Heusler alloys, which were unintentionally discovered at the start of the 20th century, have become intriguing materials for many extraordinary functional applications in the 21st century, including smart devices, spintronics, magnetic refrigeration and the shape memory effect. With this review article, we would like to provide a comprehensive review on the recent progress in the development of Heusler alloys, especially Ni-Mn based ones, focusing on their structural crystallinity, order-disorder atoms, phase changes and magnetic ordering atoms. The characterization of the different structures of these types of materials is needed, where a detailed exploration of the crystal structure is presented, encompassing the influence of temperature and compositional variations on the exhibited phases. Hence, this class of materials, present at high temperatures, consist of an ordered austenite with a face-centered cubic (FCC) superlattice as an L2₁ structure, or body-centered cubic (BCC) unit cell as a B2 structure. However, a low-temperature martensite structure can be produced as an L10, 10M or 14M martensite structures. The crystal lattice structure is highly dependent on the specific elements comprising the alloy. Additionally, special emphasis is placed on phase transitions within Heusler alloys, including martensitic transformations ranging above, near or below room temperature and magnetic transitions. Therefore, divers’ crystallographic defects can be presented in such types of materials affecting their structural and magnetic properties. Moreover, an important property of Heusler compounds, which is the ability to regulate the valence electron concentration through element substitution, is discussed. The possible challenges and remaining issues are briefly discussed.

The removal of dyes from textile effluents utilizing advanced wastewater treatment methods with high efficiency and low cost has received substantial attention due to the rise in pollutants in water. The purpose of this work is to give a comprehensive analysis of the different treatments for removing chemical dyes from textile effluents. The capability and potential of conventional treatments for the degradation of dyeing compounds in aqueous media, as well as the influence of multiple parameters, such as the pH solution, initial dye concentration, and adsorbent dose, are presented in this study. This study is an overview of the scientific research literature on this topic, including nanoreductive and nanophotocatalyst processes, as well as nanoadsorbents and nanomembranes. For the purpose of treating sewage, the special properties of nanoparticles are currently being carefully researched. The ability of nanomaterials to remove organic matter, fungus, and viruses from wastewater is another benefit. Nanomaterials are employed in advanced oxidation techniques to clean wastewater. Additionally, because of their small dimensions, nanoparticles have a wide effective area of contact. Due to this, nanoparticles’ adsorption and reactivity are powerful. The improvement of nanomaterial technology will be beneficial for the treatment of wastewater. This report also offers a thorough review of the distinctive properties of nanomaterials used in wastewater treatment, as well as their appropriate application and future possibilities. Since only a few types of nanomaterials have been produced, it is also important to focus on their technological feasibility in addition to their economic feasibility. According to this study, nanoparticles (NPs) have a significant adsorption area, efficient chemical reactions, and electrical conductivity that help treat wastewater effectively.

A high-entropy Fe₃₀Co₂₀Ni₂₀Mn₂₀Al₁₀ (at%) alloy with a face-centered cubic (FCC) crystalline phase was produced through mechanical alloying. This study examined the development of its phases, microstructure, morphology, and magnetic characteristics. Scanning electron microscopy (SEM) was applied to assess the sample morphology in relation to milling times. The changes that the material underwent during milling were investigated using X-ray diffraction. The milling time affected the phase transformation. A single FCC solid solution (crystallite size = 12 nm) was found after 50 h of milling. Additionally, the magnetic characteristics were examined and shown to be associated with microstructural changes. The powder mixture exhibited behavior consistent with soft magnetics, with an Hc value of 8 Am⁻¹ and an Ms value of 165 emu/g. The excellent soft magnetic characteristic may be related to the stability of the FCC phase, which was generated following a 30 h milling process. In addition, the low value of Ms may have originated from the presence of Al atoms in the solid solution and the development of large densities of interfaces and crystal defects.

In this study, a combined process of reduction and adsorption for the degradation of azo dye with nanocrystalline Fe₈₀Si₁₀B₁₀ powder as a reducing agent is analyzed. A mechanical alloying technique produced the powdered alloys needed for the redox process. The synthesized nanocrystalline structure favors the efficiency of the reduction step of Reactive Black 5 (RB5) azo dye. According to the UV-Vis analysis, the reductive process alone allowed for nearly complete color removal after 3 min of reaction. In this regard, the nanocrystallized FeSiB powder has excellent application potential in the first step of the reduction processes for degrading azo dye solutions. Indeed, the nanocrystalline FeSiB powder outperforms commercial Fe powders in terms of degradation efficiency because of the formation of multiple micro-batteries between the α-Fe solid solution and the Fe₃Si nanocrystalline phases, favoring the loss of electrons from iron and exhibiting different corrosion resistance. In the second step, the adsorption process, the efficient removal of intermediate undesired compounds from the reduction processes, principally aromatic amines, is analyzed. Different adsorbents, including wood, graphene oxide, activated carbon, and pine particles, were used. The results suggest that graphene oxide and activate carbon performed the best for secondary product adsorption following RB5 degradation. The current study could serve as a guide for environmental applications, such as industrial wastewater treatment, using metallic powders produced by high-energy mechanical alloying.