Photocatalytic ability of two hetero-tetranuclear complexes with CuO2Cd cores to degrade methylene blue: Influence of their structures on activity

Polyhedron ◽  
2019 ◽  
Vol 170 ◽  
pp. 253-263 ◽  
Author(s):  
Saikat Mirdya ◽  
Tanmoy Basak ◽  
Shouvik Chattopadhyay
2018 ◽  
Vol 281 ◽  
pp. 813-818 ◽  
Author(s):  
Xin Liu ◽  
Jia Ke Li

Bismuth vanadate (BiVO4 ) powders were synthesized using Bi (NO3)3.5H2O and NH4VO3 as raw materials, NaOH and HNO3 for pH adjustment. The samples were characterized by X-ray diffraction ( XRD ), scanning electron microscopy (SEM ) and UV-vis diffuse reflectance spectra techniques. The results show that the pH of precursor solution has great effect on the composition and morphology of products. Synthetic product was BiVO4 with two kinds of crystal shape ( monoclinic and tetragonal ) with pH of 3; synthetic product was pure monoclinic phase BiVO4 when the pH is between 5-9. Whereas, V2O5 and Bi2O3 appeared when the pH was 11; synthetic product was a mixture of V2O5 and Bi2O3 with pH of 13, and BiVO4 don’t exist. The photocatalytic activity was evaluated by the degradation of methylene blue solution. It is shown that the synthetic sample has the best photocatalytic ability with pH of 5. The degradation of methylene blue reaches 84.7% when irradiated for 240 min by high pressure mercury lamp, and the sample synthesized at 13 for pH has strong adsorption capacity and poor photocatalytic ability.


2015 ◽  
Vol 39 (6) ◽  
pp. 4218-4221 ◽  
Author(s):  
Yu Sun ◽  
Bongyoung Yoo

We investigated the length-controlled synthesis of 1D metalloporphyrin coordination polymer particles and achieved the formation of nanorod and nanowire structures, which showed good photocatalytic ability towards methylene blue decomposition.


Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 297 ◽  
Author(s):  
Kamal Prasad Sapkota ◽  
Insup Lee ◽  
Md. Abu Hanif ◽  
Md. Akherul Islam ◽  
Jeasmin Akter ◽  
...  

We report enhanced catalytic action of a series of copper(II)-oxide-single-walled carbon nanotube (CuO-SWCNT) composite photocatalysts (abbreviated as CuO-SWCNT-0.5, CuO-SWCNT-2, and CuO-SWCNT-5, where 0.5, 2, and 5 represent the calcination time in hours) synthesized via recrystallization followed by calcination. The photocatalytic performance of the fabricated nanocomposites was examined by evaluating the degradation of methylene blue (MB) under irradiation with visible light. All of the as-fabricated nanocomposites were effective photocatalysts for the photodegradation of a MB solution; however, the CuO-SWCNT-5 displayed the best photocatalytic ability among the investigated catalysts, achieving 97.33% degradation of MB in 2 h under visible-light irradiation. The photocatalytic action of the nanocomposites was remarkably higher than that of pristine CuO nanocrystals fabricated using the same route. The recyclability of the photocatalyst was also investigated; the CuO-SWCNT-5 catalyst could be reused for three cycles without substantial degradation of its catalytic performance or morphology.


2011 ◽  
Vol 239-242 ◽  
pp. 2993-2996 ◽  
Author(s):  
Ming Xian Liu ◽  
Li Hua Gan ◽  
Da Zhang Zhu ◽  
Zi Jie Xu ◽  
Zhi Xian Hao ◽  
...  

In this paper, we present a strategy for the preparation of Fe-doped TiO2/SiO2aerogel microspheres (Fe-TSAMs) for visible light photocatalysis degradation of methylene blue. A water- in-oil (W/O) emulsion of Span 80–Tween 85/n-heptane–n-butanol/FeCl3-doped TiO2/SiO2alcoholic sols–formamide was obtained. Wet TiO2/SiO2gel microspheres were prepared by the sol-gel process in the W/O emulsion, then they were dried at ambient pressure condition to prepare Fe-TSAMs. The Fe-TSAMs were characterized by N2adsorption and desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the resultant Fe-TSAMs possess nanoporous network structure comprising TiO2and SiO2nanoparticles with diameters of 10-20 nm. The Fe-TSAMs have a mean diameter of about 100 μm, an apparent density of 0.26 g/cm3, a specific surface area of 360 m2/g, a pore volume of 1.77 cm3/g and the most probable pore size of 18.7 nm with the porosity of 87.7%. By using methylene blue as a simulated aqueous pollutant, the visible light photocatalysis properties of the Fe-TSAMs were investigated. The results indicate that low concentration Fe ion doping (5 wt%) could avoid the formation of recombination centers for photo-generated electron/hole pairs. Compared with commercial P25 TiO2powders, Fe-TSAMs exhibit excellent photocatalytic ability for degradation of methylene blue under visible light region. The Fe-TSAMs could be reclaimed conveniently and the reused Fe-TSAMs also have a good photocatalytic activity.


2020 ◽  
Vol 15 (1) ◽  
pp. 264-279 ◽  
Author(s):  
Anh-Tuan Vu ◽  
Thi Anh Tuyet Pham ◽  
Thi Thuy Tran ◽  
Xuan Truong Nguyen ◽  
Thu Quynh Tran ◽  
...  

This study aimed to synthesize Ag•ZnO•Activated carbon (Ag•ZnO•AC ) composite from rice husk for degradation of dyes. The deposition of Ag and ZnO on AC led to decreasing the surface area and pore volume of Ag•ZnO•AC composite. In addition, when Ag and ZnO were dispersed on activated carbon, the Ag•ZnO flakes became denser and tighter, but the particle size of Ag became smaller from 5 to 7 nm. The photocatalytic ability of Ag•ZnO•AC composite was evaluated by degradation of Janus Green B (JGB) and compared with that of AC, ZnO, Ag•ZnO, and ZnO•AC samples. The effects of catalyst dosages, pH values, and initial dye concentrations on photocatalytic degradation were investigated in detail. The Ag•ZnO•AC composite had a high degradation efficiency of 100% in 60 min, showing the reaction rate of 0.120 min-1 and degradation capacity of 17.8 mg/g within 20 min. The photocatalytic performance of the Ag•ZnO•AC composite was also evaluated by cyclic test and the degradation of other persistent dyes such as Methylene Blue, Tartrazine, Congo Red, and organic compounds (Caffeine and Bisphenol A). Based on the experimental results, the possible destruction route of JGB by the as-synthesized Ag•ZnO•AC composite was suggested. Copyright © 2020 BCREC Group. All rights reserved 


Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3451
Author(s):  
Muna A. Abu-Dalo ◽  
Saja A. Al-Rosan ◽  
Borhan A. Albiss

This paper studied the photocatalytic degradation of methylene blue (MB) using polymeric membrane impregnated with ZnO nanostructures under UV-light and sunlight irradiation. ZnO nanoparticles and ZnO nanowires were prepared using the hydrothermal technique. Cellulose acetate polymeric membranes were fabricated by the phase inversion method using dimethylformamide (DMF) as a solvent and ZnO nanostructures. The structural properties of the nanostructures and the membranes were investigated using XRD, SEM, FTIR, and TGA measurements. The membranes were tested for photocatalytic degradation of MB using a UV lamp and a sunlight simulator. The photocatalytic results under sunlight irradiation in the presence of cellulose acetate impregnated with ZnO nanoparticles (CA-ZnO-NP) showed a more rapid degradation of MB (about 75%) compared to the results obtained under UV-light irradiation degradation (about 30%). The results show that CA-ZnO-NP possesses the photocatalytic ability to degrade MB efficiently at different levels under UV-light and sunlight irradiation. Modified membranes with ZnO nanoparticles and ZnO nanowires were found to be chemically stable, recyclable, and reproducible. The addition of ZnO nanostructure to the cellulose membranes generally enhanced their photocatalytic activity toward MB, making these potential membranes candidates for removing organic pollutants from aqueous solutions.


Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 301-318 ◽  
Author(s):  
Anwar Iqbal ◽  
N. H. Ibrahim ◽  
Nur Ruzaina Abdul Rahman ◽  
K. A. Saharudin ◽  
Farook Adam ◽  
...  

Wastewater contaminated with dyes produced by textile industries is a major problem due to inadequate treatment prior to release into the environment. In this paper, the ability of ZnO to enhance the interfacial photocatalytic activity of lithium titanate/TiO2 (LTO/TiO2) for the photodegradation of methylene blue (MB) under visible light irradiation (4.38 mW/cm2) was assessed. The ZnO-doped lithium titanate/TiO2 (ZnO/LTO/TiO2) was synthesized using a combination of hydrothermal and wetness impregnation methods. The high-resolution transmission electron microscope (HRTEM) and X-ray Diffraction (XRD) analyses indicate that the ZnO/LTO/TiO2 contain several phases (ZnO, LTO, and TiO2). The adsorption capacity of LTO/TiO2 (70%) was determined to be higher compared to its photocatalytic activity (25%), which is attributed to the strong interaction between the Li and surface oxygen atoms with the MB dye molecules. The introduction of ZnO improved the photocatalytic ability of LTO/TiO2 by 45% and extended the life span of ZnO/LTO/TiO2. The ZnO/LTO/TiO2 can be reused without a significant loss up to four cycles, whereas LTO/TiO2 had reduced adsorption after the second cycle by 30%. The ZnO increased the surface defects and restrained the photo-induced electrons (e−) from recombining with the photo-induced holes (h+). Scavenging tests indicated that the hydroxyl radicals played a major role in the photodegradation of MB, which is followed by electrons and holes.


Author(s):  
B. J. Panessa ◽  
J. F. Gennaro

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.


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