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The deep separation between In(III) and Fe(III) ions is considered as an important technological challenge in the engineering fields. The In(III) ions are closer to the soft acid in terms of Lewis acidity due to the smaller polarizability and greater deformability than the Fe(III) ions, which facilitates the possibility of separating them. Herein, the Lewis basicity of the N‐containing adsorption sites is regulated by the fluorine‐containing group to better match with the In(III) ions rather than Fe(III) ions, causing a significant discrepancy in the binding of the adsorption sites to them. Moreover, targeted programmed desorption techniques based on the potential energy differences of the adsorption sites can achieve the deep separation of In(III) and Fe(III) ions, and reach an exceptional concentration of 20.7 mmol L−1 for In(III) ions in the initial desorption solution with extremely high mass ratio (mIn/mFe = 151.7). This work provides a novel technique for in‐depth separation of In(III) and Fe(III) ions from mixed systems, and a new strategy for separating metal ions with similar or close properties. [ABSTRACT FROM AUTHOR]

• Cu-MOF is used to recycle Au(S 2 O 3) 2 3− from alkaline leachate for the first time. • The adsorption capacity of 206.19 mg/g is the highest in the adsorption method. • Diphenylamine and copper cluster defects are used as active sites. • Local exotherms of DMF facilitate the recovery of Au(S 2 O 3) 2 3−. • The interaction between Cu-ADA and Au(S 2 O 3) 2 3− was investigated with DFT calculation. Recycling gold from electronic waste is essential for environmental protection and resource sustainability. However, the design of adsorbents for effective recycling of Au(S 2 O 3) 2 3− from alkaline leach solutions is of great challenge and has not been investigated by using MOFs. Herein, we report the design and preparation of a Cu-MOF based on the structural characteristics of Au(S 2 O 3) 2 3−, which is constructed by 4,4′-di carboxy diphenylamine and Cu 2 -paddlewheel. Cu-ADA-53 demonstrates ultra-high adsorption capacity of 206.19 mg g -1, and the gold recovery in actual alkaline leach solutions is more than 99 %. X-ray photoelectron spectroscopy, thermodynamic study, and density functional theory calculations reveal the excellent performance of Cu-ADA-53 for Au(S 2 O 3) 2 3− results from the abundant Lewis base diphenylamine groups and open copper sites. More importantly, different from pore diffusion-promoting adsorption, the axial coordination DMF of Cu 2 -paddlewheel fell off into the water phase and then released heat locally at the adsorption sites. The local exotherms increase the temperature of the adsorption sites, further promoting the adsorption of Au(S 2 O 3) 2 3− by Cu-ADA-53. The local exotherms at adsorption sites provide a novel insight to efficiently recover Au(S 2 O 3) 2 3−. [Display omitted] [ABSTRACT FROM AUTHOR]

• A noticeable dissolution of Mn was observed in adsorption of antimony on MnO 2. • Dissolved amount of Mn depended on antimony adsorption capacity of MnO 2. • Variation of crystalline phases possessed an insignificant effect on Mn release. • Mechanisms of Sb capture and Mn release were unveiled at the atomic scale. Manganese dioxide (MnO 2) exhibits great potential for the uptake of antimony (Sb) from wastewater. Much research has been dedicated to enhancing the capacity of MnO 2 for Sb sequestration. However, the dissolution behavior of Mn has been overlooked, and the underlying relationship between Sb(III) adsorption and Mn dissolution is not clear. In this study, batch experiments evidenced that there was a noticeable dissolution of Mn during the adsorption of Sb(III) on MnO 2. A correlation analysis demonstrated that the amount of Mn dissolved was dependent on the Sb(III) adsorption capacity of MnO 2 , regardless of the crystalline phase of MnO 2. Further experimental and theoretical results (taking α-MnO 2 as an example) unveiled that Mn dissolution involved the following stages. First, Sb(III) adsorbed onto the (3 1 0) crystal plane of α-MnO 2 to form a complex via two Mn-O-Sb bonds, which can be proven by the delicate adsorption configuration and corresponding adsorption energy (E ad) of −4.04 eV. Then, three O atoms from the α-MnO 2 progressively deprived two H atoms from Sb(OH) 3 and one H atom from a water molecule bound to Sb(OH) 3 , respectively. This process was verified by the configuration of the transition state (transition state #3) and the occurrence of electron transfer (i.e., the net charge changed by + 2 e). Finally, the Mn-O bonds of α-MnO 2 were weakened and disrupted, leading to the release of Mn into the aqueous solution. This work advances the fundamental understanding of Sb adsorption onto MnO 2 , which not only promotes a re-evaluation of the utility of MnO 2 for Sb(III) elimination but also provides a theoretical guide for the design of robust MnO 2 -based adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient AC-SH adsorbent for the selective capture of Ag+ was reported. • Ultrahigh adsorption capacity was attributed to the effective S on the AC-SH surface. • Ag+ transformation pathway was primarily driven by reduction. • AC-SH exhibited strong anti-interference ability in efficient capture of Ag+ from complex wastewater. The selective capture of silver ions (Ag+) from wastewater is promising for simultaneous water purification and resource recovery but remains challenging. In this work, an adsorbent obtained by grafting sulfhydryl (SH) groups onto activated carbon (AC) from discarded cigarette butts and heated at 80 °C (AC-SH-80) was designed for Ag+ removal and exhibited a high capacity (719.2 mg/g) and remarkable selectivity. For the first time, we report that the adsorption performance of AC-SH is directly related to the structure–activity mode of surface S. Two previously unnoticed Ag+ uptake mechanisms were revealed by a quantitative analysis of the amount of adsorbed and reduced Ag+: (i) the sulfhydryl groups converted the majority of Ag+ to Ag; (ii) a minor amount of Ag+ chelated with C–O and C = O due to electrostatic effects. Benefitting from these Ag+ transformation pathways, AC-SH-80 exhibits remarkable selectivity and can realize the efficient removal of Ag+ from actual wastewater with complex backgrounds. This work uncovers the role of S in the Ag+ capture process to provide a new interpretation of the pathways involved in the adsorption of heavy metal ions to functional group-modified materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-performance gold capture material C-S-180 has been reported. • C-S-180 exhibits excellent gold selectivity in intricate wastewater. • Sulfur modulates the electronic structure of the skeleton to promote gold capture. • C-S optimized energy band gap for a more efficient gold reduction process. The efficient and selective recovery of gold from secondary sources is key to sustainable development. However, the complexity of the recovery environment can significantly complicate the compositions of utilized sorbents. Here, we report a straw-derived mesoporous carbon as an inexpensive support material. This mesoporous carbon is modified by anions (sulfur modulation, C-S-180) to improve its electron-transfer efficiency and tune the electronic structure of its skeleton toward enhanced gold reduction. The high surface area of C-S-180 (989.4 m2/g), as well as the presence of abundant C–S in the porous structure of the adsorbent, resulted in an outstanding Au3+-uptake capacity (3422.75 mg/g), excellent resistance to interference, and favorable Au3+ selectivity. Dissimilar to most existing carbon-based adsorbents, electrochemistry-based studies on the electron-transfer efficiencies of adsorbents reveal that sulfur modulation is crucial to optimizing their adsorption performances. Furthermore, the density functional theory reveals that the optimization mechanism is attributable to the adjustment of the electronic structure of the carbon skeleton by C–S, which optimizes the band-gap energy for enhanced Au3+ reduction. These findings offer a strategy for constructing green and efficient adsorbents, as well as a basis for extending the applications of inexpensive carbon materials in gold recovery from complex environments. [ABSTRACT FROM AUTHOR]