scholarly journals The Impact of Coal Fly Ash Purification on Its Antibacterial Activity

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1002
Author(s):  
Seham Alterary ◽  
Narguess H. Marei
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Fly Ash ◽  
Chemical Composition ◽  
Bacterial Growth ◽  
Broth Culture ◽  
Growth Reduction ◽  
Laser Scattering ◽  
X Ray ◽  
The Impact

Fly ash (FA) is produced from coal power plants’ combustion. FA is used in the concrete industry, as an ingredient in the brick and paving. Knowledge of the chemical composition and toxic metal content in FA is essential for evaluating its environmental risks. This study aimed to assess FA purification effect on its antibacterial activity against Escherichia coli and Bacillus cereus, by calculating percent bacterial reduction. Moreover, centrifugation time effect on the purification process was evaluated. Chemical composition and properties of purified FA were determined and compared with raw FA, using Fourier transform Infrared (FTIR); X-ray diffraction (XRD); X-ray photoelectron spectroscopy (XPS); energy-dispersive X-ray (EDXA); carbon, hydrogen, nitrogen, and sulfur (CHNS) elemental analysis; moisture content; and loss-of-ignition. Particle size was predicted by using dynamic laser scattering, BET and scanning electron microscopy (SEM). The CHNS results showed that purified FA contains the highest carbon content (88.9%), as compared to raw FA (82.1%). The particle size distribution (PSD) of FA microspheres ranges from 48.53 ± 17.9 to 52.98 ± 19.4 µm by using SEM. PSD, using dynamic laser scattering, showed polydispersed and non-uniform size in raw FA, ranging in size from 107.1 to 1027 nm, while purified FA manifests a monodispersed size from 103.3 to 127.3 nm. FA showed the least bacterial growth reduction %, while the purified fly ash (FA2) showed the highest bacterial growth reduction %, as compared to the control bacterial broth culture without fly ash.

scholarly journals Preparation, Characterization and Performance Properties of Polydodecylmethylsilsesquioxane Nanoparticles

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1045
Author(s):  
Fuquan Deng ◽  
Hua Jin ◽  
Wei Xu
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Electron Microscope ◽  
Contact Angles ◽  
Process Conditions ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Laser Scattering ◽  
Excellent Thermal Stability ◽  
X Ray

A series of polydodecylmethylsilsesquioxane (PDMSQ) nanocomposite latexes were prepared via emulsion polymerization of methyltriethoxysilane (MTES) and dodecyltrimethoxysilane (DTMS) and sodium hydroxide as the catalyst, and sodium dodecyl benzene sulfonate/Tween 80 as the mixed emulsifiers. Effects of the emulsifier doses, the reaction temperature, the catalyst concentration and the oil/water ratio on the particle size and distribution of the PDMSQ nanoparticles were discussed. Particle size and micromorphology, structure, thermal stability, crystallinity and hydrophobicity of PDMSQ nanoparticles (PDMSQ NPs) were investigated by dynamic laser scattering (DLS), Fourier transform infrared spectroscopy (FTIR), silicon-nuclear magnetic resonance (28Si-NMR), X-ray photoelectron spectroscope (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and contact angle tester. Results showed that a series of PDMSQ NPs could be obtained with an average particle size of less than 80 nm and narrow distribution as well as spherical structure under the optimal process conditions. PDMSQ NPs exhibited excellent thermal stability and were mainly amorphous but also contained some crystal structures. Importantly, the static water contact angles (WCAs) on its latex films were larger than 150° and the WCAs hysteresis were less than 10°, thus those PDMSQ nanocomposite latexes show potential in the field of superhydrophobic coatings.

scholarly journals Effects of Ultrasound on Zinc Oxide/Vermiculite/Chlorhexidine Nanocomposite Preparation and Their Antibacterial Activity

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1309 ◽  
Author(s):  
Karla Čech Barabaszová ◽  
Sylva Holešová ◽  
Kateřina Šulcová ◽  
Marianna Hundáková ◽  
Barbora Thomasová
Keyword(s):  
Antimicrobial Activity ◽  
Particle Size ◽  
Zinc Oxide ◽  
Antibacterial Activity ◽  
Ultrasonic Treatment ◽  
Nanocomposite Materials ◽  
Hybrid Nanocomposite ◽  
X Ray Diffraction ◽  
X Ray

Microbial infection and biofilm formation are both problems associated with medical implants and devices. In recent years, hybrid organic-inorganic nanocomposites based on clay minerals have attracted significant attention due to their application potential in the field of antimicrobial materials. Organic drug/metal oxide hybrids exhibit improved antimicrobial activity, and intercalating the above materials into the interlayer of clay endows a long-term and controlled-release behavior. Since antimicrobial activity is strongly related to the structure of the material, ultrasonic treatment appears to be a suitable method for the synthesis of these materials as it can well control particle size distribution and morphology. This study aims to prepare novel, structurally stable, and highly antimicrobial nanocomposites based on zinc oxide/vermiculite/chlorhexidine. The influence of ultrasonic treatment at different time intervals and under different intercalation conditions (ultrasonic action in a breaker or in a Roset’s vessel) on the structure, morphology, and particle size of prepared hybrid nanocomposite materials was evaluated by the following methods: scanning electron microscopy, X-ray diffraction, energy dispersive X-ray fluorescence spectroscopy, carbon phase analysis, Fourier transforms infrared spectroscopy, specific surface area measurement, particle size analysis, and Zeta potential analysis. Particle size analyses confirmed that the ultrasonic method contributes to the reduction of particle size, and to their homogenization/arrangement. Further, X-ray diffraction analysis confirmed that ultrasound intercalation in a beaker helps to more efficiently intercalate chlorhexidine dihydrochloride (CH) into the vermiculite interlayer space, while a Roset’s vessel contributed to the attachment of the CH molecules to the vermiculite surface. The antibacterial activity of hybrid nanocomposite materials was investigated on Gram negative (Escherichia coli, Pseudomonas aeruginosa) and Gram positive (Staphylococcus aureus, Enterococcus faecalis) bacterial strains by finding the minimum inhibitory concentration. All hybrid nanocomposite materials prepared by ultrasound methods showed high antimicrobial activity after 30 min, with a long-lasting effect and without being affected by the concentration of the antibacterial components zinc oxide (ZnO) and CH. The benefits of the samples prepared by ultrasonic methods are the rapid onset of an antimicrobial effect and its long-term duration.

CHARACTERIZATION OF FLY ASH FROM COAL-FIRED POWER PLANT AND THEIR PROPERTIES OF MERCURY RETENTION

2015 ◽  
Vol 22 (02) ◽  
pp. 1550018 ◽  
Author(s):  
PING HE ◽  
XIUMIN JIANG ◽  
JIANG WU ◽  
WEIGUO PAN ◽  
JIANXING REN
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Power Plant ◽  
Experimental Studies ◽  
Size Fraction ◽  
Elemental Mercury ◽  
Unburned Carbon ◽  
Retention Capacity ◽  
Size Fractions ◽  
X Ray

Recent research has shown that fly ash may catalyze the oxidation of elemental mercury and facilitate its removal. However, the nature of mercury-fly ash interaction is still unknown, and the mechanism of mercury retention in fly ash needs to be investigated more thoroughly. In this work, a fly ash from a coal-fired power plant is used to characterize the inorganic and organic constituents and then evaluate its mercury retention capacities. The as-received fly ash sample is mechanically sieved to obtain five size fractions. Their characteristics are examined by loss on ignition (LOI), scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), X-ray diffraction (XRD), and Raman spectra. The results show that the unburned carbon (UBC) content and UBC structural ordering decrease with a decreasing particle size for the five ashes. The morphologies of different size fractions of as-received fly ash change from the glass microspheres to irregular shapes as the particle size increases, but there is no correlation between particle size and mineralogical compositions in each size fraction. The adsorption experimental studies show that the mercury-retention capacity of fly ash depends on the particle size, UBC, and the type of inorganic constituents. Mercury retention of the types of sp2 carbon is similar to that of sp3 carbon.

Occurrences of kaolin in Koutaba (west Cameroon): Mineralogical and physicochemical characterization for use in ceramic products

Clay Minerals ◽  
2015 ◽  
Vol 50 (5) ◽  
pp. 593-606 ◽  
Author(s):  
A. Nkalih Mefire ◽  
A. Njoya ◽  
R. Yongue Fouateu ◽  
J.R. Mache ◽  
N.A. Tapon ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Thermogravimetric Analysis ◽  
Raw Materials ◽  
Physicochemical Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ball Clays ◽  
Potential Use ◽  
Representative Samples

AbstractThirty clay samples collected from three hills in Koutaba (west Cameroon) were characterized in order to evaluate their potential use as raw materials for ceramics. After preliminary mineralogical identification by X-ray diffraction, three representative samples from the three different hills, referred to hereafter as K1M, K2M and K3M, were selected for further investigation by X-ray fluorescence, plasticity, granularity and thermogravimetric analysis. The main clay minerals are kaolinite (32–51%) and illite (up to 12%). Additional major phases are quartz (32–52%), goethite (6–7%) and feldspars (0–4%). The chemical composition showed variable amounts of SiO2(60–72%), Al2O3(15–20%) and Fe2O3(1–9%), in accordance with the quartz abundance in all of the samples studied. The particle-size distribution showed a large proportion of silty fraction (64–88%) with moderate sandy (9–19%) and clayey fractions ( < 5% for K2M, 12% for K1M and 20% for K3M). All of the clays showed moderate plasticity-index values (8–11%). Because of these characteristics, K1M and K3M may be suitable for use in common bricks and hollow ceramic products. Sieving or the addition of ball clays is recommended to increase the plasticity of sample K2M for use in common bricks.

scholarly journals Parametric Strategy for Composite Cement Concrete Blended with Fly Ash & Glass Fiber

2020 ◽  
pp. 162-176
Author(s):  
Madhurima Das ◽  
Siba Prasad Mishra
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Glass Fiber ◽  
Building Materials ◽  
Cement Concrete ◽  
Strength Performance ◽  
X Ray ◽  
Natural Building ◽  
The Impact ◽  
Scanning Electron

Coping with population growth, houses are built to meet the hike. The prerequisites for concrete and steel reinforcements have surged up globally since last 3 to 4decades. Shortage of natural building materials, increased wastes from coal based industries to augment carbon foot print has worried the engineers to reuse their wastes (such as fibres, powders, granules, etc.) as building materials ingredient. Glass fibre has improved flexural capabilities with fly ash dosages in cement concrete and alternately helps in restricting environmental degradation. Present research aims at investigating the impact of glass fiber (at 1%, 2% and 3% addition) and fly ash (dosages of 10% and 20% over the existing fly ash in PPC). The ingredients and microstructure of composites are found by either X-ray fluorescent spectroscopy or scanning electron microscope. Experimental evaluation results of the blended composite concrete parameters of RCC are experimentally evaluated and compared have shown that concrete with 10% cement substitution with fly ash and 3% fibre showed optimum compressive strength performance than the concrete without fibre and fly ash and also chemically resistant against commonly used M-20 grade of Concrete.

scholarly journals Modified Fly Ash-Based Adsorbents (MFA) for Mercury and Carbon Dioxide Removal from Coal-Fired Flue Gases

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7101
Author(s):  
Marta Marczak-Grzesik ◽  
Piotr Piersa ◽  
Mateusz Karczewski ◽  
Szymon Szufa ◽  
Hilal Ünyay ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Fly Ash ◽  
Chemical Composition ◽  
Solid Waste ◽  
Flue Gas ◽  
Flue Gases ◽  
Co2 Removal ◽  
Fly Ashes ◽  
Modified Fly Ash

One of the solid waste produced during the combustion of coal are fly ashes. Disposal challenges and environmental consequences are the results of significant process yield and atmospheric emission of fly ashes. The exact chemical composition of FA depends mainly on the type of utilised fuel and combustion conditions. It consists mainly of chemically stable metal oxides, such as Al2O3, Fe2O3, SiO2, CaO, MgO, K2O, Na2O and TiO2, but its toxicity is related to the possible presence of some trace elements, such as As, Hg, Cd, Se and Cr. The chemical and physical properties of fly ash (e.g., particle size distribution, porosity, and surface area) make it suitable as an adsorbent to remove various impurities from process flows such as flue gas stream. Its suitability for capturing mercury from flue gas was experimentally confirmed due to its abundant supply, particle size, bulk density, porosity, chemical composition and low cost. Hence, the use of fly ash as adsorbents and precursors for the production of heavy metal adsorbents is of great practical importance, as it reduces the cost of mercury capture and alleviates the problems associated with the disposal of solid waste. Studies showed that the chemical components present in fly ash additives could stimulate catalytic oxidative capacity, which increases the adsorption of Hg0 oxidation and adsorption of both Hg and CO2. The presented study analysed fly ashes from different zones of the electrostatic precipitator and verified their suitability for removing impurities from flue gases, i.e., mercury and carbon dioxide. The results outlined modified fly ash as having good Hg and CO2 removal capabilities. The adsorption efficiency of Hg reached 92% for Hg and 66% for CO2, while untreated fly ash reached 67% for Hg and 59% for CO2.

scholarly journals Ivermectin (IVM) Possible Side Activities and Implications in Antimicrobial Resistance and Animal Welfare: The Authors’ Perspective

2022 ◽  
Vol 9 (1) ◽  
pp. 24
Author(s):  
Cristian Piras ◽  
Enrico Gugliandolo ◽  
Fabio Castagna ◽  
Ernesto Palma ◽  
Domenico Britti
Keyword(s):  
Antibacterial Activity ◽  
Veterinary Medicine ◽  
Chlamydia Trachomatis ◽  
Antimicrobial Resistance ◽  
Lymphatic Filariasis ◽  
Bacterial Growth ◽  
Animal Species ◽  
Resistance Mechanisms ◽  
Immune Systems ◽  
The Impact

Ivermectin has a wide number of many diverse functions. Certainly, it is irreplaceable for the treatment of parasitic pathologies in both human and veterinary medicine, and the latter represents the major field of its application. It has been called the “drug for the world’s poor” because of its role as a saviour for those living on the margins of society, in underdeveloped areas afflicted by devastating and debilitating diseases, such as Onchocerciasis and Lymphatic filariasis. It showed huge, unexpected potential as an antibacterial (Chlamydia trachomatis and mycobacteria), and it has antiviral and anti-inflammatory properties. The research line described here is placed right in the middle of the investigation on the impact of this drug as an antimicrobial and an immunomodulator. Being a drug widely employed for mass administration, it is mandatory to broaden the knowledge of its possible interaction with bacterial growth and its generation of antimicrobial resistance. Equally, it is important to understand the impact of these drugs on the immune systems of animal species, e.g., horses and dogs, in which this drug is often used. More importantly, could immunomodulation and antibacterial activity promote both bacterial growth and the occurrence of resistance mechanisms?

scholarly journals Correlation between Microstructure and Chemical Composition of Zinc Oxide Gas Sensor Layers and Their Gas-Sensitive Properties in Chlorine Atmosphere

2020 ◽  
Author(s):  
Marta Fiedot-Toboła ◽  
Patrycja Suchorska-Woźniak ◽  
Kamila Startek ◽  
Olga Rac-Rumijowska ◽  
Monika Kwoka ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Zinc Oxide ◽  
Chemical Composition ◽  
Specific Surface ◽  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
Structural Defects ◽  
X Ray ◽  
Conductance Method ◽  
The Impact

In the article we present the results concerning the impact of structural and chemical properties of zinc oxide in various morphological forms, on its gas-sensitive properties tested in an atmosphere containing a very aggressive gas such as chlorine. Two types of ZnO sensor layers obtained by two different technological methods were used. Their morphology, crystal structure, specific surface area, porosity, surface chemistry and structural defects were characterized, and then compared with gas-sensitive properties in a chlorine-containing atmosphere. To achieve this goal scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL) methods were used. The sensing properties of obtained active layers were tested by temperature stimulated conductance method (TSC). We have noticed that their response in chlorine atmosphere is not determined by the size of the specific surface or porosity. The obtained results showed that the structural defects of ZnO crystals play the most important role in chlorine detection. We demonstrated that the Cl2 adsorption is a concurrent process to oxygen adsorption. Both of them occur on the same active species (oxygen vacancies). They concentration is higher on the side planes of the zinc oxide crystal than the others. Thanks to the conducted studies authors demonstrated that to develop a new gas sensor devices not only changing of active layer chemical composition but also controlling its crystal structure and morphology could be used.

scholarly journals Mössbauer Studies of Narrow Fractions of Fly Ash Formed after Combustion of Ekibastuz Coal

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7473
Author(s):  
Mikhail Vereshchak ◽  
Irina Manakova ◽  
Adilkhan Shokanov ◽  
Sayabek Sakhiyev
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Magnetic Separation ◽  
Stoichiometric Composition ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Type ◽  
Main Components ◽  
Dominant Phase

Nuclear gamma-resonance spectroscopy on 57Fe nuclei, X-ray diffraction, and scanning electron microscopy have been used to study the narrow fractions of fly ash formed after combustion of the Ekibastuz coal. Two groups of samples of magnetic (ferrospheres) and non-magnetic type have been separated by granulometric and magnetic separation. A number of regularities associated with the granules size of fly ash have been established. According to the data of Mössbauer spectroscopy, a decrease in the magnetically ordered contribution has been identified with the growth of the particle size. After magnetic separation, iron in ferrospheres was found mainly in the structure of Fe3O4/γ-Fe2O3 and α-Fe2O3. The dominant phase was Fe3O4 (60–77%), the amount of which decreases with the growth of the grain size. With the growth of the particle size, the ratio of [Fe]tetra/[Fe]octa positions occupancy in Fe3O4 approaches 0.5; the structure of magnetite tends to the stoichiometric composition. α-Fe was found in the composition of ferrospheres, and a mechanism of its formation was proposed. The main components of the non-magnetic fractions of fly ash are mullite, hercynite, and silicate glass.

Preparation of Copper Oxide (CuO) Nanoparticles and their Bactericidal Activity

2012 ◽  
pp. 326-332
Author(s):  
F. M. Al-Marzouki ◽  
O. A. Al-Hartomy ◽  
M. A. Shah
Keyword(s):  
Particle Size ◽  
Antibacterial Activity ◽  
Chemical Composition ◽  
Copper Oxide ◽  
Bactericidal Activity ◽  
Copper Powder ◽  
Low Temperatures ◽  
Cost Effective ◽  
Cuo Nanoparticles ◽  
Uniform Particle Size

Single crystalline nanoparticles of copper oxide (CuO) having almost uniform particle size of ~40±10nm have been synthesized by a facile and versatile route. The technique employed is free from toxic solvents, organics, and amines, and is based on a simple reaction of copper powder and de-ionized water (DI) at very low temperatures of 180oC. The morphology, chemical composition, and crystalline structure of the nanoparticles were carefully investigated by the various characterization techniques. Besides simplicity, the advantages of producing nanoparticles by this method are that it is easeful, flexible, fast, cost effective, and pollution free. The synthesized nanoparticles are under investigations for various applications including their antibacterial activity.

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