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Poly(lactic acid)/sesbania gum/nano-TiO composites were prepared by melt blending in the mixing chamber of a torque rheometer in this work. The processing rheological properties, mechanical properties, morphologies, thermal properties, and optical properties of the resulting composites were evaluated. Effects of nano-TiO content and plasticizer content on the processing rheological properties and mechanical properties of composites were discussed. Scanning electron microscopy micrographs clearly revealed good dispersion of nano-TiO aggregates in the matrix at the low nano-TiO content, while higher content contributed to easy aggregation within the matrix, which was consistent with the results of mechanical properties, thermal properties, and optical properties. As for the processing rheological properties, a reasonable choice of nano-TiO and plasticizer content should be made depending on the used processing equipment and process. [ABSTRACT FROM AUTHOR]

The stability of nanoparticles (NPs) in aquatic environments is important to evaluate their adverse effects on aquatic ecosystems and human health. Nanoparticle stability is known to be influenced by coexisting ions and dissolved organic matter. This study was designed to investigate the effects of coexisting low-level Cd(II) on the stability of humic acid-coated nano-TiO (HA-TiO) particles in aquatic environments by measuring their aggregation kinetics through time-resolved dynamic light scattering (DLS) and monitoring suspended HA-TiO concentrations via optical absorbance changes over time. The particles exhibited aggregation behavior consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The results showed that Cd(II) concentration, pH, and ionic strength had various effects on the aggregation kinetics of the HA-TiO NPs. The HA-TiO particles aggregated faster as the Cd(II) concentration increased whereas the stability of the nanoparticles increased as the solution pH increased or ionic strength decreased regardless of the Cd(II) concentration. At the fixed pH and ionic strength conditions, the addition of Cd(II) promoted aggregation of nanoparticles, leading to higher attachment efficiencies. The enhanced aggregation of the HA-TiO NPs in the presence of coexisting cadmium ions in aqueous solutions indicated that the fate and transport of nanoparticles could be greatly affected by heavy metals in aquatic environments. [ABSTRACT FROM AUTHOR]

Removal of antimony, classified as a pollutant of priority importance, is a challenge due to its presence in various forms in solution and the low concentration in which it is to be removed. In this study, sorption profile and the sorption mechanisms associated with the removal of antimony in its two oxidation states (+3 and +5) have been investigated in detail through batch studies involving titania sorbents, strong base anion resin, a chelating resin, and a biosorbent. Significant sorption-associated change in solution pH was observed with all the sorbents, which revealed the nature of respective sorption equilibrium involved. The results have shown that Sb(V) is removed only as anionic species, while Sb(III) is removed either as an anionic species or as cationic species according to the functional groups present in the sorbent and the solution conditions. Titania-based sorbents were found to be effective sorbents for Sb(III) and Sb(V) within a narrow pH range, while anion resin was found to be superior for removing Sb(V) as Sb(OH) under a wide range of solution conditions. The suitability of the sorbents for column mode of operation has also been investigated. This report is a first attempt at a rational comparison of promising sorbents for antimony, and the results demonstrate the complexity involved in antimony sorption and give an understanding of the available options for handling the antimony removal problem in large-scale applications. [ABSTRACT FROM AUTHOR]

To develop high performance mixed matrix gel polymer electrolyte, the synergistic effect of blending PVDF (PEO/PVDF weigh ratio of 85:15) and adding nano-TiO (0.5-2 wt.%) to traditional monomer poly (ethylene oxide) was investigated. Thermogravimetric analysis indicated that poly (ethylene oxide)/poly (vinylidene fluoride) blend had an excellent thermal performance. X-ray diffraction analysis revealed that poly (ethylene oxide)/poly (vinylidene fluoride) blend leads to lower crystallinity and the amorphicity of corresponding gel polymer electrolyte increases with increasing nano-TiO concentration. The maximum ionic conductivity (2.12 × 10 and 6.37 × 10 S/cm) of poly (ethylene oxide)/-(TiO) and poly (ethylene oxide)/poly (vinylidene fluoride)/-(TiO) gel polymer electrolyte at room temperature (25 °C) were obtained, respectively. The prepared poly (ethylene oxide)/poly (vinylidene fluoride)-TiO gel polymer electrolyte demonstrated about 2.6 and 1.8-fold increment in the fracture strength as compared to that of poly (ethylene oxide) gel polymer electrolyte and poly (ethylene oxide)-TiO gel polymer electrolyte. The average transmittance of poly (ethylene oxide)/poly (vinylidene fluoride)-TiO gel polymer electrolyte was about 90 % in the visible region. With good electrical, mechanical and optical performance, it is very suitable for being applied in electrochromic glass. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Cell surface of aquatic organisms constitutes a primary site for the interaction and a barrier for the nano-TiO biological effects. In the present study, the biological effects of nano-TiO on a unicellular green algae Chlamydomonas reinhardtii were studied by observing the changes of the cell surface morphology and functional groups under UV or natural light. By SEM, the cell surface morphology of C. reinhardtii was changed under UV light, nano-TiO with UV light or natural light, which indicated that photocatalysis damaged cell surface. It was also observed that cell surface was surrounded by TiO nanoparticles. The ATR-FTIR spectra showed that the peaks of functional groups such as C-N, -C=O, -C-O-C and P=O, which were the important components of cell wall and membrane, were all depressed by the photocatalysis of nano-TiO under UV light or natural light. The photocatalysis of nano-TiO promoted peroxidation of functional groups on the surface of C. reinhardtii cells, which led to the damages of cell wall and membrane. [ABSTRACT FROM AUTHOR]

Nano-TiO (nTiO) is widely used in industry, and some of it is inevitably released into natural aquatic environments. nTiO can be deposited on the streambed or transported along the stream and streambed, and it can also undergo exchange-transfer processes in these systems. The behavior of nTiO in rivers includes deposition-transfer processes in the stream and exchange-transfer processes between the stream and streambed. In this work, the deposition, mass transfer, exchange, and aggregation behavior of nTiO in a simulated river were studied as a function of the solution pH, stream velocity, and anionic, cationic, and neutral surfactant concentrations. In these experiments, a recirculating flume was used to simulate a natural stream. The nTiO deposition and aggregation phenomena in the river and streambed were characterized. Of the three surfactants studied, the anionic surfactant enhanced the nTiO stability in the river and limited its aggregation most effectively, resulting in slow nTiO deposition and nTiO transport over long distances. This study provides information about nanoparticle transport phenomena in simulated natural aquatic systems. [ABSTRACT FROM AUTHOR]

Nanometer-sized titanium dioxide (TiO) is an environmentally friendly optical semiconductor material. It has wide application value in many fields due to its excellent structural, optical, and chemical properties. The photocatalytic process of nano-TiO converts light energy into electrical or chemical energy under mild conditions. In recent years, the study and application of nano-TiO in the agricultural sector has gradually attracted attention. The nano-TiO applications of degrading pesticides, plant germination and growth, crop disease control, water purification, pesticide residue detection, etc. are good prospects. This review describes all of these applications and the research status and development, including the underlying principles, features, comprehensive applications, functional modification, and potential future directions, for TiO in agriculture. [ABSTRACT FROM AUTHOR]

Ultrasonic treatment and hydrothermal method were applied in the traditional homogeneous precipitation for nano-TiO preparation, which was used as carrier material for the production of honeycomb selective catalytic reduction (SCR) catalyst. The influence rules of the two improved methods on characterization of TiO samples, denitration activity and mechanical strength of honeycomb SCR catalyst samples were mainly focused on. The results indicate that the specific surface area, particle size and uniformity of TiO samples are significantly improved by both of the ultrasonic and hydrothermal treatments compared with the traditional homogeneous precipitation. Also, the denitration activities of catalyst samples are enhanced by the two improved methods (the NO reduction ratio increases from 88.89% to 95.45% by ultrasonic homogeneous precipitation process, and to 94.12% by hydrothermal homogeneous precipitation process). On the other hand, because of good spherical shape and high particle distribution of TiO sample from hydrothermal homogeneous precipitation process, the corresponding honeycomb catalyst samples get the best mechanical strength, which is even higher than that of the reference sample from commercial nano-TiO. So, it is concluded that the hydrothermal homogeneous precipitation can be a feasible and effective preparation method of TiO carrier for the honeycomb SCR catalyst production. [ABSTRACT FROM AUTHOR]

Vanadium oxide-based catalysts were developed for the destruction of vapour phase PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans). A vapour phase PCDD/Fs generating system was designed to supply stable PCDD/Fs steam with initial concentration of 3.2 ng I-TEQ Nm. Two kinds of titania (nano-TiO and conventional TiO) and alumina were used as catalyst supports. For vanadium-based catalysts supported on nano-TiO, catalyst activity is enhanced with operating temperature increasing from 160 to 300 °C and then reduces with temperature rising further to 350 °C. It is mainly due to the fact that high volatility of organic compounds at 350 °C suppresses adsorption of PCDD/Fs on catalysts surface and then further inhibits the reaction between catalyst and PCDD/Fs. The optimum loading of vanadium on nano-TiO support is 5 wt.% where vanadium oxide presents highly dispersed amorphous state according to the Raman spectra and XRD patterns. Excessive vanadium will block the pore space and form microcrystalline VO on the support surface. At the vanadium loading of 5 wt.%, nano-TiO-supported catalyst performs best on PCDD/Fs destruction compared to AlO and conventional TiO. Chemical states of vanadium in the fresh, used and reoxidized VOx(5 %)/TiO catalysts at different operating temperature are also analysed by XPS. [ABSTRACT FROM AUTHOR]

Nano-TiO is an engineered nanomaterial whose production and use are increasing rapidly. Hence, aquatic habitats are at risk for nano-TiO contamination due to potential inputs from urban and suburban runoff and domestic wastewater. Nano-TiO has been shown to be toxic to a wide range of aquatic organisms, but little is known about the effects of nano-TiO on benthic microbial communities. This study used artificial stream mesocosms to assess the effects of a single addition of nano-TiO (P25 at a final concentration of 1 mg l) on the abundance, activity, and community composition of sediment-associated bacterial communities. The addition of nano-TiO resulted in a rapid (within 1 day) decrease in bacterial abundance in artificial stream sediments, but bacterial abundance returned to control levels within 3 weeks. Pyrosequencing of partial 16S rRNA genes did not indicate any significant changes in the relative abundance of any bacterial taxa with nano-TiO treatment, indicating that nano-TiO was toxic to a broad range of bacterial taxa and that recovery of the bacterial communities was not driven by changes in community composition. Addition of nano-TiO also resulted in short-term increases in respiration rates and denitrification enzyme activity, with both returning to control levels within 3 weeks. The results of this study demonstrate that single-pulse additions of nano-TiO to aquatic habitats have the potential to significantly affect the abundance and activity of benthic microbial communities and suggest that interactions of TiO nanoparticles with environmental matrices may limit the duration of their toxicity. [ABSTRACT FROM AUTHOR]

A new and economical synthesis of α, α′-bis(substituted-benzylidene)cycloalkanones has been achieved by the reaction of cycloalkanones with different aromatic aldehydes using nano-TiO/acetic acid as a catalyst in ethanol under reflux conditions with excellent yields. Five new products and three new single crystal structures are reported. [ABSTRACT FROM AUTHOR]

A new surface molecularly imprinted polymer (MIP) based on nano-TiO was developed using propazine (Pro) as a template molecule, ethyleneglycol dimethacrylate (EGDMA) as a crosslinker, methacrylic acid (MAA) as a functional monomer, and 2,2′-azobis (isobutyronitrile) (AIBN) as an initiator. Structures of the newly synthesized surface MIPs were characterized by Fourier transmission infrared spectrometry (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The MIP had a good adsorption capacity and high recognition selectivity to propazine. Meanwhile, it exhibited a cross-selectivity for simazine (Sim) and atrazine (Atr). The MIPs were used as a solid phase extraction (SPE) material. Concomitant extraction, purification, and determination of three pesticides (Pro, Sim, and Atr) residues in water, soil, and maize plant and grain samples were performed by MIP-SPE coupled with high performance liquid chromatography (HPLC). The highly selective separation and enrichment of Pro, Atr, and Sim from the complex environmental media can be achieved. Thus, the newly developed technique provides an analytical platform to quantify the trace amount of Pro, Sim, and Atr residues in multi environmental media and food source. [ABSTRACT FROM AUTHOR]

The effects of additives of nano-TiO, PEO-PPO-PEO/nano-TiO, oxalic acid/nano-TiO, and oxalic acid/PEO-PPO-PEO/nano-TiO on PPESK membrane performances and gelation kinetics mechanism were investigated in detail. When the single nano-TiO concentration increased from 0.2 to 1.0 wt%, the water flux and the rejection changed slightly at first and then reduced, and the gelation rate was the fastest for 0.6 wt% nano-TiO. With the PEO-PPO-PEO concentration increasing from 1.0 to 5.0 wt% which contained 0.6 wt% nano-TiO in the casting solution, the water flux floated between 368 and 530 L/m h at first and then went up significantly to 1109 L/m h, the rejection diminished remarkably, and also the gelation rate increased. With the increase in oxalic acid concentration ranging from 1.0 to 3.0 wt% (including 0.6 wt% nano-TiO in the casting solution), all the water flux, the rejection, and gelation rate changed mildly. For oxalic acid/PEO-PPO-PEO/nano-TiO blend additives, with the oxalic acid concentration increasing from 1.0 to 2.5 wt% consisting 2.0 wt% PEO-PPO-PEO and 0.6 wt% nano-TiO, the water flux and the rejection remained stable; however, the gelation rate accelerated. All the PPESK membranes in this study exhibited asymmetric finger-like structures. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The results for the degradation efficiency of 4-chloronitrobenzene (4-CNB) by various advanced oxidation processes in a batch mode using nano-structured titanium dioxide demonstrated the order of O/US/TiO > US/O > O/TiO > O > US/TiO > US. The utilized TiO nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Moreover, all processes obeyed pseudo-first order kinetics. Then, the effect of the main operational conditions including pH, ozone, initial 4-CNB concentration, TiO dosage and ultrasonic power on 4-CNB degradation was studied in the coupled O/US/TiO process as the most significant treatment method with a high synergistic effect. The optimal pH and TiO dosage were selected to be 9 and 50 mg/L owing to the efficient indirect attack of hydroxyl radicals and less screening effects of TiO particles on ultrasonic waves, respectively. By increasing the amount of O concentration and ultrasonic power, the degradation of 4-CNB was enhanced due to the more production of reactive oxygen species. However, the opposite trend was observed for 4-CNB concentration because the same amounts of generated oxidizing species under the identical experimental conditions had to degrade more organic pollutants and its degradation intermediates. Eventually, the total organic carbon (TOC) was utilized to monitor the mineralization of 4-CNB in the above-mentioned processes and the same results were obtained with lower rate constants compared to degradation rate constants. [ABSTRACT FROM AUTHOR]

The recent increase in nanomaterial usage has led to concerns surrounding its health risks and environmental impact. The food chain is an important pathway for high-trophic-level organisms absorbing and enriching nanomaterials. Our study therefore simulated nanometer titanium dioxide (nano-TiO) transfer along a 2-step food chain, from the unicellular alga Scenedesmus obliquus to the water flea Daphnia magna. We also explored the effect of sodium dodecyl benzene sulfonate (SDBS) on nano-TiO bioavailability. A suspension of 10 mg/L nano-TiO was optimally dispersed in aqueous solutions by 5 mg/L SDBS. After 72 h, S. obliquus growth was not significantly affected by 10 mg/L nano-TiO, 5 mg/L SDBS and their mixed suspension. SDBS not only improved nano-TiO stability in water, but also increased its uptake in S. obliquus and enhanced its accumulation in D. magna. Our study suggests that nano-TiO is mildly toxic to S. obliquus, and can be transferred along the aquatic food chain with a biomagnification effect. [ABSTRACT FROM AUTHOR]

The influences of nano-TiO on the setting time, hydration process, hydration productsand morphology of sulphoaluminate cement were studied by Vicat apparatus, isothermal calorimetry, X-raydiffraction (XRD), thermal analysis and scanning electron microscopy (SEM). The experimental results showthat the incorporation of nano-TiO can obviously promote the setting and hardening process of sulphoaluminatecement, and shorten the interval between the initial and final setting time, the hydration induction period ofsulphoaluminate cement is significantly shortened and the acceleration period begins immediately, but thehydration exothermic rate at hydration stationary phase is not obviously impacted. The nano-TiO additives haveinfluence on the formation rate and degree of crystallinity, but do not affect the type of hydration process. Thestructure of hydration products is compact at middle age, but their content and microstructure do not change. [ABSTRACT FROM AUTHOR]

Nano-sized titanium dioxide (nano-TiO) has wide industrial applications and therefore considerable chances of exposure are created for human beings and ecosystems. To better understand the interactions between nano-TiO and aquatic organisms, we first studied TiO uptake by algae exemplified by Pseudokirchneriella subcapitata. P. subcapitata were exposed to nano-TiO in a series of concentrations and at various pH. TiO uptake was quantified using a sedimentation curve analysis technique. After exposure of algae to TiO, the variation of zeta potential was measured and the morphology of algae-TiO aggregate was observed with scanning electron microscopy and the optical microscopy. The steady-state TiO uptake was found to be pH-dependent and the isotherms can be described well by Freundlich model. TiO deposited on algal surfaces causes the shift of pH of TiO-covered algae from that of algae toward that of TiO. The attraction between TiO-covered algal cells induces the agglomeration of algae and TiO and thus the formation of algae-TiO aggregates in the size of 12 to 50 μm. The 2-D fractal dimension of the aggregates is pH-dependent and ranges from 1.31 to 1.67. The theoretical analysis of the Gibbs energy of interaction indicates that both TiO uptake by algae and the formation of algae-TiO aggregate are influenced by the interaction between TiO particles. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In the present study, the biological effect of TiO nanoparticles on cyanobacteria cells was studied using Microcystis aeruginosa ( M. aeruginosa) as a model. Nano-TiO as a photo-catalysts agent used for water treatment may pose a risk to ecosystems, especially for the water organisms such as cyanobacteria. Scanning electron microscope (SEM) images provided that with the increasing of photocatalytic time, slime layer on the cell surface was damaged and sunk. Attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy revealed that the vibration peaks of C-C, C-H, C=O, P=O weakened within 12 h. According to the dynamic analysis of the infrared peaks, the damage on the cell groups under nano-TiO photocatalysis with different time periods was analyzed. The concentrations of K, Ca, Mg released from the cells were measured, which indicated that nano-TiO photocatalysis have changed the cell membrane permeability and fluidity of M. aeruginosa. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanoparticles (nano-TiO) show low toxic potential against a variety of environmental organisms when measured by conventional toxicity endpoints. However, the question is whether the conventional measures of toxicity can define the adverse effects of nanoparticles. The aim of this study was to asses the potential toxic and cytotoxic effects of the ingested nano-TiO (anatase, <25 nm) on a terrestrial isopod, Porcellio scaber. In addition to conventional toxicity parameters, the physiological condition of the animals was assessed. Following 28-day feeding exposure to nano-TiO at concentrations up to 5,000 μg nano-TiO/g leaf dry weight, no toxic or cytotoxic effects were demonstrated. However, the physiological condition of the animals was affected in a dose-dependent manner. The physiological state of organisms is an important parameter to assess the potential population implications due to the exposure to nanomaterials. Therefore, we suggest that only if both, the physiological state of the animals exposed to nano-TiO and the conventional toxicity markers show no effects, the exposure dose can be interpreted as non-hazardous. [ABSTRACT FROM AUTHOR]

Pure nickel and nickel matrix composite coatings containing nano-TiO particles were produced under both direct and pulse current conditions from an additive-free nickel Watts' type bath. The surface morphology, crystal size, crystallographic orientation, and microhardness of nickel matrix and the amount of embedded nano-TiO particles in the composite coatings were investigated. The corrosion performance of the coatings was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy methods. The TiO particles embedded in the nickel matrix exerted strong influence on the texture of the growing nickel layer, changing its texture under both direct and pulse current conditions. The textural perfection of the deposits revealed that the presence of TiO particles led to the deteriorating of [100] preferred orientation. Under direct current conditions, the composite coating exhibited clearly [211] fiber orientation, while pulse current working exhibited a mixed crystal orientation through [100] and [211] axes. It is concluded that in the presence of TiO nanoparticles, the adsorption-desorption phenomena occurring on the metal surface are altered. The experimental results show that composite electrodeposits prepared under pulse plating conditions exhibited higher incorporation percentages than those obtained under direct plating conditions, at particularly 10 Hz and low duty cycles. The results revealed that pulse-plated Ni/TiO nanocomposite coating provided excellent anti-corrosion performance and presented higher microhardness. [ABSTRACT FROM AUTHOR]

Titania nanoparticles (nano-TiO) core and fluoropolymer shell TiO/fluorocopolymer composites were successfully prepared by emulsion polymerization. Before synthesis, nano-TiO was modified by coupling agent 3-(trimethoxysilyl) propyl methacrylate (MPS) in advance. The chemical groups and composition of the nanocomposite were characterized by Fourier transform infrared (FTIR) and H NMR, respectively. In addition, transmission electron microscopy (TEM) was used to confirm the core-shell structure. Finally, the influence of TiO content on the properties of the nanocomposite was investigated using thermogravimetric analysis (TGA), contact angle goniometer, and atomic force microscopy (AFM). The results showed that compared with the properties of pure polymer, the addition of nano-TiO can improved the thermostability and led to the higher hydrophilic properties. [ABSTRACT FROM AUTHOR]

This study investigated ageing-resistant properties of carboxyl-terminated polyester (polyethylene glycol terephthalate) composites modified with nanoscale titanium dioxide particles (nano-TiO). The nano-TiO was pretreated by a dry coating method, with aluminate coupling agent as a functional grafting additive. The agglomeration resistance was evaluated, which exhibited significant improvement for the modified nanoparticles. Then, the effects of the modified nano-TiO on the crosslinking and ageing-resistant properties of the composites were studied. With a real-time Fourier transform infrared (FT-IR) measurement, the nano-TiO displayed promoting effect on the crosslinking of polyester resin with triglycidyl isocyanurate (TGIC) as crosslinking agent. Moreover, the gloss retention, colour aberration and the surface morphologies of the composites during accelerated UV ageing (1500 hours) were investigated. The results demonstrated much less degree of ageing degradation for the nanocomposites, indicating an important role of the nano-TiO in improving the ageing-resistant properties of synthetic polymer composites. [ABSTRACT FROM AUTHOR]

The sintered NdFeB permanent magnets are widely used in various industries because of their excellent magnetic and comprehensive properties. However, they are seriously hindered to further developments and applications owing to its poor corrosion resistance. In this paper, TiO/acrylic resin composite coatings were successfully prepared on the sintered NdFeB permanent magnets by electrochemical deposition for the first time, and the corrosion behaviors were investigated by using immersion testing and potentiodynamic polarization tests. It is found that the coating is a composite, being composed of polymerized acrylic resin as the matrix and nano-rutile TiO particles (−200 nm) as the reinforcements. It is about 25 μm in thickness and its surface and cross-section exhibit uniform and smooth with no pores, cracks, and other defects. Compared with those of the uncoated NdFeB magnets, the weight loss of the coated samples immersed in HSO solution reduces by two orders of magnitude, corrosion current density decreases by four orders of magnitude, and the corrosion potential of the coated sample is shifted in the noble direction by 400 mV. The mechanisms of corrosive resistance enhancement were discussed. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the relative impact of humic and non-humic natural organic matter (NOM) on the aggregation behaviors of engineered TiO nanoparticles (nano-TiO). After exposure of nano-TiO to varying concentrations of Suwannee River fulvic acid (SRFA) and Bacillus subtilis exudate in high and low ionic strength (IS) solutions at pH 3 to pH 7.5, aggregation behaviors were evaluated via dynamic light scattering (DLS) measurements and sedimentation studies. Although pH, IS, and NOM concentration exerted strong controls on nano-TiO aggregation behaviors, suspensions exposed to either SRFA or bacterial exudate at normalized dissolved organic carbon (DOC) concentrations exhibited remarkably similar behaviors. In high IS systems, nano-TiO exposed to either SRFA or bacterial exudate sedimented rapidly, except in the presence of high NOM concentrations at pH 6 and 7.5. Low IS treatments exhibited a larger range of effects. In fact, relative to NOM-free controls, nano-TiO aggregates in SRFA and bacterial exudate exposures sedimented up to 14 times faster at pH 3 and up to 13 times slower at pH 7.5. Adsorption of organic molecules onto nano-TiO can enhance aggregation via colloidal bridging and/or charge neutralization, or with more complete surface coverage, can diminish aggregation via electrostatic repulsion and/or steric hindrance. Collectively, these data suggest that solution pH, IS, and NOM concentration, and to a lesser extent NOM origin, can control the fate and mobility of nano-TiO in geologic systems. [ABSTRACT FROM AUTHOR]

A biocompatible block glycopolymer poly(methyl methacrylate)-b-poly(3- O-allyl-α-D-glucose) (PMAG) was employed as a polymeric dispersant for the dispersion of nano-TiO. PMAG was prepared from methyl methacrylate (MMA) and 3-O-allyl-1,2:5,6-di-O-isopropynylene-α-D-glucose (ADG) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The obtained product was characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (H NMR) spectroscopy, and gel permeation chromatography (GPC). The copolymer showed good biocompatiblity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The maximum adsorption capacity for PMAG on nano-TiO is 4.11 mg/g, which is in good agreement with Langmuir isotherm. Transmission electron microscopy (TEM) image indicated that nano-TiO is well dispersed by PMAG. Raman and FT-IR spectra demonstrated that PMAG is absorbed onto the surface of nano-TiO. [ABSTRACT FROM AUTHOR]

Reaction of vinyl acetate with tricyclo[5.2.1.1.0]deca-3,8-diene in the presence of nano-TiO (20 nm) catalyst was studied. 8-Acetoxytetracyclo[4.4.1.1.0]dodec-3-ene was obtained in 88.5% yield. Addition of saturated monobasic acids C-C to the obtained unsaturated monoester in the presence of the boron trifluoride etherate catalyst was investigated. Corresponding diesters were obtained in 68.1-93.0% yield. They can be used as the additives to synthetic oils and as components of perfumes. [ABSTRACT FROM AUTHOR]

Hyperbranched star polymer HBPS-(PPEGMA) was synthesized by atom transfer radical polymerization (ATRP) using hyperbranched polystyrene (HBPS) as macroinitiator and poly(ethylene glycol) methyl ether methacrylate (PEGMA) as monomer. The structure of the prepared hyperbranched star polymer was characterized by H NMR, ATR-FTIR, and GPC. Polymer electrolytes based on HBPS-(PPEGMA), lithium salt, and/or nano-TiO were prepared. The influences of lithium salt concentration and type, nano-TiO content, and size on ionic conductivity of the obtained polymer electrolytes were investigated. The results showed that the low crystallinity of the prepared polymer electrolyte was caused by the interaction between lithium salt and polymer. The addition of TiO into HBPS-(PPEGMA)/LiTFSI improved the ionic conductivity at low temperature. The prepared composite polymer electrolyte showed the highest ionic conductivity of 9 × 10 S cm at 30 °C when the content of TiO was 15 wt% and the size of TiO was 20 nm. [ABSTRACT FROM AUTHOR]

Preyssler-type heteropolyacid supported on TiO nanoparticles has been explored as an efficient catalyst in selective oxidation of primary aromatic amines to azoxy derivatives using trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as oxidant. The reactions proceeded smoothly under mild and green ultrasound-accelerated conditions to afford the products in high yields. The catalyst recovered from the reaction mixture exhibits long-term stability with no significant drop in its catalytic activity. Graphical abstract: [Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]

Producing fabric with multifunctional properties has been recently a center of research and utilizing nanoparticles is an efficient approach to gain this purpose. Here, nano TiO photo catalyst and polysiloxane softener were utilized as stabilizer on the acrylic fabric to obtain soft handle, hydrophilic, and self-cleaning features on the fabric. The effect of various concentrations of nano TiO and polysiloxane on the fabric handle, water droplet absorption time, and self-cleaning properties of the fabric has been mathematically modeled based on the response surface methodology (RSM). The optimized treatment conditions indicated that treated acrylic fabric with 2.19 % polysiloxane and 0.68 % nano TiO produced the rigidity of 26.8 g.cm, water absorption time of 15.8 s and self-cleaning of Δ E *=18.1. Also increasing the concentration of polysiloxane enhanced both wettability and photoactive properties of nano TiO treated acrylic fabrics. Further, the nano TiO/polysiloxane treated acrylic fabrics is significantly enable to absorb the light with wavelength lower than 400 nm and improve discoloration of C.I. Reactive Yellow 1. [ABSTRACT FROM AUTHOR]

We have developed a method for the determination of trace levels of total selenium in water samples. It integrates preconcentration, in-situ photoreduction and slurry photochemical vapor generation using TiO nanoparticles, and the determination of total selenium by AFS. The Se(IV) and Se(VI) species were adsorbed on a slurry of TiO nanoparticles which then were exposed to UV irradiation in the presence of formic acid to form volatile selenium species. The detection limits were improved 17-fold compared to hydride generation and 56-fold compared to photochemical vapor generation, both without any preconcentration. No significant difference was found in the limits of detection (LODs) for Se(IV) and Se(VI). The LOD is as low as 0.8 ng L, the precision is better than 4.5 % (at a level of 0.1 μg L of selenium). The method gave good recoveries when applied to the determination of total selenium in a certified tissue reference material (DORM-3) and in spiked drinking water and wastewater samples containing high concentrations of transition and noble metal ions. It also excels by very low LODs, a significant enhancement of sample throughput, reduced reagent consumption and sample loss, and minimal interference by transition and noble metal ions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Nano priming is a new method for the increase of seedling vigor and improvement of germination percentage and seedling growth. The experiments to evaluate the effect of different concentrations of nano-anatase on germination parameters of parsley as a completely randomized design with five replications were performed in a tissue culture laboratory of the Department of Horticulture, Shahid Chamran University of Ahvaz. In addition, nano-anatase at four concentrations (10, 20, 30, and 40 mg/ml) was added to the Murashige and Skoog medium. At the end of the experiment, the percentage of germination, germination rate index, root and shoot length, fresh weight of seedlings, vigor index, and chlorophyll content were evaluated. The results showed that an increase in the concentration of nano-anatase caused a significant increase in the percentage of germination, germination rate index, root and shoot length, fresh weight, vigor index, and chlorophyll content of seedlings. The best concentration of nano-anatase was 30 mg/ml. [ABSTRACT FROM AUTHOR]

An efficient procedure has been developed for one-pot synthesis of N-acyle-2-aryl-1,2-dihydro-(4 H)-3,1-benzoxazin-4-ones in the presence of Preyssler-type heteropolyacid acid modified nano-sized TiO as catalyst. The reactions proceed smoothly at 25 °C to afford the products in high yields. The catalyst is easily separated and re-used for the next successive reactions without significant loss of its activity. Graphical Abstract: An efficient procedure has been developed for one-pot synthesis of N-acyle-2-aryl-1,2-dihydro-(4 H)-3,1-benzoxazin-4-ones in the presence of Preyssler-type heteropolyacid acid modified nano-sized TiO as catalyst. The reactions proceed smoothly at 25 °C to afford the products in high yields. The catalyst is easily separated and re-used for the next successive reactions without significant loss of its activity.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The outstanding advantages of N-halamine materials over other antimicrobial materials are their durable and rechargeable antimicrobial properties, as well as their efficacies in inactivating a broad spectrum of pathogens. Theoretically, the oxidative chlorine of antimicrobial cotton coated with N-halamine hydantoin diol can be restored upon loss of its biocidal efficacy after exposure to ultraviolet light. In this work nano-titania particles were added into the coating solutions containing N-halamine diol and 1,2,3,4-butanetetracarboxylic acid (BTCA), and the coatings were applied to produce antimicrobial cellulose with improved UV stability. The treated cotton fabrics were characterized by FT-IR, SEM, XRD, and XPS. The effects of the coatings on tensile strength and wrinkle recovery angle were investigated. Biocidal efficacies of fabrics coated with hydantoin diol and diol/TiO against Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895) were determined using a modified AATCC 100-1999 method and showed excellent antimicrobial properties against these two bacterial species within a brief contact times. It was found that the addition of Nano-TiO in the antimicrobial coatings, especially rutile titanium dioxide, could improve the UV light stability of the chlorinated fabrics coated with hydantoin diol significantly. The UV light stability of N-halamine coatings were enhanced with increasing amounts of rutile TiO. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF)/titanium dioxide (TiO) hybrid membranes were prepared using nano-TiO as the modifier, and characterized by Transmission Electron Microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization results demonstrated that nano-sized TiO particles dispersed homogeneously within the PVDF matrix, contributing to more hydroxyls and smoother surfaces. Moreover, permeate flux, retention factor, porosity, contact angle and anti-fouling tests were carried out to evaluate the effect of TiO concentration on the performance of PVDF membranes. Among all the prepared membranes, PVDF/TiO membrane containing 10 vol.% TiO exhibited the best hydrophilicity with an average pure water flux up to 237 L·m·h, higher than that of unmodified PVDF membranes (155 L·m·h). Besides, the bovine serum albumin rejection of the hybrid membrane was improved evidently from 52.3% to 70.6%, and the contact angle was significantly lowered from 83° to 60°, while the average pore size and its distribution became smaller and narrower. [ABSTRACT FROM AUTHOR]

A nano-titanium dioxide (nano-TiO) powder, with Zr (0.5-1 %) and Nb (0.5-1 %) impurities, is fabricated using a modified hydrothermal method, with low-grade mineral precursors. Samples were then sintered at 600, 800, and 1,000 °C, then analysed using XRD (crystallite size and phase conversion temperature) scanning electron microscope (SEM) (morphology), N adsorption-desorption isotherms (surface area), and UV-vis-NIR (absorbance and optical transmission) to study the effects of sintering on the structural and optical properties of the synthesized nanopowders. It was discovered that sintering to 1,000 °C reduces the surface area by 99 %, and increases the crystallite size by almost 2,000 %. Meanwhile, the phase conversion temperature of this sample is 33.3 % higher than that reported in the literature for 600 °C. SEM shows an extensive agglomeration and uneven distribution of nano-TiO particles before sintering. However, the sintered sample shows uniformity in particle size and distribution, and even though it is reduced significantly, agglomeration is still present. The absorbance of the samples is red-shifted towards the visible region (i.e., 380-700 nm), with the optical band-gap reduced by 10 %, when sintered to 1,000 °C. The optical transmission of nano-TiO is also reduced by 10 % when sintered to 1,000 °C, due to changes in its microstructure. It is therefore concluded that sintering nano-TiO improves its structural and optical properties, and paves the way for a multitude of novel applications. [ABSTRACT FROM AUTHOR]

Silk mask paper with different adsorbability was prepared by changing the beating degree of silk pulp and the basis weight of silk paper, and photocatalytic silk mask paper was prepared by loading nanometer titanium dioxide (nano-TiO) on the silk mask paper, then degradation of formaldehyde by silk mask paper loading nano-TiO under daylight lamps and ultraviolet lamps were investigated, respectively. Results showed that silk mask paper could adsorb formaldehyde and had higher adsorption efficiency in the initial stage, and the adsorption/desorption equilibrium could be basically achieved in 60 minutes. The adsorption capacity of silk mask paper made from silk pulp with beating degree of 45 SR was relatively low, and it increased with the increase of beating degree, but there was little change in adsorption when the beating degree of silk pulp exceeded 65 SR. Under daylight lamps, 26.61 %, 31.42 % and 38.21 % of formaldehyde could be degraded in 180 minutes by silk mask paper loading 1 wt%, 3 wt% and 5 wt% nano-TiO, respectively. However, under ultraviolet (UV) lamps, 46.23 %, 55.47 % and 66.38 % of formaldehyde could be degraded within the same time, respectively. More formaldehyde could be degraded by photocatalytic silk mask paper under UV lamps than under daylight lamps, and the more the load of nano-TiO on the silk mask paper, the higher the degradation rate of formaldehyde within the same time. [ABSTRACT FROM AUTHOR]

In order to obtain paper respirator with dust resistance performance and antibacterial property, silk photo-catalytic respirator paper was made by loading nano-TiO photo-catalyst on silk based respirator paper. The pore structure, surface topography and TiO distribution, and the filtration performance of silk respirator paper were studied by using a pore size meter (PSM), a field emission scanning electron microscope (FESEM), and a filter tester, respectively. In addition, the antibacterial property of silk respirator paper was also investigated. The results showed that the pore structure and filtration performance of silk respirator paper could be controlled by changing the degree of beating of silk pulp and the basis weight of silk paper. Silk respirator paper of 45 g/m made from silk pulp having beating degree of 85 SR had high filtration efficiency and appropriate filtration resistance. Nano-TiO particles were mainly attached to the surface of silk paper, and the loading of nano-TiO photo-catalyst resulted in a slight decrease in filtration resistance and filtration efficiency of silk respirator paper. It, however, improved the antibacterial property of silk respirator paper effectively. [ABSTRACT FROM AUTHOR]

As the production and usage of nanomaterials increase, there are growing concerns on the unidentified detrimental effect of nanoparticles on human health and environmental safety. Systematic assessments of the risks associated with exposure to nanoparticles are needed. DNA microarrays have emerged as a powerful tool for toxicology research. Microarraybased toxicogenomics research provides valuable information for understanding underling mechanisms of toxicological behavior of non-classic contaminants, including ultrafine nanoparticles. In this work, we investigated the effect of nano-titanium oxide exposure on human cells by analyzing the change in transcription levels of cellular DNA. Cross-experimental analysis of heterogeneous gene expression datasets was performed using the RankProd algorithm. Multiple gene expression omnibus series obtained from various experimental conditions were combined and used for risk assessment. Several commonly regulated genes were identified as being unaffected by the laboratory specific conditions. Pathway analysis revealed the genes as being associated with six major pathways: arachidonic acid metabolism, purine metabolism, pentose phosphate pathway, mitogen-activated protein kinase signaling pathway, synthesis and degradation of ketone bodies, and methionine metabolism. The identified differently expressed genes provide a robust set of markers for exposure analysis and risk assessment of titanium oxide nanoparticles. [ABSTRACT FROM AUTHOR]

The aim of the present study is to explore the mechanism of cytotoxic and genotoxic effects of TiO nanoparticles on human embryonic kidney (HEK-293) cells. Toxicity was evaluated using changes in various cellular parameters of HEK-293 cells like morphology, viability, metabolic activity, oxidative stress and apoptosis. Oxidative stress was measured by the level of reactive oxygen species (ROS), lipid peroxidation, superoxide dismutase, catalase and glutathione peroxidase. Apoptosis induced by nano-TiO was characterized by PI staining and DNA ladder assay. Furthermore, apoptotic proteins such as p53 and Bax were analysed by western blot. Our results indicate that nano-TiO induces cytotoxicity in a time- and dose-dependent manner. Oxidative stress and apoptosis were induced by exposure to nano-TiO. Moreover, the expression of p53, Bax and caspase-3 were increased in a dose-dependent pattern. In conclusion, ROS-mediated oxidative stress, the activation of p53, Bax, caspase-3 and oxidative DNA damage are involved in the mechanistic pathways of nano-TiO-induced apoptosis in HEK-293 cells. [ABSTRACT FROM AUTHOR]

In this work, the interaction between nano-TiO and trypsin was investigated, and the mechanisms of the interaction were explored by the methods of UV-vis detection, circular dichroism (CD), and fluorescence. The results clearly demonstrated that nano-TiO had an inhibitory effect on the enzyme activity. The activity was decreased to 64% of the untreated trypsin in the presence of 300 μg/ml nano-TiO. UV spectrometry proved that nano-TiO had a strong physical absorption effect on trypsin, and the CD spectra revealed that the secondary structure of trypsin was partly destroyed while bound together with nano-TiO. The ratio of α-helix increased from 7.9% to 12.8% in the presence of 100 μg/ml TiO while the ratio of β-sheet decreased from 48.7% to 36.4%. Furthermore, the fluorescence spectrometry indicated that nano-TiO could quench the intrinsic fluorescence of trypsin through static quenching. Meanwhile, the binding constant was calculated to be 1, and the process of binding of trypsin on nano-TiO was a spontaneous molecular interaction procedure in which electrostatic interaction plays a major role. Our study was to provide a useful approach for evaluating the health risk of nanomaterials on level of proteins. [ABSTRACT FROM AUTHOR]

This study investigated the conjoined cellular oxidative damage of human embryo kidney 293T (HEK293T) cells induced by cadmium chloride (CdCl) and nanometer titanium dioxide (nano-TiO). RT-PCR technique was used to detect the expressions of Heme oxygenase-1 ( HO-1) and 8-oxoguanine DNA glycosylase ( OGG1). The activities of superoxide dismutase (SOD) and catalase enzyme (CAT) and concentrations of reactive oxygen species (ROS) and maldondialdehyde (MDA) were measured by different approaches. The results showed that CdCl and nano-TiO at a low concentration of 0.75 total toxic unit (TU) exerted an additive effects on HO-1 gene expression, CAT activities and MDA concentrations. When the total TU was increased to 1 or 1.25 TU, the interaction was synergetic. Moreover, the mixture with high proportion of CdCl produced an additive effect on the OGG1 gene expression, and the interaction was changed to be synergetic when the concentration of CdCl was lower than or equal to that of nano-TiO. Synergetic effects of CdCl and nano-TiO on cellular oxidative damage of HEK293T cells were found as indicated by the changes in the SOD activities and ROS concentrations. It was concluded that CdCl and nano-TiO exerts synergistic effects on the cellular oxidative damage of HEK293T cells, and the sensitivity of these indicators of oxidative damage varies with the proportion of CdCl and nano-TiO in the mixture. [ABSTRACT FROM AUTHOR]

Photodeposition of metal Ag on TiO surface is used to enhance its photoactivity under visible light. Pure nano-TiO was prepared by hydrothermal method at 120 °C and pH = 9, and tetra butyl titanate and absolute ethanol as starting materials. Different amounts of Ag deposited in TiO surface. Samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The photocatalytic activity of samples was determined by degradation of methylene blue aqueous solution. Also, photodegradation was carried out with Agmodified TiO exhibits higher photodegradation rate than pure nano-TiO under a maximum wavelength of 577 nm mercury lamp. Moreover, the samples with 0.75 wt.% Ag addition show the highest photocatalytic activity, which is 1.4 times higher than pure TiO. [ABSTRACT FROM AUTHOR]

By combining the organic-inorganic hybridization, wet phase inversion, and electrospinning, novel electrospun polyurethane (PU) membranes with in-situ generated nano-TiO were prepared, which satisfied the requirements of an ideal wound dressing. The morphology of the PU-TiO mats and the cross sectional morphologies of the membranes were characterized by a scanning electron microscopy (SEM). The average diameter of the individual fibers obtained from the solutions was 341±12 nm. SEM micrographs with higher magnification further showed that the in-situ generated TiO particles were well-separated and dispersed homogeneously in the membranes. The average sizes of TiO particles were increased from 31 to 57 nm, with the increase of nano-TiO concentration. The water vapor transmission rates (WVTRs) of the membranes were in the range of 373.55-3121.86 g/m·d and decreased gradually with the increase of nano-TiO concentration. The water absorption of various PU membranes was in the range of 210.90-397.98 % which was enough to prevent wound beds from exudate accumulation. Shake flask testing indicated that the PU membrane exhibited antibacterial efficiency against Pseudomonas aeruginosa (Ps. aeruginosa) and Staphylococcus aureus (S. aureus) due to in-situ generated of nano-TiO. These electrospun nanofibrous membranes also had no toxic effect and showed good and immediate adherence to L929 cells. [ABSTRACT FROM AUTHOR]

By incorporating organic-inorganic nano-hybridization into wet phase inversion coating-forming method, a novel antimicrobial polyurethane synthetic leather coating with in-situ generated nano-TiO (PUT) was prepared. The antibacterial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Micrococcus luteus, antifungal activity against Aspergillus niger and toxicity of this PUT coating were investigated respectively. Experimental results showed that the antimicrobial activity of the PUT coating increased with increasing nano-TiO concentration. Low nano-TiO concentration (≤0.50 wt%) resulted in negligible or limited antimicrobial activity. When the nano-TiO concentration increased up to 0.75 and 1.00 wt%, the antibacterial activity of the PUT coating exceeded 82 and 93 % respectively, and no Aspergillus niger growth was observed on the coating surface within 28 days. Cell culture assay indicated that the PUT coating had no detrimental effect on the morphologies and proliferation rate of normal human dermal fibroblasts, which indicated a non-toxic and skin-friendly characteristic. According to these results, the PUT coating was capable of reducing the risk of microbial contamination while remained skin-friendly to wearers. More importantly, the organic-inorganic nano-hybridization technique developed in this study was carried out simultaneously during the established wet phase inversion coating-forming method for PU leather manufacture, which promised its possible application on an industrial scale. [ABSTRACT FROM AUTHOR]

A new kind of porous nano TiO2 composite films was prepared on the glass substrate with the water glass as binders and the sodium fluorosilicate as solidifying reagent. The morphologies of the films were studied by scanning electron microscope(SEM). The UV Vis spectrophotometer was also used to investigate the absorption of the films. The gas phase photocatalytic oxidation of nitrogen oxides on the com posite film was carried out in TiO2 UV system, and some important factors affecting the photocatalytic oxidation were also studied such as the catalyst, concentration vapor pressure and the presence of oxygen. The results showed the conver sion of NO x reached 97.5°, after 2 h UV irradiation. The final product of photo oxidation was detected to be HNO3 by FT-IR. The way of photocatalytic oxidation of NO x was possibly useful in the practical application. [ABSTRACT FROM AUTHOR]

The nano-TiO particles were prepared by liquid hydrolysis method and characterized using XRD. Its antibacterial activity against two representative bacterial, Escherichia coli and Staphylococcus aureus, was also studied. The experimental results showed that the nano-TiO calcinated at 600-700 °C contained the obvious anatase phase and exerted excellent antibacterial activity. The feature of antibacterial activity of nano-TiO was non-strains specificity and exerted best antibacterial activity at concentration of 0.8 g/L. [ABSTRACT FROM AUTHOR]