scholarly journals Novel niobium-doped titanium oxide towards electrochemical destruction of forever chemicals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jesse S. Ko ◽  
Nam Q. Le ◽  
Danielle R. Schlesinger ◽  
Dajie Zhang ◽  
James K. Johnson ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Organic Contaminants ◽  
Density Functional ◽  
Reactive Oxygen ◽  
Common Species ◽  
Oxygen Free Radical ◽  
Promising Alternative ◽  
Monotonic Trend ◽  
Catalytic Material ◽  
Nb Doping

AbstractElectrochemical advanced oxidative processes (EAOP) are a promising route to destroy recalcitrant organic contaminants such as per- and polyfluoroalkyl substances (PFAS) in drinking water. Central to EAOP are catalysis-induced reactive free radicals for breaking the carbon fluorine bonds in PFAS. Generating these reactive species electrochemically at electrodes provides an advantage over other oxidation processes that rely on chemicals or other harsh conditions. Herein, we report on the performance of niobium (Nb) doped rutile titanium oxide (TiO2) as a novel EAOP catalytic material, combining theoretical modeling with experimental synthesis and characterization. Calculations based on density functional theory are used to predict the overpotential for oxygen evolution at these candidate electrodes, which must be high in order to oxidize PFAS. The results indicate a non-monotonic trend in which Nb doping below 6.25 at.% is expected to reduce performance relative to TiO2, while higher concentrations up to 12.5 at.% lead to increased performance, approaching that of state-of-the-art Magnéli Ti4O7. TiO2 samples were synthesized with Nb doping concentration at 10 at.%, heat treated at temperatures from 800 to 1100 °C, and found to exhibit high oxidative stability and high generation of reactive oxygen free radical species. The capability of Nb-doped TiO2 to destroy two common species of PFAS in challenge water was tested, and moderate reduction by ~ 30% was observed, comparable to that of Ti4O7 using a simple three-electrode configuration. We conclude that Nb-doped TiO2 is a promising alternative EAOP catalytic material with increased activity towards generating reactive oxygen species and warrants further development for electrochemically destroying PFAS contaminants.

scholarly journals Novel Niobium-doped Titanium Oxide Towards Electrochemical Destruction of Forever Chemicals

2021 ◽  
Author(s):  
Jesse S. Ko ◽  
Nam Q. Le ◽  
Danielle R. Schlesinger ◽  
James K. Johnson ◽  
Zhiyong Xia
Keyword(s):  
Titanium Oxide ◽  
Organic Contaminants ◽  
Density Functional ◽  
Reactive Oxygen ◽  
Oxygen Free Radical ◽  
Functional Theory ◽  
Promising Alternative ◽  
Viable Solution ◽  
Catalytic Material ◽  
Oxidative Processes

Abstract Electrochemical advanced oxidative processes (EAOP) are a promising route to destroy recalcitrant organic contaminants such as per- and poly- fluoroalkyl substances (PFAS) in drinking water. Central to EAOP are catalysis-induced reactive free radicals for breaking the carbon fluorine bonds in PFAS. Generating these reactive species electrochemically at electrodes provides an advantage over other oxidation processes that rely on chemicals or other harsh conditions. Herein, we report on the performance of niobium (Nb) doped rutile titanium oxide (TiO2) as a novel EAOP catalytic material, combining theoretical modeling with experimental synthesis and characterization. Calculations based on density functional theory reveal that Nb doping below 6.25 at.% is expected to reduce radical generation, and higher concentrations up to 12.5 at.% lead to increased performance, competitive with state-of-the-art Magnéli Ti4O7. Nb-doped TiO2 samples were synthesized and found to generate reactive oxygen free radical species with high oxidative stability. We conclude that Nb-doped TiO2 is a promising alternative EAOP catalytic material with increased activity towards generating reactive oxygen species, and is a viable solution for electrochemically destructing PFAS contaminants.

scholarly journals Butanol Tolerance of Lactiplantibacillus plantarum: A Transcriptome Study

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Kaloyan Petrov ◽  
Alexander Arsov ◽  
Penka Petrova
Keyword(s):  
Bacterial Species ◽  
Transcriptional Regulators ◽  
Common Species ◽  
Glycerol Metabolism ◽  
Phosphotransferase System ◽  
Promising Alternative ◽  
Butanol Tolerance ◽  
Polysaccharide Biosynthesis ◽  
Major Factors ◽  
Butanol Stress

Biobutanol is a promising alternative fuel with impaired microbial production thanks to its toxicity. Lactiplantibacillus plantarum (L. plantarum) is among the few bacterial species that can naturally tolerate 3% (v/v) butanol. This study aims to identify the genetic factors involved in the butanol stress response of L. plantarum by comparing the differential gene expression in two strains with very different butanol tolerance: the highly resistant Ym1, and the relatively sensitive 8-1. During butanol stress, a total of 319 differentially expressed genes (DEGs) were found in Ym1, and 516 in 8-1. Fifty genes were upregulated and 54 were downregulated in both strains, revealing the common species-specific effects of butanol stress: upregulation of multidrug efflux transporters (SMR, MSF), toxin-antitoxin system, transcriptional regulators (TetR/AcrR, Crp/Fnr, and DeoR/GlpR), Hsp20, and genes involved in polysaccharide biosynthesis. Strong inhibition of the pyrimidine biosynthesis occurred in both strains. However, the strains differed greatly in DEGs responsible for the membrane transport, tryptophan synthesis, glycerol metabolism, tRNAs, and some important transcriptional regulators (Spx, LacI). Uniquely upregulated in the butanol-resistant strain Ym1 were the genes encoding GntR, GroEL, GroES, and foldase PrsA. The phosphoenolpyruvate flux and the phosphotransferase system (PTS) also appear to be major factors in butanol tolerance.

Influence of titanium oxide and titanium peroxy gel on the breakdown of hyaluronan by reactive oxygen species

Biomaterials ◽  
1996 ◽  
Vol 17 (13) ◽  
pp. 1313-1319 ◽  
Author(s):  
G.C. Taylor ◽  
R.J. Waddington ◽  
R. Moseley ◽  
K.R. Williams ◽  
G. Embery
Keyword(s):  
Reactive Oxygen Species ◽  
Titanium Oxide ◽  
Reactive Oxygen ◽  
Oxygen Species

Ab Initio Studies of Nb Doping Effect on the Formation and Diffusion of Oxygen Vacancy and Ti Interstitial in Rutile TiO2

2011 ◽  
Vol 304 ◽  
pp. 142-147 ◽  
Author(s):  
Xu Wang ◽  
Fu He Wang
Keyword(s):  
Activation Energy ◽  
Oxygen Vacancy ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Formation Energy ◽  
Suppressive Effect ◽  
Nb Doping ◽  
O Vacancy ◽  
And Migration ◽  
And Diffusion

The effect of Nb doping on the formation and diffusion of O vacancies and interstitial Ti in rutile TiO2 are studied by the use of ab initio density-functional calculations. Our calculation showed that the activation energy for the diffusion of O vacancy with Nb doping is higher than that of pure. That owing to suppressive effect of Nb doping on the formation of O vacancy. Different from the effect of Nb doping on O vacancy, both of the formation energy and migration barrier of interstitial Ti increase with the Nb doping. Our calculated results may be one of the reasons why Nb doping can improve oxidation resistance of γ-TiAl.

Synthesis of Poly(vinyl alcohol)/Chitosan/Titanium Oxide Beads

2013 ◽  
Vol 65 (4) ◽  
Author(s):  
Syazwan Liyana Sulaiman ◽  
Zawati Harun ◽  
Sufizar Ahmad ◽  
Hariati Taib
Keyword(s):  
Wastewater Treatment ◽  
Titanium Oxide ◽  
Alkaline Solution ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Distilled Water ◽  
Swelling Properties ◽  
Promising Alternative ◽  
Porous Beads ◽  
Mean Time

The application of photocatalytic beads in wastewater treatment application has gained attention of many researchers. In this study, the synthesised poly(vinyl alcohol)/chitosan/Titanium oxide (PVA/CS/TiO2) beads has been considered as a promising alternative to conventional means of wastewater treatment. The present study has successfully synthesised PVA/CS/TiO2 beads through simple dropwise method in which varied concentration of CS from 1.0 g to 2.5 g. Morphological analysis of the synthesised PVA/CS/TiO2 beads investigated by the FE-SEM technique revealed that porous beads were obtained regardless of the varied CS concentration content. Furthermore, solubility and swelling properties investigation of the beads were also performed within the prescribed time of 24h in three different medium which were acidic, distilled water and alkaline solution. Result of solubility test proved that PVA/CS/TiO2 beads were insoluble only in distilled water and alkaline solution. However, the beads were found to dissolve in acidic solution due to the CS content. Meanwhile, the swelling test revealed that increased concentration of CS leads to swelling of beads in distilled water and alkaline solution. Results revealed that beads with the highest CS composition which is 2.5 g recorded 82.6% and 118.4% of swelling in distilled water and alkaline solution, respectively. In the mean time, beads with the lowest CS composition which is 1.0 g only swell for 65.8% and 93.3% in distilled water and alkaline solution, respectively. As a conclusion, the synthesised beads in this study is feasible to be applied in natural to alkaline environment.

scholarly journals Combining Density Functional Theories to Correctly Describe the Energy, Lattice Structure and Electronic Density of Functional Oxide Perovskites

2020 ◽  
Author(s):  
Kiel Williams ◽  
Lucas K. Wagner ◽  
Claudio Cazorla ◽  
Tim Gould
Keyword(s):  
Quantum Monte Carlo ◽  
Density Functional ◽  
Lattice Structure ◽  
Energy Structure ◽  
Electronic Density ◽  
Functional Theory ◽  
Promising Alternative ◽  
Fundamental Properties ◽  
Benchmark Study ◽  
Perovskite Materials

Functional oxide perovskites are the pillar of cutting-edge technological applications. Density functional theory (DFT) simulations are the theoretical methods of choice to understand and design perovskite materials. However, tests on the reliability of DFT to describe fundamental properties of oxide perovskites are scarce and mostly ill-defined due to a lack of rigorous theoretical benchmarks for solids. Here, we present a quantum Monte Carlo benchmark study of DFT on the archetypal perovskite BaTiO3 (BTO). It shows that no DFT approximation can simultaneously reproduce the energy, structure, and electronic density of BTO. Traditional protocols to select DFT approximations are empirical and fail to detect this shortcoming. An approach combining two different non-empirical DFT schemes, "SCAN" [1] and "HSE06" [2], is able to holistically describe BTO with accuracy. Combined DFT approaches should thus be considered as a promising alternative to standard methods for simulating oxide perovskites.

scholarly journals Combining Density Functional Theories to Correctly Describe the Energy, Lattice Structure and Electronic Density of Functional Oxide Perovskites

2020 ◽  
Author(s):  
Kiel Williams ◽  
Lucas K. Wagner ◽  
Claudio Cazorla ◽  
Tim Gould
Keyword(s):  
Quantum Monte Carlo ◽  
Density Functional ◽  
Lattice Structure ◽  
Energy Structure ◽  
Electronic Density ◽  
Functional Theory ◽  
Promising Alternative ◽  
Fundamental Properties ◽  
Benchmark Study ◽  
Perovskite Materials

Functional oxide perovskites are the pillar of cutting-edge technological applications. Density functional theory (DFT) simulations are the theoretical methods of choice to understand and design perovskite materials. However, tests on the reliability of DFT to describe fundamental properties of oxide perovskites are scarce and mostly ill-defined due to a lack of rigorous theoretical benchmarks for solids. Here, we present a quantum Monte Carlo benchmark study of DFT on the archetypal perovskite BaTiO3 (BTO). It shows that no DFT approximation can simultaneously reproduce the energy, structure, and electronic density of BTO. Traditional protocols to select DFT approximations are empirical and fail to detect this shortcoming. An approach combining two different non-empirical DFT schemes, "SCAN" [1] and "HSE06" [2], is able to holistically describe BTO with accuracy. Combined DFT approaches should thus be considered as a promising alternative to standard methods for simulating oxide perovskites.

scholarly journals The Carbonate-catalyzed Transesterification of Sunflower Oil for Biodiesel Production: in situ Monitoring and Density Functional Theory Calculations

2021 ◽  
Vol 74 ◽  
Author(s):  
M. Nyepetsi ◽  
F. Mbaiwa ◽  
O.A. Oyetunji ◽  
N.Y. Dzade ◽  
N.H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Sunflower Oil ◽  
Density Functional ◽  
Ph Monitoring ◽  
Transesterification Reaction ◽  
Biodiesel Production ◽  
In Situ Monitoring ◽  
Product Analysis ◽  
Functional Theory ◽  
Promising Alternative

ABSTRACT Biodiesel has emerged as a promising alternative fuel to replace dwindling fossil-based resources, particularly in view of its added environmental merit of reducing additional air pollution. Its specific attraction stems from the similarity of its physical properties to fossil fuel-derived diesel. Although the production of biodiesel is a relatively straightforward process, reaction progress monitoring and product analysis require costly specialist equipment, such as gas chromatography and mass spectrome-try. In this study, we investigate the use of pH in monitoring the progress of carbonate-catalyzed transesterification reactions. Specifically, we focus on potassium and sodium carbonates and sunflower oil. Our results are consistent with the results obtained by other studies using different methods of monitoring. To test the generality of the method, pH measurements were also used to monitor the progress of the potassium carbonate transesterification reaction in the presence of added water, glycerol and gamma-valerolactone (GVL). The obtained results are as expected, with a limited amount of water increasing the trans-esterification rate; glycerol slowing the reaction slightly in accord with Le Chatellier's principles; and GVL increasing the rate due to co-solvent effects. Atomic-level insights into the adsorption mechanism of methanol and water on the (001) surfaces of Na2CO3 and K2CO3 catalysts are provided by first-principles DFT calculations, which explain the increase in transesterification reaction rate upon the addition of water. Keywords: Transesterification, pH monitoring, biodiesel , Density Functional Theory ( DFT), co-solvent.

Reactive oxygen species inhibited by titanium oxide coatings

2003 ◽  
Vol 66A (2) ◽  
pp. 396-402 ◽  
Author(s):  
Richard Suzuki ◽  
Julie Muyco ◽  
Joanna McKittrick ◽  
John A. Frangos
Keyword(s):  
Reactive Oxygen Species ◽  
Titanium Oxide ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Oxide Coatings

scholarly journals Cobalt Oxide on a Nanoporous TUD-1 Catalyst for Methylene Blue Dye Interaction DFT Studies and Degradation

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1754
Author(s):  
Muthusamy Poomalai Pachamuthu ◽  
Sambath Baskaran ◽  
Chandrakumar Manivannan ◽  
Somasundaram Chandra Kishore ◽  
Stefano Bellucci ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Wastewater Treatment ◽  
Organic Contaminants ◽  
Density Functional ◽  
High Surface ◽  
Partial Density ◽  
Blue Dye ◽  
Spectroscopic Techniques ◽  
Amorphous Sio2 ◽  
Uniform Dispersion

Fenton and Fenton-like advanced oxidation processes (AOP) have been substantially utilized in wastewater treatment for the removal of organic contaminants. The present investigation explores the catalytic activity of cobalt dispersed over nanoporous silicate material (CoO/TUD-1), TUD-1, for the Fenton-type degradation of methylene blue (MB) dye present in wastewater, with hydrogen peroxide (H2O2) as an oxidant. The catalyst, which was prepared using the hydrothermal method, was characterized using analytical and spectroscopic techniques, such as X-ray diffraction (XRD), N2 adsorption–desorption isotherms, UV-visible diffuse reflectance (DR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR). The results indicated that the CoO/TUD-1 possessed three-dimensional structures with a high surface area and a pore diameter capable of the uniform dispersion of cobalt species. Density functional theory (DFT) simulations were performed to study the most stable tetra coordinate adsorption configuration of a single Co atom on amorphous SiO2. To understand the geometric and electronic structure of this configuration, electron density differences, Bader charge, and partial density of states were examined. The results obtained from the DFT calculations confirmed the occurrence of electron transfer from the Co atom to the amorphous SiO2. The calculated adsorption energy was found to be -1.58 eV, which indicated that the MB dye was strongly adsorbed by parallel configuration mode and degraded more easily. Further, the addition of a 0.1g/L dose of the prepared CoO /TUD degraded the MB dye effectively (~95%) within 240 min of contact. Thus, CoO/TUD-1 is a potential material for the removal of organic contaminants and the degradation of dyes in wastewater treatment.

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