scholarly journals Characteristics of Carbon Monoxide Oxidization in Rich Hydrogen by Mesoporous Silica with TiO2Photocatalyst

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Akira Nishimura ◽  
Yutaka Yamano ◽  
Tomokazu Hisada ◽  
Masafumi Hirota ◽  
Eric Hu
Keyword(s):  
Carbon Monoxide ◽  
Mesoporous Silica ◽  
Concentration Ratio ◽  
Uv Light ◽  
Polymer Electrolyte Fuel Cell ◽  
Light Illumination ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Loading Ratio ◽  
The Impact

Hydrogen (H2) is normally used as the fuel to power polymer electrolyte fuel cell (PEFC). However, the power generation performance of PEFC is harmed by the carbon monoxide (CO) in the H2that is often produced frommethane (CH4). The purpose of this study is to investigate the experimental conditions in order to improve the CO oxidization performance of mesoporous silica loaded with TiO2. The impact of loading ratio of TiO2and initial concentration ratio of O2to CO on CO oxidization performance is investigated. As a result, the optimum loading ratio of TiO2and initial concentration ratio of O2to CO were 20 wt% and 4 vol%, respectively, under the experimental conditions. Under this optimumexperimental condition, the CO in rich H2in the reactor can be completely eliminated from initial 12000 ppmV after UV light illumination of 72 hours.

scholarly journals Influence of Experimental Conditions on Deposition of Silver Nanoparticles Onto Surface of Graphene Oxide / Wpływ Warunków Eksperymentalnych Na Proces Osadzania Nanocząstek Srebra Na Powierzchni Tlenku Grafenu

2015 ◽  
Vol 60 (4) ◽  
pp. 2631-2636
Author(s):  
M. Wojnicki ◽  
I. Mania ◽  
M. Marzec ◽  
M. Gajewska ◽  
K. Mech
Keyword(s):  
Silver Nanoparticles ◽  
Graphene Oxide ◽  
Alkaline Solution ◽  
Acidic Solution ◽  
Deposition Process ◽  
Reducing Agent ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
The Impact

Present work describes the influence of silver nanoparticles precursor form as well as the impact of graphene oxide initial concentration on deposition of the silver nanoparticles onto graphene oxide. Borane dimethylamine complex (DMAB) was used as the reducing agent. It was observed that application of silver ammonia complexes as the silver nanoparticles precursor as well as alkaline solution effect in higher quantity of deposited AgNPs in comparison to deposition process with the use of silver(I) nitrate in acidic solution.

scholarly journals The Impact of Amount of Cu on CO2 Reduction Performance of Cu/TiO2 with NH3 and H2O

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 610
Author(s):  
Akira Nishimura ◽  
Yoshito Sakakibara ◽  
Akira Koshio ◽  
Eric Hu
Keyword(s):  
Tio2 Film ◽  
Uv Light ◽  
Sol Gel ◽  
Co2 Reduction ◽  
Dip Coating ◽  
Pulse Number ◽  
Unit Weight ◽  
Molar Ratio ◽  
Light Illumination ◽  
The Impact

This study has investigated the impact of molar ratio of CO2 to reductants NH3 and H2O as well as that of Cu loading on CO2 reduction characteristics over Cu/TiO2. No study to optimize the reductants’ combination and Cu loading weight in order to enhance CO2 reduction performance of TiO2 has been investigated yet. This study prepared Cu/TiO2 film by loading Cu particles during the pulse arc plasma gun process after coating TiO2 film by the sol-gel and dip-coating process. As to loading weight of Cu, it was regulated by change in the pulse number. This study characterized the prepared Cu/TiO2 film by SEM and EPMA. Additionally, the performance of CO2 reduction has been investigated under the illumination condition of Xe lamp with or without ultraviolet (UV) light. It is revealed that the molar ratio of CO2/NH3/H2O is optimized according to the pulse number. Since the amount of H+ which is the same as that of electron is needed to produce CO decided following the theoretical CO2 reduction reacting with H2O or NH3, larger H+ is needed with the increase in the pulse number. It is revealed that Cu of 4.57 wt% for the pulse number of 200 is the optimum condition, whereas the molar quantity of CO per unit weight of Cu/TiO2 with and without UV light illumination is 34.1 mol/g and 12.0 mol/g, respectively.

scholarly journals Photodegradation of Orange Green by Fe(III)–Aqua Complex

2012 ◽  
Vol 60 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Md Mufazzal Hossain ◽  
Md Rashedul Islam Rasel ◽  
Md Safiqul Islam
Keyword(s):  
Uv Light ◽  
Solar Light ◽  
Aqua Complex ◽  
Average Intensity ◽  
Light Illumination ◽  
Light Sources ◽  
Initial Concentration ◽  
Aqua Complexes

The photodegradation of orange green (OG) by excitation of Fe (III)-aqua complexes has been investigated under UV and solar light illumination. The rate of degradation has been found to be strongly influenced by the pH of the solution, initial concentration of Fe(III) and the nature of the light sources. The progress of removal of OG from solution has been monitored by recording the change of absorbance at ?max = 480 nm, (? = 1.27 × 104 L mol-1cm-1 at 30°C), with time. The pH has been varied from 1.2 to 3.5. The initial concentration of Fe (III) was between 9.0 × 10-4 mol L-1 and 2.4 × 10-3 mol L-1. The intensity of the UV artificial source was 14 Wm-2, whereas the average intensity of the solar light during the experiments was about 700 Wm-2. An optimistic result was obtained, when OG was irradiated by solar light. About 92% degradation of 1.5 × 104 mol L-1 OG solution has been done within 70 minutes by photodegradation using Fe(III)-aqua complex at pH 2.5 by UV light whereas about 86% degradation has been recorded by the solar light under the same conditions.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10334  Dhaka Univ. J. Sci. 60(1): 43-46 2012 (January)

scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2020 ◽  
Author(s):  
Julio César Morales Mejía ◽  
Karla Ibette Anselmo Cervantes ◽  
Iván García Mendoza ◽  
Rafael Almanza
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2021 ◽  
Vol 37 ◽  
Author(s):  
Julio César Morales Mejía
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

scholarly journals Glucuronides Hydrolysis by Intestinal Microbial β-Glucuronidases (GUS) Is Affected by Sampling, Enzyme Preparation, Buffer pH, and Species

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1043
Author(s):  
Christabel Ebuzoeme ◽  
Imoh Etim ◽  
Autumn Ikimi ◽  
Jamie Song ◽  
Ting Du ◽  
...  
Keyword(s):  
Enzyme Preparation ◽  
Reaction System ◽  
Reaction Rates ◽  
Experimental Conditions ◽  
Model Animal ◽  
Fresh Feces ◽  
Time Buffer ◽  
Exogenous Compounds ◽  
Activity Loss ◽  
The Impact

Glucuronides hydrolysis by intestinal microbial β-Glucuronidases (GUS) is an important procedure for many endogenous and exogenous compounds. The purpose of this study is to determine the impact of experimental conditions on glucuronide hydrolysis by intestinal microbial GUS. Standard probe 4-Nitrophenyl β-D-glucopyranoside (pNPG) and a natural glucuronide wogonoside were used as the model compounds. Feces collection time, buffer conditions, interindividual, and species variations were evaluated by incubating the substrates with enzymes. The relative reaction activity of pNPG, reaction rates, and reaction kinetics for wogonoside were calculated. Fresh feces showed the highest hydrolysis activities. Sonication increased total protein yield during enzyme preparation. The pH of the reaction system increased the activity in 0.69–1.32-fold, 2.9–12.9-fold, and 0.28–1.56-fold for mouse, rat, and human at three different concentrations of wogonoside, respectively. The Vmax for wogonoside hydrolysis was 2.37 ± 0.06, 4.48 ± 0.11, and 5.17 ± 0.16 μmol/min/mg and Km was 6.51 ± 0.71, 3.04 ± 0.34, and 0.34 ± 0.047 μM for mouse, rat, and human, respectively. The inter-individual difference was significant (4–6-fold) using inbred rats as the model animal. Fresh feces should be used to avoid activity loss and sonication should be utilized in enzyme preparation to increase hydrolysis activity. The buffer pH should be appropriate according to the species. Inter-individual and species variations were significant.

scholarly journals Comparative analysis of spreading depolarizations in brain slices exposed to osmotic or metabolic stress

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rita Frank ◽  
Ferenc Bari ◽  
Ákos Menyhárt ◽  
Eszter Farkas
Keyword(s):  
Osmotic Stress ◽  
Tissue Injury ◽  
Brain Slices ◽  
Field Potential ◽  
Metabolic Stress ◽  
Glucose Deprivation ◽  
Optical Signal ◽  
Light Illumination ◽  
Glass Capillary ◽  
Experimental Conditions

Abstract Background Recurrent spreading depolarizations (SDs) occur in stroke and traumatic brain injury and are considered as a hallmark of injury progression. The complexity of conditions associated with SD in the living brain encouraged researchers to study SD in live brain slice preparations, yet methodological differences among laboratories complicate integrative data interpretation. Here we provide a comparative evaluation of SD evolution in live brain slices, in response to selected SD triggers and in various media, under otherwise standardized experimental conditions. Methods Rat live coronal brain slices (350 μm) were prepared (n = 51). Hypo-osmotic medium (Na+ content reduced from 130 to 60 mM, HM) or oxygen-glucose deprivation (OGD) were applied to cause osmotic or ischemic challenge. Brain slices superfused with artificial cerebrospinal fluid (aCSF) served as control. SDs were evoked in the control condition with pressure injection of KCl or electric stimulation. Local field potential (LFP) was recorded via an intracortical glass capillary electrode, or intrinsic optical signal imaging was conducted at white light illumination to characterize SDs. TTC and hematoxylin-eosin staining were used to assess tissue damage. Results Severe osmotic stress or OGD provoked a spontaneous SD. In contrast with SDs triggered in aCSF, these spontaneous depolarizations were characterized by incomplete repolarization and prolonged duration. Further, cortical SDs under HM or OGD propagated over the entire cortex and occassionally invaded the striatum, while SDs in aCSF covered a significantly smaller cortical area before coming to a halt, and never spread to the striatum. SDs in HM displayed the greatest amplitude and the most rapid propagation velocity. Finally, spontaneous SD in HM and especially under OGD was followed by tissue injury. Conclusions While the failure of Na+/K+ ATP-ase is thought to impair tissue recovery from OGD-related SD, the tissue swelling-related hyper excitability and the exhaustion of astrocyte buffering capacity are suggested to promote SD evolution under osmotic stress. In contrast with OGD, SD propagating under hypo-osmotic condition is not terminal, yet it is associated with irreversible tissue injury. Further investigation is required to understand the mechanistic similarities or differences between the evolution of SDs spontaneously occurring in HM and under OGD.

Comparison of a preferred versus non-preferred waterpipe tobacco flavour: subjective experience, smoking behaviour and toxicant exposure

2017 ◽  
Vol 27 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Eleanor L Leavens ◽  
Leslie M Driskill ◽  
Neil Molina ◽  
Thomas Eissenberg ◽  
Alan Shihadeh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Subjective Experience ◽  
Smoking Behaviour ◽  
Toxicant Exposure ◽  
P Values ◽  
Smoking Topography ◽  
Exhaled Carbon Monoxide ◽  
Continued Use ◽  
The Impact ◽  
Survey Questionnaires

IntroductionOne possible reason for the rapid proliferation of waterpipe (WP) smoking is the pervasive use of flavoured WP tobacco. To begin to understand the impact of WP tobacco flavours, the current study examined the impact of a preferred WP tobacco flavour compared with a non-preferred tobacco flavoured control on user’s smoking behaviour, toxicant exposure and subjective smoking experience.MethodThirty-six current WP smokers completed two, 45-minute ad libitum smoking sessions (preferred flavour vs non-preferred tobacco flavour control) in a randomised cross-over design. Participants completed survey questionnaires assessing subjective smoking experience, exhaled carbon monoxide (eCO) testing, and provided blood samples for monitoring plasma nicotine. WP smoking topography was measured continuously throughout the smoking session.ResultsWhile participants reported an enhanced subjective smoking experience including greater interest in continued use, greater pleasure derived from smoking, increased liking and enjoyment, and willingness to continue use after smoking their preferred WP tobacco flavour (p values <0.05), no significant differences were observed in nicotine and carbon monoxide boost between flavour preparations. Greater average puff volume (p=0.018) was observed during the non-preferred flavour session. While not significant, measures of flow rate, interpuff interval (IPI), and total number of puffs were trending towards significance (p values <0.10), with decreased IPI and greater total number of puffs during the preferred flavour session.DiscussionThe current study is the first to examine flavours in WP smoking by measuring preferred versus control preparations to understand the impact on subjective experience, smoking behaviour and toxicant exposure. The pattern of results suggests that even this relatively minor manipulation resulted in significant changes in subjective experience. These results indicate a possible need for regulations restricting flavours in WP tobacco as with combustible cigarettes.

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