Electrochemical Characterization of TiO2 Nanotubular Films Exposed in an Aqueous Solution with a pH = 3.2

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2721-2728 ◽  
Author(s):  
S. Mejía Sintillo ◽  
C. Cuevas Arteaga ◽  
R. Ma. Melgoza Alemán ◽  
P. Mijaylova Nacheva

ABSTRACTTiO2 nanotubular structures were fabricated on Ti polished and unpolished foils exposed to H2O-Glycerol (50-50Vol.%)+0.27 M NH4F at 20V. The obtained TiO2 nanostructures were analyzed by SEM obtaining the morphological characterization, from which the roughness factors were calculated. Crystalline phases of both TiO2 nanotubular films were obtained by XRD after annealing at 450 °C and 600 °C for 2 h. The electrochemical stability of the TiO2 nanotubular films was obtained from the potentiodynamic polarization curves (PC) and the linear polarization resistance (Lpr) techniques, exposing the samples in 1M Na2SO4 + H2SO4 solution (pH = 3.2), such pH is in accordance with the acidic wastewater containing sulfur compounds coming from the industries or acid waters of the aquifers, which have been contaminated from the volcanoes nearby. It was concluded that the electrochemical stability of the crystallized nanotubular films is improved with the increase of the annealing temperature of the amorphous TiO2 arrays, which is associated to the higher composition of anatase and rutile, observing that the major amount of rutile improved the corrosion performance. The photoelectrochemical measurements were carried out in 0.5 M Na2SO4 solution using an 8 W UV lamp at a λ= 365 nm, whose results were recorded at zero bias during 10 min under darkness and illumination intervals of 1 min each. The obtained results were in agreement with the necessary features for being used in photocatalytic water remediation.

2019 ◽  
Author(s):  
Rene Perez Cuapio ◽  
Jose Alberto A G Alvarado Garcia ◽  
Mauricio Pacio Castillo ◽  
Antonio Arce Plaza ◽  
Carlos Bueno Avendaño ◽  
...  

In this work the synthesis of visible ZnO quantum dots (QDs) functionalized/stabilized with oleic acid and core-shelled with SiO2 is presented. A colloidal route was followed to synthesize ZnO QDs with 5 nm average size. Several characterizations were done to identify and assure the core, the stabilization, grain size and QDs emission characteristics. Techniques like FT-IR, XRD, TEM, SEM, UV-Vis, PL and an UV lamp were used to test composition, structural, morphological and emission of the as obtained quantum dots. After the structural and morphological characterization of the particles, they were functionalized with (3-aminopropyl) trimethoxysilane (APTMS).  It was observed that the size and morphology are unchanged but the stability depends directly on the APTMS oversaturation which is due to the formation of a thick SiO2 layer. From the PL characterization results it was noticed that the strong green emission is related to the APTMS content and directly related to the shell formation, this emission decreases as the core-shell thickness increases.


Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


Planta Medica ◽  
2010 ◽  
Vol 76 (05) ◽  
Author(s):  
APPR Amarasinghe ◽  
RP Karunagoda ◽  
DSA Wijesundara

2020 ◽  
Vol 13 (11) ◽  
pp. 1
Author(s):  
A. R. B. Zanco ◽  
A. Ferreira ◽  
G. C. M. Berber ◽  
E. N. Gonzaga ◽  
D. C. C. Sabino

The different integrated production systems can directly interfere with its bacterial community. The present study aimed to assess density, bacterial diversity and the influence of dry and rainy season in different integrated and an exclusive production system. The fallow and a native forest area was assessed to. Samples were collected in 2012 March and September. The isolation were carried out into Petri dishes containing DYGS medium. The number of colony forming units (CFU) was counted after 48 hours and. The bacterial density ranged between 106 and 107 CFU g-1 soil. The crop system affected the dynamics of the bacterial community only in the rainy season. The rainy season showed greater density of total bacteria when compared to the dry period regardless of the cropping system. The dendrograms with 80 % similarity showed thirteen and fourteen groups in the rainy and dry seasons. Isolates with the capacity to solubilize phosphate in vitro were obtained from all areas in the two seasons, but this feature has been prevalent in bacteria isolated during the rainy season


2020 ◽  
Vol 20 (4) ◽  
pp. 448-454
Author(s):  
Rahmita Burhamzah ◽  
Gemini Alam ◽  
Herlina Rante

Background: Endophytic fungi live in plants’ tissue and can produce the same bioactive compounds as its host plant produces. Syzygiumpolyanthum leaves have known to be one of the antibacterial compound producers. Aim and Objective: This study aimed to characterize morphologically, microscopically, and molecularly the antibacterial-producing endophytic fungi of Syzygiumpolyanthum leaves. Methods: The isolation of endophytic fungi was done by fragment planting method on PDA medium. The antibacterial screening was performed using the antagonistic test as the first screening followed by the disc diffusion test method. The morphological characterization was based on isolate’s mycelia color, growth pattern, margin, and surface texture of the colony, while the microscopic characterization was based on its hyphae characteristics. The molecular characterization of the isolate was done by nitrogen base sequence analysis method on nucleotide constituent of ITS rDNA genes of the isolate. Results: The results found that isolate DF1 has antibacterial activity against E.coli, S.aureus, P.acne, and P.aeruginosa, with the greatest inhibition at 10% concentration of broth fermentation extract on S.aureus with a diameter of inhibition of 13.77 mm. Conclusion: Based on macroscopic, microscopic, and molecular characterization, DF1 isolate is similar to Ceriporialacerate.


Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 303
Author(s):  
Rokayya Sami ◽  
Schahrazad Soltane ◽  
Mahmoud Helal

In the current work, the characterization of novel chitosan/silica nanoparticle/nisin films with the addition of nisin as an antimicrobial technique for blueberry preservation during storage is investigated. Chitosan/Silica Nanoparticle/N (CH-SN-N) films presented a stable suspension as the surface loads (45.9 mV) and the distribution was considered broad (0.62). The result shows that the pH value was increased gradually with the addition of nisin to 4.12, while the turbidity was the highest at 0.39. The content of the insoluble matter and contact angle were the highest for the Chitosan/Silica Nanoparticle (CH-SN) film at 5.68%. The use of nano-materials in chitosan films decreased the material ductility, reduced the tensile strength and elongation-at-break of the membrane. The coated blueberries with Chitosan/Silica Nanoparticle/N films reported the lowest microbial contamination counts at 2.82 log CFU/g followed by Chitosan/Silica Nanoparticle at 3.73 and 3.58 log CFU/g for the aerobic bacteria, molds, and yeasts population, respectively. It was observed that (CH) film extracted 94 regions with an average size of 449.10, at the same time (CH-SN) film extracted 169 regions with an average size of 130.53. The (CH-SN-N) film presented the best result at 5.19%. It could be observed that the size of the total region of the fruit for the (CH) case was the smallest (1663 pixels), which implied that the fruit lost moisture content. As a conclusion, (CH-SN-N) film is recommended for blueberry preservation to prolong the shelf-life during storage.


Author(s):  
N R Gazizova ◽  
A G Mannapov ◽  
V N Sattarov ◽  
V G Semenov ◽  
A I Skvortsov ◽  
...  

2021 ◽  
Vol 69 (7) ◽  
pp. 2226-2235
Author(s):  
Greta Canelli ◽  
Patricia Murciano Martínez ◽  
Sean Austin ◽  
Mark E. Ambühl ◽  
Fabiola Dionisi ◽  
...  

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