Reactive Material Research Articles

Passivation Layers in Mg-Metal Batteries: Robust Interphases for Li-Metal Batteries.

In advanced batteries, interphases serve as the key component in stabilizing the electrolyte with reactive electrode materials far beyond thermodynamic equilibria. While an active interphase facilitates the transport of working ions, an inactive interphase obstructs ion flow, constituting the primary barrier to the realization of battery chemistries. Here, a successful transformation of a traditionally inactive passivating layer on Mg-metal anode, characteristic of Mg-metal batteries with typical carbonate electrolytes, into an active and robust interphase in the Li-metal scenario is presented. By further strategically designing magnesiated Li+ electrolytes, the in situ development of this resilient interphase on Li-metal anodes, imparting enduring stability to Li-metal batteries with nickel-rich cathodes is induced. It is identified that the strong affinity between Mg2+ and anions in magnesiated Li+ electrolytes assembles ionic clusters with a bias for reducibility, thereby catalyzing the creation of anion-derived interphases rich in inorganic constituents. The prevalence of ionic clusters induced by magnesiation of electrolytes has brought properties only available in high-concentration electrolytes, suggesting a fresh paradigm of tailing electrolytes for highly reversible LMBs.

Removal of Diclofenac from Contaminated Water using Organoclay as Reactive Material

في هذه الدراسة ، تم ازالة المادة الدوائية الديكلوفيناك (Diclofenac) من المياه الملوثة عن طريق الامتزاز على البنتونيت المعدل. تم تغيير البنتونايت من مادة محبة للماء إلى كارهة للماء باستخدام بروميد الأمونيوم ثلاثي ميثيل هيكساديسيل (HTAB). استخدمت التجارب الدفعية لدراسة تأثير عدد من العوامل على كفاءة عملية الامتزاز. هذه العوامل هي: زمن التلامس ، ودرجة الحموضة (pH) للمحلول ، وسرعة الخلط ، وتركيز الملوث الأولي (Co) ، وجرعة المادة الممتزة. تم تحقيق أقصى إزالة للديكلوفيناك (97٪) في الحالات التالية: زمن التلامس 100 دقيقة ، ودرجة الحموضة 7 ، وسرعة الخلط 200 دورة في الدقيقة ، والتركيز الأولي لـ Co 50 جزء في المليون ، والجرعة الممتزة 0.3 جم بينتونيت لكل 100 مل من المحلول الملوث. تم استخدام الفحص المجهري الإلكتروني للماسح الضوئي (SEM) والتحليل الطيفي للأشعة تحت الحمراء لتحويل فورييه (FTIR) لتشخيص صفات المادة الممتزة (البنتونايت المعدل ). وجد ان موديل Langmuir هو الأنسب لتمثيل البيانات التجريبية التي تم الحصول عليها في المختبر. تم دراسة حركية عملية الامتزاز ووجد انها تتمثل بشكل جيد بتفاعل زائف من الدرجة الثانية. كانت عملية الامتزاز ماصة للحرارة وتلقائية ، وفقًا لتحليلات الديناميكا الحرارية.

The penetrating restoration mechanism of reactive polymer on slight crack of asphalt pavement

Abstract To explore the penetrating restoration mechanism of reactive polymer on slight crack (<3 mm) of asphalt pavement, based on the self-developed reactive MMA material, through the combination of viscosity control and micro-analysis methods, the penetration depth of different viscosities of binding materials to micro-crack and microstructure of the preventive maintenance interface were studied. The results show that the penetration depth of the binding material to the micro-crack is positively correlated with the viscosity of the material, and the restoration effect of the micro-crack depends on the fullness of the filling and curing state of the material in the crack. When the filler content is 20%, the penetration depth of the binding material to the micro-crack can reach 1 mm. The penetration depth can be changed through viscosity control, and a full-continuous restoration structure can be obtained. The microstructure of the micro-crack restoration area shows that the penetration enhancement of the polymer seal material to the micro-crack in the pavement includes three processes: penetration, filling, and curing.

Continuous-flow columns packed with zero-valent iron and iron sulfide as a feasible strategy to remediate the persistent contaminant nitroguanidine

The insensitive munitions compound nitroguanidine (NQ) is used by the U.S. Army to avoid unintended explosions. However, NQ also represents an emerging contaminant whose environmental emissions can cause toxicity toward aquatic organisms, indicating the need for effective remediation strategies. Thus, we investigated the feasibility of treating water contaminated with NQ in continuous-flow columns packed with zero-valent iron (ZVI) or iron sulfide (FeS). Initially, the impact of pH on NQ transformation by ZVI or FeS was evaluated in batch experiments. The pseudo first-order rate constant for NQ transformation (k1, NQ) by ZVI was 8–10 times higher at pH 3.0 compared to pH 5.5 and 7.0, whereas similar k1, NQ values were obtained for FeS at pH 5.5–10.0. Based on these findings, the influent pH fed to the ZVI- and FeS-packed columns was adjusted to 3.0 and 5.5, respectively. Both reactors transformed NQ into nitrosoguanidine (NsoQ). Further transformation of NsoQ by ZVI produced aminoguanidine, guanidine, and cyanamide, whereas NsoQ transformation by FeS produced guanidine, ammonium, and traces of urea. ZVI outperformed FeS as a reactive material to remove NQ. The ZVI-packed column effectively removed NQ below detection even after 45 d of operation (490 pore volumes, PV). In contrast, NQ breakthrough (removal efficiency <85%) was observed after 18 d (180 PV) in the FeS-packed column. The high NQ removal efficiency and long service life of the ZVI-packed column (>490 PV) suggest that the technology is a promising approach for NQ treatment in packed-bed reactors and in situ remediation.

OXIDATION CHARACTERISTICS OF THERMAL-SPRAYED COBALT-BASED SUPERALLOY COATINGS: A REVIEW

Superalloys go through cyclic oxidation which refers to the progression of reputed exposure of materials to alternating oxidizing and non-oxidizing environments at high temperatures. The oxidation behavior of cobalt-based superalloy coatings depends on several variables, including the environment, surface roughness, manufacturing conditions, &amp; coating composition. Because of their higher temperatures and protective oxide layer, coatings with a greater cobalt concentration are more oxidation-resistant. The behavior of oxidation is influenced by surface roughness, where rough surfaces offer greater surface area to oxidation while smooth surfaces decrease interaction with the environment. The microstructure and porosity of the coating are further impacted by processing variables used in thermal spraying, including temperature, particles velocity, and spray distance. Adding reactive components to the coating composition, such as silicon and aluminum, and applying post-treatments like nitriding or sealing are two ways to increase oxidation resistance. A greater temperature and particle speed can lead to a denser with less porous covering, improving the oxidation process resistance. The two typically used heat spraying techniques are high-velocity oxy-fuel (HVOF) and plasma spraying. To increase the resistance to oxidation of thermal spray cobalt-based superalloy coating, some strategies have been devised, such as inclusion of reactive materials, such as aluminum and silicon, which is the coating composition. These elements may establish an oxide layer protecting the coating’s appearance, preventing further oxidation.

Treatment efficiency and recovery in sand filters for on-site wastewater treatment: Column studies and reactive modelling

This study examined the adsorption capacity and treatment efficiency of sand filters in on-site treatment systems for cold climate regions. The effects of different operating conditions, porosity and kinetics parameters were investigated in column experiments and COMSOL Multiphysics® modelling, to comprehensively reveal the mechanisms and optimize treatment efficiency of nitrogen (N) and phosphorus (P) removal in a field tidal flow constructed wetland (TFCW), treating effluent from a package treatment plant with P filter material. The results from column experiments with sand showed that Total-P adsorption rate was dependent on feed water quality (Septic tank >0.77 ± 0.06 g kg−1; Biotreatment >0.41 ± 0.07 g kg−1; Reactive material Polonite® <0.18 ± 0.07 g kg−1). In the field TFCW trial, Total-P adsorption in the top layer (>1.42 ± 0.55 g kg−1) and middle layer (>1.06 ± 0.51 g kg−1) was twice that in laboratory columns, due to strong interaction with the air-water interface and use of fluctuated domestic wastewater solutions. The breakthrough curve (BTCs) of the coarse sand matched the physical behaviour of tracer electrical conductivity (EC) in effluent from the sand column experiments. The modelling results demonstrated that high filter porosity and low hydraulic load were significant factors for optimal removal of NH4–N, Total-N, PO4–P, Total- P in the top layer (>99.95 ± 0.03 %, 44.37 ± 28.75%, 70.89 ± 28.30%, 76.18 ± 20.3%), middle layer (>98.94 ± 1.77%, 18.23 ± 23.04%, 76.62 ± 28.73%, 65.40 ± 31.85%) and deep layer (>99.99 ± 0.02%, 65.50 ± 20.64%, 75.53 ± 23.16%, 41.54 ± 28.81%) in the TFCW system, respectively. The results show that on-site wastewater treatment in cold climate TFCW can be applied as a technology to polish effluent from a three-step pretreatment system. However, hydraulic optimization is an important factor for the design of the TFCW to receive a successful long-term operating system.

Microscopic Chemical Reaction Mechanism and Kinetic Model of Al/PTFE.

In order to study the microscopic reaction mechanism and kinetic model of Al/PTFE, a reactive force field (ReaxFF) was used to simulate the interface model of the Al/PTFE system with different oxide layer thicknesses (0 Å, 5 Å, 10 Å), and the thermochemical behavior of Al/PTFE at different heating rates was analyzed by simultaneous thermal analysis (TG-DSC). The results show that the thickness of the oxide layer has a significant effect on the reaction process of Al/PTFE. In the system with an oxide layer thickness of 5 Å, the compactness of the oxide layer changes due to thermal rearrangement, resulting in the diffusion of reactants (fluorine-containing substances) through the oxide layer into the Al core. The reaction mainly occurs between the oxide layer and the Al core. For the 10 Å oxide layer, the reaction only exists outside the interface of the oxide layer. With the movement of the oxygen ions in the oxide layer and the Al atoms in the Al core, the oxide layer moves to the Al core, which makes the reaction continue. By analyzing the reaction process of Al/PTFE, the mechanism function of Al/PTFE was obtained by combining the shrinkage volume model (R3 model) and the three-dimensional diffusion (D3 model). In addition, the activation energy of Al/PTFE was 258.8 kJ/mol and the pre-exponential factor was 2.495 × 1015 min-1. The research results have important theoretical significance and reference value for the in-depth understanding of the microscopic chemical reaction mechanism and the quantitative study of macroscopic energy release of Al/PTFE reactive materials.

Synthesis, characterization and antimicrobial analysis of metal-doped (Zn2+ and Ag+) brushite powder for bone regeneration

Brushite, or Dicalcium phosphate dihydrate (CaHPO4·2H2O), is a well-known calcium phosphate (CaP) found in mineralized tissues and is utilized in medical treatment, particularly in bone powder for bone repair. Brushites with Zn2+ and Ag + ions concentration were synthesized in an aqueous solution using the conventional precipitation procedure. The synthesized brushites were characterized using techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Powder X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), and bioassays were carried out to evaluate their antibacterial and antifungal activities. The alterations in PXRD and FTIR peak locations demonstrated that zinc and silver ions were effectively inserted into the brushite crystals. Initial tests revealed that the powders were innocuous, which make them potentially beneficial for mineralized tissue engineering. These brushites exhibited remarkable antimicrobial activities. Zn-doped brushite completely controlled the growth of fungi namely Macrophomina phaseolina and Sclerotium rolfsii at a concentration of 0.0039 mg mL−1 while Ag-doped brushite completely arrested the growth of these fungi at 0.0312 and 0.0039 mg mL−1, respectively. Likewise, both the brushite exhibited remarkable antibacterial activity against Bacillus thuringiensis and moderate activity against Escherichia coli. Brushite compounds coupled with active metal ions, notably Ag+ and Zn2+, demonstrated promise as a distinct class of reactive materials for bone-related applications.

Utilizing Waste Materials to Enhance Crop Production: A Review

Waste management is a crucial aspect of modern societies, encompassing various activities to ensure the safe and effective disposal of waste materials. It can be classified as hazardous waste, electronic trash (e-waste), industrial waste, and municipal solid waste (MSW). Sustainable waste management practices aim to reduce environmental impact while protecting public health. Urbanization leads to increased residential water consumption, however reusing wastewater for non-potable applications like agriculture can be cost-effective. The overall costs of delivering wastewater for agricultural reuse, including treatment, storage, and transportation, are less the total costs of safe environmental disposal alternatives. Drainage may also be a source of macronutrients (nitrogen, phosphorus, and potassium), which reduces the cost of wastewater for agricultural reuse. The adoption of these principles could lead to a 48% reduction in global greenhouse gas emissions by 2030. The management of hazardous waste, including toxic, flammable, corrosive, or reactive materials, is also a significant concern. In order to safeguard public health and stop the spread of infectious illnesses, animal manure management is crucial. The global generation of construction and demolition waste is expected to double by 2025, with the majority generated in Asia. Sustainable waste management practices are necessary to ensure public health and the environment.

Experimental‐Assisted Approach to Develop a Numerical Model for Simulating the Reaction Propagation in Reactive Multilayers

One outstanding feature of self‐propagating reactions is their ability to release heat of reaction over both temporal and spatial scales, enabling the sustained progression of the reaction after a local ignition. They propagate in the form of a continuous reaction front through the mixture of the starting materials. Previous research on reactive materials has predominantly focused on unraveling the microstructure property relationships influencing released energy in reacting multilayers. This involved considering coupled differential equations, including the heat conduction equation and Fick's law. In this study, the introduction of a purely thermal numerical macroscale model is made, incorporating two states of material properties that differentiate between the thermal characteristics before and after phase formation. The homogenization of material properties before the phase formation is accomplished through the consideration of directional‐temperature‐dependent thermal conductivity and temperature‐dependent‐specific heat capacity. The energy‐release function is derived using experimental data for the reaction velocity depending on bilayer thickness. This model allows for the exploration of reaction motion and temperature profiles, achieving qualitative conformity with experimental measurements for freestanding foil, and necessitating reasonable computational effort.

Damage characteristic of electronic devices caused by products generated by Al/Ep/KMnO4/TiH2 active material projectile hypervelocity impacting on aluminum target

As the space environment becomes more competitive, space offense and defense are increasing every day. Projectiles made of reactive materials can achieve highly effective target destruction due to their good penetration, ignition and detonation capabilities as the kill element in space attacks. When a spacecraft encounters a hypervelocity impact from a projectile of active material, it will have a serious impact on the surface material and internal electronics (logic chips, super-capacitors, etc.), leading to anomalies in the spacecraft's on-orbit operation. In order to study the damage characteristics of internal typical logic chips and super-capacitor modules caused by the hypervelocity impact of active material projectiles on the surface of spacecraft, the simulated satellite experiment of Al/Ep/KMnO4/TiH2 active material projectiles hypervelocity impacting on aluminum target was performed. By using the self-built experimental loading system, plasma characteristic parameter diagnosis system, radiation temperature measurement system and electronic device function detection system, the characteristic parameters of plasma, light flash radiation temperature, temperature evolution process of logic chip and super-capacitor at specific position under different impact velocities are obtained. When the damage behavior of Al/Ep/KMnO4/TiH2 active material projectile impacts on the surface of simulated satellite, the main reasons affecting electronic devices and the damage characteristics of impact products on logic chip and super-capacitor are analyzed. The experimental results show that the plasma is the main reason for interfering with the operation of logic chips and super-capacitors. When the active material projectile impacts the simulated satellite at the speed of 1.26 km/s, 1.67 km/s and 2.13 km/s, the charge and discharge time of the super-capacitor increases by 3.28 times, 4.57 times and 6 times, respectively, and the maximum operating voltage performance decreases by 12.23%, 14.44% and 18.15%, respectively. When the impact velocities are 1.67 km/s and 2.13 km/s, the output signal of the CD74HC00 chip appears transient damage due to the injection of the plasma generated by the impact, which last 0.4 ms and 1.8 ms, respectively.

Analytic ellipsometric measurement for materials under bulk encapsulation

Accurate measurement of the dielectric functions of emerging optical materials is of great importance for advancements in solid-state physics. However, it is rather challenging since most materials are highly active in ambient conditions, which makes in-situ measurements tough. Here, we report an analytical ellipsometry method (AEM) accessible in ambient conditions for measuring the dielectric functions of chemically reactive materials under bulk encapsulation. Taking the highly pursued low-loss plasmonic materials, such as sodium films, as an example, the effectiveness and measuring errors of the proposed AEM have been systematically demonstrated. This verifies AEM’s superiority in overcoming the limitations of traditional spectroscopic ellipsometry methodologies, which include complex multi-parameter fitting procedures and the issue of potentially unphysical results, especially in newly developed low-loss materials. Our results will provide a generalized and convenient ellipsometric measurement strategy for sensitive materials under bulk encapsulation.

A 7.62 mm energetic bullet filled with PTFE-Mg-based reactive materials for anti-drone application

To counter thin and lightweight targets such as drone swarms, a specialized design of 7.62 mm energetic bullets has been developed. These bullets utilize reactive materials as the core encased in a copper jacket, offering the advantages of impact-induced energy release, multiple damage, and lightweight. The study involved the preparation of three energetic bullets using the reactive materials (different ratio of PTFE-Mg-Bi2O3 and PTFE-Mg-Bi2O3-W) and systematically evaluating their destructive effect. The results showed that three energetic bullets (EB-A, EB-B, and EB-W) successfully penetrated two-layer stacked 2 mm 50# cold-rolled steel targets, and the respective reaction durations observed during the penetration process were 4.1, 3.5, and 9.2 ms. After armor-piercing, energetic bullets released an amount of chemical energy and produced fragmentation, deflagration reactions, and overpressure destructive effects. To further investigate the damage mechanism of the three reactive material-filled bullets, a detailed analysis of PTFE-Mg-based reactive material, such as reaction energy, burning rate, combustion temperature field, reaction overpressure, was conducted. Our work provides a comprehensive understanding of energy release performance of the reactive materials and damage behavior of the energetic bullets.

Optimal screening method for dosage of calcium-based nanosilica modified expansive soils improver based on cost-effectiveness

Under complex natural environments, the properties of lime-modified expansive soil may deteriorate. This facilitates the need for newer materials to develop composite modifiers to improve the anti-deterioration performance. Nanosilica (NS), which is a highly reactive material, is a good promoter of reaction systems with volcanic ash. In this paper, lime is mixed with NS according to a specified ratio to form calcium-based nanosilica (NS-C). NS-C significantly increased the unconfined compressive strength, cohesion, and internal friction angle and decreased the plasticity index, free swelling ratio, and permeability coefficient. The optimum ratio of nano-silica to lime in compound modifier was determined to be 1:8. NS can facilitate the production of a large amount of hydration products in the early stage of the reaction of stabilized soil, thus strengthening the connection between soil particles. In addition, NS exhibits good filling effect on the tiny pores between soil particles. The properties of NS-C stabilized soils with different ratios and curing times were determined to evaluate the modification effect and mechanism of composite modifier and obtain the optimal dosage for Hefei expansive soils in road-base edging technology. The optimum content of the compound modifier for expansive soils in the Hefei area should be 6 %, and the curing time should be at least 14 days.

In Situ Use of Mining Substrates for Wetland Construction: Results of a Pilot Experiment.

This paper evaluates an experimental wetland as part of a pilot soil reclamation project in a mining area. The wetland was constructed using materials of mining origin from the area; most reactive materials of acid pH were stabilised using limestone filler. The study selected macrophytes that are tolerant to potentially toxic elements (PTEs) and resistant to salinity, namely Phragmites australis, Juncus effusus, and Iris pseudacorus. These macrophytes were then placed in pots containing substrates composed of different mixtures of topsoil, peat, and mining waste (black or yellow sand). A thorough analysis of the physicochemical and mineralogical characteristics of the materials included studies of PTE mobilisation. This study emphasises the significance of the rhizosphere in directing the transfer of PTEs to the plant and the correlation between the substrate and the development of plant defence mechanisms, such as the formation of Fe-plates. Scanning electron microscopy was used to highlight these aspects and validate the results of the analytical determinations. These wetlands can be proposed as a phytoremediation strategy for areas affected by mining and maritime influence. They are easy to construct and remain stable, providing important ecosystem services such as the natural attenuation of acid mine drainage, support for vegetation development and fauna, and a clean ecosystem.

Efficient remediation of mercury-contaminated groundwater using MoS2 nanosheets in an in situ reactive zone

Mercury contamination in groundwater is a serious global environmental issue that poses threats to human and environmental health. While MoS2 nanosheets have been proven promising in removing Hg from groundwater, an effective tool for in situ groundwater remediation is still needed. In this study, we investigated the transport and retention behavior of MoS2 nanosheets in sand column, and employed the formed MoS2in situ reactive zone (IRZ) for the remediation of Hg-contaminated groundwater. Breakthrough test revealed that high flow velocity and MoS2 initial concentration promoted the transport of MoS2 in sand column, while the addition of Ca ions increased the retention of MoS2. In Hg removal experiments, the groundwater flow velocity did not influence the Hg removal capacity due to the fast reaction rate between MoS2 and Hg. With an optimized MoS2 loading, MoS2IRZ effectively reduced the Hg effluent concentration down to <1 μg/L without apparent Hg remobilization. Additionally, flake-like MoS2 employed in this study showed much better Hg removal performance than flower-like and bulk MoS2, as well as other reported materials, with the Hg removal capacity a few to tens of times higher than those materials. These results suggest that MoS2 nanosheets have the potential to be an efficient IRZ reactive material for in situ remediation of Hg in contaminated groundwater.

Effects of reactive MgO on durability and microstructure of cement-based materials: Considering carbonation and pH value

Reactive MgO is a type of eco-friendly material with a lower carbon footprint, as it is produced by calcination of magnesite (MgCO3) at 750 ℃, much less than that (i.e. 1450℃) needed for calcination of (CaCO3) to produce clinker for Portland cement. Carbonation can enhance the mechanical properties of reactive MgO-based cementitious materials but will lower the pH value, leading to the neutralization of cement-based materials and further deterioration in rebar passivation. In this study, varying amounts of reactive MgO (0%, 10%, 20%, and 30%) were incorporated into mortars as cement replacements. By adjusting the duration of CO2 curing (i.e. carbonation curing) and standard curing, it was found that the curing regime involving 36 hours of carbonation curing plus 26.5 days of standard curing led to a higher pH and compressive strength of cement mortars. The pore size distribution was improved as the internal pores of the mortar were filled with carbonation products, which hindered the reaction between CO2 and alkaline hydration products inside specimens and was conducive to maintaining the alkalinity within the mortar. Therefore, the chloride ion penetration resistance and the mechanical properties of mortar were enhanced. SEM and EDS characterization results indicate that the excessive MgO did not fully participate in carbonation and continuously hydrated to generate Mg(OH)2. The expansion of Mg(OH)2 led to crack formation inside the mortar and reduced its strength, which accelerated CO2 diffusion and further reduced the pH value of reactive MgO-based cementitious materials.

Numerical Simulation Study on Impact Initiation on Shielded Charge Using Hypervelocity Composite-Structure Reactive Fragments.

In order to study the impact initiation process and mechanism of hypervelocity PTFE/Al composite structure reactive fragments on a shielded charge, first, an existing PTFE/Al reactive fragment hypervelocity collision experiment was numerically simulated using the SPH algorithm in ANSYS/AUTODYN 17.0 software. Then, the Lee-Tarver model was verified to describe the detonation reaction behavior and explosion damage effect of reactive materials. A numerical simulation analysis of the impact of two kinds of ultra-high-speed PTFE/Al composite-structure reactive fragments on a shielded charge was carried out using the SPH algorithm. These were steel-coated PTFE/Al and steel-semi-coated PTFE/Al fragments, and they were compared with the impact of steel fragments. The results indicate that the threshold velocities of the impact initiation of the two composite-structure reactive fragments on the shielded charge were both 2.6 km/s, while the threshold velocity of the steel fragment was 2.7 km/s. Under the threshold velocity condition, the two composite-structure reactive fragments increase the time and intensity of the compressed shock wave pulse in the explosive due to the impact energy release effect of the reactive materials, causing the shielded charge to detonate under the continuous long-term pulse loads. However, the mechanism of the steel fragment on the shielded charge belongs to the shock-detonation transition. The research results can provide scientific references for the design of hypervelocity reactive fragments and the study of their damage mechanism.

Three-dimensional dendritic biosynthetic copper oxide nanoparticles: A novel approach for enhanced leaf deposition and retention to reduce environmental impact

Copper-based fungicides are commonly utilized as protective germicides; however, their susceptibility to rain-induced washing leads to a substantial copper exposure, resulting in significant environmental pollution and potential ecological risks. This study focuses on the biosynthesis of copper oxide nanoparticles at room temperature, utilizing copper sulfate pentahydrate and tea seed cake extract as reactive raw materials. The obtained copper oxide nanoparticles exhibit a distinctive dendritic three-dimensional topology. Notably, these copper oxide nanoparticles demonstrate superior wettability and spreadability on tomato, rice, and wheat leaves compared to the commercial formulation of copper hydroxide (Kocide). The retention amount of copper oxide nanoparticles on the surface of plant leaves after rain washing exhibited a 75.89% to 84.31% increase compared to that of Kocide, attributed to the structural chimerism of copper oxide nanoparticles and the micro-nano structure of leaves. Regarding antimicrobial activity against Magnaporthe oryzae and Clavibacter michiganense, copper oxide nanoparticles showed better residual activity and a longer persistent period than Kocide. Safety experiments demonstrated that copper oxide nanoparticles had minimal adverse effects on wheat plants, while in vivo studies in zebrafish revealed their effectiveness in reducing toxicity by over five-fold compared to Kocide. Furthermore, soil ecosystem assessments highlighted the high biocompatibility of copper oxide nanoparticles with Escherichia coli. Consequently, the prepared copper oxide nanoparticles hold significant promise as an eco-friendly alternative to traditional copper-based fungicides.

Regional metakaolin particle size reduction for higher strength geopolymer

AbstractThe objective of this project was to further develop new composites and a testing program for the performance‐based specification for natural Amazonian geopolymer (GP) for use in ceramics and construction. While fly ash‐based alkali activated materials are now an established technology, metakaolin‐based GPs still need to be developed and optimized regarding the knowledge of the specific characteristics and properties of local resources. Amazonian kaolin was calcined into metakaolin (AMK). AMK particle size reduction for better reactive material was evaluated by means of dry and wet ball milling and sieving. Three types of metakaolin were analyzed for particle size distribution, and their size d50 ranged from 7.9 to 2.8 µm. Further GP characterization followed physical and mechanical properties in flexural strength tests. In addition, scanning electron microscopy and energy dispersive spectroscopy were used to investigate the microstructure of the materials. Energy dispersive X‐ray fluorescence was used to measure the GP material composition. Analysis of the results revealed that the strength and stiffness of sodium–metakaolin‐based GP were inversely proportional to particle size. All distinct particle size GPs showed, in general, some increase in strength and stiffness within curing times ranging from 3 to 28 days.