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• Nano-confined rGO/CuCo-MOF membrane was synthesized by stacked self-assembly. • Analyses confirmed the rGO membrane-confined growth of CuCo-MOF crystal. • Nano-confined membrane can achieve rapid destruction of organic pollutants. • The degradation path of OTC was proposed via DFT calculation and LC-MS analysis. Fenton-like processes generate reactive oxygen species (ROS) to achieve degradation of organic pollutants, however, practical water treatment processes suffer from low ROS utilization owing to its ultra-short lifetime and mass transfer limitations. To solve these problems, a nano-confined reaction space was designed to facilitate a fast mass transfer process for efficient removal of organic pollutants. Herein, the CuCo-based bimetallic organic framework (CuCo-MOF) was loaded in the water-transporting interlayer nanochannels of reduced graphene oxide (rGO) membrane. Membrane-confined CuCo-MOF with multiple exposed reaction sites activate peroxymonosulfate (PMS), generating ROS for ultrafast removal of oxytetracycline (OTC) at a water fluxes of 87.3 L·m−2·h−1. Notably, this membrane can continuously and stably degrade OTC (100 %) within 30 h. In addition, free radical capture experiments and EPR analysis indicated that the main ROS of the reaction system were singlet oxygen (1O 2) and sulfate radical (SO 4 −). Based on Fukui index results and LC-MS analysis, reaction sites of OTC attacked by ROS were identified and it's possible degradation pathways were proposed. [ABSTRACT FROM AUTHOR]

• CuCo-based MOF was prepared via a facile solvothermal method. • CuCo-MOF displays excellent activity for NIM degradation. • The synergy between the Cu-Co dual active centers enhanced the activation of PMS. • The NIM reaction site was revealed and its degradation path was proposed. • Cu and Co dual active sites to favor Cu and Co-PMS adsorption and charge transfer. Regulation of active sites is of significant importance for boosting the catalytic properties of metal–organic frameworks (MOF). Herein, we developed a one-pot strategy to construct bimetallic organic frameworks with Cu-Co double sites (CuCo-MOF) for peroxymonosulfate (PMS) activation. CuCo-MOF exhibits excellent active oxidation capacity, enabling complete removal of NIM within 25 min (0.227 min−1). Its NIM degradation rate was 7.3 and 2.4 times higher than that of Cu-MOF and Co-MOF, respectively. The theoretical simulations unravel that doping Co into the lattice structure of Cu-MOF promotes electron transfer from the electron-rich region (benzene ring) to the electron-deficient regions around metal sites, which facilitated the optimization of the adsorption energy for PMS activation and boosted the breakage of O O bond in PMS. According to LC-MS analysis and DFT calculation, the NIM degradation pathways were proposed, and its degradation intermediates were conducted for toxicity evaluation. The findings, revealing the synergistic effect of bimetals, open a new avenue for the rational design of highly efficient MOF-based Fenton-like catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of NC-Co(PO 3) 2 adopted facile gas-solidified phosphating strategy. • NC-Co(PO 3) 2 electrode was used for the first time in the field of CDI. • NC-Co(PO 3) 2 showed better electrosorption capacity of 95.41 mg g−1. • NC-Co(PO 3) 2 had excellent selectivity in various ion-competitive environments. • Real copper-containing wastewater confirmed the great potential of NC-Co(PO 3) 2. The increasing amount of heavy metal copper ions (Cu2+) in industrial emissions, poses a serious threat to human health, biological environment, and resource scarcity. Capacitive deionization (CDI) is considered as a green and efficient method for desalination. It is crucial to develop high-performance electrodes for efficient operation of CDI that go beyond conventional carbon and yield considerable environmental benefits. Here, metal organic frameworks (MOFs) derived carbon-loaded cobalt metaphosphate (NC-Co(PO 3) 2) was prepared by low-temperature gas–solid phosphating for Cu2+ removal as CDI electrode for the first time. NC-Co(PO 3) 2 demonstrated superior electrode structure and function due to the synergistic effects of electric double layer coupling P-O bonds, the binding tendency of metaphosphate groups with Cu2+, and interfacial redox reactions induced by the labile valence state of cobalt. The optimal electrosorption capacity of NC-Co(PO 3) 2 was 95.41 mg g−1 at 1 V in 50 mL Cu2+ solution with splendid cyclic regeneration capability. Moreover, NC-Co(PO 3) 2 exhibited excellent selectivity and outstanding electrosorption performance in the presence of multiple coexisting ions and this CDI system realized the purification of actual copper-containing wastewater. A series of characterizations further revealed the specific mechanism of Cu2+ in adsorption–desorption process. Our finding strongly supported NC-Co(PO 3) 2 electrode can extend the CDI platform's capability for effectively removing and retrieving Cu2+ from wastewater. [ABSTRACT FROM AUTHOR]

• Synergistic electrosorption of HBC bilayers and MoS 2 for Cu2+ complexation. • HBC shows excellent structural stability before and after MoS 2 loading. • High selective ion removal effect is still achieved in the presence of complex ions. • Used as an electrode in capacitive deionization technology. Capacitive deionization has been considered as a promising wastewater treatment technology because of its low-cost and highly efficient. Herein, we prepared hollow bowl-type carbon materials loaded with molybdenum sulfide (HBC-MoS 2) composites and fabricated it as an innovative electrode material to remove Cu2+ in a multi-ion coexistence system. With the synergistic effect of electric double layer (EDL) and complexation between MoS 2 and Cu2+, the HBC-MoS 2 -0.02 electrode achieved effective removal of copper ions from low concentration wastewater (25 mg/L) and high electrosorption capacity of 28.97 mg g−1 at 1.0 V. Even in the presence of competing ions (Na+/Zn2+/Cu2+), the HBC-MoS 2 -0.02 electrode still can effectively remove Cu2+ with a final adsorption capacity of 28 mg g−1, showing its superiority. The mechanism of Cu2+ removal by HBC-MoS 2 is mainly due to the synergistic effect of EDL and complexation. [ABSTRACT FROM AUTHOR]