Electronic waste (e-waste) contains valuable rare earth elements (REEs) essential for various high-tech applications, making their recovery crucial for sustainable resource management. This review provides an overview of the occurrence of REEs in e-waste and discusses both conventional and emerging green technologies for their recovery. Conventional methods include physical separation, hydrometallurgy, and pyrometallurgy, while innovative approaches such as bioleaching, supercritical fluid extraction, ionic liquid extraction, and lanmodulin-derived peptides offer improved environmental sustainability and efficiency. The article presents case studies on the extraction of REEs from waste permanent magnets and fluorescent powders, highlighting the specific processes involved. Future research should focus on developing eco-friendly leaching agents, separation materials, and process optimization to enhance the overall sustainability and efficiency of REE recovery from e-waste, addressing both resource recovery and environmental concerns effectively.

Mesoporous silica SBA-15 has emerged as a promising adsorbent and separation material due to its unique structural and physicochemical properties. To further enhance its performance, various surface modification strategies, including metal oxide and noble metal incorporation for improved catalytic activity and stability, organic functionalization with amino and thiol groups for enhanced adsorption capacity and selectivity, and inorganic–organic composite modification for synergistic effects, have been extensively explored. This review provides a comprehensive overview of the recent advances in the surface modification of SBA-15 for adsorption and separation applications. The synthesis methods, structural properties, and advantages of SBA-15 are discussed, followed by a detailed analysis of the different modification strategies and their structure–performance relationships. The adsorption and separation performance of functionalized SBA-15 materials in the removal of organic pollutants, heavy metal ions, gases, and biomolecules, as well as in chromatographic and solid–liquid separation, is critically evaluated. Despite the significant progress, challenges and opportunities for future research are identified, including the development of low-cost and sustainable synthesis routes, rational design of SBA-15-based materials with tailored properties, and integration into practical applications. This review aims to guide future research efforts in developing advanced SBA-15-based materials for sustainable environmental and industrial applications, with an emphasis on green and scalable modification strategies.

The growing demand for lithium, driven by the widespread adoption of electric vehicles and renewable energy storage systems, has sparked interest in developing low-grade lithium resources. This comprehensive review explores the types, distribution, extraction technologies, challenges, and future prospects of low-grade lithium resources. This article focuses on low-grade lithium sources such as clays, brines, coal, and coal by-products, and analyzes the principles, advantages, and limitations of key extraction techniques, including acid-alkaline leaching, bioleaching, adsorption, and membrane separation. Furthermore, this review discusses the technical, economic, and environmental sustainability challenges associated with developing low-grade lithium resources and proposes corresponding strategies. Future research should focus on improving the selectivity and efficiency of extraction and processing technologies, optimizing separation processes, and developing green and cost-effective extraction methods. Establishing supportive policy frameworks, strengthening international cooperation, and knowledge sharing are crucial for promoting the sustainable development of low-grade lithium resources. This review provides stakeholders with comprehensive insights and recommendations for addressing the growing lithium demand and achieving the Sustainable Development Goals.

A complex salt roasting–water leaching process was developed and optimized for the efficient extraction of lithium (Li), rubidium (Rb), and cesium (Cs) from lepidolite. The effects of roasting parameters (temperature, time, and complex salt composition) and leaching parameters (temperature, time, and liquid–solid ratio) were systematically investigated. Optimal roasting conditions were found to be 900 °C for 60 min with a complex salt composition of Lepidolite:Na2SO4:CaCl2:CaCO3 = 1:0.5:0.3:0.05, while optimal leaching conditions were 60 °C, 60 min, and a liquid–solid ratio of 3:1, achieving the highest leaching efficiencies of 94.60%, 83.33%, and 82.95% for Li2O, Rb2O, and Cs2O, respectively. XRD and SEM characterizations confirmed the decomposition of lepidolite, formation of water-soluble phases during roasting, and selective separation of Li, Rb, and Cs from insoluble phases during leaching. The porous structure of the roasted product facilitated the dissolution of target metals. This study provides valuable insights and guidance for the efficient extraction of Li, Rb, and Cs from lepidolite, contributing to the comprehensive utilization of this resource.

Ion-adsorbing rare earth tailings (IRETs) contain a large amount of clay minerals, which are a potential source of silicon and aluminum for the preparation of zeolite materials. The complexity of the tailings’ composition and the impurity composition are the main difficulties in the controllable preparation of zeolite. Herein, IRETs were treated by classification activation technology for the preparation of IRET-ZEO, which was used for the removal of heavy metal Pb²⁺ in water. A new method of resource utilization of ion-type rare earth tailings is realized by “treating waste with waste”. The results showed that the IRETs were classified and then thermally activated, and the optimal activation parameter was calcination at 850 °C for 1 h. The optimal NaOH concentration used in the crystallization process was 5 mol/L, with a crystallization time of 3 h and a crystallization temperature of 85 °C, and the crystallization product was zeolite A. The removal rate of the Pb²⁺ solution with an initial concentration of 100 mg/L was as high as 96.7% in an acidic solution with a pH value from 2 to 5.5. In particular, when the solution pH was higher than 4.2, the adsorption rate of Pb²⁺ was close to 100%. The IRET-ZEO showed a fast adsorption rate (5 min to reach adsorption equilibrium), a large adsorption capacity (378.35 mg/g), excellent acid resistance, and selectivity and regenerability for Pb²⁺. This work provides a new strategy for the green resource utilization of IRETs and the treatment of lead-containing wastewater.

The primary aim of this study was to investigate the boron leaching process from alkali-activated ludwigite ore. Initially, the ore underwent activation through roasting at 1050 °C for 60 min with 20% sodium carbonate. Subsequently, the study examined the influence of leaching parameters, including temperature, time, liquid-to-solid ratio, and particle size, using the activated ore as the raw material. Additionally, water leaching characteristics of the residues and boron kinetics were analyzed. The results demonstrated that boron leaching efficiency reached 93.71% from the reduced ludwigite ore under specific conditions: leaching temperature of 180 °C, leaching time of 6 h, liquid-to-solid ratio of 8:1, and feed particle size of 52.31 μm (average particle size). Leach residue characteristics indicated the dissolution of minerals during the process. The boron behavior during water leaching followed the Avrami Equation, and the kinetics equation was derived by fitting the leaching data. Moreover, the activation energy (E_a) value for boron leaching was determined to be 8.812 kJ·mol⁻¹ using the Arrhenius Equation, indicating that the leaching process is controlled by diffusion.