypan Blue viability test show that the materials are biocompatible. • The organic phase is able to modulate the biocompatibility of the materials

Effectiveness acidic pre-cleaning for copper-gold ore

Directory of Open Access Journals (Sweden)

Antonio Clareti Pereira

Full Text Available Abstract The presence of copper-bearing minerals is known to bring on many challenges during the cyanidation of gold ore, like high consumption of cyanide and low extraction of metal, which are undesirable impacts on the auriferous recovery in the subsequent process step. The high copper solubility in cyanide prevents the direct use of classical hydrometallurgical processes for the extraction of gold by cyanidation. Additionally, the application of a conventional flotation process to extract copper is further complicated when it is oxidized. As a result, an acid pre-leaching process was applied in order to clean the ore of these copper minerals that are cyanide consumers. The objective was to evaluate the amount of soluble copper in cyanide before and after acidic cleaning. From a gold ore containing copper, the study selected four samples containing 0.22%, 0.55%, 1.00% and 1.36% of copper. For direct cyanidation of the ore without pre-treatment, copper extraction by cyanide complexing ranged from 8 to 83%. In contrast, the pre-treatment carried out with sulfuric acid extracted 24% to 99% of initial copper and subsequent cyanidation extracted 0.13 to 1.54% of initial copper. The study also showed that the copper contained in the secondary minerals is more easily extracted by cyanide (83%, being followed by the copper oxy-hydroxide minerals (60%, while the copper contained in the manganese oxide is less complexed by cyanide (8% a 12%. It was possible to observe that minerals with low acid solubility also have low solubility in cyanide. Cyanide consumption decreased by about 2.5 times and gold recovery increased to above 94% after acidic pre-cleaning.

DFT Studies of Adsorption of Cu7-atom Nanoclusters on TiO2 Surfaces and Application to Methanol Steam Reforming Reactions

Science.gov (United States)

Taft, Michael J., Sr.

Alcohol conversion to hydrogen, via steam reforming, is an alternative energy process that is promising for the future of clean energy economies. With advancements in fuel cell technologies, on-board hydrogen reforming could leverage already existing automotive designs and fuel infrastructure. The design of catalytic materials with tunable properties requires a level of insight that has yet to be achieved experimentally. The central objective of this project is to develop a working model of metal-oxide surface mediated copper clusters, since such catalytic beds have a wide-range of applications. More specifically, we investigate the catalytic framework of this process with theoretical models of the active metal (Cu) and metal­oxide support (TiO2). We employ a Density Functional Theory (DFT)-Generalized Gradient Approximation (GGA) approach for the quantum level electronic structure calculations of Cu, TiO2 and CH3OH. Additionally, we have generated anatase (A(001), A(101)) and rutile (R(100), R(110)) surface morphologies and 7­atom copper cluster complexes with those planes. To examine the possible influence of TiO2 on the adsorption properties of our active metal, Cu7, we have carried out adsorption studies with CH3OH. Our final data and observations predict that the Cu7 cluster adopts a symmetric pentagonal bipyramidal geometry with D5h symmetry. We find that the anatase morphology has a greater overall stability than rutile. The adsorption strength of the Cu7 cluster has been predicted in this study to be according to the following order: A(001) > A(101)> R(110). Indeed, the R(100) surface appears to be an unfavorable surface for metal cluster binding. Our data indicates that copper cluster stabilization on the metal-oxide surface depends on the nature of the crystal face. Again, we studied the adsorption properties of methanol on nascent Cu7 cluster, Cu7-TiO 2 complex and on pure TiO2-surface in A(001) polymorphic form. The calculations revealed that methanol

Fabrication of TiO2/Carbon Photocatalyst using Submerged DC Arc Discharged in Ethanol/Acetic Acid Medium

Science.gov (United States)

Saraswati, T. E.; Nandika, A. O.; Andhika, I. F.; Patiha; Purnawan, C.; Wahyuningsih, S.; Rahardjo, S. B.

2017-05-01

This study aimed to fabricate a modified photocatalyst of TiO2/C to enhance its performance. The fabrication was achieved using the submerged direct current (DC) arc-discharge method employing two graphite electrodes, one of which was filled with a mixture of carbon powder, TiO2, and binder, in ethanol with acetic acid added in various concentrations. The arc-discharge method was conducted by flowing a current of 10-20 A (~20 V). X-ray diffraction (XRD) patterns showed significant placements of the main peak characteristics of TiO2, C graphite, and titanium carbide. The surface analysis using Fourier transform infrared spectroscopy (FTIR) revealed that fabricated TiO2/C nanoparticles had stretching vibrations of Ti-O, C-H, C═O, C-O, O-H and C═C in the regions of 450-550 cm-1, 2900-2880 cm-1, 1690-1760 cm-1, 1050-1300 cm-1, 3400-3700 cm-1 and ~1600 cm-1, respectively. In addition, the study investigated the photocatalysts of unmodified and modified TiO2/C for photodegradation of methylene blue (MB) dye solution under mercury lamp irradiation. The effectiveness of the degradation was defined by the decrease in 60-minute absorbance under a UV-Vis spectrophotometer. Modified TiO2/C proved to be significantly more efficient in reducing dye concentrations, reaching ~70%. It indicated that the oxygen-containing functional groups have been successfully attached to the surface of the nanoparticles and played a role in enhancing photocatalytic activity.

Semiconducting polymer-incorporated nanocrystalline TiO2 particles for photovoltaic applications

International Nuclear Information System (INIS)

Peng Fuguo; Wu Jihuai; Li Qingbei; Wang Yue; Yue Gentian; Xiao Yaoming; Li Qinghua; Lan Zhang; Fan Leqing; Lin Jianming; Huang Miaoliang

2011-01-01

Highlights: → A P3HT-PCBM/TiO 2 trinary hybrid solar cell has been fabricated. → P3HT-PCBM heterojunction replaces the dye and electrolyte in dye-sensitized cell, → Which simplifies preparation procedure and decreases the device cost. → The hybrid cell achieves a light-to-electric conversion efficiency of 2.61%. - Abstract: In this work, we study hybrid solar cells based on blends of the semiconducting polymer poly(3-octylthiophene-2,5-diyl)(P3OT) and [6,6]-phenyl C 61 butyric acid methyl (PCBM) coated titanium dioxide (TiO 2 ) nanocrystal film. The Fourier transform infrared spectra (FTIR), UV-vis absorption spectra and PL quenching researches show that the films had a stronger absorption in visible light range. The influence of the PCBM:P3OT ratio were researched and the optimized ratio of PCBM to P3OT (1:1.5) exhibit a short circuit current of 4.42 mA cm -2 , an open circuit voltage of 0.81 V, a fill factor of 0.73 and a light-to-electric conversion efficiency of 2.61% under a simulated solar light irradiation of 100 mW cm -2 .

Recovery TiO2 by leaching process of carbothermic reduced Kalimantan ilmenite

Science.gov (United States)

Wahyuningsih, S.; Sari, P. P.; Ramelan, A. H.

2018-05-01

Ilmenite naturally occurred in iron titanate (FeTiO3) minerals. The separation of natural ilmenite into TiO2 and Fe2O3 need to be explored to gain the high purity separation product. A new combination method named of carbothermic reduction, acidic-leaching and complexation by EDTA were proposed for separation TiO2 from Ilmenite. Roasting of ilmenite was carried out at 950 °C for 1 h by the addition of activated carbon with mass ratio of ilmenite : activated carbon =4:3. The carbothermic reduction was carried out to yield a high separation of initial content of ilmenite that will be easily to dissolve within hydrochloric acid solution in leaching process. The composition of ilmenite observed by X-Ray Fluoresences (XRF) changed after the carbothermic reduction process and the dominant content is TiO2 (57.56%). X-Ray Diffraction (XRD) of roasted ilmenite composed of decomposed product of ilmenite i.e. hematite (Fe2O3), TiO2 anatase, TiO2 rutile, and inorganic salt. The leaching of the roasted ilmenite has been done by sulphuric acid solution (6 M) to gain the titanyl sulphate solution. Separation of iron impurities of TiO2 gel from titanyl sulphate (TiOSO4) solution was conducted by complexation method using EDTA as a complexation agent. The characteristic of TiO2 obtained using XRD showed that TiO2 is anatase type and the percentage of TiO2 using XRF showed that TiO2 content of 86,03%.

Influence of surface treatment on preparing nanosized TiO2 supported on carbon nanotubes

International Nuclear Information System (INIS)

Wang Shuo; Ji Lijun; Wu Bin; Gong Qianming; Zhu Yuefeng; Liang Ji

2008-01-01

In this paper, nanosize titanium dioxide (TiO 2 ) deposited on pristine and acid treated carbon nanotubes (CNTs) were prepared by a modified sol-gel method. The nanoscale materials were extensively characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and Raman spectra. The results indicated that about 6.8 nm TiO 2 nanoparticles were successfully deposited on acid-treated CNTs surface homogeneously and densely, which was smaller than TiO 2 coated on pristine CNTs. The surface state of CNTs was a critical factor in obtaining a homogeneous distribution of nanoscale TiO 2 particles. Acid oxidization could etch the surface of CNTs and introduce functional groups, which were beneficial to controllable homogeneous deposition. The TiO 2 coated on acid-treated CNTs was used as photocatalyst for Reactive Brilliant Red X-3B dye degradation under UV irradiation, which showed higher efficiency than that of TiO 2 coated on pristine CNTs and commercial photocatalyst P25.

An insight into the mechanism of charge transfer properties of hybrid organic (MEH-PPV): Inorganic (TiO2) nanocomposites

International Nuclear Information System (INIS)

Mittal, Tanu; Tiwari, Sangeeta; Mehta, Aarti; Sharma, Shailesh N.

2016-01-01

Now a days, inorganic nanoparticles are gaining importance and are potential candidate in different organic electronic device application like (LEDs, PVs) due to their novel properties and confinement in Nano-dimensions. [1, 2] In the present work, we have compared the properties of titanium di oxide (TiO 2 ) nanoparticles (NPs) synthesized by using two different chemical routes aqueous and ethanol respectively. These synthesized TiO 2 nanoparticles have been characterized by X-ray diffraction spectroscopy (XRD) for phase confirmation. It was observed that synthesized nanoparticles are in anatase phase for both preparation routes. Morphological information was collected by scanning electron microscopy (SEM) which confirms that particles are almost spherical in shape and distributed uniformly which is further ensured by transmission electron microscopy (TEM). Dynamic light scattering (DLS) technique was also used for further confirmation of size distribution of as-synthesized nanoparticles. Optical properties were also investigated by photoluminescence and UV-Vis spectroscopy and calculated bandgap was found to be in the range of 3.3-3.5eV for TiO 2 (aq/eth) nanoparticles. The increase in bandgap values with respect to bulk (3.2 eV) confirms that as- synthesized nanoparticles are confined in nanodimensions. As synthesized nanoparticles were interacted with MEHPPV polymer (donor) matrix to make their respective MEHPPV: TiO 2 nanocomposites and to confirm the charge transfer mechanism from polymer to nanoparticles. It can be observed from photoluminescence (PL) quenching experiments that continuous quenching obtained for respective nanocomposites confirms better charge transfer from polymer to inorganic TiO 2 nanoparticles respectively. Because of, better quenching and simultaneously enhanced charge transfer of respective nanocomposites, ensures that these nanocomposites are greatly applicable for photovoltaics (PVs) especially in Hybrid Solar cells (HSCs).

Well-defined copolymers synthesized by RAFT polymerization as effective modifiers to enhance the photocatalytic performance of TiO_2

International Nuclear Information System (INIS)

Vasilaki, E.; Kaliva, M.; Katsarakis, N.; Vamvakaki, M.

2017-01-01

Highlights: • Well-defined, random functional copolymers were synthesized by RAFT polymerization. • Novel TiO_2 particles in-situ modified with copolymers were synthesized. • The hybrid catalysts exhibited reduced aggregation and particle size. • The photocatalytic removal of methylene blue was higher for the hybrid catalysts. - Αbstract: The enhancement of the photocatalytic performance of anatase TiO_2 nanoparticles is demonstrated by a facile route, involving their in-situ surface modification with preformed polymer chains. Random copolymers of poly(ethylene glycol) methyl ether acrylate-co-methacrylic acid (PEGA-co-MAA) or poly(ethylene glycol) methyl ether acrylate-co-dopamine methacrylamide (PEGA-co-DMA) were synthesized by reversible addition−fragmentation chain-transfer (RAFT) polymerization and were bound onto the surface of anatase titania nanoparticles via the “grafting to” method. The hybrid nanocatalysts were characterized by fourier transform infrared spectroscopy, zeta-potential measurements, X-ray powder diffraction, thermogravimetric analysis and transmission electron microscopy. Their photocatalytic performance was evaluated by the decoloration of methylene blue (MB) dye in aqueous media under UV–vis light irradiation. The enhanced photoactivity and reusability of the polymer modified photocatalysts compared to that of bare TiO_2 nanoparticles was attributed to their improved dispersability and colloidal stability, the smaller particle size that leads to a larger surface area and the increased adsorption capacity of the dye onto the polymer modified nanoparticles.

EFFECTS.OF BORIC ACID ON THE CURE OF BORON-FILLED Y-3602 SILICONE GUM

Energy Technology Data Exchange (ETDEWEB)

Leichliter, G E

1974-10-01

The first two phases of a program designed to determine the effects of boric acid on the cure of Y-3602 silicone gum were conducted to evaluate extraction solvents and extraction time. The standard production formulation of B10-filled Y-3602 silicone gum was used in these evaluations. Results showed that the best solvent for reproducibility and high amine content was chloroform. The second phase indicated that extraction was essentially complete at the end of 4 hours.

Use of Fatty Acid Methyl Ester Profiles to Compare Copper-Tolerant and Copper-Sensitive Strains of Pantoea ananatis.

Science.gov (United States)

Nischwitz, C; Gitaitis, R; Sanders, H; Langston, D; Mullinix, B; Torrance, R; Boyhan, G; Zolobowska, L

2007-10-01

ABSTRACT A survey was conducted to evaluate differences in fatty acid methyl ester (FAME) profiles among strains of Pantoea ananatis, causal agent of center rot of onion (Allium cepa), isolated from 15 different onion cultivars in three different sites in Georgia. Differences in FAME composition were determined by plotting principal components (PCs) in two-dimensional plots. Euclidean distance squared (ED(2)) values indicated a high degree of similarity among strains. Plotting of PCs calculated from P. ananatis strains capable of growing on media amended with copper sulfate pentahydrate (200 mug/ml) indicated that copper-tolerant strains grouped into tight clusters separate from clusters formed by wild-type strains. However, unlike copper-sensitive strains, the copper-tolerant strains tended to cluster by location. A total of 80, 60, and 73% of the strains from Tift1, Tift2, and Tattnall, respectively, exhibited either confluent growth or partial growth on copper-amended medium. However, all strains were sensitive to a mixture of copper sulfate pentahydrate (200 mug/ml) and maneb (40 mug/ml). When copper-tolerant clones were analyzed and compared with their wild-type parents, in all cases the plotting of PCs developed from copper-tolerant clones formed tight clusters separate from clusters formed by the parents. Eigenvalues generated from these tests indicated that two components provided a good summary of the data, accounting for 98, 98, and 96% of the standardized variance for strains Pna 1-15B, Pna 1-12B, and Pna 2-5A, respectively. Furthermore, feature 4 (cis-9-hexadecenoic acid/2-hydroxy-13-methyltetradecanoic acid) and feature 7 (cis-9/trans-12/cis-7-octadecenoic acid) were the highest or second highest absolute values for PC1 in all three strains of the parents versus copper-tolerant clones, and hexadecanoic acid was the highest absolute value for PC2 in all three strains. Along with those fatty acids, dodecanoic acid and feature 3 (3-hydroxytetradecanoic

Limitations when use chloramphenicol-bcyclodextrins complexes in ophtalmic solutions buffered with boric acid/borax system

OpenAIRE

Todoran Nicoleta; Ciurba Adriana; Rédai Emőke; Ion V.; Lazăr Luminița; Sipos Emese

2014-01-01

Chloramphenicol eye drops are commonly prescribed in concentrations of 0.5-1% in the treatment of infectious conjunctivitis. In terms of ophthalmic solution preparation, the major disadvantage of chloramphenicol consists in its low solubility in water. The solubility is increased by substances that form chloramphenicol-complexes, for example: boric acid/borax or cyclodextrins. Objective: Experimental studies aimed to evaluate the potential advantages of enhancing the solubility and stability ...

Crystal phase evolution of TiO2 nanoparticles with reaction time in acidic solutions studied via freeze-drying method

International Nuclear Information System (INIS)

Shin, Hyunho; Jung, Hyun Suk; Hong, Kug Sun; Lee, Jung-Kun

2005-01-01

The crystal phase evolution of TiO 2 nanoparticles, during hydrolysis and condensation of titanium tetraisopropoxide, was quenched at various reaction times by a freeze-drying method, followed by various characterizations. Three types of solutions with different acid input times were studied: (1) addition in infinite time (no addition) (2) addition at 24h after the hydrolysis/condensation reaction started, and (3) addition from the beginning of the reaction. The acid-free solution yielded amorphous TiO 2 , which transformed to anatase very slowly. The acid input in 24h resulted in a fast transformation of amorphous to a metastable anatase having a highly distorted atomic arrangement: thereby its transformation to a more stable phase, rutile, was suitable. The acid addition from the beginning of the reaction yielded the formation of a relatively stable anatase from the hydrolysis seed, thereby the subsequent transformation to rutile was sluggish

Eu"2"+ doped TiO_2 nano structures synthesized by HYSYCVD for thermoluminescence dosimetry

International Nuclear Information System (INIS)

Perez A, J. A.; Leal C, A. L.; Melendrez A, R.; Barboza F, M.

2016-10-01

Titania (TiO_2) has attracted interest owing his potential applications as dosimetry material given his excellent optical, electrical and thermal properties and the ability to shape his structure make TiO_2 suitable for research and dosimetry applications. In this work, a systematic study to know the magnitude of processing parameters influence on thermoluminescent properties of undoped (TiO_2) and doped (TiO_2:Eu"2"+) nano materials obtained by hybrid precursor systems chemical vapor deposition (HYSYCVD) technique is presented. Synthesis of one dimension nano structures of TiO_2:Eu"2"+ was carried out using K_2TiF_6 and EuCl_2 as dopant at 0.5, 1, 2.5 and 5 wt %. The nano structures samples were irradiated with β-ray in a doses range of 0.083-3000 Gy. All thermoluminescence (Tl) glow curves showed 3 broad Tl peaks around 373, 473 and 573 K, and a dosimetric linear behavior from 0.083 to 300 Gy. The Tl has a good reproducibility, with deviations of around 5%, making these TiO_2:Eu"2"+ nano materials suitable for dosimetric applications. (Author)

A Molecular Cobalt Catalyst Architected and TiO2 Modified p-GaInP2 Photoelectrode for Hydrogen Production

Energy Technology Data Exchange (ETDEWEB)

Gu, Jing; Yan, Yong; Young, James; Steirer, Kenneth; Neale, Nathan R.; Turner, John A.

2017-05-01

We demonstrate that by employing a hybrid molecular/semiconductor interface with atomic layer deposited (ALD) TiO2 as an intermediate layer, a robust and corrosion resistant GaInP2-TiO2-cobaltoxime-TiO2 photocathode can be operated in alkaline media (pH =13).

Study of optical and electrical properties of water-soluble conjugated poly(3-hexylthiophene) on different grain-sized mesoporous TiO2 layers

International Nuclear Information System (INIS)

Thalluri, Gopala Krishna V.V.; Bolsée, Jean-Christophe; Madapati, Saipriya; Vanderzande, Dirk; Manca, Jean V.

2014-01-01

Solid-state hybrid solar cells are promising candidates for future low-cost photovoltaic energy generation that are based on polymer/metal oxide donor/acceptor heterojunctions. However, a critical drawback of hybrid solar cells is the usage of toxic and environmental unfriendly organic solvents in the phase of preparation. In terms of environmental impact, “green” and safer materials are required towards processing of eco-friendly hybrid solar cells. In this work, during processing phase of eco-friendly hybrid solar cells, aqueous-soluble conjugated poly(3-hexylthiophene) material is used as photo-active and hole transporting layer and TiO 2 layer as electron accepting layer. Optical, topographical and morphological characterizations on different grain-sized TiO 2 layers with polymer films are studied. The influence of eco-friendly hybrid solar cell electrical properties in combination with different grain-sized TiO 2 layers measured under N 2 and ambient conditions are discussed. It is important to understand these properties for further optimizations. - Highlights: • Morphological properties of different grain-sized TiO 2 layers. • Optical properties with and without water-soluble poly(3-hexylthiophene) on TiO 2 layers. • Electrical measurements. • Eco-friendly hybrid solar cells

Molecularly imprinted polystyrene–titania hybrids with both ionic and π–π interactions: a case study with pyrene butyric acid

International Nuclear Information System (INIS)

Selyanchyn, Roman; Lee, Seung-Woo

2013-01-01

We present hybrid films consisting of a composite prepared from polystyrene (PS) and titanium dioxide (titania; TiO 2 ) and molecularly imprinted with 1-pyrene butyric acid (PBA). The interaction of PBA with the polymer is shown to occur via binding of the carboxylic group to TiO 2 and hydrophobic interaction of the pyrene moiety with the PS network. We investigated the effects of the PS fraction on morphology, imprinting properties, and guest binding. The template could be completely removed by incubating the films in an acetonitrile solution of pyrene, which is due to the stronger π–π interaction between PBA and pyrene than the interaction between PBA and its binding site. A guest binding study with pyrene, 1-amino pyrene, pyr enemethanol, and anthracene-9-carboxylic acid showed that the hybrid films possessed selectivity and much higher binding capacity for PBA. This study demonstrates the first case of clear PS-assisted imprinting, where the π–π interaction of the template with a linear (non-crosslinked) polymer creates selective binding sites and enhances the binding capacity. This is a driving force for guest binding in addition to the interaction of the template/analyte with TiO 2 . All molecularly imprinted films displayed better binding, repeatability and reversibility compared to the respective non-imprinted films. (author)

Two-dimensional assembly structure of graphene and TiO2 nanosheets from titanic acid with enhanced visible-light photocatalytic performance

Science.gov (United States)

Hao, Rong; Guo, Shien; Wang, Xiuwen; Feng, Tong; Feng, Qingmao; Li, Mingxia; Jiang, Baojiang

2016-06-01

The titanic acid sheets were prepared by one-step hydrazine hydrate-assisted hydrothermal process. Then the reduced graphite oxide (rGO)@TiO2 nanosheet composites were finally obtained through ultrasonic exfoliation and following calcination treatment process. rGO@TiO2 nanosheet composites show excellent hydrogen production performance under AM1.5 light source. The highest hydrogen evolution yield (923.23 μmol) is nearly two times higher than that of pure TiO2, mainly due to the special electron structure and more active sites for TiO2 nanosheet. The introduction of graphene could improve the TiO2 nanosheet stability and extend visible-light absorption range.

Synthesis and enhanced electrochemical performance of the honeycomb TiO2/LiMn2O4 cathode materials

DEFF Research Database (Denmark)

Zhang, J.Y.; Shen, J.X.; Wei, C.B.

2016-01-01

angle compare to LiMn2O4, implying that TiO2 doping induced a change of crystal structure. By performing electrochemical measurements, we observed an enhancement of specific capacity (127.28 mAhg−1) and an improvement of cycling stability in the TiO2/LiMn2O4 hybrid materials. After 100 cycles of charge...

Rational design of carbon and TiO2 assembly materials: covered or strewn, which is better for photocatalysis?

Science.gov (United States)

Cui, Guan-wei; Wang, Wei-liang; Ma, Ming-yue; Zhang, Ming; Xia, Xin-yuan; Han, Feng-yun; Shi, Xi-feng; Zhao, Ying-qiang; Dong, Yu-bin; Tang, Bo

2013-07-21

The rational design of carbonaceous hybrid nanostructures is very important for obtaining high photoactivity. TiO2 particles strewn with an optimal quantity of carbon nanodots have a much higher photoactivity than that of TiO2 covered with a carbon layer, showing the importance of carbon morphology in the photocatalysis of carbonaceous hybrid nanostructures.

Photovoltaic performance enhancement of CdS quantum dot-sensitized TiO2 photoanodes with plasmonic gold nanoparticles

International Nuclear Information System (INIS)

Liu, Aiping; Ren, Qinghua; Zhao, Ming; Xu, Tao; Yuan, Ming; Zhao, Tingyu; Tang, Weihua

2014-01-01

Highlights: • CdS QD-sensitized TiO 2 porous photoanode with plasmonic gold. • A prominent light absorption enhancement of hybrid was attained by gold plasmon. • The photovoltaic response of hybrid was tunable by CdS amount. • The Au/TiO 2 /CdS hybrid had a potential application in energy conversion devices. -- Abstract: The CdS quantum dot-sensitized TiO 2 films with plasmonic gold nanoparticles were designed as photoanodes by the electrodeposition of gold combined with the “successive ionic layer adsorption and reaction” (SILAR) method for CdS deposition on porous TiO 2 films. A prominent enhancement in light absorption of Au/TiO 2 /CdS hybrid was attained by efficient light scattering of gold plasmons as sub-wavelength antennas and concentrators. The photogenerated electron formed in the near-surface region of TiO 2 and CdS were facilitated to transfer to the plasmonic gold, resulting in the enhancement of photocurrent and incident photon-to-current conversion efficiency of hybrid photoanode upon photoirradiation. Furthermore, the photovoltaic response of hybrid was highly tunable with respect to the number of SILAR cycles applied to deposit CdS. The thicker absorber layer with less porous structure and larger CdS crystals might limit the electrolyte diffusion into the hybrid electrode and impose a barrier for electron tunneling and transferring. The highly versatile and tunable properties of Au/TiO 2 /CdS photoanodes demonstrated their potential application in energy conversion devices

Characterization and Comparison of Photocatalytic Activity Silver Ion doped on TiO2(TiO2/Ag+) and Silver Ion doped on Black TiO2(Black TiO2/Ag+)

Science.gov (United States)

Kim, Jin Yi; Sim, Ho Hyung; Song, Sinae; Noh, Yeoung Ah; Lee, Hong Woon; Taik Kim, Hee

2018-03-01

Titanium dioxide (TiO2) is one of the representative ceramic materials containing photocatalyst, optic and antibacterial activity. The hydroxyl radical in TiO2 applies to the intensive oxidizing agent, hence TiO2 is suitable to use photocatalytic materials. Black TiO2was prepared through reduction of amorphous TiO2 conducting under H2 which leads to color changes. Its black color is proven that absorbs 100% light across the whole-visible light, drawing enhancement of photocatalytic property. In this study, we aimed to compare the photocatalytic activity of silver ion doped on TiO2(TiO2/Ag+) and silver ion doped on black TiO2(black TiO2/Ag+) under visible light range. TiO2/Ag+ was fabricated following steps. 1) TiO2 was synthesized by a sol-gel method from Titanium tetraisopropoxide (TTIP). 2) Then AgNO3 was added during an aging process step for silver ion doping on the surface of TiO2. Moreover, Black TiO2/Ag+ was obtained same as TiO2/Ag+ except for calcination under H2. The samples were characterized X-ray diffraction (XRD), UV-visible reflectance (UV-vis DRS), and Methylene Blue degradation test. XRD analysis confirmed morphology of TiO2. The band gap of black TiO2/Ag+ was confirmed (2.6 eV) through UV-vis DRS, which was lower than TiO2/Ag+ (2.9 eV). The photocatalytic effect was conducted by methylene blue degradation test. It demonstrated that black TiO2/Ag+ had a photocatalytic effect under UV light also visible light.

Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursors

Science.gov (United States)

Zhang, Min; Yu, Xinluan; Lu, Dandan; Yang, Jianjun

2013-12-01

Zr/N co-doped TiO2 nanostructures were successfully synthesized using nanotubular titanic acid (NTA) as precursors by a facile wet chemical route and subsequent calcination. These Zr/N-doped TiO2 nanostructures made by NTA precursors show significantly enhanced visible light absorption and much higher photocatalytic performance than the Zr/N-doped P25 TiO2 nanoparticles. Impacts of Zr/N co-doping on the morphologies, optical properties, and photocatalytic activities of the NTA precursor-based TiO2 were thoroughly investigated. The origin of the enhanced visible light photocatalytic activity is discussed in detail.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

International Nuclear Information System (INIS)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

2011-01-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

Energy Technology Data Exchange (ETDEWEB)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

2011-08-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Sandwich structured MoO2@TiO2@CNT nanocomposites with high-rate performance for lithium ion batteries

International Nuclear Information System (INIS)

Yuan, Dandan; Yang, Wanli; Ni, Jiangfeng; Gao, Lijun

2015-01-01

Titanium dioxide (TiO 2 ) is an important anode candidate for Li-ion battery (LIB) due to its properties of excellent cycle, high safety and low cost. However, the poor electrical conductivity of TiO 2 presents a significant challenge hampering its practical application in LIBs. Most researches have been concentrated on developing TiO 2 composites with metals, metal oxides and carbonaceous materials to improve its conductivity. In this work, we investigated a sandwich structured MoO 2 @TiO 2 @CNT nanocomposite through a simple three-step synthesis method. The CNT and highly conductive MoO 2 under/on the TiO 2 layer are served as flexible and strong electronic paths for rapid electron and ion transport. The resulting MoO 2 @TiO 2 @CNT hybrid structures show improved specific capacity and cycling stability compared with TiO 2 @CNT. In addition, the MoO 2 @TiO 2 @CNT composites also show a favorable rate capability, demonstrating its potential as anode material for LIBs

Noble Metal Decoration and Presulfation on TiO2: Increased Photocatalytic Activity and Efficient Esterification of n-Butanol with Citric Acid

Directory of Open Access Journals (Sweden)

Yu Niu

2016-01-01

Full Text Available TiO2 has been widely used as a key catalyst in photocatalytic reactions; it also shows good catalytic activity for esterification reactions. Different sulfated M-TiO2 nanoparticles (M = Ag, Au, Rh, and Pt were prepared by photodeposition and ultrasonic methods. The results show that the noble metal nanoparticles, which were loaded onto a TiO2 surface, slightly affected the crystal phase and particle size of TiO2. Among all the catalysts, SO42-/Au-TiO2 exhibited the best catalytic activity in the esterification reaction for the synthesis of citric acid n-butyl acetate and in the decomposition of methyl orange, as confirmed by a high conversion rate of up to 98.2% and 100% degradation rate, respectively. This can be attributed to an increase in the Lewis acidity of the catalyst and increased separation efficiency of electron-hole pairs. This superior catalyst has great potential applications in esterification reactions and wastewater treatments.

Cotton fabric coated with nano TiO2-acrylate copolymer for photocatalytic self-cleaning by in-situ suspension polymerization

International Nuclear Information System (INIS)

Jiang Xue; Tian Xiuzhi; Gu Jian; Huang Dan; Yang Yiqi

2011-01-01

Two kinds of nano TiO 2 -polyacrylate hybrid dispersions, TBM-w and TBM-e were synthesized by in-situ suspension polymerization and solution polymerization respectively, in order to fix the nano TiO 2 on fabrics. The photocatalytic self-cleaning fabrics have received much attention in recent years for its water-saving and environment-protection advantages. However, the fixation of the photocatalyst on fabrics is still a key problem that inhibits industrialization of these eco-friendly fabrics. The cotton fabric was treated by the two hybrid dispersions. The photocatalytic self-cleaning property was characterized. Infrared spectroscopy, burning loss test and thermogravimetry showed that some copolymer chains entangled with the nano TiO 2 . Transmission electron microscope illustrated that there was a polymeric layer on the surface of nano TiO 2 . The average diameter of TBM-w was smaller than that of TBM-e based on size analysis. The photocatalytic decoloration of the grape syrup indicated that the fabric with TiO 2 -polymer hybrid had excellent self-cleaning property.

TiO2 supported over porous silica photocatalysts for pesticide degradation using solar light: Part 2. Silica prepared using acrylic acid emulsion

International Nuclear Information System (INIS)

Phanikrishna Sharma, Mangalampalli V.; Durga Kumari, Valluri; Subrahmanyam, Machiraju

2010-01-01

An acrylic acid emulsion mixture is used for synthesis of novel porous silica (E-Si) material. The photocatalytic activity of TiO 2 under solar light irradiation for isoproturon (herbicide) degradation is drastically increased when dispersed over E-Si support using solid state dispersion (SSD) technique. The composite material is characterized by XRD, nitrogen adsorption-desorption isotherms, UV-vis DRS, SEM and TEM measurements. The photocatalytic activities of the composite catalysts are evaluated for different parameters. The 5 wt% TiO 2 /E-Si is found to be highly active for isoproturon degradation.

New insights into the origin of visible-light photocatalytic activity in Se-modified anatase TiO2 from screened coulomb hybrid DFT calculations

KAUST Repository

Harb, Moussab

2013-12-05

We report a systematic study on the optoelectronic properties of Se-modified anatase TiO2 investigated by DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 formalism to guarantee accurate band gap and electronic excitation predictions. Various selenium species at substitutional sites for O or Ti, at interstitial sites, as well as at mixed substitutional/interstitial sites are studied. Among the explored structures, Ti(1-2x)O2Se2x (containing Se4+ species), TiO(2-x)Sex (containing Se2- species), and TiO(2-x)Se2x (containing Se2 2- species) reveal significant enhanced visible-light optical absorption spectra with new absorption features appearing at 500, 600, and 690 nm, respectively. Our calculated spectra are found to be in good agreement with those obtained in available experimental works. The band gap narrowing in these materials originates from incorporation of newly occupied electronic levels within 0.5-1.5 eV above the original valence band of TiO 2, leading to new narrowed band gaps of 2.5, 2.0, and 1.8 eV respectively. Our calculations also reveal suitable band positions of Ti (1-2x)O2Se2x and TiO(2-x)Se x for overall water splitting, whereas TiO(2-x)Se 2x shows an unsuitable valence band position for the oxygen evolution reaction. In contrast, the localized electronic character of the new occupied states on the Se 4p orbitals and only on the O 2p orbitals linked to the Se species makes the holes mobility limited in this material and the recombination rate of charge carriers greatly increased in the bulk. © 2013 American Chemical Society.

Behavior of copper in acidic sulfate solution: Comparison with acidic chloride

Energy Technology Data Exchange (ETDEWEB)

Tromans, D.; Silva, J.C. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering

1997-03-01

The anodic polarization behavior of copper in a 0.1 M sulfuric acid (H{sub 2}SO{sub 4}) + 1 M sodium sulfate (Na{sub 2}SO{sub 4}) solution (pH = 2.0) was studied at room temperature under quiescent and stirred conditions. The behavior was compared with aqueous equilibria via construction of a potential-vs-pH (E-pH) diagram for the copper-sulfate-water (Cu-SO{sub 4}{sup 2}-H{sub 2}O) system. Interpretation of the behavior was aided by comparison with aqueous equilibria and polarization studies of copper in a 0.2 M hydrochloric acid (HCl) + 1 M sodium chloride (NaCl) solution(pH = 0.8). The initial anodic dissolution region in the acidic sulfate solution exhibited Tafel behavior with a slope consistent with formation of cupric ions (Cu{sup 2+}) whose rate of formation was charge-transfer controlled. At higher potentials, limiting current density (i{sub L}) behavior was observed under E-pH conditions that were consistent with formation of a film of copper sulfate pentahydrate (CuSO{sub 4} {degree} 5H{sub 2}O). Comparison of experimental i{sub L} values with those predicted by mass transport-controlled processes, using estimates of the diffusion layer thickness obtained from the mass transfer-influenced region of apparent Tafel behavior in the acidic chloride solution, were in sufficient agreement to indicate i{sub L} was controlled by the rate of dissolution of the CuSO{sub 4} {degree} 5H{sub 2}O film via transport of Cu{sup 2+} from the film-electrolyte interface into the bulk solution.

Water on Graphene-Coated TiO2: Role of Atomic Vacancies

Science.gov (United States)

2018-01-01

Beyond two-dimensional (2D) materials, interfaces between 2D materials and underlying supports or 2D-coated metal or metal oxide nanoparticles exhibit excellent properties and promising applications. The hybrid interface between graphene and anatase TiO2 shows great importance in photocatalytic, catalytic, and nanomedical applications due to the excellent and complementary properties of the two materials. Water, as a ubiquitous and essential element in practical conditions and in the human body, plays a significant role in the applications of graphene/TiO2 composites for both electronic devices and nanomedicine. Carbon vacancies, as common defects in chemically prepared graphene, also need to be considered for the application of graphene-based materials. Therefore, the behavior of water on top and at the interface of defective graphene on anatase TiO2 surface was systematically investigated by dispersion-corrected hybrid density functional calculations. The presence of the substrate only slightly enhances the on-top adsorption and reduces the on-top dissociation of water on defective graphene. However, at the interface, dissociated water is largely preferred compared with undissociated water on bare TiO2 surface, showing a prominent cover effect. Reduced TiO2 may further induce oxygen diffusion into the bulk. Our results are helpful to understand how the presence of water in the surrounding environment affects structural and electronic properties of the graphene/TiO2 interface and thus its application in photocatalysis, electronic devices, and nanomedicine. PMID:29368503

The role of poly(methacrylic acid) conformation on dispersion behavior of nano TiO2 powder

Science.gov (United States)

Singh, Bimal P.; Nayak, Sasmita; Samal, Samata; Bhattacharjee, Sarama; Besra, Laxmidhar

2012-02-01

To exploit the advantages of nanoparticles for various applications, controlling the dispersion and agglomeration is of paramount importance. Agglomeration and dispersion behavior of titanium dioxide (TiO2) nanoparticles was investigated using electrokinetic and surface chemical properties. Nanoparticles are generally stabilized by the adsorption of a dispersant (polyelectrolyte) layer around the particle surface and in this connection ammonium salt of polymethacrylic acid (Darvan C) was used as dispersant to stabilize the suspension. The dosages of polyelectrolyte were optimized to get best dispersion stability by techniques namely particle charge detector (13.75 mg/g) and adsorption (14.57 mg/g). The surface charge of TiO2 particles changed significantly in presence of dispersant Darvan C and isoelectric point (iep) shifted significantly towards lower pH from 5.99 to 3.37. The shift in iep has been quantified in terms of free energy of interaction between the surface sites of TiO2 and the adsorbing dispersant Darvan C. Free energies of adsorption were calculated by electrokinetic data (-9.8 RT unit) and adsorption isotherms (-10.56 RT unit), which corroborated well. The adsorption isotherms are of typical Langmuir type and employed for calculation of free energy. The results indicated that adsorption occurs mainly through electrostatic interactions between the dispersant molecule and the TiO2 surface apart from hydrophobic interactions.

SERS of semiconducting nanoparticles (TIO{sub 2} hybrid composites).

Energy Technology Data Exchange (ETDEWEB)

Rajh, T.; Musumeci, A.; Gosztola, D.; Schiller, T.; Dimitrijevic, N. M.; Mujica, V.; Martin, D.; Center for Nanoscale Materials

2009-05-06

Raman scattering of molecules adsorbed on the surface of TiO{sub 2} nanoparticles was investigated. We find strong enhancement of Raman scattering in hybrid composites that exhibit charge transfer absorption with TiO{sub 2} nanoparticles. An enhancement factor up to {approx}10{sup 3} was observed in the solutions containing TiO{sub 2} nanoparticles and biomolecules, including the important class of neurotransmitters such as dopamine and dopac (3,4-dihydroxy-phenylacetic acid). Only selected vibrations are enhanced, indicating molecular specificity due to distinct binding and orientation of the biomolecules coupled to the TiO{sub 2} surface. All enhanced modes are associated with the asymmetric vibrations of attached molecules that lower the symmetry of the charge transfer complex. The intensity and the energy of selected vibrations are dependent on the size and shape of nanoparticle support. Moreover, we show that localization of the charge in quantized nanoparticles (2 nm), demonstrated as the blue shift of particle absorption, diminishes SERS enhancement. Importantly, the smallest concentration of adsorbed molecules shows the largest Raman enhancements suggesting the possibility for high sensitivity of this system in the detection of biomolecules that form a charge transfer complex with metal oxide nanoparticles. The wavelength-dependent properties of a hybrid composite suggest a Raman resonant state. Adsorbed molecules that do not show a charge transfer complex show weak enhancements probably due to the dielectric cavity effect.

Cisplatin Loaded Hyaluronic Acid Modified TiO2 Nanoparticles for Neoadjuvant Chemotherapy of Ovarian Cancer

Directory of Open Access Journals (Sweden)

Enling Liu

2015-01-01

Full Text Available Novel tumor-targeting titanium dioxide (TiO2 nanoparticles modified with hyaluronic acid (HA were developed to explore the feasibility of exploiting the pH-responsive drug release property of TiO2 and the tumor-targeting ability of HA to construct a tumor-targeting cisplatin (CDDP delivery system (HA-TiO2 for potential neoadjuvant chemotherapy of ovarian cancer. The experimental results indicated that CDDP release from the HA-TiO2 nanoparticles was significantly accelerated by decreasing pH from 7.4 to 5.0, which is of particular benefit to cancer therapy. CDDP-loaded HA-TiO2 nanoparticles increased the accumulation of CDDP in A2780 ovarian cancer cells via HA-mediated endocytosis and exhibited superior anticancer activity in vitro. In vivo real-time imaging assay revealed that HA-TiO2 nanoparticles possessed preferable tumor-targeting ability which might potentially minimize the toxic side effects of CDDP in clinical application.

First-Principles Modeling of Polaron Formation in TiO2 Polymorphs.

Science.gov (United States)

Elmaslmane, A R; Watkins, M B; McKenna, K P

2018-06-21

We present a computationally efficient and predictive methodology for modeling the formation and properties of electron and hole polarons in solids. Through a nonempirical and self-consistent optimization of the fraction of Hartree-Fock exchange (α) in a hybrid functional, we ensure the generalized Koopmans' condition is satisfied and self-interaction error is minimized. The approach is applied to model polaron formation in known stable and metastable phases of TiO 2 including anatase, rutile, brookite, TiO 2 (H), TiO 2 (R), and TiO 2 (B). Electron polarons are predicted to form in rutile, TiO 2 (H), and TiO 2 (R) (with trapping energies ranging from -0.02 eV to -0.35 eV). In rutile the electron localizes on a single Ti ion, whereas in TiO 2 (H) and TiO 2 (R) the electron is distributed across two neighboring Ti sites. Hole polarons are predicted to form in anatase, brookite, TiO 2 (H), TiO 2 (R), and TiO 2 (B) (with trapping energies ranging from -0.16 eV to -0.52 eV). In anatase, brookite, and TiO 2 (B) holes localize on a single O ion, whereas in TiO 2 (H) and TiO 2 (R) holes can also be distributed across two O sites. We find that the optimized α has a degree of transferability across the phases, with α = 0.115 describing all phases well. We also note the approach yields accurate band gaps, with anatase, rutile, and brookite within six percent of experimental values. We conclude our study with a comparison of the alignment of polaron charge transition levels across the different phases. Since the approach we describe is only two to three times more expensive than a standard density functional theory calculation, it is ideally suited to model charge trapping at complex defects (such as surfaces and interfaces) in a range of materials relevant for technological applications but previously inaccessible to predictive modeling.

Boric/sulfuric acid anodizing of aluminum alloys 2024 and 7075: Film growth and corrosion resistance

Energy Technology Data Exchange (ETDEWEB)

Thompson, G.E.; Zhang, L.; Smith, C.J.E.; Skeldon, P.

1999-11-01

The influence of boric acid (H{sub 3}BO{sub 3}) additions to sulfuric acid (H{sub 2}SO{sub 4}) were examined for the anodizing of Al 2024-T3 (UNS A92024) and Al 7075-T6 (UNS A97075) alloys at constant voltage. Alloys were pretreated by electropolishing, by sodium dichromate (Na{sub 2}Cr{sub 2}O{sub 7})/H{sub 2}SO{sub 4} (CSA) etching, or by alkaline etching. Current-time responses revealed insignificant dependence on the concentration of H{sub 3}BO{sub 3} to 50 g/L. Pretreatments affected the initial film development prior to the establishment of the steady-state morphology of the porous film, which was related to the different compositions and morphologies of pretreated surfaces. More detailed studies of the Al 7075-T6 alloy indicated negligible effects of H{sub 3}BO{sub 3} on the coating weight, morphology of the anodic film, and thickening rate of the film, or corrosion resistance provided by the film. In salt spray tests, unsealed films formed in H{sub 2}SO{sub 4} or mixed acid yielded similar poor corrosion resistances, which were inferior to that provided by anodizing in chromic acid (H{sub 2}CrO{sub 4}). Sealing of films in deionized water, or preferably in chromate solution, improved corrosion resistance, although not matching the far superior performance provided by H{sub 2}CrO{sub 4} anodizing and sealing.

Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment

CSIR Research Space (South Africa)

Tshabalala, Zamaswazi P

2016-03-01

Full Text Available TiO2 nanoparticles were synthesized via a simple hydrothermal method in a sodium hydroxide (NaOH) aqueous solution and washed with distilled water and different concentrations of hydrochloric acid which acted as the morphological...

Boric Acid as an Accelerator of Cerium Surface Treatment on Aluminum

Directory of Open Access Journals (Sweden)

K. Cruz-Hernández

2014-01-01

Full Text Available Aluminum pieces are often used in various industrial processes like automotive and aerospace manufacturing, as well as in ornamental applications, so it is necessary to develop processes to protect these materials, processes that can be industrialized to protect the aluminum as well or better than chromate treatments. The purpose of this research is to evaluate boric acid as an accelerator by optimizing its concentration in cerium conversion coatings (CeCC with 10-minute immersion time with a concentration of 0.1 g L−1 over aluminum to protect it. The evaluation will be carried out by measuring anticorrosion properties with electrochemical techniques (polarization resistance, Rp, polarization curves, PC, and electrochemical impedance spectroscopy, EIS in NaCl 3.5% wt. aqueous solution and surface characterization with scanning electron microscopy (SEM.

Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites

International Nuclear Information System (INIS)

Xue Gang; Liu Huanhuan; Chen Quanyuan; Hills, Colin; Tyrer, Mark; Innocent, Francis

2011-01-01

A photocatalyst comprising nano-sized TiO 2 particles on granular activated carbon (GAC) was prepared by a sol-dipping-gel process. The TiO 2 /GAC composite was characterized by scanning electron microscopy (SEM), X-ray diffractiometry (XRD) and nitrogen sorptometry, and its photocatalytic activity was studied through the degradation of humic acid (HA) in a quartz glass reactor. The factors influencing photocatalysis were investigated and the GAC was found to be an ideal substrate for nano-sized TiO 2 immobilization. A 99.5% removal efficiency for HA from solution was achieved at an initial concentration of 15 mg/L in a period of 3 h. It was found that degradation of HA on the TiO 2 /GAC composite was facilitated by the synergistic relationship between surface adsorption characteristics and photocatalytic potential. The fitting of experimental results with the Langmuir-Hinshelwood (L-H) model showed that the reaction rate constant and the adsorption constant values were 0.1124 mg/(L min) and 0.3402 L/mg. The latter is 1.7 times of the calculated value by fitting the adsorption equilibrium data into the Langmuir equation.

Incorporation of Kojic Acid-Azo Dyes on TiO2 Thin Films for Dye Sensitized Solar Cells Applications

Directory of Open Access Journals (Sweden)

Carolynne Zie Wei Sie

2017-01-01

Full Text Available Sensitization of heavy metal free organic dyes onto TiO2 thin films has gained much attention in dye sensitized solar cells (DSSCs. A series of new kojic acid based organic dyes KA1–4 were synthesized via nucleophilic substitution of azobenzene bearing different vinyl chains A1–4 with kojyl chloride 4. Azo dyes KA1–4 were characterized for photophysical properties employing absorption spectrometry and photovoltaic characteristic in TiO2 thin film. The presence of vinyl chain in A1–4 improved the photovoltaic performance from 0.20 to 0.60%. The introduction of kojic acid obtained from sago waste further increases the efficiency to 0.82–1.54%. Based on photovoltaic performance, KA4 achieved the highest solar to electrical energy conversion efficiency (η = 1.54% in the series.

Effects of sublethal exposure to boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta.

Science.gov (United States)

Ali, Arshad; Xue, Rui-De; Barnard, Donald R

2006-09-01

Effects of sublethal exposure to 0.1% boric acid sugar bait on adult survival, host-seeking, bloodfeeding behavior, and reproduction of Stegomyia albopicta were studied in the laboratory. Survival of males as well as females was significantly reduced when exposed to the bait, compared to control adults. The host-seeking and bloodfeeding activities in the baited females decreased, but the mean duration of blood engorgement (probing to voluntary withdrawal of proboscis) was not significantly different between the baited and control females. The landing and biting rates (human forearm) were significantly reduced in the baited females compared to nonbaited controls. Fecundity and fertility (based on number of laid eggs per female and percentage egg hatch, respectively) in the baited females were significantly reduced, and ovarian development was retarded. Sublethal exposure to sugar-based boric acid bait has the potential to reduce adult populations of St. albopicta.

The Effects of Leaching Process to the TiO2 Synthesis from Bangka Ilmenite

Science.gov (United States)

Wahyuningsih, S.; Ramelan, A. H.; Pramono, E.; Argawan, P.; Djatisulistya, A.; Firdiyono, F.; Sulistiyono, E.; Sari, P. P.

2018-03-01

Ilmenite mineral is a naturally occurring iron titanate (FeTiO3) and is abundant in nature. The separation of components into TiO2 and Fe2O3 must be expand. The purpose of this research is to synthesis TiO2 nanoparticles from the filtrate of Bangka ilmenite leaching process. Leaching of ilmenite was done with H2SO4 and HCl at various concentrations. The formation of TiO2 crystal determined by hydrolysis conditions and condensation reaction. TiO2 synthesized from the filtrate of sulfuric acid leaching that produced from TiO2 anatase phase when hydrolyzed in an aquaregia solvent and low concentrations of HCl (0.1M). Hydrolysis conditions at higher concentrations of HCl (1M) was produced TiO2 anatase-rutile phase. The synthesis of TiO2 from the filtrate of hydrochloric acid leaching was produced anatase phase. While the condition under the alcoholic solvent (2-propanol: H2O (v/v) = 9: 1) anatase phase crystallites grow in the temperature range up to 550 °C, above this temperature, TiO2 transform into rutile phase.

Three-dimensional observation of TiO2 nanostructures by electron tomography

KAUST Repository

Suh, Young Joon; Lu, Ning; Park, Seong Yong; Lee, Tae Hun; Lee, Sang Hoon; Cha, Dong Kyu; Lee, Min Gun; Huang, Jie; Kim, Sung Soo; Sohn, Byeong Hyeok; Kim, Geung Ho; Ko, Min Jae; Kim, Jiyoung; Kim, Moon J.

2013-01-01

Three-dimensional nanostructures of TiO2 related materials including nanotubes, electron acceptor materials in hybrid polymer solar cells, and working electrodes of dye sensitized solar cells (DSSCs) were visualized by electron tomography as well

Efficient solar light-driven degradation of Congo red with novel Cu-loaded Fe3O4@TiO2 nanoparticles.

Science.gov (United States)

Arora, Priya; Fermah, Alisha; Rajput, Jaspreet Kaur; Singh, Harminder; Badhan, Jigyasa

2017-08-01

In this work, Cu-loaded Fe 3 O 4 @TiO 2 core shell nanoparticles were prepared in a single pot by coating of TiO 2 on Fe 3 O 4 nanoparticles followed by Cu loading. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), Brunauer-Emmett- Teller (BET), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), and valence band X-ray photoelectron spectroscopy (VB XPS) techniques were used for characterization of as prepared nanoparticles. Synergism between copper and titania was evaluated by studying the solar light-driven photodegradation of Congo red dye solution in the presence of Fe 3 O 4 @TiO 2 nanoparticles on one side and Cu-loaded Fe 3 O 4 @TiO 2 nanoparticles on the other side. The latter performed better than the former catalyst, indicating the enhanced activity of copper-loaded catalyst. Further photodegradation was studied by three means, i.e., under ultraviolet (UV), refluxing, and solar radiations. Cu-loaded Fe 3 O 4 @TiO 2 enhanced the degradation efficiency of Congo red dye. Thus, Cu act possibly by reducing the band gap of TiO 2 and widening the optical response of semiconductor, as a result of which solar light could be used to carry out photocatalysis. Graphical abstract Photodegradation of congo red over Cu-loaded Fe 3 O 4 @TiO 2 nanoparticles.

Non-enzymatic detection of glucose in fruits using TiO2-Mn3O4 hybrid nano interface

Science.gov (United States)

Jayanth Babu, K.; Sasya, Madhurantakam; Nesakumar, Noel; Shankar, Prabakaran; Gumpu, Manju Bhargavi; Ramachandra, Bhat Lakshmishri; Kulandaisamy, Arockia Jayalatha; Rayappan, John Bosco Balaguru

2017-08-01

Consumption of fruits leads to increase in glucose level in blood for diabetic patients, which in turn leads to peripheral, vascular, ocular complications and cardiac diseases. In this context, a non-enzymatic hybrid glucose biosensor was fabricated for the first time to detect glucose by immobilizing titanium oxide-manganese oxide (TiO2-Mn3O4) nanocomposite and chitosan membrane on to the surface of Pt working electrode (Pt/TiO2-Mn3O4/chitosan). TiO2-Mn3O4 nanocomposite catalyzed the oxidation of glucose to gluconolactone in the absence of glucose oxidase enzyme with high electron transfer rate, good biocompatibility and large surface coverage. Electrochemical measurements revealed the excellent sensing response of the developed biosensor towards glucose with a high sensitivity of 7.073 µA mM-1, linearity of 0.01-0.1 mM, low detection limit of 0.01 µM, reproducibility of 1.5% and stability of 98.8%. The electrochemical parameters estimated from the anodic process were subjected to linear regression models for the detection of unknown concentration of glucose in different fruit samples.

Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

International Nuclear Information System (INIS)

Wu, Jeffrey C.S.; Tseng, I.-Hsiang; Chang, W.-C.

2001-01-01

Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO 2 was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500 deg. C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO 2 was further hydrogen-reduced at 300 deg. C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO 2 particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO 2 and reduced Cu/TiO 2 range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p 3/2 is 933.4 eV indicating primary Cu 2 O form on the TiO 2 supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO 2 support

Synthesis of Titania-supported Copper Nanoparticles via Refined Alkoxide Sol-gel Process

Science.gov (United States)

Wu, Jeffrey C. S.; Tseng, I.-Hsiang; Chang, Wan-Chen

2001-06-01

Nanoparticles of titania and copper-loaded titania were synthesized by a refined sol-gel method using titanium butoxide. Unlike the conventional sol-gel procedure of adding water directly, the esterification of anhydrous butanol and glacial acetic acid provided the hydrolyzing water. In addition, acetic acid also served as a chelating ligand to stabilize the hydrolysis-condensation process and minimize the agglomeration of titania. Following the hydrolysis, Cu/TiO2 was prepared by adding copper chloride to titania sol. The sol was dried, then calcined at 500°C to remove organics and transformed to anatase titania which was verified by XRD. Cu/TiO2 was further hydrogen-reduced at 300°C. The recovery of Ti was exceeded by an average of 95% from titanium butoxide. TEM micrographs show that the Cu/TiO2 particles are near uniform. The average crystallite sizes are 17-20 nm estimated from the peak broadening of XRD spectra. The bandgaps of TiO2 and reduced Cu/TiO2 range from 2.70 to 3.15 eV estimated from the diffusive reflective UV-Vis spectra. XPS analysis shows that Cu 2p3/2 is 933.4 eV indicating primary Cu2O form on the TiO2 supports. The binding energy of Ti does not exhibit chemical shift suggesting negligible interaction of Cu cluster and TiO2 support.

Enhanced photoelectrocatalytic performance for degradation of diclofenac and mechanism with TiO2 nano-particles decorated TiO2 nano-tubes arrays photoelectrode

International Nuclear Information System (INIS)

Cheng, Xiuwen; Liu, Huiling; Chen, Qinghua; Li, Junjing; Wang, Pu

2013-01-01

In this study, TiO 2 nano-particles decorated TiO 2 nano-tubes arrays (TiO 2 NPs/TiO 2 NTAs) photoelectrodes have been successfully prepared through anodization, combined with ultrasonic strategy, followed by annealing post-treatment. The morphology and structure of the as-prepared TiO 2 NPs/TiO 2 NTAs photoelectrodes were characterized by scanning electrons microscopy (SEM), N 2 adsorption/desorption isotherms, X-ray diffraction (XRD) and UV–visible light diffuse reflection spectroscopy (DRS). In addition, the generation of hydroxyl radicals (·OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Furthermore, the photoelectrochemical (PECH) properties of TiO 2 NPs/TiO 2 NTAs photoanode were investigated through transient open circuit potential (OCP), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). It was found that TiO 2 NPs/TiO 2 NTAs photoelectrode exhibited a distinct decrease of OCP of −0.219 mV cm −2 and PCR of 0.049 mA cm −2 , while a significantly enhanced photoelectrocatalytic (PEC) efficiency of 63.6% (0.4 V vs. SCE) for the degradation of diclofenac. Moreover, the enhanced PEC mechanism of TiO 2 NPs/TiO 2 NTAs photoanode was proposed. The high PEC performance could be attributed to the decoration of TiO 2 NPs, which could improve the mobility and separation efficiency of photoinduced charge carriers under external potential

New Hybrid Properties of TiO2 Nanoparticles Surface Modified With Catecholate Type Ligands

Directory of Open Access Journals (Sweden)

Džunuzović Enis

2009-01-01

Full Text Available Abstract Surface modification of nanocrystalline TiO2 particles (45 Å with bidentate benzene derivatives (catechol, pyrogallol, and gallic acid was found to alter optical properties of nanoparticles. The formation of the inner-sphere charge–transfer complexes results in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The binding structures were investigated by using FTIR spectroscopy. The investigated ligands have the optimal geometry for chelating surface Ti atoms, resulting in ring coordination complexes (catecholate type of binuclear bidentate binding–bridging thus restoring in six-coordinated octahedral geometry of surface Ti atoms. From the Benesi–Hildebrand plot, the stability constants at pH 2 of the order 103 M−1 have been determined.

Crystalline TiO2 grafted with poly(2-methacryloyloxyethyl phosphorylcholine) via surface-initiated atom-transfer radical polymerization

International Nuclear Information System (INIS)

Zhao Yuancong; Tu Qiufen; Wang Jin; Huang Qiongjian; Huang Nan

2010-01-01

Crystalline TiO 2 films were prepared by unbalanced magnetron sputtering and the structure was confirmed by XRD. An organic layer of 11-hydroxyundecylphosphonic acid (HUPA) was prepared on the TiO 2 films by self-assembling, and the HUPA on TiO 2 films was confirmed by FTIR analysis. Simultaneously, hydroxyl groups were introduced in the phosphonic acid molecules to provide a functionality for further chemical modification. 2-Methacryloyloxyethyl phosphorylcholine (MPC), a biomimetic monomer, was chemically grafted on the HUPA surfaces at room temperature by surface-initiated atom-transfer radical polymerization. The surface characters of TiO 2 films modified by poly-MPC were confirmed by FTIR, XPS and SEM analysis. Platelet adhesion experiment revealed that poly-MPC modified surface was effective to inhibit platelet adhesion in vitro.

Crystalline TiO 2 grafted with poly(2-methacryloyloxyethyl phosphorylcholine) via surface-initiated atom-transfer radical polymerization

Science.gov (United States)

Zhao, Yuancong; Tu, Qiufen; Wang, Jin; Huang, Qiongjian; Huang, Nan

2010-12-01

Crystalline TiO 2 films were prepared by unbalanced magnetron sputtering and the structure was confirmed by XRD. An organic layer of 11-hydroxyundecylphosphonic acid (HUPA) was prepared on the TiO 2 films by self-assembling, and the HUPA on TiO 2 films was confirmed by FTIR analysis. Simultaneously, hydroxyl groups were introduced in the phosphonic acid molecules to provide a functionality for further chemical modification. 2-Methacryloyloxyethyl phosphorylcholine (MPC), a biomimetic monomer, was chemically grafted on the HUPA surfaces at room temperature by surface-initiated atom-transfer radical polymerization. The surface characters of TiO 2 films modified by poly-MPC were confirmed by FTIR, XPS and SEM analysis. Platelet adhesion experiment revealed that poly-MPC modified surface was effective to inhibit platelet adhesion in vitro.

Synthesis and photocatalytic activity of Ce-doped TiO2 and TiO2 nanotubes

International Nuclear Information System (INIS)

Arruda, L.B.; Pereira, E.A.; Paula, F.R.; Lisboa Filho, P.N.

2016-01-01

samples with pH 7, XRD measurements showed the coexistence of TiO2 and sodium titanate phase. By decreasing the pH during acid washing the sodium content was eliminated leaving only the main phase. This behavior was observed for samples containing Cerium concentrations up to 0.2%. The obtained nanotubes presented multiple walls, having dimensions of 5 nm of diameter and about 200 nm of length. Energy dispersive X-ray spectroscopy analyzes revealed that nanotubes are mainly composed of titanium and oxygen, with small amounts of sodium when pH is 7 and sodium no was observed for the sample obtained at pH 4. It shows that synthesis conditions are very important in order to obtain single-phase structures. In addition, TiO2 nanotubes showed good photocatalytic activity with degradation around 100 minutes.(author)

Synthesis and photocatalytic activity of Ce-doped TiO2 and TiO2 nanotubes

Energy Technology Data Exchange (ETDEWEB)

Arruda, L.B.; Pereira, E.A.; Paula, F.R.; Lisboa Filho, P.N. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), SP (Brazil)

2016-07-01

samples with pH 7, XRD measurements showed the coexistence of TiO2 and sodium titanate phase. By decreasing the pH during acid washing the sodium content was eliminated leaving only the main phase. This behavior was observed for samples containing Cerium concentrations up to 0.2%. The obtained nanotubes presented multiple walls, having dimensions of 5 nm of diameter and about 200 nm of length. Energy dispersive X-ray spectroscopy analyzes revealed that nanotubes are mainly composed of titanium and oxygen, with small amounts of sodium when pH is 7 and sodium no was observed for the sample obtained at pH 4. It shows that synthesis conditions are very important in order to obtain single-phase structures. In addition, TiO2 nanotubes showed good photocatalytic activity with degradation around 100 minutes.(author)

Effect of chemisorbed surface species on the photocatalytic activity of TiO2 nanoparticulate films

International Nuclear Information System (INIS)

Cao Yaan; Yang Wensheng; Chen Yongmei; Du Hui; Yue, Polock

2004-01-01

TiO 2 sols prepared in acidic and basic medium were deposited into films by a spin coating method. Photodegradation experiments showed that photocatalytic activity of the films prepared from acidic sol was much higher than that from basic sol. It is identified that there are more chemisorbed species of CO 2 on the surface of the TiO 2 films from the basic sol than on the surface of the TiO 2 films from the acidic sol. The chemisorbed species of CO 2 reduce the concentration of active species such as hydroxyl group and bridging oxygen on surface of the TiO 2 film and contribute to the formation of surface electron traps in the band gap which are detrimental to charge separation, thus lowering the photocatalytic activity

Method for the reprocessing of liquid wastes containing boric acid, radioactive antimony and other radioactive nuclides and similar, especially of the evaporator concentrates of nuclear power plants

International Nuclear Information System (INIS)

Doerr, A.

1978-01-01

The liquid wastes are evaporated, H 2 SO 4 and methanol are added, and the formed boric acid methylester is distilled off. The residue with Sb-124, Cs, Co and Mn is then stored two years until the activity of Sb-124 has decayed. Afterwards the radioactive nuclides are precipitated. (DG) [de

The influence of TiO2 particle size and conductivity of the CuCrO2 ...

Indian Academy of Sciences (India)

38

Keywords: Solid-state dye-sensitized solar cells, Sol-Gel method, TiO2 nanoparticle, .... at 2.0 by dropwise addition of 0.1 M hydrochloric acid with vigorous stirring. The ... The TiO2 pastes were prepared by Pechini-type sol-gel method [26, 27].

Interchange reaction of disulfides and denaturation of oxytocin by copper(II)/ascorbic acid/O2 system.

Science.gov (United States)

Inoue, H; Hirobe, M

1987-05-29

The interchange reaction of disulfides was caused by the copper(II)/ascorbic acid/O2 system. The incubation of two symmetric disulfides, L-cystinyl-bis-L-phenylalanine (PP) and L-cystinyl-bis-L-tyrosine (TT), with L-ascorbic acid and CuSO4 in potassium phosphate buffer (pH 7.2, 50 mM) resulted in the formation of an asymmetric disulfide, L-cystinyl-L-phenylalanine-L-tyrosine (PT), and the final ratio of PP:PT:TT was 1:2:1. As the reaction was inhibited by catalase and DMSO only at the initial time, hydroxyl radical generated by the copper(II)/ascorbic acid/O2 system seemed to be responsible for the initiation of the reaction. Oxytocin and insulin were denatured by this system, and catalase and DMSO similarly inhibited these denaturations. As the composition of amino acids was unchanged after the reaction, hydroxyl radical was thought to cause the cleavage and/or interchange reaction of disulfides to denature the peptides.

Preparation and performance of photocatalytic TiO2 immobilized on palladium-doped carbon fibers

International Nuclear Information System (INIS)

Zhu Yaofeng; Fu Yaqin; Ni Qingqing

2011-01-01

Pd-modified carbon fibers (CFs) are obtained by a facile oxidation-reduction method and then dip-coated in a sol-gel of titanium dioxide (TiO 2 ) to form supported TiO 2 /Pd-CF photocatalysts. The morphology of the Pd-modified CFs and the amount Pd deposited are characterized by field emission scanning electron microscopy and atomic absorption spectrometry, respectively. X-ray diffraction is used to investigate the crystal structures of the TiO 2 photocatalyst. Acid orange II is used as a model contaminant to evaluate the photocatalytic properties of the photocatalyst under UV irradiation. TiO 2 /Pd-CF exhibits higher catalytic activity than TiO 2 /CF towards the degradation of acid orange II. Optimum photocatalytic performance and support properties are achieved when the Pd particle loading is about 10.8 mg/g.

Internalisation of hybrid titanium dioxide/para-amino benzoic acid nanoparticles in human dendritic cells did not induce toxicity and changes in their functions.

Science.gov (United States)

Migdal, Camille; Rahal, Raed; Rubod, Alain; Callejon, Sylvie; Colomb, Evelyne; Atrux-Tallau, Nicolas; Haftek, Marek; Vincent, Claude; Serres, Mireille; Daniele, Stéphane

2010-11-10

Nanoparticles (NPs) have been reported to penetrate into human skin through lesional skin or follicular structures. Therefore, their ability to interact with dendritic cell (DC) was investigated using DCs generated from monocytes (mono-DCs). Hybrid titanium dioxide/para-amino benzoic acid (TiO(2)/PABA) NPs did not induce any cell toxicity. NPs were internalised into DCs through macropinocytosis and not by a receptor-mediated mechanism. Confocal microscopy showed that NPs were not detected in the nucleus. These data are confirmed by electronic microscopy which demonstrated that hybrid NPs were rapidly in contact with cellular membrane and localised into cytoplasmic vesicles without colocalisation with clathrin-coated vesicles. Hybrid NPs did not induce CD86 or HLA-DR overexpression or cytokine secretion (IL-8 and TNF-α) indicating no DC activation. Internalisation of hybrid NPs did not modify DC response towards sensitisers such as nickel and thimerosal or LPS used as positive controls. Moreover, hybrid NPs did not induce any oxidative stress implicated in DC activation process. After mono-DC irradiation by ultraviolet A (UVA), hybrid NP-treated cells did not produce UVA-induced reactive oxygen species (ROS) and exhibited a better cell viability compared with UVA-irradiated control cells, suggesting a protecting effect of hybrid TiO(2)/PABA NPs against UVA-induced ROS. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment

CSIR Research Space (South Africa)

Tshabalala, Zamaswazi P

2016-03-01

Full Text Available and Actuators B: Chemical Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment Z.P. Tshabalalaa,b, D.E. Motaunga,∗, G.H. Mhlongoa,∗, O.M. Ntwaeaborwab,∗ a DST/CSIR, National Centre...

Experimental Investigations to Enhance the Tribological Performance of Engine Oil by Using Nano-Boric Acid and Functionalized Multiwalled Carbon Nanotubes: A Comparative Study to Assess Wear in Bronze Alloy

Science.gov (United States)

Ajay Vardhaman, B. S.; Amarnath, M.; Ramkumar, J.; Rai, Prabhat K.

2018-04-01

In various mechanical systems, lubricants are generally used to reduce friction and wear; thus, the total energy loss in the mechanical systems can be minimized by the proper enhancement of lubrication properties. In general, friction modifiers and antiwear additives are used to improve the tribological properties of the lubricant. However, the use of these additives has to be phased out due to their fast chemical degradation in their applications and other environmental issues. In recent years, the use of nanoparticles as a potential lubricant additive has received considerable attention because of its excellent mechanical and tribological characteristics. The present work describes the tribological behavior of nano-boric acid, multiwalled carbon nanotubes (MWCNTs), and functionalized multiwalled carbon nanotubes (FMWCNTs) modified with carboxylic acid. These nanoparticles were used to enhance the tribological properties of engine oil (SAE20W40) used to lubricate bronze alloy samples. The performance of these nano-coolants was assessed on a linear reciprocating ball-on-flat tribometer. Results highlight the friction and wear behavior of the nano-boric acid, MWCNTs, and FMWCNTs under three varying parameters such as the effect of nanoparticles concentration, load-carrying capacity, and sliding speed. The addition of nano-boric acid, MWCNTs, and FMWCNTs has significantly improved the tribological properties of the base lubricant. The addition of 0.5 wt.% of nano-boric acid, MWCNTs, and FMWCNTs to the base lubricant has decreased the coefficient of friction by 19.76, 30.55, and 35.65%, respectively, and a significant reduction in wear volume by 55.17, 71.42, and 88.97% was obtained in comparison with base lubricant.

Electrospinning processed nanofibrous TiO2 membranes for photovoltaic applications

Science.gov (United States)

Onozuka, Katsuhiro; Ding, Bin; Tsuge, Yosuke; Naka, Takayuki; Yamazaki, Michiyo; Sugi, Shinichiro; Ohno, Shingo; Yoshikawa, Masato; Shiratori, Seimei

2006-02-01

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO2 membranes as electrode materials. A thin TiO2 film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF4 aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO2 film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO2 membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO2 membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N'-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO2 film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO2 membranes. The efficiency of the fibrous TiO2 photoelectrode with the average membrane thickness of 3.9 µm has a maximum value of 4.14%.

TiO2-SnS2 nanocomposites: solar-active photocatalytic materials for water treatment.

Science.gov (United States)

Kovacic, Marin; Kusic, Hrvoje; Fanetti, Mattia; Stangar, Urska Lavrencic; Valant, Matjaz; Dionysiou, Dionysios D; Bozic, Ana Loncaric

2017-08-01

The study is aimed at evaluating TiO 2 -SnS 2 composites as effective solar-active photocatalysts for water treatment. Two strategies for the preparation of TiO 2 -SnS 2 composites were examined: (i) in-situ chemical synthesis followed by immobilization on glass plates and (ii) binding of two components (TiO 2 and SnS 2 ) within the immobilization step. The as-prepared TiO 2 -SnS 2 composites and their sole components (TiO 2 or SnS 2 ) were inspected for composition, crystallinity, and morphology using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analyses. Diffuse reflectance spectroscopy (DRS) was used to determine band gaps of immobilized TiO 2 -SnS 2 and to establish the changes in comparison to respective sole components. The activity of immobilized TiO 2 -SnS 2 composites was tested for the removal of diclofenac (DCF) in aqueous solution under simulated solar irradiation and compared with that of single component photocatalysts. In situ chemical synthesis yielded materials of high crystallinity, while their morphology and composition strongly depended on synthesis conditions applied. TiO 2 -SnS 2 composites exhibited higher activity toward DCF removal and conversion in comparison to their sole components at acidic pH, while only in situ synthesized TiO 2 -SnS 2 composites showed higher activity at neutral pH.

Titanium dioxide–cellulose hybrid nanocomposite and its glucose biosensor application

International Nuclear Information System (INIS)

Maniruzzaman, Mohammad; Jang, Sang-Dong; Kim, Jaehwan

2012-01-01

Highlights: ► An organic–inorganic hybrid nanocomposite was fabricated by blending TiO 2 nanoparticles and cellulose solution. ► The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO 2 . ► Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO 2 and GOx was confirmed by X-ray photoelectron analysis. ► Linear response of the glucose biosensor was obtained in the range of 1–10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO 2 )–cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO 2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO 2 –cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO 2 –cellulose hybrid nanocomposite via covalent bonding between TiO 2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1–10 mM. This study demonstrates that TiO 2 –cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

Photo-electrocatalytic activity of TiO2 nanotubes prepared with two-step anodization and treated under UV light irradiation

Directory of Open Access Journals (Sweden)

Mohamad Mohsen Momeni

2016-01-01

Full Text Available To improve the photo-catalytic degradation of salicylic acid, we reported the fabrication of ordered TiO2 nanotube arrays by a simple and effective two-step anodization method and then these TiO2 nanotubes treated in a methanol solution under UV light irradiation. The TiO2 nanotubes prepared in the two-step anodization process showed better photo-catalytic activity than TiO2 nanotubes prepared in one-step anodization process. Also, compared with TiO2 nanotubes without the UV pretreatment, the TiO2 nanotubes pretreated in a methanol solution under UV light irradiation exhibited significant enhancements in both photocurrent and activity. The treated TiO2 nanotubes exhibited a 5-fold enhancement in photocurrent and a 2.5-fold increase in the photo-catalytic degradation of salicylic acid. Also the effect of addition of persulfate and periodate on the photo-catalytic degradation of salicylic acid were investigated. The results showed that the degradation efficiency of salicylic acid increased with increasing persulfate and periodate concentrations. These treated TiO2 nanotubes are promising candidates for practical photochemical reactors.

First-principles study of Mn-S codoped anatase TiO2

Science.gov (United States)

Li, Senlin; Huang, Jinliang; Ning, Xiangmei; Chen, Yongcha; Shi, Qingkui

2018-04-01

In this work, the CASTEP program in Materials Studio 2017 software package was applied to calculate the electronic structures and optical properties of pure anatase TiO2, S-doped, Mn-doped and Mn-S co-doped anatase TiO2 by GGA + U methods based on the density function theory (DFT). The results indicate that the lattice is distorted and the lattice constant is reduce due to doping. The doping also introduces impurity energy levels into the forbidden band. After substitution of Mn for Ti atom, band gap narrowing of anatase TiO2 is caused by the impurity energy levels appearance in the near Fermi surface, which are contributed by Mn-3d orbital, Ti-3d orbital and O-2p orbital hybridization. After substitution of S for O atom, band gap narrowing is creited with the shallow accepter level under the conduction hand of S-3p orbital. The Mn-S co-doped anatase TiO2 could be a potential candidate for a photocatalyst because of tis enhanced absorption ability of visible light. The results can well explain the immanent cause of a band gap narrowing as well as a red shift in the spectrum for doped anatase TiO2.

Fabrication, characterization and photocatalytic properties of Ag nanoparticles modified TiO2 NTs

International Nuclear Information System (INIS)

Wang Qingyao; Yang Xiuchun; Liu Dan; Zhao Jianfu

2012-01-01

Graphical abstract: The TiO 2 NTs were first treated with bi-functional mercaptoacetic acid linkers (HOOC–R–S). The –OH group on the surface of TiO 2 NT provides a strong affinity with the carboxylate group in the linker molecules. The thiol functional group in the linker molecules facilitates the binding with Ag from AgNO 3 solution. After Ag + ions were reduced by NaBH 4 , Ag nanoparticles formed by nucleation and growth. Highlights: ► Ag nanoparticles with an average diameter of 9.2 nm were filled in the TiO 2 nanotubes by a successive ionic layer adsorption and reaction (SILAR) technique. ► Bi-functional mercaptoacetic acid linkers were used to bind TiO 2 nanotubes with Ag nanoparticles. ► Ag nanoparticles modification of TiO 2 NTs largely enhanced the photocatalytic degradation of methyl orange under ultraviolet light irradiation. - Abstract: Ordered anatase TiO 2 nanotubes (TiO 2 NTs) on Ti substrate were synthesized by electrochemical anodization and subsequently vapor-thermal treatment. Ag nanoparticles were decorated on TiO 2 NTs by successive ionic layer adsorption and reaction (SILAR) technique. Raman spectroscopy, X-ray absorption near edge spectroscopy (XANES), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for the characterization of surface morphology, phase composition, and microstructure of the original TiO 2 NTs, the vapor-thermally treated TiO 2 NTs and the Ag nanoparticles decorated TiO 2 NTs. The results indicate that vapor-thermal treatment favors to the transformation of amorphous TiO 2 into anatase phase. Increasing the SILAR cycle times favors to increase the loaded amounts of Ag nanoparticles in TiO 2 NTs. Ag nanoparticles are uniformly distributed in the TiO 2 NTs, and the SILAR process does not damage the ordered tubular structure. A possible formation mechanism of Ag/TiO 2 NTs has also been proposed. The

Nanocomposites of TiO2/cyanoethylated cellulose with ultra high dielectric constants

International Nuclear Information System (INIS)

Madusanka, Nadeesh; Shivareddy, Sai G; Hiralal, Pritesh; Choi, Youngjin; Amaratunga, Gehan A J; Eddleston, Mark D; Oliver, Rachel A

2016-01-01

A novel dielectric nanocomposite containing a high permittivity polymer, cyanoethylated cellulose (CRS) and TiO 2 nanoparticles was successfully prepared with different weight percentages (10%, 20% and 30%) of TiO 2 . The intermolecular interactions and morphology within the polymer nanocomposites were analysed. TiO 2 /CRS nanofilms on SiO 2 /Si wafers were used to form metal–insulator–metal type capacitors. Capacitances and loss factors in the frequency range of 1 kHz–1 MHz were measured. At 1 kHz CRS-TiO 2 nanocomposites exhibited ultra high dielectric constants of 118, 176 and 207 for nanocomposites with 10%, 20% and 30% weight of TiO 2 respectively, significantly higher than reported values of pure CRS (21), TiO 2 (41) and other dielectric polymer-TiO 2 nanocomposite films. Furthermore, all three CRS-TiO 2 nanocomposites show a loss factor <0.3 at 1 kHz and low leakage current densities (10 −6 –10 −7 A cm −2 ). Leakage was studied using conductive atomic force microscopy and it was observed that the leakage is associated with TiO 2 nanoparticles embedded in the CRS polymer matrix. A new class of ultra high dielectric constant hybrids using nanoscale inorganic dielectrics dispersed in a high permittivity polymer suitable for energy management applications is reported. (paper)

Synthesis, structure and photocatalytic activity of nano TiO2 and ...

Indian Academy of Sciences (India)

salicylic acid over combustion-synthesized nano TiO2 under UV and solar exposure has been carried out. Under identical conditions of UV exposure, the initial degra- dation rate of phenol with combustion-synthesized TiO2 is two times higher than the initial degradation rate of phenol with Degussa P25, the commercial ...

Photoassist-phosphorylated TiO2 as a catalyst for direct formation of 5-(hydroxymethyl)furfural from glucose.

Science.gov (United States)

Hattori, Masashi; Kamata, Keigo; Hara, Michikazu

2017-02-01

Photo-assisted phosphorylation of an anatase TiO 2 catalyst was examined to improve its catalytic performance for the direct production of 5-(hydroxymethyl)furfural (HMF), a versatile chemical platform, from glucose. In phosphorylation based on simple esterification between phosphoric acid and surface OH groups on anatase TiO 2 with water-tolerant Lewis acid sites, the density of phosphates immobilized on TiO 2 is limited to 2 phosphates nm -2 , which limits selective HMF production. Phosphorylation of the TiO 2 surface under fluorescent light irradiation increases the surface phosphate density to 50%, which is higher than the conventional limit, thus preventing the adsorption of hydrophilic glucose molecules on TiO 2 and resulting in a more selective HMF production over photoassist-phosphorylated TiO 2 .

Interfacial Structure and Photocatalytic Activity of Magnetron Sputtered TiO2 on Conducting Metal Substrates

DEFF Research Database (Denmark)

Daviðsdóttir, Svava; Petit, Jean-Pierre; Mermoux, Michel

2014-01-01

The photocatalytic behavior of magnetron sputtered anatase TiO2 coatings on copper, nickel, and gold was investigated with the aim of understanding the effect of the metallic substrate and coating-substrate interface structure. Stoichiometry and nanoscale structure of the coating were investigated...

Stability of Hydrogen-Bonded Supramolecular Architecture under High Pressure Conditions: Pressure-Induced Amorphization in Melamine-Boric Acid Adduct

International Nuclear Information System (INIS)

Wang, K.; Duan, D.; Wang, R.; Lin, A.; Cui, Q.; Liu, B.; Cui, T.; Zou, B.; Zhang, X.

2009-01-01

The effects of high pressure on the structural stability of the melamine-boric acid adduct (C3N6H6 2H3BO3, M 2B), a three-dimensional hydrogen-bonded supramolecular architecture, were studied by in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy. M 2B exhibited a high compressibility and a strong anisotropic compression, which can be explained by the layerlike crystal packing. Furthermore, evolution of XRD patterns and Raman spectra indicated that the M 2B crystal undergoes a reversible pressure-induced amorphization (PIA) at 18 GPa. The mechanism for the PIA was attributed to the competition between close packing and long-range order. Ab initio calculations were also performed to account for the behavior of hydrogen bonding under high pressure.

Hierarchically multifunctional K-OMS-2/TiO2/Fe3O4 heterojunctions for the photocatalytic oxidation of humic acid under solar light irradiation.

Science.gov (United States)

Zhang, Tong; Yan, Xiaoli; Sun, Darren Delai

2012-12-01

A multifunctional heterojunctioned K-OMS-2/TiO(2)/Fe(3)O(4) (KTF) nanocomposite was successfully synthesized using a combination of hydrothermal and co-precipitation techniques. The resultant sample was characterized by XRD, FESEM, TEM, N(2) adsorption, XPS and VSM. Its photocatalytic activity was demonstrated in the photocatalytic degradation of humic acid (HA). Morphology characterization showed the hierarchical structure of the synthesized material, and XRD results revealed that both the rutile and anatase TiO(2) structures are present in the sample. The average pore diameters and BET surface area of the synthesized KTF heterojunctions were 40 nm and 134.42 m(2)/g, respectively. XPS spectra confirmed the presence of Fe(3)O(4) and TiO(2) in the synthesized material, and the valences of Mn were kept at +3 and +4 after the grafting of Fe(3)O(4) and TiO(2). The synthesized material showed good magnetic response and photocatalytic activity under simulated solar light irradiation, and 85.7% of HA was decomposed after 120 min in the presence of KTF nanocomposites. The reusability study suggested that the magnetic recovered material was stable enough for multiple recycling usages, verifying its potential application in water purification. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of the antifouling and photocatalytic properties of poly(vinylidene fluoride) plasma-grafted poly(acrylic acid) membrane with self-assembled TiO2

International Nuclear Information System (INIS)

You, Sheng-Jie; Semblante, Galilee Uy; Lu, Shao-Chung; Damodar, Rahul A.; Wei, Ta-Chin

2012-01-01

Highlights: ► Plasma and grafting parameters that maximized TiO 2 binding sites were found. ► PVDF hydrophilicity was vastly improved compared to other modification techniques. ► At least 1.5% TiO 2 and 30 min UV exposure were needed to attain full flux recovery. ► Photocatalytic membranes could remove up to 42% of 50 mg/l RB5 dye. - Abstract: Immobilization of TiO 2 is a promising approach that produces antifouling and photocatalytic membranes that could help advance wastewater treatment and re-use processes. In this study, poly(acrylic acid) (PAA) was plasma-grafted on commercial poly(vinylidene fluoride) (PVDF) to introduce functional groups on the membrane surface that can support the nanoparticles. It was found that plasma treatment at 100 W for 120 s followed by liquid grafting with 70% aqueous AA at 60 °C for 2 h maximized the number of TiO 2 binding sites. Membrane hydrophilicity was tremendously enhanced by the self-assembly of TiO 2 , following a direct proportionality to TiO 2 loading. The membrane with 0.5% TiO 2 loading maintained the highest pure water flux and the best protein antifouling property. UV irradiation triggered the photodegradation of strongly bound foulants, but at least 1.5% TiO 2 and 30 min cumulative irradiation were necessary to completely recover the membrane's original performance. The TiO 2 -modified membranes removed 30–42% of 50 mg/l aqueous Reactive Black 5 (RB5) dye. The fabricated membranes demonstrate huge potential for use in membrane reactors with high hydrophilicity, fouling mitigation, and photocatalytic capability.

Uniform Gold-Nanoparticle-Decorated {001}-Faceted Anatase TiO2 Nanosheets for Enhanced Solar-Light Photocatalytic Reactions.

Science.gov (United States)

Shi, Huimin; Zhang, Shi; Zhu, Xupeng; Liu, Yu; Wang, Tao; Jiang, Tian; Zhang, Guanhua; Duan, Huigao

2017-10-25

The {001}-faceted anatase TiO 2 micro-/nanocrystals have been widely investigated for enhancing the photocatalysis and photoelectrochemical performance of TiO 2 nanostructures, but their practical applications still require improved energy conversion efficiency under solar-light and enhanced cycling stability. In this work, we demonstrate the controlled growth of ultrathin {001}-faceted anatase TiO 2 nanosheets on flexible carbon cloth for enhancing the cycling stability, and the solar-light photocatalytic performance of the synthesized TiO 2 nanosheets can be significantly improved by decorating with vapor-phase-deposited uniformly distributed plasmonic gold nanoparticles. The fabricated Au-TiO 2 hybrid system shows an 8-fold solar-light photocatalysis enhancement factor in photodegrading Rhodamine B, a high photocurrent density of 300 μA cm -2 under the illumination of AM 1.5G, and 100% recyclability under a consecutive long-term cycling measurement. Combined with electromagnetic simulations and systematic control experiments, it is believed that the tandem-type separation and transition of plasmon-induced hot electrons from Au nanoparticles to the {001} facet of anatase TiO 2 , and then to the neighboring {101} facet, is responsible for the enhanced solar-light photochemical performance of the hybrid system. The Au-TiO 2 nanosheet system addresses well the problems of the limited solar-light response of anatase TiO 2 and fast recombination of photogenerated electron-hole pairs, representing a promising high-performance recyclable solar-light-responding system for practical photocatalytic reactions.

Completely oriented anatase TiO2 nanoarrays: topotactic growth and orientation-related efficient photocatalysis

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Yang, Jingling; Wu, Qili; He, Shiman; Yan, Jing; Shi, Jianying; Chen, Jian; Wu, Mingmei; Yang, Xianfeng

2015-08-01

A TiO2 film has been facilely grown on a Ti foil via a general and simple acid vapor oxidation (AVO) strategy. Based on detailed characterization by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the TiO2 film was composed of anatase nanoarrays highly oriented along their direction, resulting in a large exposed {001} top surface on the film. The growth mechanism based on a topotactic transformation was proposed according to a careful study of time-dependent experimental results. Resulting from the evaluation of photocatalytic performance compared with a commercial TiO2 photocatalyst (Degussa P25), the as-prepared oriented anatase TiO2 film showed higher efficiency for degradation of atrazine and acid orange II (AOII). The performance of photocatalysis is highly relevant to the preferential orientation. The efficient photocatalysis could be attributed to the highly reactive {001} facets on the anatase nanoarrays with super-hydrophilicity.A TiO2 film has been facilely grown on a Ti foil via a general and simple acid vapor oxidation (AVO) strategy. Based on detailed characterization by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we found that the TiO2 film was composed of anatase nanoarrays highly oriented along their direction, resulting in a large exposed {001} top surface on the film. The growth mechanism based on a topotactic transformation was proposed according to a careful study of time-dependent experimental results. Resulting from the evaluation of photocatalytic performance compared with a commercial TiO2 photocatalyst (Degussa P25), the as-prepared oriented anatase TiO2 film showed higher efficiency for degradation of atrazine and acid orange II (AOII). The performance of photocatalysis is highly relevant to the preferential orientation. The efficient photocatalysis could be attributed to the highly reactive {001

Novel TiO2/C nanocomposites: synthesis, characterization, and application as a photocatalyst for the degradation of organic pollutants.

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da Costa, Elias; Zamora, Patricio P; Zarbin, Aldo J G

2012-02-15

Novel TiO(2)/carbon nanocomposites were prepared through the pyrolysis of TiO(2)/poly(furfuryl alcohol) hybrid materials, which were obtained by the sol-gel method, starting from titanium tetraisopropoxide (TTIP) and furfuryl alcohol (FA) precursors. Six different TiO(2)/C samples were prepared based on different TiO(2) nanoparticle sizes and TiO(2)/FA ratios. All of the samples were characterized using X-ray diffraction, infrared, and Raman spectroscopy. The results indicated effective FA polymerization onto the TiO(2) (anatase) nanoparticles, polymer conversion to disordered carbon following the pyrolysis, and a simultaneous TiO(2) anatase-rutile phase transition. The resulting TiO(2)/carbon composites were used as photocatalysts in the advanced oxidative process (AOP) for the degradation of reactive organic dyes in aqueous solution. The results indicate excellent photocatalytic performance (degradation of 99% of the dye after 60 min) with several advantages over traditional TiO(2)-based photocatalysts. Copyright © 2011 Elsevier Inc. All rights reserved.

Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

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Nguyen Huy Hao

2016-08-01

Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

Transport of Nanoparticles of Zerovalent Copper, Zinc Oxide, and Titanium Dioxide in Saturated Porous Media

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Column tests show nanoparticles (NPs) of Cu(0) and ZnO were immobile at neutral pH in saturated sand.They became mobile in the presence of trizma, humic/fulvic, and citric/oxalic/formic acids. Copper NPs were mobile at pH 9. The deposition rates of TiO2 NP aggregates in both KCl ...

Multitarget Molecular Hybrids of Cinnamic Acids

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Aikaterini Peperidou

2014-12-01

Full Text Available In an attempt to synthesize potential new multitarget agents, 11 novel hybrids incorporating cinnamic acids and paracetamol, 4-/7-hydroxycoumarin, benzocaine, p-aminophenol and m-aminophenol were synthesized. Three hybrids—2e, 2a, 2g—and 3b were found to be multifunctional agents. The hybrid 2e derived from the phenoxyphenyl cinnamic acid and m-acetamidophenol showed the highest lipoxygenase (LOX inhibition and analgesic activity (IC50 = 0.34 μΜ and 98.1%, whereas the hybrid 3b of bromobenzyloxycinnamic acid and hymechromone exhibited simultaneously good LOX inhibitory activity (IC50 = 50 μΜ and the highest anti-proteolytic activity (IC50= 5 μΜ. The hybrid 2a of phenyloxyphenyl acid with paracetamol showed a high analgesic activity (91% and appears to be a promising agent for treating peripheral nerve injuries. Hybrid 2g which has an ester and an amide bond presents an interesting combination of anti-LOX and anti-proteolytic activity. The esters were found very potent and especially those derived from paracetamol and m-acetamidophenol. The amides follow. Based on 2D-structure–activity relationships it was observed that both steric and electronic parameters play major roles in the activity of these compounds. Molecular docking studies point to the fact that allosteric interactions might govern the LOX-inhibitor binding.

Solvothermal synthesis of TiO2 nanocrystals with {001} facets using titanic acid nanobelts for superior photocatalytic activity

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Cao, Yuhui; Zong, Lanlan; Li, Qiuye; Li, Chen; Li, Junli; Yang, Jianjun

2017-01-01

Anatase TiO2 nanocrystals exposed with {001} facets were fabricated by solvothermal strategy in HF-C4H9OH mixed solution, using titanic acid nanobelts (TAN) as a precursor. The shape of TAN is a long flat plane with a high aspect ratio, and F- is easily adsorbed on the surface of the nanobelts, inducing a higher exposure of {001} facet of TiO2 nanoparticles during the structure reorganization. The exposed percentage of {001} facets could vary from 40 to 77% by adjusting the amount of HF. The as-prepared samples were characterized by transmission electron microscopy, N2 adsorption-desorption isotherms, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscope. The photocatalytic measurement showed that TiO2 nanocrystals with 77% {001} facets exhibited much superior photocatalytic activity for photodegradation of methyl orange, methylene blue, and rhodamine B. And what's more, the mineralization rate of methyl orange was as high as 96% within 60 min. The photocatalytic enhancement is due to a large amount of the high energetic {001} facets exposing, the special truncated octahedral morphology and a stronger ability for dyes adsorption.

A large interconnecting network within hybrid MEH-PPV/TiO2 nanorod photovoltaic devices

International Nuclear Information System (INIS)

Zeng, T-W; Lin, Y-Y; Lo, H-H; Chen, C-W; Chen, C-H; Liou, S-C; Huang, H-Y; Su, W-F

2006-01-01

This is a study of hybrid photovoltaic devices based on TiO 2 nanorods and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). We use TiO 2 nanorods as the electron acceptors and conduction pathways. Here we describe how to develop a large interconnecting network within the photovoltaic device fabricated by inserting a layer of TiO 2 nanorods between the MEH-PPV:TiO 2 nanorod hybrid active layer and the aluminium electrode. The formation of a large interconnecting network provides better connectivity to the electrode, leading to a 2.5-fold improvement in external quantum efficiency as compared to the reference device without the TiO 2 nanorod layer. A power conversion efficiency of 2.2% under illumination at 565 nm and a maximum external quantum efficiency of 24% at 430 nm are achieved. A power conversion efficiency of 0.49% is obtained under Air Mass 1.5 illumination

Hydrothermal solid-gas route to TiO2 nanoparticles/nanotube arrays for high-performance supercapacitors

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Fan, Haowen; Zhang, He; Luo, Xiaolei; Liao, Maoying; Zhu, Xufei; Ma, Jing; Song, Ye

2017-07-01

Although TiO2 nanotube arrays (TNTAs) have shown great promise as supercapacitor materials, their specific capacitances are still not comparable with some typical materials. Here, TiO2 nanoparticles (NPs)/TNTAs hybrid structure has been derived from the anodized TNTAs by a facile hydrothermal solid-gas method (HSGM), which can avoid cracking or curling of the TNTAs from Ti substrate. The obtained NPs/TNTAs hybrid structure can exhibit a ∼4.90 times increase in surface area and a ∼5.49 times increase in areal specific capacitance compared to the TNTAs without HSGM treatment. Besides, the argon-atmosphere annealing can offer improved areal capacitance and cycling stability relative to the air-atmosphere annealing. The hydrothermal vapor pressure is a key factor for controlling microscopic morphologies of TNTAs, the morphology transformations of TNTAs during the HSGM treatment can be accelerated under enhanced vapor pressures. The highest areal capacitance of HSGM-treated TNTAs is up to 76.12 mF cm-2 at 0.5 mA cm-2, well above that of any TiO2 materials reported to date.

Enhancement of photocatalytic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation

International Nuclear Information System (INIS)

Zhao Xu; Li Zongwei; Chen Yi; Shi Liyi; Zhu Yongfa

2008-01-01

Solid-phase photocatalytic degradation of polyethylene (PE) plastic, one of the most common commercial plastic, over copper phthalocyanine (CuPc) modified TiO 2 (TiO 2 /CuPc) photocatalyst was investigated in the ambient air under solar light irradiation. Higher PE weight loss rate, greater texture change; more amount of generated CO 2 , which is the main product of the photocatalytic degradation of the composite PEC plastic can be achieved in the system of PE-(TiO 2 /CuPc) in comparison with PE-TiO 2 system. The CuPc promoted charge separation of TiO 2 and enhanced the photocatalytic degradation of PE based on the analysis of surface photovoltage spectroscopy (SPS). During the photodegradation of PE plastic, the reactive oxygen species generated on TiO 2 or TiO 2 /CuPc particle surfaces play important roles. The present study demonstrates that the combination of polymer plastic with TiO 2 /CuPc composite photocatalyst in the form of thin film is a practical and useful way to photodegrade plastic contaminants under solar light irradiation

Probing Photocatalytic Characteristics of Sb-Doped TiO2 under Visible Light Irradiation