Kinetic Model for Simultaneous Adsorption/Photodegradation Process of Alizarin Red S in Water Solution by Nano-TiO2 under Visible Light.

The simultaneous adsorption and visible light photodegradation of Alizarin Red S in water solutions were studied in real time mode by using nano-TiO2, such as Anatase and Aeroxide P-25, supported on polypropylene strips. Kinetic results of the overall process were compared with those obtained from separated steps of adsorption and photodegradation previously studied; kinetic advantages were evidenced with the simultaneous approach. From the study of different dye concentrations, a kinetic model has been proposed which describes the overall process. This model considered two consecutive processes: The adsorption of dye on TiO2 surface and its photodegradation. The obtained results were in good agreement with experimental data and can predict the profiles of free dye, dye adsorbed on TiO2 and photoproduct concentrations during the total process

Kinetic Model for Photocatalytic Degradation of Alizarin Red-S by Polypropylene coated nano-TiO2

The aim of this study is optimize and clarify the total mechanism of adsorption/ visible-photodegradation of Alizarin Red S polypropylene coated nano-TiO2 Degussa P-25 and TiO2 Anatase as photocatalysts. The characterization of Alizarin Red S and its chemical interaction with TiO2 surface has been studied. The acid dissociation constants of Alizarin Red S are determined. Adsorption and photodegradation steps were simultaneously studied in order to propose a simple kinetic model which can describe the process in an adequate way. The results obtained from this kinetics model are in good agreement with experimental data

Graphene/TiO2 Nanocomposite for Efficient Visible-Light Photocatalysis: Synthesis, Characterization and Photocatalytic Applications.

The production of graphene in large quantities is an ongoing challenge for large-scale applications. A number of processes are used to produce graphene from graphene oxide but they need strong oxidizing and reducing agents [1]. However, graphene fabricated under these chemical conditions tends to have a certain number of structural defects, when compared to that produced from other techniques. For that purpose, top-down method such as the exfoliation of graphite powder in liquid phase by sonication is a very promising route due to its simplicity, its versatility and its low-cost [2]; besides, ultrasound treatment offers a suitable option to create high-quality graphene in great quantity. Graphene with the thickness of a single carbon atom owns unique physical and chemical properties including highly flexible structure, large surface area, high electrical and thermal conductivity and high chemical stability; also, in graphene, electrons have a linear relation between energy and momentum, so its band structure has no energy gap [3]. With these properties, graphene is an attractive material in applications that require a fast electron transfer, such as photocatalysis; it has been reported that graphene based semiconductor nanocomposites are considered as good photocatalyst for pollutant degradation [4]. Graphene is an ideal nanomaterial for doping TiO2 because the formation of Ti-O-C bonds extend the visible light absorption of TiO2. Moreover, electrons are easily transported from TiO2 to the graphene nano-sheets and the electron-hole recombination is significantly reduced; this is enhances the oxidative reactivity [5]. In this work, it was used an aqueous solution of a non-ionic surfactant, that acted like dispersing agent and as stabilizer to prevent layer stacking, for the direct exfoliation of graphite by sonication. The obtained graphene dispersion is characterized by X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS) and UV-Visible spectroscopy, and it is used for the preparation of heterogeneous GR@TiO2 photocatalyst supported on polypropylene (PP). GR@TiO2 nanocomposites are used to treat water with environmental pollutants by photocatalytic

Band Gap Implications on Nano-TiO2 Surface Modification with Ascorbic Acid for Visible Light-Active Polypropylene Coated Photocatalyst

The effect of surface modification using ascorbic acid as a surface modifier of nano-TiO2 heterogeneous photocatalyst was studied. The preparation of supported photocatalyst was made by a specific paste containing ascorbic acid modified TiO2 nanoparticles used to cover Polypropylene as a support material. The obtained heterogeneous photocatalyst was thoroughly characterized (scanning electron microscope (SEM), RAMAN, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and Diffuse Reflectance Spectra (DRS) and successfully applied in the visible light photodegradation of Alizarin Red S in water solutions. In particular, this new supported TiO2 photocatalyst showed a change in the adsorption mechanism of dye with respect to that of only TiO2 due to the surface properties. In addition, an improvement of photocatalytic performances in the visible light photodegration was obtained, showing a strict correlation between efficiency and energy band gap values, evidencing the favorable surface modification of TiO2 nanoparticles

From TiO2 and Graphite to Graphene doped TiO2 for visible light photocatalytic degradation of refractory dye.

Graphene production is an ongoing challenge for large-scale applications. Many processes are used to produce graphene 1. Top-down method such as the exfoliation of graphite powder in liquid phase by sonication is a promising route to create high quality graphene in great quantity due to its simplicity, its versatility and its low-cost 2. Graphene with the thickness of a single carbon atom owns unique physical and chemical properties like large surface area, highly flexible structure, high electrical and thermal conductivity and high chemical stability 3. With these properties, graphene is an attractive material in applications that require a fast electron transfer, such as photocatalysis. In fact, graphene based semiconductor nanocomposites are considered as good photocatalyst for pollutant degradation 4. Graphene is an ideal nanomaterial for doping TiO2 because the formation of Ti-O-C bonds extend the visible light absorption of TiO2. Furthermore, electrons are easily transported from TiO2 to graphene nano-sheets and the electron-hole recombination is reduced; this is enhances the oxidative reactivity 5. In this work, graphene doped TiO2 nanocomposite was used as photocatalytic materials for the Alizarin Red S degradation in water solutions. Graphene dispersions were prepared by liquid-phase exfoliation of graphite in the presence of a non-ionic surfactant, Triton X-100. The obtained graphene dispersion was characterized by X-Ray Diffraction, Dynamic Light Scattering and UV-Visible spectroscopy and was subsequently used for the preparation of graphene doped-TiO2 photocatalyst. Graphene doped-TiO2 nanocomposites showed higher adsorption of Alizarin Red S on the catalyst surface and higher photocatalytic activity for its degradation under visible light irradiation, respect to those obtained with pure TiO2 6. References: 1) Dimiev, A. M.; Tour, J. M. ACS Nano, 2014, 8, 3060 - 3068. 2) Samorì, P. et al. Chemical Society Reviews, 2014, 43, 381 - 398. 3) Geim, A.K.; Novoselov, K. S. Nature Materials, 2007, 6, 183 - 191. 4) Khalid, N. R.; Hong, Z. et al. Current Applied Physics, 2013, 13, 659 - 663. 5) Li, F.; Cheng, H. M. et al. Advanced Functional Materials, 2011, 21, 1717 - 1722. 6) Giovannetti, R.; D’ Amato, C. A. et al. Scientific Reports, 2015, 5, 17801

Unstable Maternal Environment, Separation Anxiety, and Heightened CO2 Sensitivity Induced by Gene-by-Environment Interplay

Background: In man, many different events implying childhood separation from caregivers/unstable parental environment are associated with heightened risk for panic disorder in adulthood. Twin data show that the occurrence of such events in childhood contributes to explaining the covariation between separation anxiety disorder, panic, and the related psychobiological trait of CO2 hypersensitivity. We hypothesized that early interference with infant-mother interaction could moderate the interspecific trait of response to CO2 through genetic control of sensitivity to the environment. Methodology: Having spent the first 24 hours after birth with their biological mother, outbred NMRI mice were crossfostered to adoptive mothers for the following 4 post-natal days. They were successively compared to normally-reared individuals for: number of ultrasonic vocalizations during isolation, respiratory physiology responses to normal air (20%O2), CO2-enriched air (6% CO2), hypoxic air (10%O2), and avoidance of CO2-enriched environments. Results: Cross-fostered pups showed significantly more ultrasonic vocalizations, more pronounced hyperventilatory responses (larger tidal volume and minute volume increments) to CO2-enriched air and heightened aversion towards CO2- enriched environments, than normally-reared individuals. Enhanced tidal volume increment response to 6%CO2 was present at 16–20, and 75–90 postnatal days, implying the trait’s stability. Quantitative genetic analyses of unrelated individuals, sibs and half-sibs, showed that the genetic variance for tidal volume increment during 6%CO2 breathing was significantly higher (Bartlett x = 8.3, p = 0.004) among the cross-fostered than the normally-reared individuals, yielding heritability of 0.37 and 0.21 respectively. These results support a stress-diathesis model whereby the genetic influences underlying the response to 6%CO2 increase their contribution in the presence of an environmental adversity. Maternal grooming/licking behaviour, and corticosterone basal levels were similar among cross-fostered and normally-reared individuals. Conclusions: A mechanism of gene-by-environment interplay connects this form of early perturbation of infant-mother interaction, heightened CO2 sensitivity and anxiety. Some no

Predicting needlestick and sharps injuries in nursing students: Development of the SNNIP scale

© 2020 The Authors. Nursing Open published by John Wiley & Sons Ltd. Aim: To develop an instrument to investigate knowledge and predictive factors of needlestick and sharps injuries (NSIs) in nursing students during clinical placements. Design: Instrument development and cross-sectional study for psychometric testing. Methods: A self-administered instrument including demographic data, injury epidemiology and predictive factors of NSIs was developed between October 2018–January 2019. Content validity was assessed by a panel of experts. The instrument's factor structure and discriminant validity were explored using principal components analysis. The STROBE guidelines were followed. Results: Evidence of content validity was found (S-CVI 0.75; I-CVI 0.50–1.00). A three-factor structure was shown by exploratory factor analysis. Of the 238 participants, 39% had been injured at least once, of which 67.3% in the second year. Higher perceptions of “personal exposure” (4.06, SD 3.78) were reported by third-year students. Higher scores for “perceived benefits” of preventive behaviours (13.6, SD 1.46) were reported by second-year students

Sensitization of monolayer transparent TiO2 thin films with metal-porphyrin dyes for DSSC applications. Equilibrium and kinetic aspects.

For the best manufacture of dye-sensitized solar cell (DSSC) systems (Figure 1), optimum objectives are represented from very rapid and complete adsorption of single layer of dye on the semiconductor surface [1,2]. Cu(II) and Zn(II) complexes of Coproporphyrin-I or CPI (Figure 2), has been synthesized in our laboratory and tested as sensitizers in DSSC devices [3,4]. A systematic study of kinetic and equilibrium for the adsorption of metal-CPI-dyes onto TiO2 monolayer surfaces, have permit to establish the best experimental conditions for the adsorption of these dyes and have demonstrated that the metal-CPI-dyes, according to the Langmuir model and with pseudo first-order kinetics, are adsorbed effectively in the support of TiO2 monolayer without chemical changes. The suppression of the dyes aggregation have permitted the optimization of selective adsorption of one layer of dyes molecules to stoichiometric ratios improving performances in DSSC indicating therefore a powerful experimental strategy, that can be enlarged to other dyes

Spectroscopic studies of porphyrin functionalized multiwalled carbon nanotubes and their interaction with TiO2 nanoparticles surface

UV-vis and fluorescence investigations about the non-covalent interaction, in ethanolic solutions, of multi-wall carbon nanotube (MWCNT) with Coproporphyrin-I, and its Cu(II) and Zn(II) complexes (MCPIs) have been reported. Evidence of binding between MWCNTs and porphyrins was discovered from spectral adsorption decrease with respect to free porphyrins and by the exhibition of photoluminescence quenching with respect to free porphyrins demonstrating that MWCNT@MCPIs are potential donor-acceptor complexes. Equilibrium and kinetic aspects in the interactions with monolayer transparent TiO2 thin films with the obtained MWCNT@MCPIs are clarified showing their effective adsorption by porphyrin links on the TiO2 monolayer support, with respect to not only MWCNTs, according to the Langmuir model and with pseudo-first-order kinetics. Morphological description of the adsorption of MWCNT@MCPIs on TiO2 with scanning electron microscopy has been reported. The obtained experimental evidences describe therefore MWCNT@MCPIs as potential sensitizers in the DSSC (Dye-Sensitized Solar Cell) applications

Equilibrium and kinetic aspects in photoactivity of Polypropilene coated Nano-TiO2

Water pollution has always been a major problem to the environment; the discharge of pollutants into water bodies is illegally and it is a source of organic compounds in wastewater . These pollutants are resistant to the biological and phisical treatments and in particular, dyes are the first pollutant species identified due to their obvious color and they are undesirable in water, even in very small amounts. The treatment of these dyes effluents is highly desired for the preservation of the environment. Heterogeneous photocatalysis has attracted considerable attention and the most used photocatalyst is TiO2 which show advantages such as chemical and biological resistance, low price, expensive recycling and recovery of the photocatalyst [2]. The aim of present work is the study and the use of two commercial types of TiO2 such as Anatase and Degussa P-25 supported on Polypropylene (PP) strips using Visible light in the photodegradation of two reference dyes, Methylorange and Alizarin Red S, in acid, basic and neutral conditions. The optimization of TiO2 pastes preparation using two commercial TiO2 has been performed and a low-cost dip-coating procedure was developed. Scan Electron Microscopy and Atomic Force Microscopy were used in order to obtain morphological information of TiO2 on support material. Equilibrium and kinetic aspects in the adsorption and photodegradation of Methylorange and Alizarin Red S are described using Polypropylene-TiO2 films in the Visible/TiO2/air reactor showing efficient dyes degradation. [1] C. Guillard, H. Lachheb, A. Houas, M. Ksibi, E. Elaloui, J. Herrmann, Journal of Photochemistry and Photobiology, 158 (2003) 27–36. [2] D. S. Bhatkhande, V. G. Pangarkar and A. ACM Beenackers, Journal of chemical technology and biotechnology, 77 (2001) 102