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Heavy metal cations such as Ag+, Pb2+, and Hg2+ can accumulate in living organisms, posing severe risks to biological systems, including humans. Therefore, removing heavy metal cations from wastewater is crucial before discharging them to the environment. However, trace levels and high-capacity removal of the heavy metals remain a critical challenge. This work demonstrates the synthesis and characterization of [Mo2S12]2− intercalated cobalt aluminum-layered double hydroxide, CoAl―Mo2S12―LDH (CoAl―Mo2S12), and its remarkable sorption properties for heavy metals. This material shows high efficiency for removing over 99.9% of Ag+, Cu2+, Hg2+, and Pb2+ from 10 ppm aqueous solutions with a distribution constant, Kd, as high as 107 mL/g. The selectivity order for removing these ions, determined from the mixed ion state experiment, was Pb2+ < Cu2+ ≪ Hg2+ < Ag+. This study also suggests that CoAl―Mo2S12 is not selective for Ni2+, Cd2+, and Zn2+ cations. CoAl―Mo2S12 is an efficient sorbent for Ag+, Cu2+, Hg2+, and Pb2+ ions at pH~12, with the removal performance of both Ag+ and Hg2+ cations retaining > 99.7% across the pH range of ~2 to 12. Our study also shows that the CoAl―Mo2S12 is a highly competent silver cation adsorbent exhibiting removal capacity (qm) as high as ~918 mg/g compared with the reported data. A detailed mechanistic analysis of the post-treated solid samples with Ag+, Hg2+, and Pb2+ reveals the formation of Ag2S, HgS, and PbMoO4, respectively, suggesting the precipitation reaction mechanism. 

Water constitutes an indispensable resource for global life but remains susceptible to pollution from diverse human activities. To mitigate this issue, researchers are committed to purifying water using a variety... 

Abstract Chalcogel represents a unique class of meso‐ to macroporous nanomaterials that offer applications in energy and environmental pursuits. Here, the synthesis of an ion‐exchangeable amorphous chalcogel using a nominal composition of K₂CoMo₂S₁₀(KCMS) at room temperature is reported. Synchrotron X‐ray pair distribution function (PDF), X‐ray absorption near‐edge structure (XANES), and extended X‐ray absorption fine structure (EXAFS) reveal a plausible local structure of KCMS gel consisting of Mo⁵⁺₂and Mo⁴⁺₃clusters in the vicinity of di/polysulfides which are covalently linked by Co²⁺ions. The ionically bound K⁺ions remain in the percolating pores of the Co–Mo–S covalent network. XANES of Co K‐edge shows multiple electronic transitions, including quadrupole (1s→3d), shakedown (1s→4p + MLCT), and dipole allowed 1s→4p transitions. Remarkably, despite a lack of regular channels as in some crystalline solids, the amorphous KCMS gel shows ion‐exchange properties with UO₂²⁺ions. Additionally, it also presents surface sorption via [S∙∙∙∙UO₂²⁺] covalent interactions. Overall, this study underscores the synthesis of quaternary chalcogels incorporating alkali metals and their potential to advance separation science for cations and oxo‐cationic species by integrating a synergy of surface sorption and ion‐exchange. 

This study reports an amorphous Zn_xMo₃S₁₃chalcogel, reveals its local structure, and shows outstanding Li/Zn_xMo₃S₁₃electrochemical performance enabled by its amorphous structure, Zn-mediated polysulfide anchoring, and a stable SEI layer.