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Water Science and Technology : a... Mar 2023Although spinel ferrite (MFeO, M = Zn, Ni, Mn, etc.) has been reported as a promising catalyst, its low photocatalytic activity under visible light greatly restricts its... (Review)
Review
Although spinel ferrite (MFeO, M = Zn, Ni, Mn, etc.) has been reported as a promising catalyst, its low photocatalytic activity under visible light greatly restricts its practical application. Spinel ferrite-based photocatalytic composites have exhibited improved efficiency for pollutant degradation, due to interface charge carrier mobility and structural modification. Meanwhile, due to its magnetism and stability, spinel ferrite composite can be easily recycled for long-term utilization, showing its high application potential. In this review, the recent advances in the construction and photocatalytic degradation of spinel ferrite composites are discussed, with an emphasis on the relationship between structural property and photocatalytic activity. In addition, to improve their photocatalytic application, the challenges, gaps and future research prospects are proposed.
Topics: Aluminum Oxide; Environmental Pollutants; Light
PubMed: 37001160
DOI: 10.2166/wst.2023.077 -
Operative Dentistry May 2021The aim of this study was to determine the flexural properties and surface characteristics of a structural colored resin composite after different finishing and...
OBJECTIVE
The aim of this study was to determine the flexural properties and surface characteristics of a structural colored resin composite after different finishing and polishing methods, in comparison to those of conventional resin composites.
METHODS AND MATERIALS
A structural color resin composite, Omnichroma (OM, Tokuyama Corp, Chiyoda City, Tokyo, Japan), and two comparison resin composites, Filtek Supreme Ultra (FS, 3M, St Paul, MN, USA) and Tetric EvoCeram (TE, Ivoclar Vivadent, Schaan, Liechtenstein), were used. The flexural properties of the resin composites were determined in accordance with the ISO 4049 specifications. For surface properties, 70 polymerized specimens of each resin composite were prepared and divided into seven groups of 10. Surface roughness (Sa), gloss (GU), and surface free energy (SFE) were investigated after the following finishing and polishing methods. Three groups of specimens were finished with a superfine-grit diamond bur (SFD), and three with a tungsten carbide bur (TCB). After finishing, one of the two remaining groups was polished with a one-step silicone point (CMP), and the other with an aluminum oxide flexible disk (SSD). A group ground with SiC 320-grit was set as a baseline.
RESULTS
The average flexural strength ranged from 116.6 to 142.3 MPa in the following order with significant differences between each value: FS > TE > OM. The average E ranged from 6.8 to 13.2 GPa in the following order with significant differences between each value: FS > TE > OM. The average R ranged from 0.77 to 1.01 MJ/mm3 in the following order: OM > FS > TE. The Sa values of the OM groups polished with CMP and SSD were found to be significantly lower than those of the other resin composites, regardless of the finishing method. The GU values appeared to be dependent on the material and the finishing method used. The OM specimens polished with SSD showed significantly higher GU values than those polished with CMP. Most of the resin composites polished with SSD demonstrated significantly higher γS values compared to the other groups. Extremely strong negative correlations between Sa and GU in the combined data from the three resin composites and each resin composite and between Sa and γS in the OM specimens were observed; GU showed a strong positive correlation with γS in the same material.
CONCLUSION
These findings indicate that both flexural and surface properties are material dependent. Furthermore, the different finishing and polishing methods used in this study were observed to affect the Sa, GU, and SFE of the resin composites.
Topics: Aluminum Oxide; Composite Resins; Dental Polishing; Flexural Strength; Materials Testing; Surface Properties
PubMed: 34370032
DOI: 10.2341/20-154-L -
The Journal of Prosthetic Dentistry Oct 2022Ceria-stabilized zirconia-alumina nanocomposite (Ce-TZP-AlO) has properties that may be suitable for partial denture frameworks. However, studies on its adhesion...
STATEMENT OF PROBLEM
Ceria-stabilized zirconia-alumina nanocomposite (Ce-TZP-AlO) has properties that may be suitable for partial denture frameworks. However, studies on its adhesion strength and durability with denture base resin are lacking.
PURPOSE
The purpose of this in vitro study was to determine the optimal surface treatment for Ce-TZP-AlO to secure a durable bond with an acrylic resin.
MATERIAL AND METHODS
The surface of Ce-TZP-AlO test specimens was alumina airborne-particle abraded (Group APA) and then treated with 10-methacryloyloxydecyl dihydrogen phosphate (MDP) (Group MDP) and 2 silica coating methods: the flame spraying method (Group SLP) and the tribochemical treatment (110 μm: Group TRB-P, 30 μm: Group TRB-S). TRB-P and TBR-S were further treated by MDP (Group CBT-P and CBT-S). Autopolymerizing acrylic resin was bonded to the specimens, and the shear bond strength was tested after thermocycling (5 °C and 60 °C, 10 000 cycles). The area of the resin remaining on the fractured surfaces was also measured. To evaluate the effect of the surface treatment condition on shear bond strength and the resin remaining, 1-way analysis of variance (ANOVA) was conducted, followed by the Tukey multiple comparison post hoc test. Additionally, the effect of thermocycling on the specimens was evaluated by the Student t test.
RESULTS
After placement in deionized water for 24 hours, the shear bond strengths of Group MDP and 2 types of combination treatment (Groups CBT-P and CBT-S) were significantly higher than those of Groups SLP, TRB-P, and TRB-S (P<.05). Moreover, the fractured surface of all the treatment conditions except Group APA showed cohesive failure. The shear bond strength as a result of all treatment conditions decreased significantly after thermocycling (P<.05). Group CBT-S showed the highest shear bond strength; however, no significant differences were found between Groups CBT-S and MDP (P=.908). In particular, the area of resin remaining on the fractured surfaces of Group CBT-S was 100% (cohesive failure).
CONCLUSIONS
The combined surface treatment of alumina airborne-particle abrasion and tribochemical treatment, along with primer treatment using silane coupling and an MDP monomer, improved the adhesion strength and adhesion durability between base resins and Ce-TZP-AlO.
Topics: Humans; Aluminum Oxide; Resin Cements; Dental Bonding; Acrylic Resins; Surface Properties; Materials Testing; Zirconium; Shear Strength; Nanocomposites; Dental Stress Analysis
PubMed: 33731268
DOI: 10.1016/j.prosdent.2021.01.019 -
British Dental Journal Feb 2022Alumina is a well-known dental ceramic material that has made waves within the dental industry for its good aesthetics and strength when compared to older materials for...
Alumina is a well-known dental ceramic material that has made waves within the dental industry for its good aesthetics and strength when compared to older materials for fixed prostheses, such as crown and bridgework. To be able to confidently use this material, a clinician should understand the physical and optical properties so as to know why and how this material might work in various clinical settings. This part of the ceramic series aims to explore the various alumina-based ceramic systems available on the market and discuss their properties, applications and indications. We also intend to briefly describe the preparation design requirements and cementation protocol for this type of ceramic.
Topics: Aluminum Oxide; Ceramics; Dental Porcelain; Esthetics, Dental; Surface Properties
PubMed: 35217739
DOI: 10.1038/s41415-022-3937-z -
Toxicology in Vitro : An International... Sep 2019Dermal exposure to Aluminium nanoparticles (AlNPs) can occur in occupationally- and non occupationally exposed- population, due to the use of Al salts-based...
Dermal exposure to Aluminium nanoparticles (AlNPs) can occur in occupationally- and non occupationally exposed- population, due to the use of Al salts-based antiperspirants. No AlNPs transdermal permeation data exists. Our study investigated in vitro the permeation of 30-60 nm AlONPs dispersed in synthetic sweat (20 g/L) using excised human skin on Franz cells. Experiments were performed using intact (experiment 1) and needle-abraded skin (experiment 2). After 24 h traces of Al were detectable in receiving solution of exposed cells (35.0 ± 6.0 ng/cm for intact and 88.5 ± 34.2 ng/cm for damaged skin, mean and SD) and in blank cells (36.3 ± 7.0 ng/cm), without statistical significance (p = 0.08, Mann-Whitney test). The average amount of Al into intact and damaged skin samples was 3.96 ± 0.20 μg/cm for intact and 4.36 ± 0.47 μg/cm for damaged skin (p = 0.08). Al content was similar in epidermal and dermal layers of intact and damaged skin (1.95 ± 0.13 μg/cm and 2.31 ± 0.12 μg/cm epidermal, 2.01 ± 0.25 μg/cm and 2.05 ± 0.35 μg/cm dermal). Al is a trace element in human body and the amount found in receiving solutions could be due as background impurity. This data suggest a reassuring transdermal permeation profile for AlONPs.
Topics: Aged; Aluminum Oxide; Female; Humans; In Vitro Techniques; Metal Nanoparticles; Middle Aged; Skin; Skin Absorption
PubMed: 31002974
DOI: 10.1016/j.tiv.2019.04.015 -
Molecules (Basel, Switzerland) Sep 2019A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon...
A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon nanotube nanocomposites with surface porosities. The mechanical properties (flexural strength and fracture toughness), surface area, and electrical conductivities were characterized and compared. The nanocomposites were extensively analyzed by field emission scanning electron microscopy (FE-SEM) for 2D qualitative surface morphological analysis. Adding CNTs in ceramic matrices and then systematically oxidizing them, without substantial reduction in densification, induces significant capability to achieve desirable/application oriented balance between mechanical, electrical, and catalytic properties of these ceramic nanocomposites. This novel strategy, upon further development, opens new level of opportunities for real-world/industrial applications of these relatively novel engineering materials.
Topics: Aluminum Oxide; Ceramics; Electric Conductivity; Nanocomposites; Nanotubes, Carbon
PubMed: 31480573
DOI: 10.3390/molecules24173176 -
The Journal of Adhesive Dentistry 2020To evaluate the influence of new air-abrasion powders with different silica concentrations (silica-coated aluminum oxide) and aging on the bond strength between...
PURPOSE
To evaluate the influence of new air-abrasion powders with different silica concentrations (silica-coated aluminum oxide) and aging on the bond strength between composite cement and Y-TZP ceramic.
MATERIALS AND METHODS
Ceramic slices (7 x 6.3 x 2 mm3) were randomly allocated into 8 groups (n = 20) considering different surface treatments (SiC: silica-coated aluminum oxide particles; AlOx: aluminum oxide particles; 7% Si and 20% Si: experimental powders consisting of 7% and 20% silica-coated of AlOx respectively) and aging (baseline: 24 h at 37°C in water; aged: 90 days at 37°C in water + 12,000 thermal cycles). A blinded researcher performed the air-abrasion procedure for 10 s (identical parameters for all groups). Composite resin cylinders (Ø = 3 mm) were cemented onto the silanized ceramic surfaces, light cured, and subjected to shear bond-strength testing (wire loop Ø = 0.5 mm). The topography of the powders and air-abraded surfaces was analyzed using SEM and atomic force microscopy (AFM). The elemental composition of the powders and air-abraded surfaces was analyzed with energy dispersive spectroscopy (EDS), and surface wetting of the air-abraded surfaces was also determined by contact-angle measurements.
RESULTS
Under baseline conditions, all groups presented similar bond strengths, but only SiC and 7% Si yielded unaltered bond strength after aging. SiC and 7% Si presented lower contact angles. All groups presented similar surface topographies. The silica content was also similar among groups, except for AlOx.
CONCLUSION
7% Si and SiC presented similar bond strength and better bonding performance after aging than AlOx and 20% Si. A higher silica concentration was not able to promote stable adhesion of composite cement after aging.
Topics: Air Abrasion, Dental; Aluminum Oxide; Ceramics; Dental Bonding; Resin Cements; Silicon Dioxide; Surface Properties; Yttrium; Zirconium
PubMed: 32322836
DOI: 10.3290/j.jad.a44151 -
Environmental Science and Pollution... Apr 2023It is important to remove active substances from secondary aluminum dross (SAD) to meet the reuse of SAD. In this work, the removal of active substances from different...
It is important to remove active substances from secondary aluminum dross (SAD) to meet the reuse of SAD. In this work, the removal of active substances from different particle sizes of SAD was studied using roasting improvement with particle sorting. The results showed that roasting after particle sorting pretreatment can effectively remove fluoride and aluminum nitride (AlN) from SAD, while getting the high-grade alumina (AlO) crude materials. The active substances of SAD mainly contribute to AlN, aluminum carbide (AlC), and soluble fluoride ions. AlN and AlC mainly exist in particles of 0.05-0.1 mm, while Al and fluoride are mainly in particles of 0.1-0.2 mm. The SAD of particle size ranging 0.1-0.2 mm has high activity and leaching toxicity; the gas emission was reached 50.9 mL/g (limit value of 4 mL/g), and the fluoride ion concentration in the literature was 137.62 mg/L (limit value of 100 mg/L) during the identification for reactivity and leaching toxicity according to GB5085.5-2007 and GB5085.3-2007, respectively. Roasting at 1000 °C for 90 min, the active substances of SAD were converted to AlO, N, and CO; meanwhile, soluble fluoride converted to stable CaF. The final gas release was reduced to 2.01 mL/g while soluble fluoride from SAD residues was reduced to 6.16 mg/L, respectively. The AlO content of SAD residues was determined at 91.8% and has been classified as category I solid waste. The results suggested that the roasting improvement with particle sorting of SAD can meet the reuse of valuable materials at full scale.
Topics: Aluminum; Fluorides; Aluminum Compounds; Aluminum Oxide
PubMed: 36872407
DOI: 10.1007/s11356-023-26201-3 -
Bulletin of Experimental Biology and... Feb 2022A comparative study of the effect of a sorbent with nanotubes (AlO@ WCNT-PDMS) and a carbon-mineral sorbent (AlO@C) on the parameters of human erythrocytes was carried...
A comparative study of the effect of a sorbent with nanotubes (AlO@ WCNT-PDMS) and a carbon-mineral sorbent (AlO@C) on the parameters of human erythrocytes was carried out. Using scanning flow cytometry, the morphological and functional parameters of venous blood erythrocytes as well as drainage blood after its perfusion through columns with sorbents were determined. The compared samples AlO@SWCNT-PDMS and AlO@C are similar by their effect on the morphological and functional parameters of erythrocytes. The maximum membrane extensibility increased to a greatest extent after contact with AlO@C, the amount of hemoglobin in erythrocytes decreased to the greatest extent after perfusion through a column with AlO@SWCNT-PDMS sorbent. The scanning flow cytometry is promising for assessing the effect on erythrocytes of new sorption materials intended for blood detoxification. Changes in the parameters of erythrocytes of blood collected in a sterile drainage system for subsequent reinfusion were revealed.
Topics: Aluminum Oxide; Dimethylpolysiloxanes; Erythrocytes; Humans; Minerals; Nanotubes, Carbon
PubMed: 35175474
DOI: 10.1007/s10517-022-05417-2 -
Bulletin of Environmental Contamination... Jul 2022Red mud (RM) is a highly alkaline by-product produced by the aluminium industry. The total stockpile of RM in the world is evaluated to be close 4 billion tons, which... (Review)
Review
Red mud (RM) is a highly alkaline by-product produced by the aluminium industry. The total stockpile of RM in the world is evaluated to be close 4 billion tons, which caused serious soil and water pollution. The use of RM in masonry materials has proven to be a prospective strategy to alleviate the environmental problems caused by RM. During the past decades, various economical treatment methods have been developed for utilization of RM as a masonry material. There are two general categories of products using RM in masonry materials: sintered products and non-sintered products. In this review, the physicochemical properties of RM are introduced, and the different application scenarios for RM in masonry materials are summarized, which is valuable for solving the environmental problems caused by the accumulation of bauxite residue. Moreover, the potential environmental risks of utilizing RM are described. Finally, suggestions for solving the RM problem are proposed.
Topics: Aluminum; Aluminum Oxide; Prospective Studies; Soil
PubMed: 34997264
DOI: 10.1007/s00128-021-03437-8