Synthesis and Photocatalytic Evaluation of Nanocrystalline ZnO Obtained by High Energy Milling

Photocatalytic processes have been applied to treatment of organic effluents through the mineralization of these pollutants on a semiconductor surface. Obtaining nanosemiconductors is desirable for the increasing of particle surface area and improvement in photocatalytic efficiency. In this paper, it was evaluated the influence of High Energy Milling (HEM) as a technique to produce nanocrystalline zinc oxide. The photocatalytic activity of the milled powders to degrade Rhodamine-B dye when exposed to ultraviolet and visible radiation also was investigated. The powders were milled during 4 and 10 hours by dry media milling and 10 hours by wet media milling. The results indicated that there were no detectable powder contamination during the millings and the reduction of crystallite size was function of time and media of milling. All of the assessed samples demonstrate high degradation of the dye, which corroborates with the potentiality of this technique to photocatalysts production. The material milled during 10 hours by dry media milling showed the best results under the experimental conditions.

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Effect of High-energy Milling on the Solid State Formation of Zinc Manganites (ZnxMn3-xO4, 0.5 ≤ x ≤ 1.5) from the System ZnC2O4 · 2H2O-n MnCO3 (n = 1, 1.5 and 2)

Zeitschrift für Naturforschung B ◽

10.1515/znb-2007-0506 ◽

2007 ◽

Vol 62 (5) ◽

pp. 663-668

Author(s):

Vittorio Berbenni ◽

Chiara Milanese ◽

Amedeo Marini

Keyword(s):

High Energy ◽

Physical Mixture ◽

Manganese Carbonate ◽

Calorimetric Data ◽

Experimental Conditions ◽

Enthalpy Of Dehydration ◽

High Energy Milling ◽

Partial Formation ◽

Zinc Oxalate ◽

Mechanism Of The Reaction

Abstract By combination of TG/DSC and XRPD measurements it has been shown that zinc manganites form (ZnxMn3−xO4 with 0.5 ≤ x ≤ 1.5) starting from mixtures of zinc oxalate dihydrate and manganese carbonate subjected to mechanical activation by high energy milling. Solid solutions ZnOMn3O4- ZnMn2O4 are the products obtained by the same experimental conditions, when starting from a physical mixture. Furthermore milling, besides changing the enthalpy of dehydration of zinc oxalate, induces a partial formation of amorphous Mn3O4 at r. t. In particular ZnMn2O4 can be prepared by annealing the milled mixture for 18 h at 650 °C while a temperature > 1000 °C is needed to prepare ZnMn2O4 from a physical mixture. Finally, the calorimetric data suggest that the mechanism of the reaction is different in the two kinds of mixtures.

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Estimative of the Stacking Fault Energy for a FeNi(50/50) Alloy and a 316L Stainless Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.591-593.3 ◽

2008 ◽

Vol 591-593 ◽

pp. 3-7 ◽

Cited By ~ 5

Author(s):

Marcos Flavio de Campos ◽

S.A. Loureiro ◽

Daniel Rodrigues ◽

Maria do Carmo Silva ◽

Nelson Batista de Lima

Keyword(s):

Stainless Steel ◽

316L Stainless Steel ◽

Milling Time ◽

High Energy ◽

Stacking Fault ◽

Stacking Fault Energy ◽

X Ray Diffraction ◽

Experimental Conditions ◽

X Ray ◽

High Energy Milling

The effect of high energy milling on powders of a FeNi (50/50) alloy and a 316L stainless steel has been evaluated by means of X-Ray Diffraction (XRD). The average microstrain as function of the milling time (1/2h, 1h and 8h) was determined from XRD data. The displacement and broadening of the (XRD) peaks were used for estimate the stacking fault energy (SFE), using the method of Reed and Schramm. It was estimated SFE=79 mJ/m2 for the FeNi (50/50) alloy and SFE=14 mJ/m2 for the 316L stainless steel. The better experimental conditions for determining the SFE by XRD are discussed.

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The Effect of High Energy Milling on the Solid State Synthesis of MnFe2O4 from Mixtures of MnO-Fe2O3 and Mn3O4-Fe2O3

Zeitschrift für Naturforschung B ◽

10.1515/znb-2003-0510 ◽

2003 ◽

Vol 58 (5) ◽

pp. 415-422 ◽

Cited By ~ 8

Author(s):

V. Berbenni ◽

A. Marinia ◽

A. Profumo ◽

L. Cucca

Keyword(s):

Solid State ◽

Thermal Treatment ◽

Ball Milling ◽

High Energy ◽

Physical Mixture ◽

Solid State Synthesis ◽

Experimental Conditions ◽

High Energy Milling ◽

Mn Oxides

A thermal treatment at 900°C (under nitrogen) of a milled mixture MnO-Fe2O3 yields MnFe2O4 mainly as the product of the reaction between Mn3O4 (produced by ball milling) and Fe2O3. Under the same experimental conditions but starting from an unmilled MnO- Fe2O3 mixture, the formation of MnFe2O4 is only partial and occurs through Mn3O4 (formed by oxidation of MnO). The same thermal treatment (900°C under nitrogen) of a milled Mn3O4-Fe2O3 mixture yields MnFe2O4 mainly as the product of the reaction between Mn3O4 and Mn2O3/MnO2 (the higher Mn oxides being produced by ball milling) and Fe2O3. The effect of high energy milling is more pronounced in the case of the Mn3O4-Fe2O3 system since no MnFe2O4 formation is observed when starting from a physical mixture.

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Photocatalytic Degradation of Rhodamine B Dye through Zinc Oxide Obtained by High Energy Milling

Materials Science Forum ◽

10.4028/www.scientific.net/msf.881.398 ◽

2016 ◽

Vol 881 ◽

pp. 398-403

Author(s):

Jeferson Almeida Dias ◽

Vera Lúcia Arantes ◽

Alfeu Saraiva Ramos ◽

Tania Regina Giraldi ◽

Marília Zani Minucci ◽

...

Keyword(s):

Photocatalytic Degradation ◽

Rhodamine B ◽

Life Time ◽

High Energy ◽

Heterogeneous Photocatalysis ◽

Semiconductor Surface ◽

X Ray Diffraction ◽

X Ray ◽

High Energy Milling ◽

Rhodamine B Dye

The heterogeneous photocatalysis has been developed to treatment of recalcitrant organic effluents such as the dyes. The chemical reactions occur on a semiconductor surface exposed to electromagnetic radiation. The objective of this study was evaluate the high energy milling as a mechanism to obtain fine powders of ZnO to utilization in photocatalysis. Raw ZnO was characterized by X-Ray diffraction, BET, sedigraph and Helium pycnometry and it was milled during four and ten hours in dry and wet media. The milled powders were characterized by X-Ray diffraction and they were evaluated in photocatalytic degradation of Rhodamine B dye. The results showed high purity of the powders before and after milling and the photocatalytic efficiency was function of processing conditions. The average half-life time for the dye varied between of 990.2 and 7.6 min wherein the powder obtained by four hours in dry media milling showed the best results of photodegradation.

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INFLUENCE OF ACETONE AND METHANOL PROCESS CONTROL AGENTS IN THE SIZE AND MORPHOLOGY OF THE PARTICLES IN THE HIGH ENERGY MILLING OF THE NB-25%AL ALLOY

10.26678/abcm.cobem2019.cob2019-0034 ◽

2019 ◽

Author(s):

Ágata Pontes ◽

EDWIN MEDINA ◽

Fabiano Sangi de Oliveira ◽

Gilbert Silva ◽

Marcos Cirilo ◽

...

Keyword(s):

Process Control ◽

High Energy ◽

Al Alloy ◽

High Energy Milling ◽

Size And Morphology

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Quantities Directly Measurable by Scattering

10.1093/oso/9780199670871.003.0003 ◽

2018 ◽

Author(s):

Eaton E. Lattman ◽

Thomas D. Grant ◽

Edward H. Snell

Keyword(s):

Molecular Weight ◽

Particle Shape ◽

Particle Surface ◽

Scattering Data ◽

Radius Of Gyration ◽

Particle Volume ◽

Particle Surface Area ◽

Scattering Angle ◽

Particle Dimension ◽

Maximum Particle

In this chapter we note that solution scattering data can be divided into four regions. At zero scattering angle, the scattering provides information on molecular weight of the particle in solution. Beyond that, the scattering is influenced by the radius of gyration. As the scattering angle increases, the scattering is influenced by the particle shape, and finally by the interface with the particle and the solution. There are a number of important invariants that can be calculated directly from the data including molecular mass, radius of gyration, Porod invariant, particle volume, maximum particle dimension, particle surface area, correlation length, and volume of correlation. The meaning of these is described in turn along with their mathematical derivations.

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Low-Energy Electron Damage to Condensed-Phase DNA and Its Constituents

International Journal of Molecular Sciences ◽

10.3390/ijms22157879 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7879

Author(s):

Yingxia Gao ◽

Yi Zheng ◽

Léon Sanche

Keyword(s):

Condensed Phase ◽

Genetic Material ◽

High Energy ◽

Dna Lesions ◽

Low Energy ◽

Experimental Investigations ◽

Experimental Conditions ◽

Strand Breaks ◽

Sequence Of Events ◽

Wide Range

The complex physical and chemical reactions between the large number of low-energy (0–30 eV) electrons (LEEs) released by high energy radiation interacting with genetic material can lead to the formation of various DNA lesions such as crosslinks, single strand breaks, base modifications, and cleavage, as well as double strand breaks and other cluster damages. When crosslinks and cluster damages cannot be repaired by the cell, they can cause genetic loss of information, mutations, apoptosis, and promote genomic instability. Through the efforts of many research groups in the past two decades, the study of the interaction between LEEs and DNA under different experimental conditions has unveiled some of the main mechanisms responsible for these damages. In the present review, we focus on experimental investigations in the condensed phase that range from fundamental DNA constituents to oligonucleotides, synthetic duplex DNA, and bacterial (i.e., plasmid) DNA. These targets were irradiated either with LEEs from a monoenergetic-electron or photoelectron source, as sub-monolayer, monolayer, or multilayer films and within clusters or water solutions. Each type of experiment is briefly described, and the observed DNA damages are reported, along with the proposed mechanisms. Defining the role of LEEs within the sequence of events leading to radiobiological lesions contributes to our understanding of the action of radiation on living organisms, over a wide range of initial radiation energies. Applications of the interaction of LEEs with DNA to radiotherapy are briefly summarized.

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