Md. Atikur Rahman, Promit Debnath, Md. Tanvir Hossain
et al.
This study presents CdS and ZnS nanoparticles as multifunctional photocatalysts for simultaneous degradation of fluoroquinolone antibiotics (ciprofloxacin and levofloxacin) and Congo red dye with concurrent antimicrobial activity under visible-light irradiation. Nanoparticles synthesized via chemical precipitation exhibited cubic zinc-blende structures with crystallite sizes of 2.1 -2.6 nm (CdS) and 23.5-31.3 nm (ZnS), confirmed by XRD analysis. FTIR spectroscopy revealed metal-sulfur lattice vibrations at 632 cm-1 (Cd-S) and 650 cm-1 (Zn-S), while EDX confirmed stoichiometric composition (CdS: 75.01 wt% Cd, 24.99 wt% S). Williamson-Hall analysis indicated microstrain values of 1.98-7.77 × 10-3 for CdS and 4.42-5.89 × 10-2 for ZnS, suggesting moderate lattice distortion. CdS demonstrated superior photocatalytic performance attributed to its optimal bandgap and point of zero charge (PZC ≈ 6.0), achieving near-complete degradation of target pollutants through enhanced reactive oxygen species generation. Antimicrobial assays revealed CdS exhibited broad-spectrum activity against S.aureus (9.3±0.36 mm) and S.abony (8.3±0.42 mm), while ZnS showed limited activity only against S.abony (9.5±0.50 mm). Both materials remained inactive against L. monocytogenes, E. coli and Candida albicans (<6 mm). The superior multifunctional performance of CdS, combining efficient visible-light photocatalysis with selective antimicrobial activity, establishes it as a promising single-material solution for next-generation water treatment systems addressing pharmaceutical contamination and microbial threats in aquatic environments.
Kimiyasu Sato, Ryutaro Usukawa, Yusuke Imai
et al.
ABSTRACT Plastic‐forming methods of ceramic pastes, such as extrusion, have been significant in the ceramics industry for many years. Despite its significance, the plasticity of ceramic pastes is poorly understood. It is essential to understand the fundamentals of ceramic paste plasticity to develop a forming technology with superior performance. The ceramic pastes’ plasticity can be characterized by the co‐existence of apparently opposing properties, that is, “flowability” and “rigidity.” It has been claimed that the apparently opposing properties can be achieved by controlling the interparticle interaction that is attractive at long range and repulsive at short range. The present article aims to verify the model based on experimental results from interaction force measurements. The interaction forces are gathered by the atomic force microscope (AFM) colloid probe technique. On the basis of the discussion, it is concluded that the above microscopic model is available to interpret ceramic pastes’ macroscopic behaviors.
A. Kalendová, J. Kupková, Martina Urbaskova
et al.
Clays and clay minerals are common natural materials, the unique properties of which have attracted the interest of the industry, especially because these materials are easily available, cheap, and non-toxic. Clays and clay minerals are widely used in many applications, such as in ceramic production, in the clarification of liquids, pollutant adsorbers, filler in composites and nanocomposites, soil amendments, in pharmacy, etc. This review assesses the development in the area of clay application in nanocomposites and ceramics. The first part of this study covers polymer/clay nanocomposites. Topics of interest include nanofiller sources for polymer nanocomposites, the possible ways of clay modification, polymer/clay nanocomposite classification and their processing, and polymer matrix overview with possible enhancement of nanocomposite properties. Some of the applications have already been commercialized. Approximately 80% of the polymer/clay nanocomposites are destined for the automotive, aeronautical, and packaging industries. The second part of this study describes ceramic materials with a focus on silicate ceramics. Talc and kaolinite represent the main natural raw materials for traditional ceramic applications. Less traditional cordierite, steatite, and forsterite could offer property enhancement and seem to be useful in electronics, electrical engineering, catalysts, solar thermal storage, or medical applications.
Abubakar Ibrahim-Dey, Samuel Nortey, Wemegah Wemegah
The study explored the textures of tree barks in combination with various materials, including clay, laterite, feldspar, manganese and waste glass, to create ceramic art tiles. An art-based research design was employed throughout the project. Utilising a range of ceramic manufacturing techniques such as pulverisation, blending, slabbing, sprinkling, impressing and cutting, the researchers combined clay, feldspar, manganese and glass to produce slabs. These slabs were then coated with pulverised laterite to create the ceramic art tiles. Their surfaces were impressed with tree bark textures, resulting in unique tactile effects. A total of 2,450 tiles were produced, each measuring 9x16 centimetres. The tiles were robust, colourful, and impervious to water. The findings of the study established that art tiles can be produced locally to meet the demands of the construction industry and for export purposes, using recycled materials like waste glass and other readily available ceramic raw materials. The research advocates for the use of indigenous raw materials and techniques in the production of essential products such as art tiles. Incorporating recycled glass alongside ceramic materials offers an innovative approach to waste management.
Zircon (ZrSiO4) is widely utilized as an opacifying agent in the glazes of sanitary-ware and ceramic tile. Zircon is dispersed in the glassy phase during the manufacture process of glaze, contributing a high refractive index and enhanced mechanical properties. However, significant price fluctuation and natural radioactivity of zircon have motivated extensive research to find alternative compositions. This study investigates the surface characteristics and radiation properties of sanitary-ware glazes prepared by replacing zircon with SnO2 and CaTiO3 in the raw materials. Analysis of the radioactivity index (Iγ) for glaze raw materials revealed that zircon exhibited the radioactivity index of 9.7, which is significantly higher than that of other mineral-based raw materials. To reduce the radiation emission from glaze, zircon was replaced with CaTiO3 and SnO2, which are radiation-free materials. The glaze prepared using CaTiO3 and SnO2 showed thermal behavior and surface characteristics comparable to those of zircon-containing glaze. Furthermore, the radioactivity index of clay specimen coated with zircon-containing glaze was measured at 1.09, while the radioactivity index of clay specimen coated with zircon-free glaze was significantly reduced to 0.62.
Marc Bohner, Fabrizio Bigolin, Isabelle Bohner
et al.
α-tricalcium phosphate (α-TCP) is the most widespread raw material for hydraulic calcium phosphate cements (CPCs). CPCs are widely used in bone repair due to their injectability, setting ability, and osteoconductivity. This study investigated the reactivity of α-TCP powders, focusing on the impact of minor phase impurities, β-calcium pyrophosphate and hydroxyapatite, and the synthesis temperature. The α-TCP powders were synthesized via a solid-state reaction of calcium carbonate and anhydrous dicalcium phosphate, with varying Ca/P molar ratios (1.4850–1.5075) and synthesis temperatures (1175°C–1350 °C). Powders produced with a Ca/P molar ratio below 1.50 and synthesized at a temperature above the melting point of β-CPP (1296 °C) had a broader size distribution and a two to fourfold lower hydraulic reactivity. Conversely, a higher Ca/P molar ratio improved reactivity. The study underscores the importance of precise control over synthesis parameters to enhance the performance of α-TCP-based CPCs, offering insights for optimizing material design in biomedical applications.
The growing interest in combining the photocatalytic properties of semiconductors like ZnO and TiO2 with the superior electron conduction capabilities of graphene has resulted in the successful synthesis of in-situ reduced graphene oxide (rGO) supported ZnO-TiO2 nanostructures through a simple microwave-assisted synthesis method. X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–visible spectroscopy (UV–vis), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize structural, morphological and optical properties as well as surface functional groups of the synthesized products. The XRD measurements of our synthesized samples confirm both structural crystallinity and phase purity, while the FTIR analysis verifies the complete reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The synthesized ternary nanocomposite ZnO-TiO2-rGO exhibited a remarkable 100 % adsorption-assisted removal efficiency for 20 mg/L methylene blue (MB) dye under ultraviolet light illumination within 120 min, along with a 56 % dye adsorption removal efficiency in the same time interval. In comparison, pure ZnO showed 0 % adsorption and only 31 % photocatalytic efficiency at the similar condition. Remarkably, the ZnO-TiO2-rGO nanocomposite exhibited exceptional photocatalytic activity mediated by adsorption, achieving complete degradation of MB dye within 5 min under sunlight irradiation. The photocatalytic efficiency and dye adsorption capacity were found to be significantly lower for the anionic dye methyl orange (MO) compared to the cationic MB dye. The study thoroughly investigated the influence of catalyst dose and initial dye concentration on photodegradation. The proposed mechanism indicates that the extensive surface area and numerous active sites on the rGO promote adsorption, which is then followed by degradation through the metal oxides. Overall, the results unveil that the microwave-assisted synthesis of ZnO-TiO2-rGO nanocomposite is a promising and environmentally friendly approach for efficiently degrading dyes from contaminated wastewater using both UV light and natural sunlight irradiation.
Afqir Mohamed, Fasquelle Didier, Tachafine Amina
et al.
Lu-doped SrBi2Ta2O9 (SrBi2-xLuxTa2O9 where x = 0, 0.025, 0.05, 0.75 and 0.1) powders were synthesized by combination of molten salt method and solid-state route. FTIR, Raman and XRD techniques were performed to follow the transformation of reactants into the desired products. Characterization of all samples shows pure and single-phase orthorhombic structured materials obtained with plate-like morphology that is composed of fine and coarse-grained particles. The prepared powders were pressed and sintered at different temperatures up to 1200°C. Microstructure of the sintered samples is also likely to be affected by doping. The first study of dielectric measurements describes the effect of the application of DC bias, at roomtemperature, on the undoped and Lu-doped ceramics and shows that there is little or no effect of DC bias. The sample SrBi1.95Lu0.05Ta2O9 had maximal dielectric constant (ε′) and minimal dielectric loss (tanδ). In the second part of this work, the temperature dependence of ε′ and tan_ was considered. It was concluded that Lu-doping not only reduces the Curie temperature, but also brings a diffused phase transition, showing a crossover between displacive and diffusive behaviour.
Waste CRT funnel glass (FG) is a typical hazardous waste produced by the electronics industry that contains toxic lead oxide, red mud (RM) is the first waste produced during alumina production. Both of these are extremely difficult to reuse. Here, we report a method to control FG waste, in which RM was used to enhance the removal of Pb from FG via a vacuum thermal process. The removed residual glass was utilized to create glass-ceramics. The results showed that RM can enhance the lead removal from waste CRT funnel glass by the vacuum thermal process. When 30% RM was added, the removal rate reached 98.54%. A significant mechanism of enhancing delead is investigated by a Fourier transform infrared (FTIR) spectrometer and X-ray photoelectron spectroscopy (XPS). The results showed that the -Pb-O-Si-O- network structure was broken by the free calcium ions of RM. Afterward, valuable glass-ceramics with tetragonal-KAlSi2O6 and triclinic-CaSiO3 crystals were synthesized using the residual glass. The Pb, Ba, Cr, and Cu leaching concentrations of the glass-ceramics were well below the regulatory limit (5 mg/L) of the CA-EPA, as measured by the toxicity characteristic leaching procedure (TCLP) test. Overall, the results indicated that RM enhanced the removal of lead during the vacuum thermal process. The synthesis of value-added glass-ceramics reutilized silicate resources from waste cathode ray tube (CRT) funnel glass and RM.
Algirdas Augonis, Ernestas Ivanauskas, V. Bocullo
et al.
In the construction industry, the selection of sustainable materials leads to a movement towards more sustainable construction. In this study, lightweight aggregate shotcrete based on expanded glass (EG) and expanded clay (EC) is investigated. The goal of the study is to determine the influence of EG and EC inclusion on the properties of shotcrete. Ordinary Portland cement (OPC) powder with supplementary cementitious materials, such as silica fume and ground glass waste, are used as binders. The mechanical, physical and morphological properties, as well as the mineral and oxygen compositions, are obtained through compressive and flexural strength tests, thermal conductivity measurements, scanning electron microscopy with energy dispersive X-ray spectrometry (SEM–EDX), X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis. In this study, the mechanical, physical and thermal properties and waste utilization as cement supplementary materials are balanced. The shotcrete samples show that a density of 790 kg/m3 had a good thermal performance (thermal conductivity coefficient of 0.174 W/(m·K)) with the sufficient compressive strength of 6.26 MPa.
With the rapid development of the microelectronics industry, many efforts have been made to improve glass-ceramics’ sinterability, thermal conductivity, and dielectric properties, which are essential components of electronic materials. In this study, low-alkali borosilicate glass-ceramics with PVA addition and glass-BN composites were prepared and successfully sintered at 770 °C. The phase composition, density, microstructure, thermal conductivity, and dielectric constant were investigated. It was shown that PVA addition contributes to the densification process of glass-ceramics (~88% relative density, with closed/open pores in the microstructure) and improves the thermal conductivity of glass material from 1.489 to 2.453 W/K.m. On the other hand, increasing BN addition improves microstructures by decreasing porosities and thus increasing relative densities. A glass-12 wt. % BN composite sample exhibited almost full densification after sintering and presented apparent and open pores of 2.6 and 0.08%, respectively. A high thermal conductivity value of 3.955 W/K.m and a low dielectric constant of 3.00 (at 5 MHz) were observed in this material. Overall, the resulting glass-ceramic samples showed dielectric constants in the range of 2.40–4.43, providing a potential candidate for various electronic applications.
Ghaemi Mohammad Hossein, Sayenko Sergiy Y., Shkuropatenko Volodymyr
et al.
Ionic substitutions play important role in the modifications of biological apatites. Recently, the attention has been focused on the co-doping effects on functional properties of apatite based biomaterials. In this research work, the dense samples of fluorapatites, Ca10(PO4)6F2 and Ca8MgSr(PO4)6F2, were produced after sintering at 1250°C for 6 h in air. Structural characterization, carried out with XRD, IR, Raman and SEM, confirmed the formation of dense and homogeneous structure with main fluorapatite and small amount of Ca3(PO4)2 phase. The presented results also demonstrate the stability of structural and mechanical properties of fluorapatites after immersion tests in saline and buffer solutions. The durability of mechanical properties and biocompatibility of the Ca10(PO4)6F2 and Ca8MgSr(PO4)6F2 fluorapatites make these materials highly attractive for biomedical application.
Michel Henze, Wanja Reichert, Thorsten Tonnesen
et al.
Abstract Refractory linings are, in addition to loads due to corrosion and creep processes, particularly affected by thermomechanical stresses caused by the restricted thermal expansion of the lining. These stresses can occur within individual components as well as in bricks and can lead to plastic deformation, cracks, and material failure. Thus, comprehensive knowledge about thermomechanical behavior is mandatory for an accurate prediction of occurring stresses to design load‐optimized linings. This paper presents a method for utilizing refractoriness under load (RUL) tests to determine a temperature dependent static Young's modulus for refractories. In a first step, RUL tests with a negligible load are carried out in order to determine the materials temperature dependent thermal expansion coefficient. Afterwards, several RUL tests with higher loads are carried out. The measured data of change in temperature and length are then corrected by the thermal expansion and used to construct elastic lines for several temperatures, where the elastic slope is determined using the change in length and the respective load. Thus, Young's modulus for several temperatures can be determined. The obtained values for the Young's modulus are then compared to resonant frequency damping analysis measurements and validated using a finite element (FE) model of the RUL test.
Monoclinic zirconia (ZrO2) whiskers were made via the molten salt method using zirconyl chloride octahydrate (ZrOCl2 • 8H2O) as zirconium source, potassium chloride (KCl) as molten salt and lithium fluoride (LiF) as a mineraliser. DSC-TG, XRD, FE-SEM, Raman and TEM were performed to study the effects of heat treatment temperature, holding time and heating rate on the synthesis of zirconia whiskers. The results indicate that zirconia whiskers with diameters of 50-80 nm and aspect ratios of 10-30 can be obtained by heating the precursor at slow rate (3°C/min) to 718°C for 1 h and then at faster rate (7°C/min) to 950°C for 3 h. The whiskers have a smooth surface and grow in [001] direction. The key to the ZrO2 whiskers growth is the controlled dissolution and precipitation of the ZrO2 in a LiF-KCl molten salt solution environment.
Abstract The high-purity and superfine high-entropy zirconate nanopowders, namely (Y0.25La0.25Sm0.25Eu0.25)2Zr2O7 nanopowders, without agglomeration, were successfully synthesized via polymerized complex method at low temperatures for the first time. The results showed that the crystallinity degree, lattice strain, and particle size of the as-synthesized powders were gradually enhanced with the increase of the synthesis temperature from 800 to 1300 °C. The as-synthesized powders involved fluorite phase in the range of 800–1200 °C while they underwent the phase evolution from fluorite to pyrochlore at 1300 °C. It is worth mentioning that the as-synthesized powders at 900 °C are of the highest quality among all the as-synthesized powders, which is due to the fact that they not only possess the particle size of 11 nm without agglomeration, but also show high purity and good compositional uniformity.
In this study, MnO2-doped 0.96Pb(Zr0.515,Ti0.485)O3-0.04Pb(Sb0.5,Nb0.5)O3 (0.96PZT-0.04PSN) hard piezoelectric ceramics were fabricated by employing a conventional mixed-oxide process. Hard piezoelectric materials are suitable for mechanical device applications such as transducers or piezoelectric ultrasonic motors owing to their high mechanical quality factor. To improve the hard piezoelectric properties, MnO2 was selected and doped into 0.96PZT-0.04PSN ceramics in this study. When MnO2 was introduced into piezoelectric lead zirconate titanate (PZT) ceramics, the resistivity and dielectric permittivity decreased, leading to an increase in the mechanical quality factor. MnO2-doped 0.96PZT-0.04PSN ceramics have a lower piezoelectric charge coefficient and dielectric permittivity compared to those of 0.96PZT-0.04PSN ceramics. However, an enhanced mechanical quality factor of 1600 was obtained for the 0.96PZT-0.04PSN ceramics doped with 0.5 wt% of MnO2. In contrast to other hard piezoelectric materials, MnO2 doped 0.96Pb(Zr0.515,Ti0.485)O3-0.04Pb(Sb0.5,Nb0.5)O3 ceramics have a high Qm value while having an appropriate piezoelectric charge coefficient d33 and electromechanical coupling coefficient kp.