scholarly journals TiO2 Nanostructures for Photoelectrocatalytic Degradation of Acetaminophen

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 583 ◽  
Author(s):  
Joan Borràs-Ferrís ◽  
Rita Sánchez-Tovar ◽  
Encarnación Blasco-Tamarit ◽  
Maria José Muñoz-Portero ◽  
Ramón M. Fernández-Domene ◽  
...  
Keyword(s):  
Tio2 Nanotubes ◽  
Degradation Mechanism ◽  
Renewable Energy Sources ◽  
Statistical Significance ◽  
Oxygen Demand ◽  
Reynolds Numbers ◽  
Electrochemical Anodization ◽  
Confocal Laser ◽  
Hydrodynamic Conditions ◽  
Photoelectrocatalytic Degradation

Advanced oxidation processes driven by renewable energy sources are gaining attention in degrading organic pollutants in waste waters in an efficient and sustainable way. The present work is focused on a study of TiO2 nanotubes as photocatalysts for photoelectrocatalytic (PEC) degradation of acetaminophen (AMP) at different pH (3, 7, and 9). In particular, different TiO2 photocatalysts were synthetized by stirring the electrode at different Reynolds numbers (Res) during electrochemical anodization. The morphology of the photocatalysts and their crystalline structure were evaluated by field emission scanning electron microscopy (FESEM) and Raman confocal laser microscopy (RCLM). These analyses revealed that anatase TiO2 nanotubes were obtained after anodization. In addition, photocurrent densities versus potential curves were performed in order to characterize the electrochemical properties of the photocatalysts. These results showed that increasing the Re during anodization led to an enhancement in the obtained photocurrents, since under hydrodynamic conditions part of the initiation layer formed over the tubes was removed. PEC degradation of acetaminophen was followed by ultraviolet-visible absorbance measurements and chemical oxygen demand tests. As drug mineralization was the most important issue, total organic carbon measurements were also carried out. The statistical significance analysis established that acetaminophen PEC degradation improved as hydrodynamic conditions linearly increased in the studied range (Re from 0 to 600). Additionally, acetaminophen conversion had a quadratic behavior with respect to the reaction pH, where the maximum conversion value was reached at pH 3. However, in this case, the diversity of the byproducts increased due to a different PEC degradation mechanism.

scholarly journals Architecture of a Nascent Sphingomonas sp. Biofilm under Varied Hydrodynamic Conditions

2005 ◽  
Vol 71 (5) ◽  
pp. 2677-2686 ◽  
Author(s):  
V. P. Venugopalan ◽  
M. Kuehn ◽  
M. Hausner ◽  
D. Springael ◽  
P. A. Wilderer ◽  
...  
Keyword(s):  
Time Lapse ◽  
Reynolds Numbers ◽  
Water Channels ◽  
Confocal Imaging ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Hydrodynamic Conditions ◽  
Flow Conditions ◽  
Flow Cells ◽  
Biofilm Development

ABSTRACT The architecture of a Sphingomonas biofilm was studied during early phases of its formation, using strain L138, a gfp-tagged derivative of Sphingomonas sp. strain LB126, as a model organism and flow cells and confocal laser scanning microscopy as experimental tools. Spatial and temporal distribution of cells and exopolymer secretions (EPS) within the biofilm, development of microcolonies under flow conditions representing varied Reynolds numbers, and changes in diffusion length with reference to EPS production were studied by sequential sacrificing of biofilms grown in multichannel flow cells and by time-lapse confocal imaging. The area of biofilm in terms of microscopic images required to ensure representative sampling varied by an order of magnitude when area of cell coverage (2 × 105 μm2) or microcolony size (1 × 106 μm2) was the biofilm parameter under investigation. Hence, it is necessary to establish the inherent variability of any biofilm metric one is attempting to quantify. Sphingomonas sp. strain L138 biofilm architecture consisted of microcolonies and extensive water channels. Biomass and EPS distribution were maximal at 8 to 9 μm above the substratum, with a high void fraction near the substratum. Time-lapse confocal imaging and digital image analysis showed that growth of the microcolonies was not uniform: adjacently located colonies registered significant growth or no growth at all. Microcolonies in the biofilm had the ability to move across the attachment surface as a unit, irrespective of fluid flow direction, indicating that movement of microcolonies is an inherent property of the biofilm. Width of water channels decreased as EPS production increased, resulting in increased diffusion distances in the biofilm. Changing hydrodynamic conditions (Reynolds numbers of 0.07, 52, and 87) had no discernible influence on the characteristics of microcolonies (size, shape, or orientation with respect to flow) during the first 24 h of biofilm development. Inherent factors appear to have overriding influence, vis-à-vis environmental factors, on early stages of microcolony development under these laminar flow conditions.

scholarly journals TiO2 Nanotubes Architectures for Solar Energy Conversion

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 931
Author(s):  
Yin Xu ◽  
Giovanni Zangari
Keyword(s):  
Solar Energy ◽  
Tio2 Nanotubes ◽  
Fossil Fuels ◽  
Photovoltaic Effect ◽  
Electric Energy ◽  
Chemical Species ◽  
Electrochemical Anodization ◽  
Science And Engineering ◽  
Electric Energy Storage ◽  
The Usa

Electromagnetic light from the Sun is the largest source, and the cleanest energy available to us; extensive efforts have been dedicated to developing science and engineering solutions in order to avoid the use of fossil fuels. Solar energy transforms photons into electricity via the photovoltaic effect, generating about 20 GW of energy in the USA in 2020, sufficient to power about 17 million households. However, sunlight is erratic, and technologies to store electric energy storage are unwieldy and relatively expensive. A better solution to store energy and to deliver this energy on demand is storage in chemical bonds: synthesizing fuels such as H2, methane, ethanol, and other chemical species. In this review paper we focus on titania (TiO2) nanotubes grown through electrochemical anodization and various modifications made to them to enhance conversion efficiency; these semiconductors will be used to implement the synthesis of H2 through water splitting. This document reviews selected research efforts on TiO2 that are ongoing in our group in the context of the current efforts worldwide. In addition, this manuscript is enriched by discussing the latest novelties in this field.

Anodic synthesis of TiO2 nanotubes by step-up voltages

2021 ◽  
pp. 002199832110237
Author(s):  
V Sivaprakash ◽  
R Narayanan
Keyword(s):  
Corrosion Resistance ◽  
Tio2 Nanotubes ◽  
Biomedical Applications ◽  
Phase Changes ◽  
Electrochemical Anodization ◽  
Corrosion Resistant ◽  
Anodization Process ◽  
Anodic Synthesis ◽  
Input Potential

Fabrication of TiO2 nanotubes (NTs) has extensive application properties due to their high corrosion resistant and compatibility with biomedical applications, the synthesis of TiO2 nanotubes over titanium has drawn interest in various fields. The synthesis of TiO2 NTs using novel in-situ step-up voltage conditions in the electrochemical anodization process is recorded in this work. For manufacturing the NTs at 1 hour of anodization, the input potential of 30, 40 and 50 V was selected. With increasing step-up voltage during the anodization process, an improvement in the NTs was observed, favoring corrosion resistance properties. The surface of NTs enhances the structure of the ribs, raising the potential for feedback over time. XRD was used to analyze phase changes, and HR-SEM analyzed surface topography. Impedance tests found that longer NTs improved the corrosion resistance.

scholarly journals Highly Ordered TiO2 Nanotube Arrays with Engineered Electrochemical Energy Storage Performances

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 510
Author(s):  
Wangzhu Cao ◽  
Kunfeng Chen ◽  
Dongfeng Xue
Keyword(s):  
Tio2 Nanotubes ◽  
Lithium Ion ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Electrochemical Anodization ◽  
Nanotube Arrays ◽  
Free Standing ◽  
Structured Materials ◽  
Self Organized ◽  
Binder Free

Nanoscale engineering of regular structured materials is immensely demanded in various scientific areas. In this work, vertically oriented TiO2 nanotube arrays were grown by self-organizing electrochemical anodization. The effects of different fluoride ion concentrations (0.2 and 0.5 wt% NH4F) and different anodization times (2, 5, 10 and 20 h) on the morphology of nanotubes were systematically studied in an organic electrolyte (glycol). The growth mechanisms of amorphous and anatase TiO2 nanotubes were also studied. Under optimized conditions, we obtained TiO2 nanotubes with tube diameters of 70–160 nm and tube lengths of 6.5–45 μm. Serving as free-standing and binder-free electrodes, the kinetic, capacity, and stability performances of TiO2 nanotubes were tested as lithium-ion battery anodes. This work provides a facile strategy for constructing self-organized materials with optimized functionalities for applications.

Enhanced Visible Light Sensitization of N-Doped TiO2 Nanotubes Containing Ti-Oxynitride Species Fabricated via Electrochemical Anodization of Titanium Nitride

2018 ◽  
Vol 123 (4) ◽  
pp. 2189-2201 ◽  
Author(s):  
Andrea Merenda ◽  
Akshita Rana ◽  
Albert Guirguis ◽  
De Ming Zhu ◽  
Lingxue Kong ◽  
...  
Keyword(s):  
Visible Light ◽  
Titanium Nitride ◽  
Tio2 Nanotubes ◽  
Electrochemical Anodization ◽  
Doped Tio2

scholarly journals ACID ORANGE 52 DYE DEGRADATION BY ELECTROCATALYTIC PLUS PHOTOCATALYTIC TECHNIQUE AND INTERMEDIATES DETECTION

2018 ◽  
Vol 61 (4-5) ◽  
pp. 111
Author(s):  
Hui Zhao ◽  
Heng Zhong ◽  
Lei Sun ◽  
Alexander V. Nevsky ◽  
Dongsheng Xia
Keyword(s):  
Dye Degradation ◽  
Removal Rate ◽  
Degradation Mechanism ◽  
Oxygen Demand ◽  
Ionization Mass ◽  
Light Spectrum ◽  
Resource Saving ◽  
Acid Orange ◽  
Visible Part ◽  
Photocatalytic Processes

The degradation efficiency of Acid Orange 52 dye in an aqueous solutions using the combination of electrocatalytic and photocatalytic processes has been studied. Electrocatalytic and photocatalytic methods in practice reckon among advanced oxidation processes (AOPs). The effect of catalyst B dosage and irradiarion time on the rate of mentioned dye degradation was studied in the photocatalytic process. It was shown, that when Acid Orange 52 simulated dye wastewater was treated by electrocatalytic technique under optimal conditions with catalyst A, the decolorization treatment effect was 95 % in visible part of light spectrum (464 nm) and 38.6 % in ultraviolet part (270 nm), respectively. When the combined electrocatalytic-photocatalytic technique was processed with catalysts A and B, the color removal rate of dye could reach 99.3% (464 nm) and 91.5% (270 nm), respectively. The large amount of products of small mole weight was formed in the course of oxidation reaction. Moreover, the obtained values of chemical oxygen demand (COD) and total organic carbon (TOC) witnessed, that the combination of electrocatalytic and photocatalytic processes could significantly improve the biodegradability of dye as a whole．It was shown, that the removal rate of COD and TOC, respectively, were 54.3% and 72.8%. The reaction intermediates were determined by electrospray ionization-mass spectrometry (ESI-MS) analysis, and as a result, the probable degradation mechanism (pathway) has been proposed. The results of the work may be useful as theoretical bases for designing effective resource-saving, technically efficient and economically sound wastewater treatment systems, containing hardly biodegradable azo dyes.Forcitation:Zhao H., Zhong H., Sun L., Xia D., Nevsky A.V. Acid Orange 52 dye degradation by electrocatalytic plus photocatalytic technique and intermediates detection. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 4-5. P. 111-118

scholarly journals Interaction of Operational and Physicochemical Factors Leading to Gordonia amarae-Like Foaming in an Incompletely Nitrifying Activated Sludge Plant

2012 ◽  
Vol 78 (23) ◽  
pp. 8165-8175 ◽  
Author(s):  
Pitiporn Asvapathanagul ◽  
Zhonghua Huang ◽  
Phillip B. Gedalanga ◽  
Amber Baylor ◽  
Betty H. Olson
Keyword(s):  
Steady State ◽  
Removal Rate ◽  
Statistical Significance ◽  
Oxygen Demand ◽  
Ammonium Ion ◽  
Content Type ◽  
Mixed Liquor ◽  
Physicochemical Changes ◽  
Cell Concentrations ◽  
Gordonia Amarae

ABSTRACTThe overgrowth ofGordonia amarae-like bacteria in the mixed liquor of an incompletely nitrifying water reclamation plant was inversely correlated with temperature (r= −0.78;P< 0.005) and positively correlated with the solids retention time (SRT) obtained a week prior to sampling (r= 0.67;P< 0.005). Drops followed by spikes in the food-to-mass ratio (0.18 to 0.52) and biochemical oxygen demand concentrations in primary effluent (94 to 298 mg liter−1) occurred at the initiation ofG. amarae-like bacterial growth. The total bacterial concentration did not increase as concentrations ofG. amarae-like cells increased, but total bacterial cell concentrations fluctuated in a manner similar to that ofG. amarae-like bacteria in the pseudo-steady state. The ammonium ion removal rate (percent) was inversely related toG. amarae-like cell concentrations during accelerated growth and washout phases. The dissolved oxygen concentration decreased as theG. amarae-like cell concentration decreased. The concentrations ofG. amarae-like cells peaked (2.47 × 109cells liter−1) approximately 1.5 months prior to foaming. Foaming occurred during the late pseudo-steady-state phase, when temperature declines reversed. These findings suggested that temperature changes triggered operational and physicochemical changes favorable to the growth ofG. amarae-like bacteria. Fine-scale quantitative PCR (qPCR) monitoring at weekly intervals allowed a better understanding of the factors affecting this organism and indicated that frequent sampling was required to obtain statistical significance with factors changing as the concentrations of this organism increased. Furthermore, the early identification ofG. amarae-like cells when they are confined to mixed liquor (107cells liter−1) allows management strategies to prevent foaming.

scholarly journals All-Solid-State Lithium Ion Batteries Using Self-Organized TiO2 Nanotubes Grown from Ti-6Al-4V Alloy

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2121
Author(s):  
Vinsensia Ade Sugiawati ◽  
Florence Vacandio ◽  
Thierry Djenizian
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Tio2 Nanotubes ◽  
Coulombic Efficiency ◽  
Lithium Ion ◽  
Electrochemical Anodization ◽  
Self Organized ◽  
Solid State Batteries ◽  
One Step ◽  
Tio2 Nts

All-solid-state batteries were fabricated by assembling a layer of self-organized TiO2 nanotubes grown on as anode, a thin-film of polymer as an electrolyte and separator, and a layer of composite LiFePO4 as a cathode. The synthesis of self-organized TiO2 NTs from Ti-6Al-4V alloy was carried out via one-step electrochemical anodization in a fluoride ethylene glycol containing electrolytes. The electrodeposition of the polymer electrolyte onto anatase TiO2 NTs was performed by cyclic voltammetry. The anodized Ti-6Al-4V alloys were characterized by scanning electron microscopy and X-ray diffraction. The electrochemical properties of the anodized Ti-6Al-4V alloys were investigated by cyclic voltammetry and chronopotentiometry techniques. The full-cell shows a high first-cycle Coulombic efficiency of 96.8% with a capacity retention of 97.4% after 50 cycles and delivers a stable discharge capacity of 63 μAh cm−2 μm−1 (119 mAh g−1) at a kinetic rate of C/10.

scholarly journals Plasma-Induced Crystallization of TiO2 Nanotubes

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 626 ◽  
Author(s):  
Metka Benčina ◽  
Ita Junkar ◽  
Rok Zaplotnik ◽  
Matjaz Valant ◽  
Aleš Iglič ◽  
...  
Keyword(s):  
Tio2 Nanotubes ◽  
Oxygen Plasma ◽  
Biological Response ◽  
Electrochemical Anodization ◽  
X Ray Diffraction ◽  
Rapid Crystallization ◽  
Amorphous Tio2 ◽  
Tio2 Nts ◽  
First Time

Facile crystallization of titanium oxide (TiO2) nanotubes (NTs), synthesized by electrochemical anodization, with low pressure non-thermal oxygen plasma is reported. The influence of plasma processing conditions on TiO2 NTs crystal structure and morphology was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). For the first time we report the transition of amorphous TiO2 NTs to anatase and rutile crystal structures upon treatment with highly reactive oxygen plasma. This crystallization process has a strong advantage over the conventional heat treatments as it enables rapid crystallization of the surface. Thus the crystalline structure of NTs is obtained in a few seconds of treatment and it does not disrupt the NTs’ morphology. Such a crystallization approach is especially suitable for medical applications in which stable crystallized nanotubular morphology is desired. The last part of the study thus deals with in vitro biological response of whole blood to the TiO2 NTs. The results indicate that application of such surfaces for blood connecting devices is prospective, as practically no platelet adhesion or activation on crystallized TiO2 NTs surfaces was observed.

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