scholarly journals Musa acuminata peel extract mediated eco-friendly synthesis of solar light-active ZnO nanosponge for enhanced dyeing wastewater degradation

2020 ◽  
Vol 167 ◽  
pp. 01003
Author(s):  
Jin-Chung Sin ◽  
Ka-Wey Ong ◽  
Sze-Mun Lam ◽  
Honghu Zeng

ZnO nanosponge was synthesized for the first time via a green method using Musa acuminata peel extract. The X-ray diffraction, Raman, energy dispersive X-ray and fourier-transform infrared analyses demonstrated that the synthesized sample was well crystallized and possessed hexagonal wurtzite pure ZnO. The field-emission scanning electron microscopy observation revealed that the ZnO nanosponge was assembled by aggregated spherical particles with sizes of 30-128 nm. Under simulated solar light irradiation, the ZnO nanosponge acted as an excellent photocatalyst for methylene blue and rhodamine B mixtures degradation compared to commercially available TiO2-P25. The enhanced photocatalytic activities of ZnO sample can be attributed to the high generation of hydroxyl radicals as a result of its unique sponge-like porous structure with large surface area. Furthermore, the ZnO nanosponge can be used effectively on the photodegradation of real textile dye wastewater. These characteristics showed that the biosynthesized ZnO nanosponge can be employed as a photocatalyst for environmental remediation.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Guiyun Yi ◽  
Baolin Xing ◽  
Jianbo Jia ◽  
Liwei Zhao ◽  
Yuanfeng Wu ◽  
...  

Macroporous TiO2photocatalyst was synthesized by a facile nanocasting method using polystyrene (PS) spherical particles as the hard template. The synthesized photocatalyst was characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), thermogravimetry-differential thermogravimetry (TG-DTG), X-ray diffraction (XRD), and N2-sorption. TEM, SEM, and XRD characterizations confirmed that the macroporous TiO2photocatalyst is composed of anatase phase. The high specific surface area of 87.85 m2/g can be achieved according to the N2-sorption analysis. Rhodamine B (RhB) was chosen as probe molecule to evaluate the photocatalytic activity of the TiO2catalysts. Compared with the TiO2materials synthesized in the absence of PS spherical template, the macroporous TiO2photocatalyst sintered at 500°C exhibits much higher activity on the degradation of RhB under the UV irradiation, which can be assigned to the well-structured macroporosity. The macroporous TiO2material presents great potential in the fields of environmental remediation and energy conversion and storage.


2021 ◽  
Author(s):  
Asia Naqeeb ◽  
Sirajul Haq ◽  
Rimsha Ehsan ◽  
Muhammad Imran Shahzad ◽  
Nadia Shahzad ◽  
...  

Abstract The synthesis of zinc stannate nanocomposite (Zn2SnO4 NC) was carried out using an environment friendly process that included the use of Ficus carica (F. carica) leaves extract as a capping and reducing agent. X-ray diffraction (XRD) analysis was used to analyze the structural and crystallographic parameters, and the crystallite was discovered to have cubic geometry. The elemental composition of the studied Zn2SnO4 NC was investigated using energy dispersive X-ray (EDX), which revealed that it was extremely pure. The band gap (3.12 eV) was calculated through Tauc plot using diffuse reflectance (DRS) data where the functional groups were explored through Fourier transform infrared (FTIR) spectroscopy. Prior to the photocatalytic reaction, some preliminary experiments were performed, which proposed that pH 9 is suitable for the mineralization of methylene blue (MB) (10 ppm) in the presence of 20 mg of Zn2SnO4 NC and simulated solar light. The 96 % of MB was degraded in 80 min with the degradation rate of 0.038 min-1.


2019 ◽  
Vol 484 (4) ◽  
pp. 451-454
Author(s):  
V. V. Chesnokov ◽  
A. S. Chichkan ◽  
V. N. Parmon

Coking of anthracene at 400–600°C in the presence or in the absence of a cobalt catalyst supported on carbon nanotubes (CNTs) was studied for the first time. The coking products were examined by X-ray diffraction and electron microscopy. The CoO-CNTs catalyst considerably (by 50°C) decreased the temperature of the onset of coking and accelerated the coke formation. The presence of CoO-CNTs changed the coke morphology. Whereas coking of pure anthracene affords ~1 micron spherical particles of poorly crystallized carbon, in the presence of the catalyst, a carbon “coating” covering the CNT surface is formed.


2012 ◽  
Vol 519 ◽  
pp. 74-78 ◽  
Author(s):  
Hui Zhang ◽  
Chen Chen ◽  
Xiao Long Xu ◽  
Rong Wu ◽  
Fan Li ◽  
...  

For the first time, mesoporous ZnO and SnO2 spherical particles were synthesized by spray reaction (SR) process. The synthesized materials were characterized by thermo-gravimetry/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results reveal that few ZnO microspheres were formed after calcined at 700 °C while large quantity of non-spherical ZnO particles was produced. And the predominant hexagonal ZnO (h-ZnO) is attained when heated at 700 °C. Mesoporous SnO2 microspheres prepared at 800 °C possess an average size ~2.22 μm and a major tetragonal phase (t- SnO2) with crystallite size 7.8 nm.


2021 ◽  
Vol 12 (2) ◽  
pp. 117-123
Author(s):  
Zhenzhao Pei ◽  
Feng Li

In this study, it was discovered for the first time that the BiOBr/Bi3.84W0.16O6.24 catalyst can efficiently degrade sulfadiazine (SDZ). Multiple techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis diffuse reflection spectroscopy (DRS) were applied to research the structures, morphology and photocatalytic properties of as-prepared samples. In addition, the effect of different synthesis pH environment and initial SDZ solution pH on the catalyst degradation efficiency were discussed. The BiOBr/Bi3.84W0.16O6.24 catalyst synthesized under the condition of pH = 7 exhibited excellent photocatalytic activity for photodegradation of SDZ of 91% within 120 min under simulated solar light irradiation. Also, the roles of the radical species have been studied, and the ·O2- and h+ were proved to dominate the photocatalytic process. Based on the experimental results, the photocatalytic mechanism was proposed.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.


Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract


Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.


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