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[Display omitted] • A perforated CuFe 2 O 4 /Fe 2 O 3 composite was designed by a MOF-derived solid-state process. • The composite shows efficient PMS activation for sulfamethoxazole degradation. • Both radical and non-radical degradation contributed to SMX remediation. • Possible degradation mechanisms were proposed. • The catalyst shows excellent stability and reusability via magnetic recovery. Design of metal–organic framework (MOF) derived metal oxides is an effective approach for environmental remediation. The current study describes the fabrication of MIL-53-derived perforated CuFe 2 O 4 /Fe 2 O 3 using a facile, one-step, post-thermal solid-state approach by varying Cu/Fe ratios. Herein, the release of CO 2 and H 2 O during the thermal treatment facilitates the incorporation of Cu2+ onto the Fe 2 O 3 structure, forming a perforated hollow CuFe 2 O 4 /Fe 2 O 3 composite via an in-situ ion-exchange mechanism. The optimised catalyst CF-0.5 displays a high degradation efficiency for the removal of sulfamethoxazole (SMX) by heterogeneous activation of peroxymonsulfate (PMS), ascribing to the better textural, morphological, and elemental properties of the novel catalyst. Important reaction parameters such as pH, catalyst loading, PMS dosage, pollutant kind and concentration, and reaction temperature are further optimised to develop a cost-effective catalytic system. The magnetically recoverable catalyst outlines a high stability rate, and only a 9 % efficiency loss is observed even after the fourth cycle. Reactive oxygen species (ROS) are identified by electron paramagnetic resonance spectroscopy (EPR) and their roles are determined by performing quenching experiments. In the end, a detailed study of the mineralisation ability and reaction intermediates is performed and possible pathways for the degradation mechanism are proposed. This study not only introduces a facile approach for the fabrication of MOF-driven nanomaterials but provides insights into the removal of emerging contaminants such as SMX. [ABSTRACT FROM AUTHOR]

Over the past few years, advanced oxidation processes (AOPs) have shown promising efficiencies for wastewater remediation. Carbocatalysis, in particular, has been exploited widely thanks to its sustainable and economical properties but has an issue of recovery and reusability of the catalysts. To address this, three-dimensional (3D) binary and ternary graphene-based composites in the form of macro discs were created to activate peroxymonosulfate (PMS) for catalytic oxidation of sulfamethoxazole (SMX). Graphene oxide served as the base, while graphitic carbon nitride (g-C 3 N 4) and/or single-walled carbon nanotubes (SWCNTs) were added. Among the various discs synthesized, rGNTCN discs (ternary composite) were proven to be the most efficient by completely degrading SMX in 60 min owing to their large surface area and nitrogen loading. The catalytic system was further optimized by varying the reaction parameters, and selective radical quenching and electron paramagnetic resonance tests were performed to identify the active radical, revealing the synergistic role of both radical and non-radical pathways. This led to the development of possible SMX degradation pathways. This research not only provides insights into ternary carbocatalysis but also gives a novel breakthrough in catalyst recovery and reusability by transforming nanocatalysts into macro catalysts. [Display omitted] • Novel graphene-based binary and ternary macro discs were fabricated. • The discs can activate peroxymonosulfate (PMS) for catalytic oxidation. • The identification of dominant reactive species was conducted. • PMS activation and sulfamethoxazole degradation pathways were illustrated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen-doped reduced graphene oxide beads (NrGOb) were fabricated by a one-step self-assembly strategy. • The lightweight NrGOBs and peroxymonosulfate system presented high activity in oxidative degradation of organic pollutants. • The catalytic beads were packed in a fixed-bed column reactor to maintain a continuous process. • Reactive radicals were identified by the quenching tests and electron paramagnetic resonance spectra. • Mechanistic studies on peroxymonosulfate activation and degradation pathways of hydroxybenzoic acid were performed. Metal-free graphene-based catalysts have demonstrated excellent performance in advanced oxidation processes (AOPs). However, the recovery and reusability of these nanocatalysts are still a major issue. In this study, three dimensional (3D) nitrogen-doped reduced graphene oxide beads (NrGOb) were synthesized via a self-assembly method and then applied in heterogeneous activation of peroxymonosulfate (PMS) for the oxidation of hydroxybenzoic acid (HBA). The materials (NrGOb) were annealed at various temperatures ranging from 500 to 1000 °C, and the resulting NrGOb derived from 800 °C (NrGOb-800) exhibited the best performance for PMS activation. To avoid the challenging recovery, the degradation experiments were also performed in a packed-bed catalytic reactor. Various reaction parameters were investigated to optimize the efficiency of the system. Electron paramagnetic resonance (EPR) and quenching tests were carried out to differentiate the contribution of reactive radicals (SO 4 •- and •OH) in the degradation process and then aided in illustrating the degradation mechanism. Finally, the stability and reusability of the catalytic beads were investigated. The efficiency slightly declined with increased cycles; however, catalyst regeneration would be able to partially restore the active sites. The results suggest the feasibility of exploiting graphene-based macrostructures on the AOPs platform for the degradation of organic pollutants in commercial wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Membrane separation and sulfate radicals-based advanced oxidation processes (SR-AOPs) can be combined as an efficient technique for the elimination of organic pollutants. The immobilization of metal oxide catalysts on ceramic membranes can enrich the membrane separation technology with catalytic oxidation avoiding recovering suspended catalysts. Herein, nanostructured Co 3 O 4 ceramic catalytic membranes with different Co loadings were fabricated via a simple ball-milling and calcination process. Uniform distribution of Co 3 O 4 nanoparticles in the membrane provided sufficient active sites for catalytic oxidation of 4-hydroxybenzoic acid (HBA). Mechanistic studies were conducted to determine the reactive radicals and showed that both SO 4 •− and •OH were present in the catalytic process while SO 4 •− plays the dominant role. The anti-fouling performance of the composite Co@Al 2 O 3 membranes was also evaluated, showing that a great flux recovery was achieved with the addition of PMS for the fouling caused by humic acid (HA). [Display omitted] • Co 3 O 4 integrated ceramic membranes were fabricated via a simple ball-milling and sintering approach. • Catalytic oxidation of 4-hydroxybenzoic acid was conducted in a crossflow membrane reactor. • Both SO 4 •− and •OH were present in the degradation with SO 4 •− as the dominant species. • Anti-fouling performance of the membranes was observed. [ABSTRACT FROM AUTHOR]