Rare earth elements (REEs) are at the forefront of discussions, given their crucial role in cutting-edge and eco-friendly innovations that propel the industrial revolution towards a green economy. These elements have become indispensable to various modern technologies, such as smartphones, electronic devices, and renewable energy sources. Many different concepts and analyses have been introduced, such as the chemical similarities among REEs, health risks and ecological damages, the negative environmental impacts of current recovery processes, and strategies for advancing REE recovery towards a circular economy. Although these elements have been widely used in various applications over the last 20 years, the literature on these aspects is fragmented and spread across different research areas, shared by multiple branches and application fields. These fields include safety concerns, economic challenges, and technology. Summarizing and classifying this literature is challenging due to its fragmented nature, the variety of topics, and the different approaches used. The quest for cleaner recycling strategies necessitates a comprehensive assessment covering economic, technological, and environmental aspects. The primary goal of this review is to provide a holistic perspective on REEs, with a central focus on their economic, technological, and environmental dimensions, particularly emphasizing reuse, recycling, and occupational safety. The review begins by addressing complexities of REEs, highlighting the associated technologies, environmental concerns, and economic considerations. It further explores the aspects of reuse and recycling of REEs, shedding light on the advantages, drawbacks, hazards, and costs associated with recycling technologies for REE recovery. Additionally, the review summarizes occupational exposure and safety considerations related to REEs.

Metallurgy is pivotal for societal progress, yet it yields wastewater laden with hazardous compounds. Adhering to stringent environmental mandates, the scientific and industrial sectors are actively researching resilient treatment and disposal solutions for metallurgical effluents. The primary origins of organic pollutants within the metallurgical sector include processes such as coke quenching, steel rolling, solvent extraction, and electroplating. This article provides a detailed analysis of strategies for treating steel industry waste in wastewater treatment. Recent advancements in membrane technologies, adsorption, and various other processes for removing hazardous pollutants from steel industrial wastewater are comprehensively reviewed. The literature review reveals that advanced oxidation processes (AOPs) demonstrate superior effectiveness in eliminating persistent contaminants. However, the major challenges to their industrial-scale implementation are their cost and scalability. Additionally, it was discovered that employing a series of biological reactors instead of single-step biological processes enhances command over microbial communities and operating variables, thus boosting the efficacy of the treatment mechanism (e.g., achieving a chemical oxygen demand (COD) elimination rate of over 90%). This review seeks to conduct an in-depth examination of the current state of treating metallurgical wastewater, with a particular emphasis on strategies for pollutant removal. These pollutants exhibit distinct features influenced by the technologies and workflows unique to their respective processes, including factors such as their composition, physicochemical properties, and concentrations. Therefore, it is of utmost importance for customized treatment and disposal approaches, which are the central focus of this review. In this context, we will explore these methods, highlighting their advantages and characteristics.

The demand for REEs is continuously increasing in the European Union due to the rapid development of high-tech applications that contain REEs, mainly those based on electrification. However, the REE supply in Europe is limited because of the exclusive production of these metals by third-world countries. The European supply/demand gap for REEs can be covered with the development of recycling technologies from secondary resources, such as REE permanent magnets. NdFeB and SmCo magnets are the two main categories of REE-containing permanent magnets. In the following work, studies focusing on the preprocessing and leaching methods in order to extract REEs were identified and discussed. Although preprocessing includes controversial steps, i.e., milling and demagnetizing, numerous studies have focused on the leaching of REEs from NdFeB magnets using either inorganic or organic solvents. Meanwhile, the literature based on Sm recovery methods from SmCo magnets has been limited.

Fire is a fundamental ecological process with a long history on Earth, determining the distribution of vegetation formations across the globe. Fire, however, does not only affect the vegetation but also the soil on which vegetation grows, creating a post-fire environment that differs significantly in terms of soil chemical and physical properties from the pre-fire environment. The duration of these alterations remains largely unknown and depends both on the vegetation condition and the fire characteristics. In the current study, we investigate the effect of fire on some chemical and physical properties 11 years after the event in four plant communities. Two of them constitute typical Mediterranean fire-prone plant communities, dominated by sclerophyllous Mediterranean shrubs, such as Quercus coccifera and Q. ilex, while the other two are not considered fire prone and are dominated by deciduous broadleaved species such as Q. petraea and Castanea sativa, respectively. The results indicate that fire affects the soil properties of the various communities in a different manner. Burned sites in the Q. coccifera community have a significantly lower concentration of organic matter, total nitrogen, and available magnesium. At the same time, they have a significantly higher concentration of sand particles and a lower concentration of clay particles. The effect of fire on the soil properties of the other three communities is less dramatic, with differences only in total phosphorus, organic matter, and total nitrogen. The results are discussed in relation to the site conditions and the post-fire regeneration of plant communities.

The pursuit of sustainable and clean energy solutions has led to increased interest in hydrogen as an efficient energy carrier. This paper presents a comprehensive analysis of state-of-the-art technologies for hydrogen production through seawater electrolysis and desalination, addressing the critical need for clean energy generation and sustainable water supply. It emphasizes the importance of hydrogen as a versatile and environmentally friendly energy source, as well as the significance of seawater desalination in addressing water scarcity challenges. “The analysis encompasses a comparison of the three existing commercial electrolysis technologies”: solid oxide electrolysis (SOE), alkaline electrolyzers (AE), and proton exchange membrane (PEM) electrolysis. Factors such as energy requirements, capital and maintenance costs, and offshore suitability are considered, facilitating an informed evaluation of the most suitable electrolysis method for seawater hydrogen production. Additionally, three desalination technologies with commercial applications are under evaluation: reverse osmosis (RO), thermal desalination, and membrane desalination. The assessment takes into account investment and operation costs, energy demand, and environmental impact, providing insights into the feasibility and sustainability of integrating hydrogen production with seawater desalination. The findings reveal the energy, economic, and environmental aspects of hydrogen production via seawater electrolysis and desalination, shedding light on the synergies and challenges involved. The study concludes by summarizing the main results, identifying research gaps, and outlining future directions for further advancements in the field. This condensed review serves as a valuable resource for policymakers, researchers, and practitioners in understanding the complex interplay between hydrogen production, seawater electrolysis, and desalination. It provides a perspective on energy demands, environmental impact, and investment of various technologies, enabling informed decision-making toward a more sustainable and resilient energy–water nexus. Overall, this study contributes to the growing body of knowledge on hydrogen production and seawater desalination, offering insights that can inform strategic planning, policy development, and technological advancements in achieving a greener and more sustainable future.