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Emerging contaminants are considered as some substances of actual or potential threat to human health or environment, which include endocrine disruptors, pharmaceutical, personal care products, nanoparticles, antibiotic resistance genes and chemicals used in packaging products, etc. The disposal and treatment of emerging contaminants has become a key problem in the field of water pollution control. The purpose of this review is to summarize published researches on emerging pollutants treatment in 2015. [ABSTRACT FROM AUTHOR]

A facile high-energy ball-milling method is developed to synthesize MoS2–graphite (MoS2–C) nanocomposites, which can be used for scalable industrial mass production. As an anode material for a lithium-ion battery, the obtained MoS2–C composite with 30% C shows a discharge capacity as high as 736 mA h g−1 in the first cycle and retains the capacity of up to 720 mA h g−1 after 200 cycles at a current density of 100 mA g−1. Even at a large rate of 2000 mA g−1, the reversible capacity is still 428 mA h g−1. Moreover, a high Coulombic efficiency is attained. After carefully comparing it with a MoS2–C composite with 20% C, raw MoS2 and pure ball-milled MoS2, we ascribe the remarkably improved performance of the MoS2–C composite with 30% C to the synergistic effect of carbon coating and nano-crystallization derived by ball milling. [ABSTRACT FROM AUTHOR]

Abstract: Fe3O4 nanoparticles were prepared by carbothermal reduction method using glucose as carbon source. Heating temperature and holding time effects on crystalline phase composition and magnetic properties of Fe3O4 nanoparticles were investigated by X-ray diffraction, field-emission scanning electron microscopy and vibrating sample magnetometer. Pure Fe3O4 nanoparticles with an average crystallite size of 48nm was obtained at higher heating temperature of 650°C and shorter holding time of 0.5h, or at lower heating temperature of 450°C and longer holding time of more than 6h. The crystallite size of Fe3O4 nanoparticles increases with heating temperature and holding time. Fe3O4 nanoparticles heated at 650°C for 2h have the highest saturation magnetization (M s =97.99emug−1), higher than Fe3O4 prepared by other techniques due to better microstructure, crystallinity and expanded crystalline cell. [ABSTRACT FROM AUTHOR]

Abstract: When sintered Sm(Co, Fe, Cu, Zr) z permanent magnets are prepared by metal injection molding, some organic binders are added in alloy powder, which leads to much residual carbon in the magnets. The residual carbon decreases magnetic properties and destroys the microstructure of the magnets. In this paper, the behavior of carbon in Sm(Co, Fe, Cu, Zr) z permanent magnets has been studied. The results indicate that Sm(Co, Fe, Cu, Zr) z magnets can keep excellent magnetic properties when the carbon content is below 0.1wt.%: Br≥10kGs, H cj ≥22kOe, BHmax ≥25MGOe. When the carbon content is above 0.1wt.%, Br, H cj and BHmax decrease with increasing carbon content evidently. Carbon consumes Zr content and forms ZrC, which reduces the volume fraction of the lamella and Sm(Co, Cu)5 phases. Thus, the cell size increases and the cellular microstructure deteriorates. When the carbon content reaches 0.43wt.%, there is not enough Sm(Co, Cu)5 phase to form a uniform cellular microstructure. Br, H cj and BHmax are approximate to zero. Since carbon has little influence on the content of Sm2(Co, Fe)17 phase, Ms can keep a high value (≥100emu/g). ZrC has high melting point (3420°C) and acts as dispersion particle in the magnets, which prevents the grains of SEM structure growing and reduces the liquid content of green compacts during sintering. Therefore, the density of the magnets decreases. [Copyright &y& Elsevier]

Spherical or nearly regular hexagonal Nd powders with the size of 20–150 nm, Fe powders with the size of 20–150 nm and Mo powders with the size of 80–100 nm were prepared by Argon and Hydrogen arc plasma. The nanostructural NdFe10.5Mo1.5 compound with ThMn12-type structure have been formed after having been mechanically alloyed for 6–12 hours and crystallized at 700–850 °C under high purified Argon atmosphere. After having been nitrided at 400–500 °C for 2 hours, NdFe10.5Mo1.5N x nanopowders with ThMn12-type structure can be obtained, which have excellent permanent magnetic properties such as iH c within range of 360.4–716.2 kA/m (4528–8997 Oe), Br within range of 0.6363–0.9831 T (6363–9831 Gs), ( BH)max within range of 42.87–166.2 kJ/m3 (5.386–20.88 MGOe). [ABSTRACT FROM AUTHOR]

• Simple evaluation for platinum group metals (PGMs) recovery from primary and secondary sources was made. • Various separation technologies for PGMs recycling from secondary resources are reviewed. • Advantages, challenges and outlook of recycling technologies are discussed. • Considerations on further promotion have been proposed. In the past decades, the demand for platinum group metals (PGMs) has increased rapidly in various applications such as electronics, chemical engineering, biomedical devices, and automotive catalytic converters. Recovery of PGMs from secondary resources is necessary for addressing the supply issues. The migration of PGMs from solid to liquid streams is irreplaceable for achieving high-purity products. Hence, it is a meaningful issue to reduce resource depletion and avoid environmental pollution during separation processes. This paper systematically reviews various improvements and new technologies for the separation and purification of PGMs, including solvent extraction, membranes separation, supercritical fluids, solid-phase extraction, photoreduction, and electrochemical methods. The separation mechanism and optimized process parameters are summarized. Particularly, the advantages, challenges, and perspective are highlighted in terms of commercial applications. This study aims to present the current research for scholars, and to identify a promising PGMs separation method that is safe and effective. Finally, several recommendations have been proposed for the further promotion of separation technologies. [ABSTRACT FROM AUTHOR]

• Highly porous ceramics were fabricated by particle-stabilized foams method. • Slags from smelting of spent automotive catalysts have been utilized. • Sintering temperature and dosage of slag determined the properties of porous ceramics. • The obtained porous ceramics show excellent physical properties. Spent automotive catalysts are the most crucial secondary resources of platinum group metals (PGMs). Currently, the iron-capturing method is one of the most promising technologies for PGMs recycling. The residual smelting slags contain large amounts of CaO, Al 2 O 3 , MgO, SiO 2 , Na 2 O, and the trace of heavy metals (e.g. Cr, Pb, Ni), which are classified as solid waste or even hazardous waste, which are typically treated by landfills, and poses severe threats to the environment. In this paper, based on the specific chemical composition of smelting slags, ceramic foams with high porosity, low density and good thermal insulation were fabricated by particle-stabilized foams method, where long-chain surfactant hexadecyltrimethylammonium chloride served as the hydrophobic modifier of slag particles and colloidal silica as binding agent. Herein, the influence of sintering temperature and the amount of smelting slag on the physical properties of obtained porous ceramics were systematically investigated. The results showed that porous ceramics with a bulk density of 0.40–0.64 g/cm3, open porosity of 74.7–83.4%, thermal conductivity of 0.10–0.21 W/(m∙K) and compressive strength of 1.04–4.01 MPa can be obtained with the mass ratio of slag: colloidal silica of 2:1, 3:1 and 4:1 sintered at 1000°C for 2 h. The porous ceramics with these unique properties are promising to be applied as thermal insulation materials. This convenient, facile and versatile approach is also expected to fabricate porous ceramics by using other solid waste as raw materials. [ABSTRACT FROM AUTHOR]

• Iron was used as collector for PGMs recovery. • Recovery efficiency of PGMs was 99.25 % by iron melting collection. • The formation of ferrosilicon was avoided at 1300–1400 °C. • The effect of slag have been studied in detail. • The recovery efficiency was over 99 % at 50 kg scale experiments. Automobile catalysts sector is the largest consumption field of platinum group metals (PGMs) worldwide, and they are the most important secondary resources of Pt, Pd, and Rh once they reach the end of life. However, recycling PGMs from spent automotive catalysts is of great difficulty due to their complex physicochemical characteristics and low concentrations. A highly efficient technology for recovery of Pt, Pd, and Rh by iron melting collection was proposed. Owing to the same face-centred cubic structure and close atomic radius, iron powder is used as collector since Fe and PGMs can form continuous solid solution. PGMs are concentrated and formed Fe-PGMs alloy phase at a relatively low temperature of 1300–1400 °C through adjustment of slag compositions. The principles of slag design were put forward, and the effects of basicity, slag compositions and collector dosage on the recovery efficiency of PGMs were studied. Factsage 7.0 software (CRCT-Thermfact and GTT-Technologies) was used to calculate slag viscosity and simulate slag reaction equilibrium during the melting process. The recovery efficiency of PGMs was 99.25 % under the optimized conditions: mass ratio of CaO/Na 2 O=35:20, CaF 2 5 wt.%, Na 2 B 4 O 7 8.5 wt.%, collector Fe 15 wt.%, and 5 wt.% C, where the concentration of Pt, Pd and Rh in slag phase were 2.398, 3.879, and 0.976 g/t, respectively. Meanwhile, the formation of ferrosilicon (FeSi 2 , FeSi) was avoided. 50 kg pilot-scale experiments also achieved over 99 % recovery efficiency of PGMs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The advances in recycling LiFePO 4 have been reviewed. • Direct regeneration technologies of LiFePO 4 are discussed. • Hydrometallurgical leaching methods of LiFePO 4 are outlined. • Challenges and future directions for LiFePO 4 recycling are proposed. LiFePO 4 batteries have become one of the most promising batteries due to their excellent electrochemical performances, long life cycle, safety, and abundant mineral resources. As a result, the demand and scraped LiFePO 4 batteries increased dramatically in recent years. The recycling of waste LiFePO 4 batteries has raised great attention with the consideration of environmental issues and resources conservation. To date, there are massive literatures on the recycling of LiFePO 4 batteries aiming at providing an effective, economic and environmentally sustainable approach. Consequently, this review sorts out and analyzes the current advances in recycling LiFePO 4 from spent lithium batteries with the purpose of promoting the improvement of their recycling. Based on the damage degree of LiFePO 4 materials, direction regeneration and hydrometallurgical leaching are the main recycling processes. The direction regeneration of LiFePO 4 routes including high temperature solid regeneration, hydro/solvent thermal regeneration and electrochemical lithiation are discussed in detail. Inorganic or organic acid leaching, mechanically activated leaching and other leaching methods are reviewed as well. Finally, by comparing the various recycling technologies, the challenges are outlines and future directions for promoting the recycling effectiveness are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heavy metals in MSWI fly ash were reduced into alloy by SAD. • Reduction rates of iron and zinc were 67 and 100% • Transparent glass for building was made from MSWI fly ash. • 115 ∼ 213 dollars were earned after disposing of 500 kg of MSWI fly ash. Municipal solid waste incineration (MSWI) fly ash is a hazardous waste containing heavy metals. Secondary aluminum dross (SAD) is a hazardous waste discharged from aluminum smelting, containing active aluminum nitride (AlN). In this work, heavy metals from MSWI fly ash were reduced into alloy by AlN from SAD, and the slag was manufactured into transparent glass for building. Reduction of iron and zinc was 67 and 100 %, respectively. Reduction mechanism was explored after applying XRD, XRF and thermodynamics analysis. It was found that the reduction reaction was an ion reaction. The AlN and heavy metal oxide transformed into anionic group containing nitrogen and heavy metal cation, after entering slag. The heavy metals were reduced into alloy after electron was transferred from anionic group to cation. In addition, the reduced iron and zinc could merge into alloy, which inhibited evaporation of zinc. Yellow transparent glass was obtained after the reduction process. Yellow was come from titanium oxide, which could not be reduced by AlN. Microhardness, density and water absorption of the transparent glass were 741 HV, 2.86 g·cm−3 and 0.04 %, respectively. Leaching content of Ni, Cu, Zn and Pb of the glass were 0.1, <0.1, 0.6 and < 0.1 mg/L, respectively, all below the TCLP limit. About 115 ∼ 213 dollars were earned after manufacturing 500 kg of MSWI fly ash into transparent glass. This work provided a novel idea of recycling solid waste into alloy and transparent glass for building. [ABSTRACT FROM AUTHOR]

Aluminum dross (AD) and red mud (RM) are waste discharged from aluminum industry. AD and RM contain 5-15 wt% of hazardous aluminum nitride (AlN) and 20–50 wt% of iron oxide, respectively. In this work, alumina-based cermet was in-situ prepared from AD and RM, after reduction of iron oxide with AlN by pyrometallurgy. Cermet was consisted of metal reinforcement phase about 1 μm, alumina matrix phase and low-melting aluminosilicate binder. Mechanism of in-situ preparation was studied after exploring phase composition of the cermet powder. Iron, silicon and titanium oxide from RM was reduced into Fe 3 Si and TiN, which acted metal reinforcement phase in cermet. Reaction was consisted of two steps, Fe 2 O 3 , TiO 2 and AlN dissolving into low-melting aluminosilicate and electron transferring from AlN to Fe 2 O 3 , SiO 2 and TiO 2. Content of Fe in ceramic phase was decreased from 6 at.% to 1 at.% after reduction reaction. Low-melting aluminosilicate acted both reaction solvent for reduction reaction, and binder for metal reinforcement phase and alumina matrix phase. More low-melting aluminosilicate was formed when temperature was increased from 1200 °C to 1400 °C, which made more metal balls be formed. The metal ball and alumina were bonded by low-melting aluminosilicate, which increased the bond strength between reinforcement phase and ceramic phase in cermet. This work achieved a total recycle of AD and RM into cermet. It was proposed a novel idea of in-situ preparing cermet, which was generating metal reinforcement phase in ceramic matrix phase. [Display omitted] [ABSTRACT FROM AUTHOR]

To prepare bio-scaffolds with multi-stage pores, excellent mechanical and biological properties to meet the requirements of personalized bone repair, digital light processing using Pickering emulsion as paste has been proposed here firstly for porous hydroxyapatite scaffolds with complex shape and fine microstructure. It is found that dispersant content, solid loading and oil to water ratio of Pickering emulsions play vital roles on the controlling of pore morphology and pore size distribution of final hydroxyapatite ceramic foams. The multi-stage pores consist of millimeter-scale pores designed by 3D models and micro-pores below 10 µm derived from emulsion droplets. Due to the integration of hierarchical pores at different scale levels and micropores, hydroxyapatite ceramic foams possess outstanding compressive strength of 4.46–8.03 MPa at porosity of 76.59-72.96%. In vitro cell experiments illustrate that rat bone mesenchymal stem cells can spread and adhere to bio-scaffolds, promoting cell proliferation effectively and further verifying their good biocompatibility. [ABSTRACT FROM AUTHOR]

Electrolytic manganese residue (EMR) is toxic industrial solid waste. Electrolytic manganese enterprises have established a desulfurization and sulfuric acid production process to address its storage risks leaving desulfurized EMR (DEMR). In this study, DEMR was used as a raw material to prepare glass-ceramics. A method of melting and one-stage heat treatment was used to realize controlled crystallization of diopside, with calcium fluoride sludge (FS) as a nucleating agent. The impact of CaF 2 on the glass network structure, as well as on the microstructure and performance of the glass-ceramics, are discussed. CaF 2 can greatly improve the nucleation ability of glass precursors. When the addition of FS is small, the phase transition of glass is dominated by the diffusion of atoms and growth of diopside, forming dendritic crystals. When introducing more FS, the glass-ceramics form smaller island-shaped crystals due to many nucleation sites. The prepared glass-ceramics show excellent mechanical properties and chemical stability. Its hardness exceeds 6.5 GPa, with bending strength over 110 MPa. The acid resistance of glass-ceramics is higher than 99.5%, and the toxic metals in the raw materials are stable solidified. This study perfects the technology of EMR desulfurization pretreatment, which provides an effective graded recycling approach for EMR. [ABSTRACT FROM AUTHOR]

Eu is completely recovered from BaMgAl10O17:Eu2+ (I) by disintegration via alkaline fusion using NaOH and (I) in a 1:1 mass ratio for ball milling followed by heating (Fe crucible, 150-375 °C, 2 h). [ABSTRACT FROM AUTHOR]

The reactive AlN, heavy metal ions, and salts in secondary aluminum dross make them harmful to the environment and difficult to handle, and therefore categorized as hazardous solid waste. A novel, simple, and versatile technique has been proposed here to prepare hierarchically porous ceramics using secondary aluminum dross as the sole raw material, namely, the hydrolysis‐induced simultaneous foaming and coagulation casting method. As the main component, Al and AlN could be hydrolyzed to generate aluminum hydroxide sol, which can form three‐dimensional network and lead to the outstanding compressive strength of green body (7.03 MPa). Gas release during hydrolysis, high‐temperature oxidation of AlN, and metallic Al based on Kirkendall effect could account for the final multilevel pores. The utilization of harmful components in secondary aluminum dross, supplys an alternative colloidal forming way for porous green body with complex shape when combined with other ceramic powders or inorganic solid waste. Low sintering shrinkage of 1.38%–3.60% for hierarchically porous ceramics offers this highly effective and low‐cost method to be easily promoted for industrial production. [ABSTRACT FROM AUTHOR]

CaO MgO SiO 2 (CMS) glass-ceramics preparation normally needs two-step heat treatment (nucleation and crystal growth). In this work, CMS glass-ceramics are successfully produced by one-step heat treatment by building Ca 2+ and Mg 2+ fast diffusion layer between the residual glass and diopside crystal. High-temperature X-ray diffraction (HTXRD) shows that diopside crystals formed during the crystallization of CMS glass. At the glass layer between diopside crystal and residual glass, an enrichment of Na + is observed by energy dispersive spectroscopy line scanning (EDSLS), which increases the Si O Na bonds that promote Ca 2+ and Mg 2+ ions diffusion. This layer eventually promotes further growth or ripening of the diopside crystals. Thus, nucleation and crystal growth of the CMS glass proceed continuously at the crystallization peak temperature (T nc ), detected by differential scanning calorimetry. Thereby, one-step crystallization of the CMS glass-ceramics becomes possible and practical. [ABSTRACT FROM AUTHOR]

Particle-stabilized foams employing dual-phase sol of boehmite in combination with silica to prepare mullite ceramic foams has been proposed for the first time. The obtained mullite ceramic foams possess hierarchical pores, that is micropores derived from the air bubble templates and open windows formed by grain growth at thin area of pore wall according to the mullitization reaction. Furthermore, nanoparticles favor the improvement of specific surface area of ceramic foams, and wrinkles caused by drying shrinkage would retain when sintering at low temperature of 900℃-1100℃, leading to high specific surface area of 94.4-219.2 m2/g. The achieved mullite ceramic foams present relatively high compressive strength of 6.6−40.4 MPa at a high open porosity of 64.0 %–87.0 %, and their thermal conductivity could reach as low as 0.10 W/(m·K), which would make them promising lightweight materials applied in broad fields including thermal insulations, filters, bio-scaffolds, catalyst supports and the like. [ABSTRACT FROM AUTHOR]

Secondary aluminum dross (SAD) and red mud (RM) are solid waste discharged from aluminum industry. SAD contains 10–25 wt% aluminum nitride (AlN) and RM contains 20–50 wt% iron oxide. In this work, porous metal-ceramic composite was in-situ made from SAD and RM. Iron oxide was reduced into Fe 2 Si by AlN, and the generated nitrogen created pores. It was studied that effect of raw material and thermal treatment on pore structure and properties of the composite. Porosity, bulk density and compressive strength of composite were 65.78%, 1.03 g/cm3 and 17.77 MPa, when SAD content was 40 wt% and sintering temperature was 1450 °C. About 95.9% of malachite green in waste water was adsorbed by composite after 24 h. The composite could be recycled by magnetic separation after adsorption, attributed to the magnetic Fe 2 Si. This work proposed a novel idea of making recyclable porous material for adsorption of organics in waste water. [Display omitted] • Porous metal-ceramic composite was in-situ made from SAD and RM. • Porosity and bulk density of composite were 65.78% and 1.03 g/cm3. • 95.9% of malachite green in waste water was adsorbed by composite after 24 h. • The composite could be recycled by magnetic separation after adsorption. [ABSTRACT FROM AUTHOR]

In this study, blast furnace slag (BFS) was activated using water- and ethanol-assisted milling (AM). BFS-cement composites (BFS-CC) were prepared using milled BFS and cement. The effects of the activation process on the mechanical properties and hydration of BFS-CC were investigated. Results showed that water- and ethanol-AM significantly reduced the median particle size (D50) and improved the particle size distribution of BFS compared to dry milling. Water-AM increased the compressive strength of BFS-CC at 3 days by 19.9 % and decreased the compressive strength at 28 days by 6.7 %. While ethanol-AM increased the compressive strengths at 3 and 28 days by 17.2 and 22.4 %, respectively. Water-AM improved the early strength of BFS-CC, whereas ethanol-AM contributed significantly to the late strength development of BFS-CC. This study provides an effective and convenient method for regulating the mechanical properties of cement composites containing high-volume BFS. • Dry milling and water- and ethanol-AM are used to activate the BFS, respectively • Water-AM system develops at a faster rate and achieves an increase in early strength • Ethanol-AM promotes the dissolution of BFS and the stimulation of pozzolanic activity • AM process regulates the early and late strength by controlling the reactivity of BFS [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs) are strategic metals. Auto-exhaust catalysts are their main application fields. The recovery of PGMs from spent auto-exhaust catalysts has remarkable economic value and strategic significance. Aiming at the problems of ferrosilicon generation for Fe capturing and subsequent oxygen blowing to remove iron with high energy consumption and heat release, a technology of Fe–Sn synergistic capturing PGMs was proposed. Taking full the advantage of the lower melting point of Fe–Sn alloy (<1200 °C) and its unique affinity for PGMs, the PGMs were captured at approximate 1400 °C with Fe–Sn as the collector. In experiment, 500 g of spent auto-exhaust catalysts were employed to minimize error and approximate industrial production. The mechanism of Fe–Sn synergistic capturing PGMs was elucidated. The generation of Fe–Sn-PGMs alloy lowered the activity of [PGMs] in the system, accelerated the reduction of the PGMs oxides and promoted the alloying of [PGMs]. Therefore, Fe–Sn synergistic capturing PGMs was realized. The inability of Si to enter the alloy phase was confirmed by theoretical calculations, avoiding the generation of ferrosilicon. The effects of basicity, CaF 2 , m (Fe)/ m (Sn) and the amount of collector on capturing PGMs were optimized. Under the optimized conditions (basicity R = 1.1, spent auto-exhaust catalysts 70 wt%, CaO 30 wt%, B 2 O 3 10 wt%, CaF 2 7 wt%, m (Fe)/ m (Sn) = 1/1 and the collector 15 wt%), the content of PGMs in the slag phase was 2.46 g/t. It is feasible to remove Fe and Sn by oxidation to achieve the purpose of PGMs enrichment. This technology offers guidance on the safe, environmentally sound, and efficient disposal of spent auto-exhaust catalysts, promoting the sustainable development of PGMs. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphite carbon nitride (g-C 3 N 4) is regarded as a potential candidate to settle environmental and energy issues, but its activity remains unsatisfactory due to the huge exciton effect and delayed charge transfer. Herein, the effects of phosphorus-doping and two-dimensional (2D) porous structures on the transition among singlet excitons, triplet excitons, and carriers and consequently the regulation mechanism of reactive oxygen species have been intensively studied. The calculations of the density functional theory and experimental results confirmed that P-doping could induce a dual built-in electric field to provide a driving force (up to 0.3 eV) for exciton dissociation. The light response capability, exciton dissociation, and carrier migration efficiency were significantly enhanced by the synergistic effect of the dual electric field and 2D porous structure. The optimal sample exhibited excellent H 2 evolution rate and tetracycline degradation rate under visible-light irradiation which were approximately 25 and 7.1 times higher than those of bulk g-C 3 N 4 , respectively. The improved photocatalytic activity can also be demonstrated by a 2.9-fold and 3.2-fold increase in ·O 2 – and H 2 O 2 production, respectively. This work provides a new perspective and approach to improve the performance of polymer photocatalysts and the targeted regulation of active species using exciton engineering. [Display omitted] •P-doping and 2D porous structure boost exciton dissociation and charge transfer. •P–CNS-0.8 exhibits outstanding H 2 production and molecular oxygen activation. •The mechanism of Double Electric Field Driven Exciton Dissociation was first proposed. •This work provides a new approach for targeted regulation of reactive oxygen species. [ABSTRACT FROM AUTHOR]

Abstract: Radially oriented Sm(Co,Fe,Cu,Zr) z ring magnets are prepared by powder metallurgy with appropriate magnetic field molding, sintering process and aging treatment. The results indicate that radially oriented Sm(Co,Fe,Cu,Zr) z ring magnets have obvious anisotropy of thermal expansion and sintering shrinkage, which easily lead to the splits and deformation of the ring magnets. So, slow heating, vacuum pre-sintering in sintering process and various quenching processes at different steps during quenching are adopted. The magnets have excellent magnetic properties: B r =10.8 kGs, Hcj =27.6 kOe, BHmax =28.1 MGOe. Besides, there is a uniform magnetization field on the surface of the ring magnets. The average surface magnetization field () is 1.502 kGs. The deviation from average (α) is only 4.2%. The microstructure of the magnets consists of a mixture of homogeneous cellular and lamella structures. [Copyright &y& Elsevier]

Graphitic carbon nitride (g-C 3 N 4) can be used to degrade organic pollutants in wastewater owing to its excellent chemical stability, tunable band structure, and visible light (VL) responsiveness. Nevertheless, the application of pristine g-C 3 N 4 is significantly hindered by its low specific surface area, unsatisfactory VL utilization (<460 nm), high exciton binding energy (E b ≈ 0.2 eV), and low photoinduced carrier separation. Development of strategies to overcome these limitations and improve the degradation efficiency has attracted considerable attention. Considering the principles of photoexcitation, this paper describes two unique photoexcitation processes, the carrier and exciton processes, of which the strong exciton effect of g-C 3 N 4 has not been extensively discussed in prior reviews. In addition, we comparatively present the latest progress and related mechanisms of the modification strategies such as morphology controlling, elemental doping, defect engineering, and heterojunction building employed in polluted water treatment are compared from the carrier and exciton perspectives. Finally, the unique characteristics, challenges, and future directions are discussed. This review presents research progress on the photoexcitation processes involved in g–C 3 N 4 –based materials, and proposes that the modification based on the exciton effect and direct verification of the transfer mechanism in the heterojunction can be potential areas of future investigations. [Display omitted] • Energy band theory and exciton effect related to photoexcitation mechanism were discussed. • Various modification strategies for enhancing the photocatalytic activity of g-C 3 N 4 are reviewed. • Construction of the Z-scheme system can improve photocatalytic activity. [ABSTRACT FROM AUTHOR]

Secondary aluminum dross (SAD) is a solid waste of aluminum dross after it is extracted aluminum. Soda-lime-aluminosilicate (SLAS) glass-ceramics with high alumina contents (over 30 wt%) were successfully manufactured from SAD using pyrometallurgy without additional nucleation agents. The nucleation process of SLAS glass was studied, and 670 °C was selected as the nucleation temperature according to differential scanning calorimetry and X-ray diffraction results. Field-emission transmission electron microscopy was applied to study the microstructure of the specimens thermally treated at 670 °C for 3 and 12 h. Nucleation consisted of two parts: iron oxide nucleation and jadeite nucleation. During iron oxide nucleation, when the thermal treatment time increased from 3 to 12 h, the iron oxides first congregated in an amorphous phase and a small amount of metastable crystal; then, the congregated iron oxides crystallized into hematite and magnetite, which acted as crystal nuclei. During jadeite nucleation, the jadeite spontaneously crystallized from the glass matrix after thermal treatment at 670 °C. When the thermal treatment time increased from 3 to 12 h, the size of the jadeite crystals increased from approximately 6 to 12 nm. Jadeite crystals with a diameter of 12 nm acted as crystal nuclei. For glass-ceramics with a high content of aluminum and sodium, jadeite crystals can act as crystal nuclei without additional nucleation agents. [Display omitted] [ABSTRACT FROM AUTHOR]

In consideration of recycling solid waste to achieve high value-added products, glass-ceramics have been fabricated from municipal solid waste incineration (MSWI) fly ash, pickling sludge (PS), and waste glass (WG) by melting at 1450 °C firstly to achieve parent glass and then crystallizing at 850 °C. Results demonstrated that heavy metals have been well solidified in the prepared glass-ceramics, and relatively/extremely low leaching concentrations of heavy metals have been detected. The synthetic toxicity index of heavy metals has been greatly reduced from 7-18 to <3.2 after crystallization treatment, and the leaching concentrations of Cr, Ni, Zn, Cu, and Pb are 0.15, 0.05, 0.26, 0.12, 0.19 mg L-1 respectively. Chemical morphology analysis, principal component analysis, TEM and EPMA were utilized to clarify the migration, transformation, and solidification mechanism of heavy metals from the as-received solid wastes. The major heavy metals, Cr and Ni which is responsible for the most toxicity, mainly exist in form of the oxidation state and residual state in parent glass, while the residual state in the glass-ceramics. The solidification performance was mostly positively correlated with the form of residue state, which the stability of heavy metals in glass-ceramics is improved. The solidification mechanism of heavy metals in glass-ceramics could be explained by the combination of chemical solidification/stabilization and physical coating. The TEM and EPMA confirmed that Cr and Ni mainly exist in the spinel crystalline (NiCr 2 O 4 , Fe 0.99 Ni 0.01 Fe 1.97 Cr 0.03 O 4) by solid solution or chemical substitution, and a small amount of Cr in the diopside phase. Pb, Cu, and Zn are homogenously dispersed in the glass-ceramics, which is considered as physical coating solidification. [Display omitted] [ABSTRACT FROM AUTHOR]