Composite Materials

The increasing concern about waste generation in the industry also encompasses the granite cutting sector. In this context, there is an interest in exploring the potential of these waste materials for applications in new materials (composites). This study aims to evaluate how the incorporation of granite particulates affects the compressive properties of an epoxy system, as well as to characterize the utilized waste material. The waste material was characterized using laser granulometry. Subsequently, the particulates were used in the fabrication of polymers composites at different volumetric fractions of waste (0, 12.5, 25, 37.5, and 50%). These composites were tested according to ASTM D695 and subsequently analyzed through Analysis of Variance and Tukey’s test. The obtained results provided information regarding the particle size distribution of the waste material, as well as the impact of these wastes on strength of the polymer matrix composites.

Fibre reinforced polymer (FRP) composites are prominent materials used for manufacturing various products due to their distinct properties. It has been observed that the addition of nanofillers improved various properties of the FRP composites. Very few researchers have combined more than one nanofiller for producing FRP composites. The objective of the present work is to study the feasibility of combined effect of silicon carbide (SiC)–zinc oxide (ZnO) nanofillers in the development of Kevlar/Epoxy composite and examine their effect on the various mechanical properties such as tensile strength, flexural strength, and inter laminar shear strength. The composite material infused with the above-mentioned nanofillers was fabricated by using three different weight percentages of both the nanofillers. The experimental results showed that the addition of the SiC-ZnO nanofillers with the weight percentages of 0.75% and 1%, respectively, to the Kevlar/Epoxy composite exhibited higher tensile, flexural, and interlaminar shear strength.

Natural lignocellulosic fibers (NFLs) are considered a promising alternative to synthetic fibers in composite materials due to their economic, technical, environmental, and social advantages. In this study, corn stalk husk, an abundant and significant part of corn, was investigated as reinforcement in epoxy resin composites. The addition of 10, 20, and 30 vol% cornstalk husk was performed and the properties related to impact strength were evaluated in Izod and Charpy configurations, according to ASTM-D256 and ASTM-D6110 standards. Ten impact specimens were tested for each level of fiber reinforcement (vol%). The results revealed that the incorporation of 30 vol% cornstalk husk as reinforcement in the composites resulted in a significant increase in toughness, evidenced by Izod and Charpy impact test. All results were statistically analyzed by analysis of variance (ANOVA), with a 95% confidence level.

The rock production process generates a significant amount of waste that can be utilized for various applications, such as the production of new composites. This allows for the acquisition of new materials while minimizing waste disposal and resource consumption. In this regard, the objective of this study is to evaluate how the incorporation of granite waste into epoxy matrix particulate composites affects impact resistance. The waste was characterized in terms of size as well as used to fabricate test specimens with 0, 12.5, 25, 37.5, and 50% waste (% vol.). These specimens were subjected to impact testing using the Izod configuration, following ASTM D256 standards. Finally, the results were analyzed using Analysis of Variance (ANOVA) and Tukey’s test. These results allowed for the characterization of the waste and indicated that its inclusion significantly enhances impact resistance.

The half-lives of radionuclides range from fractions of a second to billions of years. Since no practical method of altering radioactive decay exists, and since exposure to either the energy emitted from radioactive decay or chemical properties of radionuclides poses dire health risks, radioactive materials must be segregated and controlled. The capture, treatment, and disposition of radioactive materials remain an extraordinary challenge. In here, we focus our attention on the synthesis and characterization of a unique class of nanocomposite materials that have potential for removal of radionuclide contamination. Specifically, we report a simple approach to decorate the surface of iron-based (Fe/Fe_xO_y) material with various nano-catalysts. Specifically, copper (Cu), tin (Sn), and silver (Ag) nanoparticles were prepared through two different reduction approaches, namely, citrate and cetyltrimethylammonium bromide (CTAB) methods, on the iron-based material surface. All samples were characterized by a variety of analytical tools, which included scanning electron microscopy (SEM), electron-dispersive X-ray microanalysis (EDS), and EDS mapping to elucidate materials’ morphology as well as nano-catalysts’ loading and location on the iron-based structures.

One method for denitration of nitric acid used in nuclear facilities is to use formic acid as a reductant. The major problem with formic acid denitration is an induction period of varying duration that may result in excessive accumulation of formic acid at the reaction onset. This accumulation poses an off-gas process control issue. In this paper, we will describe the use of titania-based photocatalysts for the treatment of nitric acid and nitrate wastes. We find that the photocatalytic process is a simple and straightforward method to completely destroy nitrate ions at room temperature without any initiation period.

Degradable polymers and composites have found extensive applications in various industries but are currently limited to low-temperature usage due to their low glass transition temperature (typically <80 °C). High-T_g polymer composites, predominantly composed of epoxy resin, present challenges in decomposition, often necessitating high temperature, pressure, corrosive environments, and even supercritical fluids. The increasing adoption of fiber-enhanced composites for weight reduction and corrosion resistance further aggravates environmental concerns. This study addresses these challenges by introducing a pioneering solution in the form of a novel high-T_g (>130 °C) epoxy composite that exhibits water degradability below 100 °C. The material development process and degradation mechanism will be comprehensively elucidated. To the best of our knowledge, this marks the industry's first water-degradable high-T_g epoxy composite, unlocking a plethora of new applications across industries and providing an environmentally friendly, green composite material.

In this work, the inhibition performance of snail shell nanoparticle extract (SSNE) on API 5L X65 steel corrosion in 1 M HCL acid environment was investigated. SEM, EDX, and electrochemical approaches were used to characterize and evaluate the inhibitor. An inhibition efficiency of 99.65% at 5 g/L inhibitor concentration was achieved. SSNE adsorbed on the X65 steel surface through a combination of anodic and cathodic inhibition mechanisms, which was corroborated by the SEM micrograph. The non-inhibited sample had a heavily corroded surface with a noticeable macro-pit generated by the aggressive solutions on the X65 steel, but the inhibited sample had a superior surface due to the SSNE molecules’ protective role. This performance is attributed to the active ingredients of SSNE, which improve the creation of a protective barrier over the steel surface, minimizing corrosion. This study reveals the possibility of developing sustainable and appropriate nanoparticle corrosion inhibitors from agro-waste resources.

Additive Manufacturing (AM), or 3D printing, is a unique technology in which structurally complex objects can be easily manufactured. While AM allows for the creation of intricate 3D objects, these objects are inactive and motionless. With recent incorporation of a “pre-programmed functionality” into the 3D printed objects, a new concept has emerged, 4D printing. In this context, the pre-programmed functionality refers to the materials that have properties related to their electrical, magnetic, optical properties, etc., that can be manipulated in predictable ways by application of external stimuli. Therefore, the 4D printing technology enables a static 3D printed object to change its shape, functionality, or property over time upon exposure to specific stimuli such as heat, stress, light, pH, moisture, etc. We describe a variety of functional composite (4D) materials developed for incorporation in hydrogen storage-based applications.

The demand for anticorrosive protection materials is well established, and the utilization of industrial pipe coatings presents a viable solution. Within this realm of protection, the utilization of particulate composites is common, as it facilitates the establishment of a protective barrier between the pipe and the corrosive environment. The objective of this study is to evaluate the feasibility of integrating additives to reduce the permeability and porosity of pipe coatings. A water vapor permeability test was conducted in accordance with ASTM D1653 (Method B-Condition C), while porosity was assessed following the guidelines of NACE SP0394. The evaluated coating uses organic and/or inorganic particulate waste. Finally, a variance analysis and Tukey test were conducted to analyze the results. The results of this work allowed verifying the need to use this additive for the development of the evaluated coatings.

Vanadium is an important strategic material that is widely utilized in aerospace, national defense, and metallurgical and chemical engineering fields. V(IV) is a stable form which is derived from the traditional sodium salt roasting-water leaching process for vanadium extraction that widely exists in the leaching solution. To achieve the recovery of V(IV) from the leaching solution, Fe-MOF was employed as an adsorbent for the adsorption of V(IV) from solution in this paper. The influences of reaction time, adsorbent dose, and solution pH on V(IV) adsorption were systematically examined. Under the conditions of initial V(IV) concentrations of 10 mg/L and 100 mg/L, a solution pH of 7, and an adsorbent dosage of 400 mg/L, the removal rates of V(IV) were 97.27% and 52.46%, and the adsorption capacities were 17.62 mg/g and 91.68 mg/g, respectively. The results demonstrated that Fe-MOF can realize the effective recovery of vanadium resources in solution.

Wastewater containing Cr(III) ions in hydrometallurgy is likely to cause harm to the surrounding environment and the human body. In this paper, Fe-MOF was synthesized by a solvothermal method and employed as an adsorbent to remove Cr(III) ions from hydrometallurgical wastewater. The effects of initial concentration and pH on the chemical forms of Cr(III) were mainly evaluated, while the influence of adsorption time and solution pH on the removal of Cr(III) ions under different initial concentration conditions were comprehensively analyzed. Under a contact time of 2 h, pH 7.0, and concentration of 100 mg·L⁻¹, the optimum adsorption efficiency of Cr(III) ions was 82.63%. The adsorption methods of Cr(III) by Fe-MOF were investigated by batch adsorption experiments and kinetic simulations, and the results suggested that Fe-MOF has a promising application in the treatment of high-concentration Cr(III)-containing waste liquids.

Large quantities of selenium (Se)-containing wastewater are generated by the coal mining process. Therefore, it is urgent to treat wastewater containing high concentrations of Se(IV). In this study, MIL-101-NH₂ was synthesized by a hydrothermal method, and the effects of parameters, such as pH and contact time on the removal of Se(IV), were evaluated. The adsorption kinetics of MIL-101-NH₂ on Se(IV) were evaluated using pseudo-first-order and pseudo-second-order models. Langmuir and Freundlich models were used to analyze the equilibrium isotherms of the system. The maximum adsorption was 32.289 mg/g according to the Langmuir model. The results showed that the removal efficiency of Se(IV) by MIL-101-NH₂ was 75.96% at pH = 6 and adsorption time = 3 h. This study demonstrated that MIL-101-NH₂ has great potential for wastewater treatment.