Urban mineral resources, with their significant recycling potential, have increasingly accumulated worldwide and become an important source for extracting valuable metals, particularly critical rare dispersed metals (CRDMs) such as gallium, germanium, and indium. As the electronics industry continues to grow rapidly, the demand for CRDMs is rising. However, CRDMs in primary mineral resources are often found in small, dispersed concentrations, making extraction challenging. In contrast, urban mineral resources contain relatively higher concentrations of CRDMs, making their comprehensive exploitation more advantageous than that of primary minerals. This paper underscores the importance of metal recycling by examining the current state of e-waste recycling from urban mineral resources in China. It outlines the general process of e-waste recycling, briefly compares the advantages and disadvantages of common metal recycling methods, and summarizes the current status of CRDMs recycling from various electronic wastes. Finally, this paper discusses the development trends and future prospects of metal recycling technology in urban minerals.

An efficient protocol for photocatalytic degradation of organic dyes and antibiotics has been successfully established via MOF-derived (MOF = metal-organic framework) Ni, Co-embedded N-doped bimetallic porous carbon nanocomposites (NiCo/NC). Such a NiCo/NC nanocomposite features well-distributed structures, suitable specific surface areas, and more active sites determined by various characterization analyses. The catalyst exhibits higher photocatalytic performance and stability toward the liquid-phase degradation of methylene blue (MB) under visible light irradiation for 60 min, after the adsorption-desorption equilibrium and the thorough degradation into H₂O and CO₂. Radical quenching experiments further confirmed the dominant effect of electron holes h⁺ and superoxide radical anions ·O₂^- for the MB photodegradation process. NiCo/NC was also appropriate for the degradation of Rhodamine B, methyl orange, tetracycline hydrochloride, and norfloxacin. Moreover, NiCo/NC is robust, and its photocatalytic activity is basically maintained after 8 cycles. This work is expected to provide additional information for the design of MOF-derived carbon material with more excellent properties and lay the foundation for further industrial applications.

Photocatalytic degradation of organic pollutants in wastewater is recognized as a promising technology. However, photocatalyst Bi₂O₃ responds to visible light and suffers from low quantum yield. In this study, the α-Bi₂O₃ was synthetized and used for removing Cl⁻ in acidic solutions to transform BiOCl. A heterostructured α-Bi₂O₃/BiOCl nanosheet can be fabricated by coupling Bi₂O₃ (narrow band gap) with layered BiOCl (rapid photoelectron transmission). During the degradation of Rhodamine B (RhB), the Bi₂O₃/BiOCl composite material presented excellent photocatalytic activity. Under visible light irradiation for 60 min, the Bi₂O₃/BiOCl photocatalyst delivered a superior removal rate of 99.9%, which was much higher than pristine Bi₂O₃ (36.0%) and BiOCl (74.4%). Radical quenching experiments and electron spin resonance spectra further confirmed the dominant effect of electron holes h⁺ and superoxide radical anions ·O₂⁻ for the photodegradation process. This work develops a green strategy to synthesize a high-performance photocatalyst for organic dye degradation.