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[Display omitted] • MOFs act as dual-functional adsorbents and electrocatalysts for the removal of PPCPs. • Real active sites of MOFs are pinpointed using in-situ electrochemical methods. • Fe-MOFs exhibit high efficacy and stability in practical wastewater treatment. Pharmaceuticals and personal care products (PPCPs) pose a significant wastewater pollution concern. While electrochemical oxidation is promising, it struggles with slow mass transfer. To address this, we propose a novel strategy utilizing bifunctional metal–organic frameworks (MOFs) that couple an adsorbent with an electrocatalyst. The real active sites within iron-based MOFs responsible for the adsorption of PPCPs are MIL-101(Fe) molecules, while the in-situ formed active sites, α -FeOOH, accelerate the charge transfer under bias, contributing to the electrooxidation of PPCPs. The rapid destruction of adsorbed organics on the dual-functional electrode surface enables to release adsorption sites. This, in turn, paves the way for fast and efficient re-adsorption of PPCPs molecules, consequently promoting mass transfer. Iron-based MOFs exhibit excellent adsorption capacity (∼60 mg g−1 for sulfosalicylic acid, ∼15 mg g−1 for acetaminophen) and electrooxidation ability (94 % removal in 2 h, 31.2 kWh kg−1 COD) with good stability in realistic pharmaceutical wastewater treatment. This study offers a novel strategy for removing PPCPs using molecular electrocatalysts and provides new insights for designing and constructing MOFs for refractory wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adjustment of structure and interface of MFOC through soft-template is successful. • SMFO-B can achieve high removal rate and efficacy of Sb(V) and strong stability. • Direct tools with EXAFS and CD-MUSIC model showed specific inner-sphere complex. • E2 complex played the most important role in the Sb(V) adsorption onto SMFO-B. To achieve high removal rate and efficacy of Sb(V) from textile wastewater and simultaneously realize cyclic Sb(V) recovery, the structure and surface property of amorphous Mn-doped Fe oxide composite (MFOC) were regulated via the combination of facile soft-template synthesis and sintering treatment. Characterization and adsorption results indicated MFOC structure was greatly changed from aggregated large sphere to dispersive small sphere after adjusted by the optimal Brij-58 (SMFO-B). Because of the generated fasciculate micelle, long carbon chain feature and the lowest residual amount of Brij-58, abundant mesopores were generated and the aggregation of unit particles was apparently decreased for SMFO-B. Surface area and total pore volume of SMFO-B became 10 and 6 times of MFOC and more functional hydroxyl groups were generated and exposed on the interface between SMFO-B and water solution. Additionally, the surface positive potential of SMFO-B under neutral condition was also greatly increased. Thus, the maximum adsorption capacity and rate of SMFO-B towards Sb(V) reached to 147 mg/g and 0.1067 mg/(g·min), 2 and 5 times of MFOC. SMFO-B also possessed better selective adsorption ability, exhibited stronger static and dynamic adsorption performance in real textile wastewater and realized the cyclic desorption and enrichment of Sb(V) due to its better phase stability. X-ray absorption spectroscopy showed two main specific forms, such as bidentate edge-(E2) and corner-sharing (C2) complexes, for the inner-sphere complexation during Sb(V) adsorption and E2 complex was proved to play the most important role through the analysis of CD-MUSIC model. This study supplied an excellent adsorbent for Sb(V) removal from textile wastewater and a deeper insight about Sb(V) adsorption onto amorphous Fe oxide. [ABSTRACT FROM AUTHOR]

Abstract: In this study a systematic investigation of two specified MWCNTs-Pd/Fe nanocomposites to remove 2,4-dichlorophenol (2,4-DCP) is presented. Two specified Multi-Walled Carbon Nanotubes (MWCNTs), i.e., 60–100nm and 10–20nm were introduced in nZVI synthesis in order to improve its adsorption–dechlorination efficiency. Both MWCNTs-Pd/Fe nanocomposites showed excellent adsorption efficiencies for phenols and followed the sequential order; 2,4-DCP>p-CP>o-CP>P. Batch sorption experiments including kinetics and isotherm were also intensively investigated. Significantly high 2,4-DCP removal was observed after 1min when it reached to 49.7% and 53.2%, then continuously increased up to 95.2% and 77.7% after 5h at 0.20wt.% Pd loading by 60–100nm and 10–20nm MWCNTs-Pd/Fe nanocomposites, respectively. However, stronger dechlorination and weaker adsorption was found in 60–100nm MWCNTs-Pd/Fe nanocomposites. Moreover, an integrated approach of physical adsorption by 60–100nm MWCNTs and chemical reduction by Pd/Fe nanoparticles to remove 2,4-DCP was successfully achieved. The property of quick adsorption of targeted pollutants and steady release of dechlorination products enhance the applicability of this process for an in situ pollution remediation measures. [Copyright &y& Elsevier]

[Display omitted] • A functionalized material (CTAB-Pd/GAC) was synthesized as the catalyst. • CTAB could reduce the consumption of Pd for the catalyst. • Adsorption performance of catalyst was controlled by the amount of CTAB load. • Selective adsorption performance of the catalysts to 2,4-DCBA was enhanced. • The adsorption-desorption for 2,4-DCBA and BA was a dynamic process. The CTAB-Pd/GAC catalyst was obtained by functionalizing palladium/granular activated carbon (Pd/GAC) with cetyltrimethylammonium bromide (CTAB), which was used for the electrocatalytic reductive dechlorination of 2,4-dichlorobenzoic acid (2,4-DCBA). The degradation rate of 2,4-DCBA by 40 mg g−1 CTAB-Pd/GAC was 9.8 × 10−3 (min−1 g−1 Pd), which was 11 folds than that by Pd/GAC (0.9 × 10−3 min−1 g−1 Pd), and the value of q e, 2,4-DCBA / q e, BA was 2.33 as compared to 0.67 for Pd/GAC. The combined result of dechlorination and adsorption experiments suggested that the functionalization by CTAB would enhance the 2,4-DCBA concentration on the surface of CTAB-Pd/GAC, and accelerate the degradation rate. However, the removal efficiency of 2,4-DCBA would decrease when the CTAB load reached 80 mg g−1, due to the excessive adsorption capacity for dechlorinated product. Density functional theory (DFT) calculations also proved that CTAB would increase adsorption capacity of catalyst and selective adsorption behavior of 2,4-DCBA, which accelerated the degradation rate of 2,4-DCBA. [ABSTRACT FROM AUTHOR]

• Doping of suitable Si oxide greatly decrease the aggregation of SFOC. • Coordination interaction between Si-OH and Fe-OH led to property change of SFOC. • More functional Fe-OH groups (adsorption sites) were exposed after Si doping. • Almost no phase transformation of SFOC 10 happened during long cycle use. The development of amorphous iron oxide-based composites for the Sb(V) removal is limited by their easy phase transformation, aggregation, and unstable nature. Herein, novel modified Si-doped Fe oxide composites (SFOC) were prepared to break through the current obstacle. Characterization results of SFOC with a suitable amount of doped Si indicated that the coordination interaction between Si-OH and Fe-OH blocked the crystal growth sites in both Si and Fe oxide, and the crystal unit cells of same element were difficult to contact with each other. Hence, the crystal growth of Si and Fe oxide was retarded and their unit particle size became smaller. Meanwhile, the crystal phase transformation of amorphous ferrihydrite was prevented and the aggregation extent of Fe oxide was greatly decreased after Si doping. These changes caused that more Fe vacancies were generated on the surface of amorphous Fe oxide unit and the surface area of SFOCs also increased, resulting in the great increasement of exposed Fe hydroxyl groups in SFOC. As compared to pristine Fe oxide, the optimal SFOC 10 with Fe/Si molar ratio of 10:1 exhibited the highest surface area of 363.9 m2/g, the maximum Sb(V) removal capacity of 176.1 mg/g, and higher selective Sb(V) adsorption performance. The introduction of Si oxide also endowed SFOC 10 with much better phase stability and Sb(V) removal capacity during the long cyclic adsorption-desorption process. Moreover, the inner-sphere complexation of Fe-OH and Sb(OH) 6 − played a key role in adsorption. Furthermore, optimal SFOC 10 was sufficient for the Sb(V) removal from real textile wastewater in both the batch and dynamic column adsorption processes. [ABSTRACT FROM AUTHOR]