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The increasing use of TiO2 nanomaterials (TiNMs) in bone tissue engineering raises concerns about their biocompatibility. To date, majority of biological testing was focused on the cytotoxicity of TiO2 nanoparticles and their composites. However, evaluation of immunocompatibility and effects on hemostasis is crucial for successful clinical applications of bone regeneration materials. Such data are scarce for TiNMs. To fill this gap, this study aimed to investigate impact of TiNMs with different morphologies and their composites with calcium deficient hydroxyapatite (CaDHA/TiNMs) on hemostasis, as well as the cell viability and inflammatory response of Jurkat T cells. Four different TiNMs, nanoparticles (TiNPs), nanoplates (TiNPls), nanotubes (TiNTs), nanowires (TiNWs), and their composites with CaDHA were studied. Among investigated materials, the least effect was observed for CaDHA. Effect on plasma coagulation was observed only for TiNPs, which shortened the prothrombin time. All TiNMs affected global hemostasis, especially the elongated TiNWs. Coating TiNMs with CaDHA resulted in a less pronounced effect compared to TiNMs. No significant effect on the viability of Jurkat T cells was observed for TiNMs, while composites increased it. Analysis of the expression of pro-inflammatory (IL-6, IL-8 and TNFα) and anti-inflammatory (IL-10) cytokines indicated inflammatory potential of investigated materials. Among TiNMs, TiNWs had the most pronounced pro-inflammatory effect, while CaDHA/TiNTs and CaDHA/TiNWs showed the most pronounced effect among composites. The obtained results confirm the potential of investigated materials for biomedical applications. However, further studies are needed to establish a more precise relationship between the materials' physico-chemical properties and their biological effects, thus ensuring their safe application. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO2) nanomaterials have been comprehensively studied in recent decades because of their possible practical applications in diverse fields, including photocatalysis, energy storage, sensing and biomedicine. Numerous strategies have been reported on preparing TiO2 nanostructures with regulated sizes, shapes and surface ligands; however, developing a simple, eco-friendly, cost-effective and scalable procedure for the fabrication of TiO2 nanomaterials while controlling those properties is still challenging. Herein, titanium dioxide nanostructures, e-TiO2, are prepared using a scalable green electrochemical approach, in which Ti foils act as precursors. Electrolysis is carried out in an electrolyte solution containing only a surfactant in water. This approach reduces the use of toxic chemicals, and thus it is eco-friendly and cost-effective. Moreover, the electrochemical synthesis of colloidal e-TiO2 can be successfully scaled up to 5 L. Three cationic surfactants, tetrapropylammonium bromide (TPAB), tetrabutylammonium bromide (TBAB) and cetyltrimethylammonium bromide (CTAB), are employed as electrolytes to fabricate e-TiO2, resulting in the formation of three types of nanostructures: negatively charged e-TiO2/TPAB nanospheres, negatively charged e-TiO2/TBAB nano-ellipses and positively charged e-TiO2/CTAB nanorods. They are characterized to clarify the roles of surfactants in controlling sizes, shape and surface properties of e-TiO2 nanostructures. Dispersibility of three types of e-TiO2 is investigated in aqueous and nonpolar solvents. e-TiO2/TPAB and e-TiO2/TBAB are only well-dispersed in aqueous media. In particular, e-TiO2/CTAB can be dissolved in both kinds of solvents. Thanks to the unique rotatable property of the coating agent (CTAB), a "smart" TiO2 nanomaterial (e-TiO2/CTAB nanorod) has been fabricated, which can migrate from an aqueous medium to a nonpolar one and vice versa. [ABSTRACT FROM AUTHOR]

TiO2-based nanomaterials are very effective for water and air purification and act as good antibacterial agents due to their unique physicochemical properties. TiO2 is a promising nanocatalyst because of its non-toxicity, chemical stability, and low cost. The wide band gap and rapid electron-hole recombination limit its performance which can be overcome by doping with metals and non-metal ions. Metal doping improves the trapping of electrons to inhibit electron-hole recombination and non-metal doping reduces the bandgap of TiO2. These doped TiO2 materials can be synthesized by different routes like the Sol-gel method, hydrothermal method, precipitation method, impregnation method, etc. Among these, the Sol-gel method is reported as the best and most accurate for the synthesis of TiO2 particles in the nano scale range. Because it allows the incorporation of dopant ions at the molecular level with homogeneity and high chemical purity. The structural, morphological, and optical properties of as-synthesized TiO2 nanocatalysts can be well characterized by XRD, SEM, EDX, FT-IR, UV Vis-DRS, TEM, BET, and PL. In this review article, we would like to discuss the advantage of the Sol-gel method over other preparative methods of TiO2 nanomaterials and experimental techniques related to their characterization.

Hazardous gases have been strongly associated with being a detriment to human life within the environment. The development of a reliable gas sensor with high response and selectivity is of great significance for detecting different hazardous gases. TiO2 nanomaterials are promising candidates with great potential and excellent performance in gas sensor applications, such as hydrogen, acetone, ammonia, and ethanol detection. This review begins with a detailed discussion of the different dimensional morphologies of TiO2, which affect the gas sensing performance of TiO2 sensors. The diverse morphologies of TiO2 can easily be tuned by regulating the manufacturing conditions. Meanwhile, they exhibit unique characteristics for detecting gases, including large specific surface area, superior electron transport rates, extraordinary permeability, and active reaction sites, which offer new opportunities to improve the gas sensing properties. In addition, a variety of efforts have been made to functional TiO2 nanomaterials to further enhance sensing properties, including TiO2-based composites and light-assisted gas sensors. The enhanced gas sensing mechanisms of multi-component composite nanomaterials based on TiO2 include loaded noble metals, doped elements, constructed heterojunctions, and compounded with other functional materials. Finally, several studies have been summarized to demonstrate the comparative sensing properties of TiO2-based gas sensors.

Carbon fiber reinforced polymers (CFRPs) have spread to a wide range of industries in recent decades, including the automobile, aeronautics, and space industries. Recently, the emergence of new requirements for improved properties and features has become one of the major drivers of the introduction of innovative methodologies and process optimization. In this study, the effect of nanomaterials on the behavior of carbon fiber-reinforced polymer (CFRP) composites was investigated experimentally. The grafting of TiO2 and SiC nanomaterials onto the surface of fibers was performed by mixing nanomaterials in the epoxy resin. CFRPs were manufactured using vacuum assisted resin transfer molding (VARTM) in this study and characterized using mechanical and thermal testing. The primary test parameters were carbon fiber with epoxy resin and 0% nanomaterials by weight. An increase in properties was observed in nanocomposite with 2% wt. of nanomaterials when compared with 0, 0.5, and 1% wt. Between 0 wt.% and 2 wt.%, the tensile strength, flexural strength, impact strength, hardness, and HDT properties were increased by 17%, 39%, 32%, 14% and 21%, respectively, due to the addition of nanomaterials into the resin. [ABSTRACT FROM AUTHOR]

This work has been done to study the barrier potential and charge trapping effect of two organic devices which comprises Phenosafranin and Crystal Violet dye respectively and to estimate the influence of Titanium Dioxide (TiO2) nanomaterials in particle form on these two parameters. This paper also shows the correlation between the charge trapping and barrier potential for both of these devices. Spin coating techniques are used to prepare these two devices. To estimate the barrier potential, the current-voltage characteristics of these devices have been analyzed. Barrier potential of both these devices comprising of Phenosafranin and Crystal Violet dyes shows decrease in value from 0.81 ​eV to 0.44 ​eV and 0.80 ​eV to 0.43 ​eV respectively under the influence of Titanium Dioxide nanomaterials. Norde method has been employed to check the consistency of these values of barrier potential which also shows the decrease in value for both these devices from 0.83 ​eV to 0.47 ​eV and 0.83 ​eV to 0.45 ​eV respectively due to the incorporation of nanomaterials. Presence of traps affects the barrier potential resulting in lowering of flow of charge. By using G (V) – V plot, it has been shown that the presence of Titanium Dioxide nanomaterials improve the trap-filling process which in turn reduces barrier potential at the interface of metal – organic dye for both these devices. Improvement of charge injection process occurs at the interface of metal – organic layer due to reductions of charge trapping effect and barrier potential.

The aim of this research was to examine gas sensing properties of TiO2 based nanomaterials. Nanopowders of Cr doped TiO2 with constant Specific Surface Area, SSA, were obtained using Flame Spray Synthesis technique, FSS. Nanomaterials were characterized by Brunauer – Emmett – Teller adsorption isotherms, BET, X – ray diffraction, XRD, Transmission Electron Microscopy, TEM, optical spectrometry UV – vis with the use of an integrating sphere as well as impedance spectroscopy. Detection of hydrogen was carried out over the concentration range of 50 - 3000 ppm at the temperatures extending from 200 to 400°C and synthetic air working as a reference atmosphere. As a result of experiments it appeared that incorporation of 5 at.% of Cr into TiO2 improved hydrogen sensing features due to small crystallite size and predominance of rutile polymorphic phase.

Quasi-one-dimensional (Q1D) titanium dioxide (TiO2) nanomaterials have attracted attention in photocatalytic applications because of their high oxidative potential coupled with increasing active sites. In this study, Q1D TiO2 samples with different phase structure, crystal size, and specific surface area were produced using a hydrothermal method by varying the reaction conditions (temperature, alkaline concentration, and the TiO2 precursor concentration). A three-factor three-level Box–Behnken design (BBD) with three replicates (15 conditions) at the center point was employed to evaluate and optimize the hydrothermal synthesis factors in terms of photocatalysis of rhodamine B (RhB), phenol, methyl orange, and methylene blue. The BBD demonstrated that the temperature and the NaOH concentration significantly affected the Q1D TiO2 crystal size, phase structure, bandgap, and photocatalytic activity. A reduce temperature at 120°C and a low NaOH concentration at 5 M were favorable in producing a biphasic anatase–rutile structure with optimum photocatalytic activity. Under a higher temperature of 190°C and with ≥ 10 M NaOH concentration, the presence of TiO2-B phase resulted in the lowest photocatalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • The kinetic parameters of BSA adsorption on different types of CaPs, TiNMs, and their composites (CaPs/TiNMs) were determined. • The kinetics of BSA adsorption on all studied materials was best described by pseudo-second order kinetics. • Adsorption on nanowires, calcium deficient hydroxyapatite and all composites involved intraparticle diffusion. • Stronger binding was observed for the titanium nanomaterials on which adsorption was slower. • Even small differences in materials properties can lead to significant differences in their interaction with BSA. Among key factors determining the fate of biomaterials in vivo are their interactions with blood serum proteins, which can lead to either successful integration or rejection/encapsulation. Although there are a number of studies investigating the interactions between proteins and bioimplants, comparable data for different types of biomaterials are lacking. To fill this gap, the adsorption kinetics and binding interactions of bovine serum albumin (BSA) with calcium phosphates (CaPs), namely hydroxyapatite (HA) and calcium deficient apatite (CaDHA), different TiO 2 nanomaterials (TiNMs) presenting various morphologies such as nanoparticles (TiNPs), nanoplatelets (TiNPls), nanotubes (TiNTs) and nanowires (TiNWs), as well as their composites with CaDHA (CaDHA/TiNMs) were investigated. The kinetics of BSA adsorption on all studied materials was best described by pseudo-second order kinetics. The rate coefficient values obtained for the composites were lower than those for CaDHA and the corresponding TiNMs, while the adsorption density was higher for the composites than for CaDHA, except for the composites with TiNTs. Adsorption on TiNWs, CaDHA and all composites involved intraparticle diffusion, which was the rate-limiting step only for CaDHA/TiNTs. Fluorimetric titration experiments revealed that the number of binding sites was in larger than 1, except for TiNTs and TiNWs, indicating positive binding cooperativity. Interestingly, the values of the binding constants were lower for the TiNMs with a higher adsorption rate coefficient. Overall, BSA adsorption on the studied materials proved to be a complex process, which depended on the different surface properties of the adsorbents. Which property had a dominant role depended on the chemical identity of the adsorbent. The obtained comparable data for different types of materials point to the way of modifying their protein adsorption and binding properties. [ABSTRACT FROM AUTHOR]

Abstract High-yield synthesis of TiO2 one-dimensional (1D) nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials, higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength are ~56.3 and 1.4 GPa, respectively.

The current antibacterial treatment methods of silk sutures can only be finished by surface modification, leading to problems of short antibacterial effects, easy slow-release consumption, prominent toxicity, and susceptibility to drug resistance. Speculatively, surgical sutures combining antibacterial material internally will possess a more promising efficacy. Hence, we extracted recycled regenerated silk fibroin (RRSF) from waste silk resources to make RRSF solutions. Internally combining with inorganic titanium dioxide (TiO 2 ) nanoparticles, we fabricated antibacterial RRSF-based surgical sutures. The morphologies, mechanical and antibacterial properties, biocompatibility tests, and in vivo experiments were carried out. The results showed that the surgical sutures with 1.25 wt % TiO 2 acquired 2.40 N knot strength (143 μm diameter) and achieved a sustainable antibacterial effect of 93.58%. Surprisingly, the sutures significantly reduced inflammatory reactions and promoted wound healing. Surgical sutures in this paper realize high-value recovery of waste silk fibers and provide a novel approach to preparing multifunctional sutures.

Selective upgrade of lignocellulosic biomass-derived aromatic compounds by photocatalytic oxidation is assumed as a prosperous, environmentally friendly, and cost-effective process. We present for the first time the application of various advantageous titanium oxide nano-photocatalysts for the additives-free selective partial oxidation of benzyl alcohol to benzaldehyde at ambient conditions. The two best-performing materials were found titanate nanotubes and nanocores of anatase surrounded by amorphous titanium hydroxide phase. The results obtained by scavenger tests on top of the DFT calculations led us to conclude that various reactions and active species are responsible by a complex way for materials' photoreactivity. Depending on nanocatalysts' physicochemical features as well as the light irradiation (ultraviolet vs. royal-blue), different mechanisms/oxidation-pathways are photo-catalyzed. Finally, we show that utilizing organic compounds like benzoquinone as scavenger hides risks due to the interactions with the targeted to be converted organic that results in elevated photolytic decomposition even under royal-blue light. [Display omitted] • Novel titanium oxide nanomaterials showed elevated photocatalytic benzyl alcohol oxidation. • The presence of the surface hydroxyl groups affects positively the selectivity. • DFT calculations and scavenger tests showed that various mechanisms are involved. [ABSTRACT FROM AUTHOR]

The aim of this research was to examine gas sensing properties of TiO2 based nanomaterials. Nanopowders of Cr doped TiO2 with constant Specific Surface Area, SSA, were obtained using Flame Spray Synthesis technique, FSS. Nanomaterials were characterized by Brunauer - Emmett - Teller adsorption isotherms, BET, X - ray diffraction, XRD, Transmission Electron Microscopy, TEM, optical spectrometry UV - vis with the use of an integrating sphere as well as impedance spectroscopy. Detection of hydrogen was carried out over the concentration range of 50 - 3000 ppm at the temperatures extending from 200 to 400°C and synthetic air working as a reference atmosphere. As a result of experiments it appeared that incorporation of 5 at.% of Cr into TiO2 improved hydrogen sensing features due to small crystallite size and predominance of rutile polymorphic phase. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2 with different design was prepared using the hydrothermal method. [•] HTNT-400 and HTNW-700 possess far superior photocatalytic activities than P25. [•] TiO2 morphology, texture and structure affect the photocatalytic activity. [•] The enhanced activity is attributed to the smaller crystallite size of anatase. [•] The HCOO− and HCOOH coexistence is favourable for better photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic dyes are a major part of our life as they are found in the various products ranging from clothes to leather accessories to furniture. These carcinogenic compounds are the major constituents of the industrial effluents. Various approaches have been developed to remove organic dyes from the natural environment. Over the past few years, there has been an enormous amount of research with advanced oxidation processes (AOPs) as an effective method of wastewater treatment. Among AOPs, heterogeneous photocatalytic process using TiO2 nanomaterials appears as the most emerging destructive technology due to its cost effectiveness and the catalyst inert nature and photostability. This review deals with the photocatalytic degradation of organic dyes containing different functionalities using TiO2 nanomaterials in aqueous solution. It first discusses the photocatalytic properties of nanostructured TiO2. The photocatalytic degradation rate strongly depends on the basic structure of the molecule and the nature of auxiliary groups attached to the aromatic nuclei of the dyes. So, this review then explains the influence of structure of dyes on their photocatalytic degradation rates. The influences of different substitutes such as alkyl side chains, methyl, nitrate, hydroxyl and carboxylic groups as well as the presence of chloro atom have been discussed in detail. [Copyright &y& Elsevier]

High-yield synthesis of TiO2 one-dimensional (1D) nanostructures was realized by a simple annealing of Ni-coated Ti grids in an argon atmosphere at 950 °C and 760 torr. The as-synthesized 1D nanostructures were single crystalline rutile TiO2 with the preferred growth direction close to [210]. The growth of these nanostructures was enhanced by using catalytic materials, higher reaction temperature, and longer reaction time. Nanoscale tensile testing performed on individual 1D nanostructures showed that the nanostructures appeared to fracture in a brittle manner. The measured Young’s modulus and fracture strength are ~56.3 and 1.4 GPa, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscale titanium dioxide (TiO2) is massively produced and widely used in living environment, which hence make the potential risk to human health. Central nervous system (CNS) is the potential susceptible target of inhaled nanoparticles, but the studies on this aspect are limited so far. We report the accumulation and toxicity results in vivo of two crystalline phases of TiO2 nanoparticles (80nm, rutile and 155nm, anatase; purity >99%). The female mice were intranasally instilled with 500μg of TiO2 nanoparticles suspension every other day for 30 days. Synchrotron radiation X-ray fluorescence analysis (SRXRF) and inductively coupled plasma mass spectrometry (ICP–MS) were used to determine the contents of titanium in murine brain. Then, the pathological examination of brain tissue, oxidative stress-mediated responses, and levels of neurochemicals in the brain of exposed mice were also analyzed. The obvious morphological changes of hippocampal neurons and increased GFAP-positive astrocytes in the CA4 region were observed, which were in good agreements with higher Ti contents in the hippocampus region. Oxidative stress occurred obviously in whole brain of exposed mice such as lipid peroxidation, protein oxidation and increased activities of catalase, as well as the excessive release of glutamic acid and nitric oxide. These findings indicate anatase TiO2 nanoparticles exhibited higher concern on some tested biological effects. To summarize, results provided the preliminary evidence that nasal instilled TiO2 nanoparticles could be translocated into the central nervous system and cause potential lesion of brain, and the hippocampus would be the main target within brain. [Copyright &y& Elsevier]

Abstract: Nanoparticles can be administered via nasal, oral, intraocular, intratracheal (pulmonary toxicity), tail vein and other routes. Here, we focus on the time-dependent translocation and potential damage of TiO2 nanoparticles on central nervous system (CNS) through intranasal instillation. Size and structural properties are important to assess biological effects of TiO2 nanoparticles. In present study, female mice were intranasally instilled with two types of well-characterized TiO2 nanoparticles (i.e. 80nm, rutile and 155nm, anatase; purity>99%) every other day. Pure water instilled mice were served as controls. The brain tissues were collected and evaluated for accumulation and distribution of TiO2, histopathology, oxidative stress, and inflammatory markers at post-instillation time points of 2, 10, 20 and 30days. The titanium contents in the sub-brain regions including olfactory bulb, cerebral cortex, hippocampus, and cerebellum were determined by inductively coupled plasma mass spectrometry (ICP-MS). Results indicated that the instilled TiO2 directly entered the brain through olfactory bulb in the whole exposure period, especially deposited in the hippocampus region. After exposure for 30days, the pathological changes were observed in the hippocampus and olfactory bulb using Nissl staining and transmission electron microscope. The oxidative damage expressed as lipid peroxidation increased significantly, in particular in the exposed group of anatase TiO2 particles at 30days postexposure. Exposure to anatase TiO2 particles also produced higher inflammation responses, in association with the significantly increased tumor necrosis factor alpha (TNF-α) and interleukin (IL-1β) levels. We conclude that subtle differences in responses to anatase TiO2 particles versus the rutile ones could be related to crystal structure. Thus, based on these results, rutile ultrafine-TiO2 particles are expected to have a little lower risk potential for producing adverse effects on central nervous system. Although understanding the mechanisms requires further investigation, the present results suggest that we should pay attention to potential risk of occupational exposure for large-scaled production of TiO2 nanoparticles. [Copyright &y& Elsevier]

[Display omitted] • Arsenic photo-oxidation/adsorption bi-function by TiO 2 nanostructures was studied. • Correlation between generated ROS and photocatalytic activity was established. • One-dimensional morphology of TiO 2 nanotubes promotes higher As(III) photooxidation. • Bi-functional behavior took place exclusively on TiO 2 nanoparticles. • Higher density of –OH groups favors As(V) adsorption by the complexes formation. Arsenic water pollution is a serious global environmental issue because of the high toxicity of this chemical element. Hence, the development of versatile materials that can efficiently remove different arsenic species from water is a global challenge. In this study, the bi-functionality of anatase TiO 2 nanostructures (nanoparticles (TNP) and nanotubes (TNT)) for the simultaneous photo-oxidation of As(III) to As(V) and adsorption of the generated As(V) was evaluated, and the effect of morphology on the photo-oxidation and adsorption behaviors of the nanomaterials at different pH conditions was determined. In the dark, both the photocatalysts exhibited a remarkably high As(III) adsorption capacity in alkaline conditions because of the high hydroxylation of the nanomaterial surfaces at a basic pH. Upon irradiation, the As(III) ions completely oxidized into As(V) ions in a short time by the TNT and TNP samples at different initial pHs. However, compared with TNP, TNT exhibited a remarkably enhanced photoactivity because of their one-dimensional nanotubular morphology that facilitates the transfer of the photogenerated electron-hole to the surface, improving the hydroxyl radicals photogeneration. Moreover, post-reaction XPS analysis revealed that the As(III) ions adsorbed on TNP under dark conditions completely oxidized into As(V) upon irradiation. As evidenced by the experimental results, TNP exhibited excellent bi-functionality for arsenic removal since the As(V) ions generated by As(III) oxidation both on the material surface and in the aqueous medium were simultaneously adsorbed on the nanoparticle surface. Thus, a better understanding of the morphological effect on the photocatalytic system for oxidizing As(III) and adsorbing As(V) at different pHs was presented and mechanisms are proposed. The study provides guidance for the development of bi-functional nanoparticles through morphological design and surface engineering. [ABSTRACT FROM AUTHOR]

Nanoparticulate mineral UV filters, such as titanium dioxide (TiO 2) nanocomposites, are being increasingly used in sunscreens as an alternative to organic UV filters. However, there is still a lack of understanding regarding their fate and behavior in aquatic environments and potential environmental impacts after being released from a bather's skin during recreational activities. In this work, we assessed the release, fate, and transformation of two commercial nanocomposite TiO 2 UV filters, one hydrophobic and one hydrophilic, in ultrapure water and simulated fresh- and seawater. The hydrophobic TiO 2 nanocomposite, T-SA, was coated with a primary Al 2 O 3 photopassivation layer and a secondary stearic acid layer, while the hydrophilic TiO 2 nanocomposite, T-SiO 2 , was coated with a single SiO 2 photopassivation layer. The influence of the sunscreen formulation was examined by dispersing the TiO 2 nanocomposites in their typical continuous phase (i.e., oil for T-SA and water for T-SiO 2) before introduction into the aqueous system. After 48 h of aqueous aging and 48 h of settling, 88–99% of the hydrophobic T-SA remained floating on top of the water column in all aqueous systems. On the other hand, 100% of the hydrophilic T-SiO 2 settled out of the water column in the fresh- and seawaters. With respect to the photopassivation coatings, no loss of the T-SA Al 2 O 3 layer was detected after aqueous aging, but 99–100% dissolution of the SiO 2 layer on the T-SiO 2 nanocomposite was observed after 48 h in the fresh- and seawaters. This dissolution left behind T-SiO 2 by-products exhibiting a photocatalytic activity similar to that of bare rutile TiO 2. Overall, the results demonstrated that the TiO 2 surface coating and sunscreen formulation type drive environmental behavior and fate and that loss of the passivation layer can result in potentially harmful, photoactive by-products. These insights will help guide regulations and assist manufacturers in developing more environmentally safe sunscreens. Image 1 • Nanoparticulate TiO 2 UV filters are a potential pollutant of recreational waters. • TiO 2 surface coating and sunscreen formulation type drive environmental fate. • Loss of surface coating can leave behind photo-active by-products. [ABSTRACT FROM AUTHOR]

This study presents a multi-residue method for simultaneous qualitative and quantitative analysis of eight antibiotics from some common classes, including beta-lactam, tetracyclines, lincosamides, glycopeptides, and sulfonamides in 39 aquaculture and river water samples from the Mekong Delta (Vietnam) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). As a result, doxycycline (DXC), oxytetracycline (OTC), lincomycin (LCM), sulfamethoxazole (SMX), and sulfamethazine (SMZ) were detected with high frequency over 65% and an average concentration of 22.6–76.8 ng·mL−1. The result suggests that antibiotic residues in the aquaculture and river waters are considered as an emerging environmental problem of the region. To address this issue, we fabricated the well-defined TiO2 nanotube arrays (TNAs) and nanowires on nanotube arrays (TNWs/TNAs) using the anodization method. The TNAs had an inner tube diameter of ~95 nm and a wall thickness of ~25 nm. Meanwhile, the TNWs/TNAs had a layer of TiO2 nanowires with a length of ~6 µm partially covering the TNAs. In addition, both TNAs and TNWs/TNAs had pure anatase phase TiO2 with (101) and (112) dominant preferred orientations. Moreover, the TNAs and TNWs/TNAs effectively and rapidly degraded the antibiotic residues under UV-VIS irradiation at 120 mW/cm2 and obtained over 95% removal at 20 min. Indeed, the photocatalytic reaction rate constants (k) were in the range of 0.14–0.36 min−1 for TNAs, and 0.15–0.38 min−1 for TNWs/TNAs. Noticeably, the k values of TNWs/TNAs were slightly higher than those of TNAs for LCM, DXC, OTC, SMZ, and SMX that could be attributed to the larger surface area of TNWs/TNAs than TNAs when TNWs/TNAs had an additional ~6μm TNWs top layer. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts have attracted a great amount of multidiscipline research due to their distinctive potential for solar-to-chemical-energy conversion applications, ranging from water and air purification to hydrogen and chemical fuel production. This unique diversity of photoinduced applications has spurred major research efforts on the rational design and development of photocatalytic materials with tailored structural, morphological, and optoelectronic properties in order to promote solar light harvesting and alleviate photogenerated electron-hole recombination and the concomitant low quantum efficiency. This book presents a collection of original research articles on advanced photocatalytic materials synthesized by novel fabrication approaches and/or appropriate modifications that improve their performance for target photocatalytic applications such as water (cyanobacterial toxins, antibiotics, phenols, and dyes) and air (NOx and volatile organic compounds) pollutant degradation, hydrogen evolution, and hydrogen peroxide production by photoelectrochemical cells. [ABSTRACT FROM AUTHOR]

Antibiotic residues in aquaculture wastewater are considered as an emerging environmental problem, as they are not efficiently removed in wastewater treatment plants. To address this issue, we fabricated TiO2 nanotube arrays (TNAs), TiO2 nanowires on nanotube arrays (TNWs/TNAs), Au nanoparticle (NP)-decorated-TNAs, and TNWs/TNAs, which were applied for assessing the photocatalytic degradation of eight antibiotics, simultaneously. The TNAs and TNWs/TNAs were synthesized by anodization using an aqueous NH4F/ethylene glycol solution. Au NPs were synthesized by chemical reduction method, and used to decorate on TNAs and TNWs/TNAs. All the TiO2 nanostructures exhibited anatase phase and well-defined morphology. The photocatalytic performance of TNAs, TNWs/TNAs, Au-TNAs and Au-TNWs/TNAs was studied by monitoring the degradation of amoxicillin, ampicillin, doxycycline, oxytetracycline, lincomycin, vancomycin, sulfamethazine, and sulfamethoxazole under ultraviolet (UV)-visible (VIS), or VIS illumination by LC-MS/MS method. All the four kinds of nanomaterials degraded the antibiotics effectively and rapidly, in which most antibiotics were removed completely after 20 min treatment. The Au-TNWs/TNAs exhibited the highest photocatalytic activity in degradation of the eight antibiotics. For example, reaction rate constants of Au-TNWs/TNAs for degradation of lincomycin reached 0.26 min−1 and 0.096 min−1 under UV-VIS and VIS irradiation, respectively; and they were even higher for the other antibiotics. The excellent photocatalytic activity of Au-TNWs/TNAs was attributed to the synergistic effects of: (1) The larger surface area of TNWs/TNAs as compared to TNAs, and (2) surface plasmonic effect in Au NPs to enhance the visible light harvesting. [ABSTRACT FROM AUTHOR]

The predictive self-assembly of tunable nanostructures is of great utility for broad nanomaterial investigations and applications. The use of equilibrium-based approaches however prevents independent feature size control. Kinetic-controlled methods such as persistent micelle templates (PMTs) overcome this limitation and maintain constant pore size by imposing a large thermodynamic barrier to chain exchange. Thus, the wall thickness is independently adjusted via addition of material precursors to PMTs. Prior PMT demonstrations added water-reactive material precursors directly to aqueous micelle solutions. That approach depletes the thermodynamic barrier to chain exchange and thus limits the amount of material added under PMT-control. Here, an ex situ hydrolysis method is developed for TiO 2 that mitigates this depletion of water and nearly decouples materials chemistry from micelle control. This enables the widest reported PMT range (M:T = 1.6-4.0), spanning the gamut from sparse walls to nearly isolated pores with ≈2 Å precision adjustment. This high-resolution nanomaterial series exhibits monotonic trends where PMT confinement within increasing wall-thickness leads to larger crystallites and an increasing extent of lithiation, reaching Li 0.66 TiO 2 . The increasing extent of lithiation with increasing anatase crystallite dimensions is attributed to the size-dependent strain mismatch of anatase and bronze polymorph mixtures., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)