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Singlet oxygen (1O 2) is a highly effective reactive species in selectively oxidizing organic pollutants. However, it is still challenging to rationally design robust catalysts for the selective generation of 1O 2. Herein, the coordination and engineering architecture of the foam board-like CoSe 2 alloy were facilely constructed through a green solvent-free method and displayed almost 100% 1O 2 production selectivity. The CoSe 2 alloy showed excellent catalytic ability for the efficient and fast removal of organic pollutants via peroxymonosulfate (PMS) activation compared with previously reported cobalt-based catalysts. The CoSe 2 /PMS system exhibited strong resistance for a broad pH range (3.0–11.0) and various coexisting inorganic ions owing to the advantage of the strong bonding of Co-Se in CoSe 2 alloy. Mechanism studies revealed that 1O 2 was the only reactive oxygen species in the CoSe 2 /PMS system. Theoretical calculations demonstrated that Co was the dominant adsorption site for PMS in CoSe 2 , and the production pathway of 1O 2 was PMS* → *OH → *O → 1O 2. In addition, it was proved that *OH and *O served as the rate-determining steps for the formation of 1O 2 by PMS activation on CoSe 2 alloy. These findings provide a rational strategy for preparing a series of low-cost transition metal-based alloy catalysts for PMS activation to achieve high-efficiency 1O 2 production in the elimination of organic pollutants. [Display omitted] • The foam board-like CoSe 2 alloy was facilely fabricated through a green solvent-free method. • CoSe 2 exhibited excellent catalytic performance for PMS activation. • The CoSe 2 /PMS system achieved almost 100% 1O 2 production selectivity. • *OH and *O served as the rate-determining steps for the formation of 1O 2. • 100% sulfadiazine was stably removed via a continuous flow reactor in 6 h. [ABSTRACT FROM AUTHOR]

• Coral reef-like FeS 2 /C cs was prepared by a one-step solvothermal method. • FeS 2 in situ grew on the surface of waste corn stalks-derived carbon (FeS 2 /C cs). • FeS 2 /C cs exhibited a superior ability for activating PMS to degrade OTC. • SO 4 − and OH were identified as the major radicals for attacking OTC. • Toxicity of OTC could be effectively reduced via the FeS 2 /C cs + PMS system. Over the past few decades, organic pollution such as tetracyclines and dyes has caused harm to the environment, biology, and human health. Therefore, developing a green and efficient method for organic pollutant removal is urgent. Herein, a coral reef-like FeS 2 /C cs was successfully constructed by one-step solvothermal growth of FeS 2 on waste corn stalks-derived carbon. The as-prepared FeS 2 /C cs catalyst exhibited much better performance in activating peroxymonosulfate (PMS) for removing organic pollutants than the other candidates previously reported. Almost 100 % of oxytetracycline (OTC) could be degraded within 20 min. Various factors like PMS concentration, catalyst dosage, initial pH values, and temperature that influenced the degradation process were then investigated. Through quenching experiments and electron paramagnetic resonance (EPR), O 2 −, 1O 2 , SO 4 − and OH were determined to be involved in attacking OTC, in which SO 4 − play a major role and OH acted as the secondary role. Subsequently, degradation pathways of OTC were rationally proposed. Toxicity simulations demonstrated that the toxicity of OTC could be effectively reduced after degradation. Universal experiments showed that FeS 2 /C cs + PMS system could also effectively degrade other typical tetracyclines and dyes, such as tetracycline (TC, ∼100 %), chlortetracycline hydrochloride (CTC, ∼100 %), methylene blue (MB, ∼83 %) and rhodamine B (RhB, ∼95 %). Moreover, the FeS 2 /C cs could remain high catalytic activity in five cycles test. This study provides a green and efficient method for organic pollution removal and technical guidance for analyzing its environmental toxicology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fine-grained CoFe 2 O 4 nanoparticles are facilely anchored on porous carbon. • Porous carbon boosts the mass transfer efficiency and prevents Co and Fe leaching. • CoFe 2 O 4 @PC facilitates the simultaneous removal of TC and As(III) via PMS activation. • Radical and nonradical pathways contribute to the oxidation of TC. • The degradation pathways and toxicity analysis of TC are proposed. The coexistence of tetracycline (TC) and arsenite (As(III)) in livestock wastewater threatens public health, and the heterogeneous Fenton-like system is a practical approach for the simultaneous removal of TC and As(III). In this work, fine CoFe 2 O 4 nanoparticles are facilely anchored on heretically porous carbon (CoFe 2 O 4 @PC) via a microwave-assisted calcination method and used for eliminating TC and As(III) via peroxymonosulfate (PMS) activation. The CoFe 2 O 4 @PC/PMS system exhibits excellent performance in the simultaneous removal of 96% of 10 mg/L TC and 86% of 50 μM As(III) within 30 min, whereas the porous carbon can boost the mass transfer efficiency and protect CoFe 2 O 4 against Co and Fe ions leaching. The CoFe 2 O 4 @PC/PMS system maintains satisfactory activity and stability in a broad pH range (3–11) and anti-interference capacity (anions, humic acid and water matrices). Meanwhile, the CoFe 2 O 4 @PC with the strong magnetic property was readily recovered from the reaction solution. Moreover, the cooperation of radical (·OH, ·SO 4 - and ·O 2 –) and nonradical (1O 2) pathways was documented to play critical roles in enhancing the oxidation of TC and As(III), which effectively reduces the toxicity of degradation intermediates. This work offers a facile strategy for constructing spinel-based catalysts and opens a broad prospect for removing TC and As(III) in livestock wastewater. [ABSTRACT FROM AUTHOR]

How to efficiently and fast remove the serious perniciousness of the residual antibiotics in water environment is crucial for protecting ecosystem. Herein, we reported the Fenton-like system based on layered double hydroxides (LDHs) nanosheets for direct peroxymonosulfate (PMS) activation efficient for fast removing the typical five fluoroquinolones antibiotics ciprofloxacin (CIP), norfloxacin (NOR), levofloxacin (LEV), enrofloxacin (ENR) and ofloxacin (OFL). A series of CoFe-LDHs nanosheets was one-step fabricated by integrating coprecipitation and in-situ exfoliation method. The as-obtained CoFe-LDHs nanosheets catalysts exhibit thin nanosheets (~3 nm) with high redox properties, abundant oxygen vacancies, appreciable adsorption capacity, remarkable catalytic performance and favorable stability. The variable valent state, cheap, easy-to-obtain and low-toxic Co and Fe elements were used to construct stable LDHs for efficient activation of PMS to degrade quinolone antibiotics. Among them, Co 1 Fe 1 -LDHs nanosheets exhibited the best CIP degradation efficiency of 86.9% within 12 min, which is superior to most of previous candidates. The impacts of different reaction parameters, catalyst stability, main reactive oxygen species, the main CIP degradation mechanism and rational degradation pathways were systematically studied. This work offers a feasible strategy to tune the performance of LDHs-based materials in Fenton-like system degradation of antibiotics. [Display omitted] • A series of CoFe-LDHs nanosheets were used to activate PMS to degrade quinolones. • The structure-activity relationship of CoFe-LDHs was studied. • The Co 1 Fe 1 -LDHs/PMS/CIP system could degrade 86.9% CIP within 12 min. • Degradation mechanism and pathway of ciprofloxacin was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The garland-like MIL-101(Fe)/MoS 2 nanosheets activated PMS to degrade SMX. • .OH and 1O 2 were the dominant ROS in the MMS-0.1/PMS/SMX system. • Sulfur vacancies and Mo6+/Mo4+ sites accelerated the cycle of Fe3+/Fe2+. • Fukui index and LC-MS fully validated the rational degradation pathway of SMX. • The non-toxicity transformation of SMX was proved by toxicity analysis. Iron-based molybdenum disulfide (Fe-MoS 2) has emerged as a Fenton-like catalyst for the highly efficient degradation of antibiotics, but the structure–activity relationship remains elusive. Herein, garland-like MIL-101(Fe)/MoS 2 nanosheets (MMS) with dual metal active sites (Fe and Mo) and rich sulfur vacancies were fabricated to directly activate peroxymonosulfate (PMS) for fast degradation of different organic pollutants (phenols, dyes and drugs), even in real water bodies. The MMS exhibited extremely fast catalytic rate constant of 0.289 min−1 in the degradation of sulfamethoxazole (SMX), which was about 36 and 29 times that of single MoS 2 (0.008 min−1) and MIL-101(Fe) (0.01 min−1). Moreover, MMS with good stability and reusability could reach 92% degradation of SMX after 5 cycles. Quenching experiments and electron spin resonance (ESR) tests revealed that hydroxyl radicals (. OH) and singlet oxygen (1O 2) were the dominant reactive oxygen species (ROS) for SMX degradation. The integration of experimental works, characterization techniques and density functional theory (DFT) calculations unraveled that the formation of sulfur vacancies in MMS catalyst could expose more Mo sites, improve the charge density and boost the electron transfer, which was conducive to accelerating the Fe3+/Fe2+ cycle for enhancing the activation of PMS. Finally, the C-N, N-O, S-N, C-O and C-S bonds of SMX were easily attacked by ROS to generate the nontoxic intermediates in the MMS/PMS/SMX system. This study offers a new approach to designing high-performance Fe-MoS 2 catalysts for the removal of organic pollutants. [ABSTRACT FROM AUTHOR]