Milling Method Research Articles

One-step hydrothermal synthesis of CeVO4/bentonite nanocomposite as a dual-functional photocatalytic adsorbent for the removal of methylene blue from aqueous solutions

Cerium vanadate/modified bentonite (CeVO4/mbt) nanocomposite with different composition percentages was synthesized through a simple one-step hydrothermal method at 180 ℃, and then its photocatalytic activity was evaluated by decolorizing methylene blue (MB) in an aqueous solution under light exposure. In order to increase the surface area as an important parameter in photocatalytic processes, bentonite was modified by ball mill method. The structural and optical properties of the synthesized composites were determined by XRD, FT-IR, DRS, FESEM, EDS, and BET measurements. XRD and EDS results confirmed the successful synthesis of pure CeVO4. FESEM images and EDS mapping showed a proper distribution of rice-like CeVO4 nanoparticles on bentonite. The removal efficiency of MB with only 0.1 g of CeVO4/mbt nanocomposite in 15 min was about 99%, which is significant compared to neat bentonite and pure CeVO4 with efficiency of 30% and 57%. The mentioned nanocomposite followed the first-order kinetics, had a reaction rate constant equal to 0.1483 min–1, and showed acceptable stability in five consecutive cycles.

Effects of longitudinal ultrasonic vibration on tool wear behaviors in side milling of GH4169D superalloy

The GH4169D superalloy, a novel Nickel-based material widely acknowledged for its exceptional high temperature strength and fatigue resistance properties, plays a pivotal role in the production of critical components of contemporary aero-engines. The material, however, falls under the category of a typical difficult-to-cut metallic material due to the substantial cutting forces and significant tool wear experienced during the machining process. In this paper, a method of longitudinal ultrasonic vibration assisted side milling (LUVM) was developed to extend tool life. The investigation primarily involved an analysis of tool wear behaviors, including milling force, tool life, morphologies of tool wear, and various underlying wear mechanisms in LUVM and conventional milling (CM) of GH4169D superalloy. The results demonstrate that LUVM exhibits the advantage of reducing milling forces and prolonging tool life in comparison to CM. Throughout the entire milling process, the maximum milling force of LUVM is consistently smaller than that of CM, displaying a comparatively slower growth trend. At the conclusion of machining, while CM reaches a maximum milling force of 360.3 N, the maximum milling force of LUVM (195.9 N) is significantly lower. The tool life of LUVM is 28.2 min, representing a 33 % increase compared to CM (21.2 min). Material adhesion, coating delamination, and built-up edge (BUE) phenomena can be observed on both the tool rake face and flank face in CM. LUVM contributes to mitigation of bonding phenomena, prevention of BUE formation, and avoidance of abrasive wear in comparison to CM. However, it is prone to lead to tool tip chipping. For CM, the tool wear mechanisms include adhesive wear, oxidation wear, abrasive wear and diffusion wear; whereas for LUVM, the tool wear mechanisms comprise of adhesive wear, oxidation wear and diffusion wear.

Enhanced Hard Magnetic Performance for MnBi Green Powders

Mn55Bi45 melt - spun ribbons were prepared by using the melt-spinning technique followed by annealing in Ar/5%H2 gas mixture. The in-situ formation of ferromagnetic phase (denoted as LTP) of MnBi was observed by the multi-section cycled Differential Scanning Calorimetry (DSC) method. It was found that, the optimal annealing temperature range for forming MnBi LTP is 250 – 280 oC. The prolonging annealing time increases the content of MnBi LTP leading to the increase of saturation magnetization Ms but paid by the drop of the intrinsic coercivity iHc. The MnBi green powders were prepared by the Low Energy Ball Milling method (LEBM) in N2 liquid. The maximum energy product of MnBi green powders is estimated about 10.8 MGOe.

Mechanothermal-milling-assisted removal of native passivation layer for refreshing lithium metal anodes

Securing the stable and reliable operation of high-energy lithium (Li) metal batteries (LMBs) is crucial for fundamental studies and practical applications. However, commercial Li metal anodes (LMAs) suffer from unreliable pre-passivation during vendor-specific manufacturing, which deteriorates their surface quality and compromises the reproducibility of novel post-treatments and new electrolytes. To avoid chemical and structural degradation originating from the initial LMA, this study presents a mechanothermal milling (MTM) method using heating blades to smoothly peel off the native passivation layer (NPL) on the LMA surface, thereby exposing near-fresh Li. Compared to as-received LMA, the LMA revitalized by the MTM process (MTM-Li) exhibited faster kinetics and less interfacial resistance, promoting spatially uniform, dendrite-less Li plating and pit-less Li stripping. The MTM-guided surface equalization of the LMA enables an accurate comparison of the electrolyte-derived SEI properties, which is essential for identifying an electrolyte that is genuinely compatible with freshly exposed Li. By combining it with highly stable electrolytes, MTM-Li can regulate the structural evolution of LMAs, effectively securing cycling stability for LMBs, even under stringent conditions.

Optimizing interfacial modification for enhanced performance of Na3V2(PO4)3 cathode in sodium-ion batteries

A novel cathode material, Na3V2(PO4)3C@CNT (NVP/C@CNT), was designed and synthesized by a low-temperature solid-phase drying ball milling method. The nanoparticles are covered by an amorphous carbon layer, and simultaneously enveloped and embedded by carbon nanotubes on the surface. Consequently, a carbon network consisting of carbon nanotubes and amorphous carbon layers is formed in the material. Notably, no phase transition during the intercalation process of sodium ions, confirming the stable crystal structure, which ensures the stability and reversibility of the large-capacity cathode in the large-volume change. The addition of CNTs can regulate the size of NVP particles, increase the contact area between NVP and electrolyte, leading to an enhancement in the sodium ion diffusion coefficient. The NVP/C@CNT electrode exhibits a capacity of 114.5 mA h g−1 at 0.1 C. After 2650 cycles, the discharge capacity retention rate is 98.2 % at 10 C. Even at 20 C, the discharge capacity is still 93.3 mA h g−1 after 2710 cycles, with a retention rate of 99.5 %. This work provides a feasible approach for the design of low-cost, long-life, high-performance cathode materials for sodium-ion batteries.

Microstructure Analysis and Powder Bed Fusion of Inconel 738 Powder Materials Mixed with Nano-Sized Ceramic Powders

Powder materials strengthened by oxide dispersion are generally made by in-situ method; direct oxide dispersing in matrix powders during atomization. There is also ex-situ method; oxides dispersing by mixing with matrix powders. In this study powder mixtures (Inconel 738 matrix powder + SiO2 powder + Al2O3 powder) were mechanically manufactured by ex-situ process, a lowenergy ball milling method. Then, specimens of the as-mill powders were manufactured by laser powder bed fusion (L-PBF) method and spark plasma sintering (SPS) process. The microstructures of each prepared specimen were compared according to process variables. SEM, EDS, XRD, and Electron Backscatter Diffraction (EBSD) analyses were applied in this study.

Effect of ball milling time on Sr0.7Sm0.3Fe0.4Co0.6O2.65 perovskites and their application as semiconductor layers in dye-sensitized solar cells

The practical utilization of TiO2 as a semiconductor in dye-sensitized solar cells (DSSCs) has been set back by poor visible light absorption, high charge carrier recombination, and low electrical conductivity, which reduce the power conversion efficiency (PCE) and sustainability of the device. In this respect, perovskites with excellent properties, such as large surface area, good optical properties, high electrical conductivity, and superior electrochemical stability, have recently emerged as promising alternatives capable of overcoming the drawbacks of TiO2. Herein, Sr0.7Sm0.3Fe0.4Co0.6O2.65 (SSFC) perovskites were prepared via the ball milling method at various milling times of 0, 5, and 10 h, and the obtained samples were denoted by SSFC-0, SSCF-5, and SSCF-10, respectively. Increasing the ball milling time led to a significant reduction in nanoparticle size and agglomeration, which, in turn, increased the surface area and electrical conductivity of the samples. As a consequence, the SSFC-10 perovskite exhibited the smallest average particle sizes (18.9 nm) with the largest surface area (61.8 m2 g−1) and minimum defects, which allowed for efficient electron transport, resulting in the best electrical conductivity of 49.8 S cm−1. Ultimately, DSSCs fabricated using SSFC-10 semiconductor layers achieved an optimum PCE of 6.01 %, which is an improvement of 8.67 %, 1.1 %, and 6.56 % for SSFC-0 (3.69 %), SSFC-5 (4.96 %), and TiO2 (5.64 %), respectively. Thus, varying the ball milling time can be used as an effective technique to tailor the physicochemical properties of SSFC to suit desired applications, particularly the fabrication of highly efficient and sustainable DSSC semiconductor layers.

Analysis and Optimization of a Novel Compact Compliant 2-DOF Positioner for Positioning to Assess Bio-Specimen Characteristics

A novel compact 2-DOF compliant positioner is developed for the purpose of achieving good characteristics such as high natural frequency, high displacement amplification ratio, good linear motion, and compact structure based on its symmetrical structure. To be specific, the developed stage is proposed according to an advanced six-lever displacement amplifier arranged at an inclination angle of the rigid bar utilizing right circular hinges and a parallel guiding mechanism with integrated flexure leaf hinges to attain the above-mentioned characteristics and reduce the decoupling mobility error. First, to quickly assess the initial quality response, an integration method of kinetostatic analysis, the Lagrange method, and finite element analysis was applied to evaluate and verify the quality characteristic of the stage. The experimental result showed that the error between the analytical method and the FEA method was 1.3%, which was relatively small and reliable for quickly assessing the primary quality response of the proposed positioner. Next, to boost the important output characteristics of the developed positioner, the integration approach of the response surface method and NSGA-II algorithm was utilized to find the optimal design variables. Finally, a prototype was manufactured based on the CNC milling method to validate the experimental and FEA analysis results. The attained results show that the optimal results of safety factor and output displacement were 2.4025 and 248.9 µm. Moreover, the FEA verification results were 2.4989 and 242.16 µm, with errors for safety factor and output displacement between the optimal result and the FEA result of 3.86% and 2.78%, respectively. In addition, the simulation and experimental results of the first natural frequency were 371.83 Hz and 329.59 Hz, respectively, and the error between the FEA result and experimental result for the first natural frequency was 11.36%. Furthermore, the achieved results show that the relationship between input displacement and output displacement of the experimental result and the FEA result of the developed structure achieved a good linear connection. These results suggest that the proposed positioner will be a potential structure employed in precise positioning systems and nanoindentation testing positioning systems for checking bio-specimens’ behaviors.

Visible‐Light Photoreforming of Biomass Derivatives through MBi2O4‐P25 Heterostructures: Study of the Influence of Metals (M = Cu, Ni, Zn, Co)

AbstractIn this work, MBi2O4‐P25 (M = Cu, Ni, Co, Zn) composites are successfully synthesized by a simple ball milling method by varying some parameters (rotation speed, rotation time, metal/TiO2 ratio) to optimize the preparation conditions. The noble metal‐free TiO2‐based photocatalysts are used to carry out the partial oxidation of glucose and glycerol with the simultaneous H2 production under simulated solar light irradiation. Starting from glucose, 2.6 mmol of H2 are obtained with a conversion of 34%, along with arabinose, formic acid and gluconic acid as main intermediates. By using glycerol, 3.2 mmol of H2 are produced, with 17% conversion and the production of dihydroxyacetone and glycolic acid. The composites exhibit higher activity than pure P25 and CuBi2O4 (CBO). The produced H2 amount is comparable to that reported in the literature by using Pt–TiO2 photocatalysts. This study offers a paradigm for the future design of bifunctional photocatalysts for simultaneous noble metal‐free H2 production and biomass valorization under environmentally friendly conditions with a possible scale up of the process.

One-pot synthesis of Li3xLa2/3−xTiO3/PVA composite with high tunable electrical attributes governed by the Li+ content

The primary goal of this study is to elucidate the structural and electrical characteristics, alongside potential applications, of ceramic-polymeric composites. These composites are achieved by incorporating lithium-lanthanum titanates (Li3xLa2/3−xTiO3 - LLTO) into a polyvinyl alcohol polymeric matrix (PVA). The synthesis of lithium-lanthanum titanates occurred through high-energy ball milling method. Then, three types of composites were produced using the solvent casting method: a sample of pure Poly (vinyl alcohol) polymer (PVA), a second PVA composite with the addition of La0·59Li0·24TiO3 (Li-0.24) and a third sample with La0·56Li0·33TiO3 (Li-0.33). SEM and AFM analyzes revealed notable changes in the morphology and 3D spatial patterns of the films upon incorporating lithium-lanthanum titanates into the PVA matrix. The PVA film presents a topography featuring a more evenly distributed range of topographic heights, indicating a smoother surface structure. With varying LLTO content, the morphology of the PVA composite underwent changes. The lower roughness of the PVA surface is evident from its measured average roughness value (Ra = 1.9 ± 0.5 nm). Upon incorporating LLTO, the surfaces displayed increased roughness, measuring specifically at 40.1 ± 7.3 nm (Li-0.24) and 22.7 ± 5.5 nm (Li-0.33). Notably, there was an approximately 43 % reduction in the average roughness value from Li-0.24 to Li-0.33. The analysis by Raman allowed the identification of functional groups of the PVA polymeric chain, in addition to the presence of some vibrational modes related to the structure of lithium-lanthanum titanates for the sample with the highest content of Li+ ions (Li-0.33). Finally, the sample Li-0.33 showed the lowest value of electrical resistance (67 kΩ) and of phase angle (16°), compared to the PVA (100 MΩ and 90°). These results show that the presence of the LLTO changed the insulating behavior of the PVA matrix changed and improved potential to electronic applications.

Structural modulation of Nb2O5 for enhanced Lithium-ion battery Performance: Insights from density functional theory and electrochemical characterization

Lithium-ion batteries (LIBs), extensively utilized today, encounter challenges with anode materials, such as capacity degradation and shortened cycle life during prolonged cyclic charging and discharging. These issues significantly hinder further advancements and applications of LIBs. Among various innovative anode materials, niobium pentoxide (Nb2O5) has garnered considerable interest due to its high specific capacity and exceptional cycling stability. However, different crystal types of Nb2O5 have different structures and properties, so they need to be studied in depth to find better anode materials for LIBs. In this paper, pseudo-hexagonal (TT-Nb2O5), orthorhombic (T-Nb2O5), and monoclinic (H-Nb2O5) crystalline forms of Nb2O5 have been prepared by simple ball milling and calcination methods. We have calculated the structural model of the material based on the density flooding theory (DFT), and the results have demonstrated that the T-Nb2O5 has a large structural advantage, which is characterized by a very low diffusion energy barrier, a low internal resistance, and a higher conductivity. The electrochemical properties of the material were also analyzed, and T-Nb2O5 has excellent cycling stability and rate performance. After 200 cycles (at 0.1A/g), the specific capacity of T-Nb2O5 was maintained at 440.8mAh/g. 3000 cycles at high current (at 5A/g) maintained a specific capacity of 95mAh/g. T-Nb2O5 has great potential, which has already been proved. With the continuous pursuit and development of energy storage technology, we believe that the research of different crystalline types of Nb2O5 will provide us with more efficient and reliable energy storage solutions.

A parameter-variant trochoidal-like tool path planning method for chatter-free and high-efficiency milling

Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling. However, the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths. To address these issues, this paper introduces a parameter-variant trochoidal-like (PVTR) tool path planning method for chatter-free and high-efficiency milling. This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step. Initially, the nonlinear equation for the PVTR toolpath is established. Then, a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle. The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process. Finally, several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.

Electro-thermal and mechanical property analysis of powder metallurgy processed, multi-stage ball milled aluminium-copper-multi walled carbon nanotube composite

Aluminium Metal Matrix Composite (Al-MMC) is a favourable option for industries like automotive, aerospace, sports equipment, electronic packaging and renewable energy because of its impressive strength-to-weight ratio, effective thermal and electrical conductivity, abundant availability and reasonable cost of aluminium. Carbon nanotube (CNT) reinforced Al-MMC is popular among researchers due to its impressive strength and stiffness. The electrical and thermal conductivity of Al-CNT is a less focused field with challenges like uniform dispersion and structural integrity of CNT depending on the manufacturing process. In this paper, a novel method of Multistage ball milling (MSBM) was introduced to develop a powder metallurgy processed Al-MMC, consisting of 5-weight percentage (5 wt%) of copper (Cu) and 0.5 to 1.5 volume percentage (0.5–1.5 vol%) multi-walled carbon nanotubes (MWCNT). In MSBM, mixing was done in two stages with two different rpms of the ball mill to add the advantages of flake powder metallurgy with lower chances of structural damage and the agglomeration of CNT. Mechanical, electrical, thermal, and microstructure characteristics of the fixed-speed single-stage ball milling (SSBM) process and the MSBM were compared. MSBM-processed Al-5Cu-0.5CNT composites showed higher electrical conductivity (15.03%), thermal conductivity (5.88%) and hardness (9.68%) than SSBM-processed composites. Al-5Cu-0.5CNT developed by the MSBM process achieved superior electrical and thermal conductivity, surpassing pure sintered Al by 138.45% and 9.39%, respectively.

Novel artificial tricalcium phosphate and magnesium composite graft facilitates angiogenesis in bone healing

BackgroundBone grafting is the standard treatment for critical bone defects, but autologous grafts have limitations like donor site morbidity and limited availability, while commercial artificial grafts may have poor integration with surrounding bone tissue, leading to delayed healing. Magnesium deficiency negatively impacts angiogenesis and bone repair. Therefore, incorporating magnesium into a synthetic biomaterial could provide an excellent bone substitute. This study aims to evaluate the morphological, mechanical, and biological properties of a calcium phosphate cement (CPC) sponge composed of tetracalcium phosphate (TTCP) and monocalcium phosphate monohydrate (MCPM), which could serve as an excellent bone substitute by incorporating magnesium. MethodsThis study aims to develop biomedical materials composed mainly of TTCP and MCPM powder, magnesium powder, and collagen. The materials were prepared using a wet-stirred mill and freeze-dryer methods. The particle size, composition, and microstructure of the materials were investigated. Finally, the biological properties of these materials, including 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay for biocompatibility, effects on bone cell differentiation by alkaline phosphatase (ALP) activity assay and tartrate-resistant acid phosphatase (TRAP) activity assay, and endothelial cell tube formation assay for angiogenesis, were evaluated as well. ResultsThe data showed that the sub-micron CPC powder, composed of TTCP/MCPM in a 3.5:1 ratio, had a setting time shorter than 15 minutes and a compressive strength of 4.39±0.96 MPa. This reveals that the sub-micron CPC powder had an adequate setting time and mechanical strength. We found that the sub-micron CPC sponge containing magnesium had better biocompatibility, including increased proliferation and osteogenic induction effects without cytotoxicity. The CPC sponge containing magnesium also promoted angiogenesis. ConclusionIn summary, we introduced a novel CPC sponge, which had a similar property to human bone promoted the biological functions of bone cells, and could serve as a promising material used in bone regeneration for critical bone defects.

Obtaining ultra-high hardness in spark plasma sintered Ge40As40Se20 bulk glass

In order to overcome the narrow glass-forming compositional range with traditional melt-quenching method, we here performed the mechanical milling and Spark Plasma Sintering technology to fabricate a high Ge content chalcogenide glass, the Ge40As40Se20 glass, which locates edge of the Ge-As-Se glass-forming domain. By using the optimal ball milling time of 50 h and sintering stress of 37.5 MPa, the large size Ge40As40Se20 bulk glasses were obtained, which possesses both a large Vickers hardness of 369 kgf/mm2 and a relative high infrared optical transmission of 43 % (@5 and 9 μm). Moreover, it was found there are pores in the sintered glasses more or less, and the pore size and number significantly affect the transmission, i.e., the optimal Ge40As40Se20 bulk glasses were demonstrated has the smallest and least pores via scanning electron microscope. The combination of mechanical milling and low-temperature sintering methods has been confirmed can be used to improve the glass formability and then obtain the high Ge content component with a potential high hardness glass to break through the limited mechanical property of chalcogenides.

Construction of novel S-defects rich ZnCdS nanoparticles for synergistic visible light assisted photocatalytic degradation of rhodamine B: Insights into mechanism, pathway and by-products toxicity evaluation

The contamination of wastewater by azo dyes indicates serious environmental risks. Currently, industries worldwide use approximately 700,000 tons of these dyes annually, making their removal a significant challenge. In photocatalysis research, a prominent area of dedication to the advancement of visible light photocatalysis aims to achieve superior performance in overall activity. In this study, we fabricated ZnCdS nanoparticles (NPs) via a simple co-precipitation strategy, and sulphur (S)-defect-rich ZnCdS NPs (D-ZnCdS) were created through the ball milling method. These S-defect nanoparticle (NPs) catalysts were utilized for rhodamine B (RhB) dye photocatalytic degradation experiment. (XRD) X-ray diffractometer, X-ray photoelectron spectroscopy (XPS), surface-enhanced Raman spectroscopy, and photoluminescence (PL) spectroscopy characterization studies explained the induced S-defect rich in D-ZnCdS NPs. Further, the morphological, band gap determination, and photogenerated charge carrier recombination efficiency were studied using different analytical and spectroscopic characterization techniques. The Brunauer-emmett-teller (BET) results indicate the increased surface area of D-ZnCdS NPs thereby providing more active sites. The photocatalytic degrading efficiency of D-ZnCdS over RhB explains the complete degradation of pollutants within 260 min. This enhancement in the catalytic process is attributed to the increased absorption of photon energy from the visible light and large defect-rich active sites. Further, the involvement of hydroxyl (*OH) and superoxide radicals (O2*-) in the degradation of RhB along with the presence of sulphur defects, significantly improves the charge transfer in ZnCdS NPs. The involvement of certain factors like pH, ions, NCs catalyst and different RhB concentrations on RhB degradation was investigated. Additionally, D-ZnCdS NPs showed stable degrading capability even after six consecutive cycles of catalytic RhB degradation. The by products formed during the RhB photodegradation experiment were identified using Gas chromatography-mass spectrometer (GC-MS) analysis, and toxicity in fish, daphnia, and algae was examined using the Ecological structure-activity relationships (ECOSAR) program. From the above findings, the current research work provides a new strategy for utilizing defect-engineered D-ZnCdS NPs as a promising catalyst for various environmental remediation applications and paves a ways for manufacturing innovation.

Effect of ball milling energy and carbon content on electrochemical properties of FeF3/acetylene black composites for high-capacity thermal battery

Recently, there has been an increasing demand for high-voltage thermal batteries. FeF3 has a high open-circuit voltage of 2.7 V and is gaining attention as a potential alternative. However, it involves the problem of a low electrical conductivity owing to the wide band gap (5.96 eV) and the generation of lithium fluoride (LiF), which is a discharge product in the conversion reaction. To address this issue, acetylene black with high conductivity is utilized to enhance the electrochemical activity of metal fluoride (FeF3). At present, FeF3/AB is produced by low- and high-collision-energy ball milling. These are mechanical milling methods that involve different collision energies. High-collision-energy ball milling has been demonstrated to degrade the electrochemical performance owing to crystal deformation. In contrast, low-collision-energy ball milling has demonstrated the potential for application in thermal batteries by minimizing crystal deformation and enhancing the electrical conductivity. In this study, the amount of added carbon was optimized to enhance the performance of thermal battery materials. Both low- and high-collision-energy ball-milling processes exhibited remarkable thermal stability when 5.0 wt% carbon was added. However, the high-collision-energy ball-milling process did not effectively enhance the thermal cell performance because the electrical conductivity did not increase significantly. Therefore, FeF3/5.0 wt% AB produced by low-collision-energy ball milling exhibited remarkable thermal stability and electrical conductivity. This indicates its potential for use in thermal batteries.

Steam explosion-assisted grinding improves the functional properties and antioxidant activity of Java tea-leaf powders (Clerodendranthus spicatus).

Java tea is widely consumed and has multiple health effects. This study established a steam explosion (SE) pretreatment method to prepare Java tea-leaf powders. The physicochemical, functional properties, phenolic extraction, and antioxidant activity of Java tea-leaf powders produced by simple and SE-assisted milling methods were investigated. In comparison with simple milling, SE pretreatment broke the cell wall effectively and reduced the particle size of Java tea-leaf powders. Steam explosion-treated powders showed higher values for sensory signals, bulk and tap density, and for the water solubility index. After SE treatment, the adsorption capacities to glucose, soybean oil, and cholesterol of leaf powders were increased by up to 55, 95, and 80% respectively. The extracts from SE-treated powders also showed higher total polyphenol content and antioxidant activity. Steam explosion treatment is helpful for the improvement of functional properties and antioxidant activity, which can benefit the development and application of Java tea-leaf powders. © 2024 Society of Chemical Industry.

Enhanced photocatalytic performance of gadolinium-doped lithium manganese oxide (Li4Mn5O12) by conventional ball milling method

Abstract Current research aims to improve the characteristics of lithium manganese oxide (LiMn2O4), a highly prospective for waste water treatment applications, by incorporating gadolinium (Gd-0.25 %) into the manganese position. This integration, achieved via conventional ball milling, aims to improve the structural, morphological, and electrical characteristics of Li4Mn5O12. A range of analytical methods, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and impedance testing, were utilized to evaluate the influence of Gd-0.25 % on Li4Mn5O12. The results indicate that the inclusion of Gd at the manganese sites enhances the thermal conductivity of Li4Mn5O12 (Li4Mn4.75Gd0.25O12), leading to improved conductivity compared to undoped Li4Mn5O12. Additionally, the enhanced material exhibits promising potential as an efficient photocatalyst, demonstrated by its degradation of methylene blue (MB) dye.

Size reduction of biochar to nanoscale decrease polycyclic aromatic hydrocarbons (PAHs) and metals content and bioavailability in nanobiochar

Objective of this research was to investigate ball milling of biochar from various feedstocks (willow, rice husk, oilseed rape, sewage sludge) under different pyrolysis conditions (500 and 750 °C, N2 and CO2 atmosphere) on polycyclic aromatic hydrocarbons (PAHs) and metals content. A significant reduction in both total (Ctotal Σ16) (1.1 to 2.4-fold decrease) and freely available (Cfree Σ16) (1.1 to 2.9-fold decrease) PAHs in nanobiochar (n-BC), particularly in sewage sludge (SSL)-derived n-BC was observed. The changes in biochar surface characteristics induced by ball milling, such as surface area, pore volume, and hydrophilicity, contribute to the decreased PAHs content. Mechanisms involving mechanochemical degradation, free-radical reactions, and defects on the biochar surface may explain the decrease of PAHs. The n-BC showed lower log Kd values for PAHs (reduced by 14 to 41 %) compared to bulk biochar (b-BC), indicating reduced effectiveness in immobilizing PAHs. The ball milling significantly reduced also metal contents by 37 to 55 %, especially in willow pellets and agricultural residue (rice husk and oilseed rape straw) with optimal reduction (by 55 %) observed for WL-derived n-BC produced at 650 °C. Importantly, no metals were detected in the aqueous phase after ball milling, ensuring environmental safety of these materials. Reduction mechanisms of metals during ball milling include stable aggregate formation, enhanced defects in crystalline structures, and irreversible adsorption onto new surfaces. The results demonstrate that the application of an eco-friendly ball milling method allows for the production of materials characterized by reduced contamination levels, which is crucial from an environmental protection viewpoint.