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The development of suitable catalysts poses a challenge for the peroxymonosulfate (PMS) activation system used in decontamination process. Here we constructed a series of vacancy-strengthened Cu/Co composite oxides (CuCoO) composed of CuCo 2 O 4 and CuO containing multiple Lewis acid sites. The results demonstrate that the as-prepared CuCoO-2 exhibited exceptional activation performance, broad-ranging degradation capacity, remarkable reusability and stability. The optimized CuCoO-2+PMS system achieved complete removal of methylene blue (MB) in 40 min, while maintaining a degradation efficiency of above 86 % even after 5 cycles. A comprehensive survey revealed that hydroxyl radical (·OH), sulfate radical (SO 4 .-) and singlet oxygen (1O 2) collectively contribute to the degradation of MB in the CuCoO-2+PMS system. Especially, 1O 2 was the dominant active species. The synergism of various Lewis acid sites (Cu+/2+, Co2+/3+ and V O/N) as unsaturated surface-bound centers played a pivotal role in promoting non-radical-driven activation of PMS. Meanwhile, the generated V O/N facilitated enhanced metallic valence circulation in CuCoO-2, strengthening electron mediation between PMS and MB. Additionally, possible degradation pathways and toxicity evaluations of MB and its intermediates were proposed. In conclusion, this work offers valuable insights into PMS activation by vacancy-strengthened CuCoO and is of great significance for water purification. [Display omitted] • Vacancy-strengthened CuCoO containing multiple Lewis acid sites were prepared. • The optimal CuCoO-2+PMS system achieved complete removal of MB in 40 min. • Lewis acid sites on CuCoO-2 facilitated the non-radical dominated activation of PMS. • 1O 2 was the primary active species in the CuCoO-2+PMS system for MB elimination. • By-products identification and software calculation confirmed the ecotoxicity decrease. [ABSTRACT FROM AUTHOR]

Magnetic porous manganese ferrite nanoparticles (MnxFe3-xO4) with diverse ingredient Mn/Fe mole ratios were synthesized to degrade sulfamethoxazole (SMX) antibiotic residues involving peroxymonosulfate (PMS) dissociation to produce free radical SO4•−, •OH and singlet oxygen 1O2 in the absence of heat and light. With the increase in proportion of manganese, the degradation efficiency of SMX increased from 19 to 70% in 30 min. The removal efficiency of SMX increased following the concentration increase of PMS (from 1 ~ 10 mM). After 60 min, the total organic carbon went down by 20%, and the concentration of NH4+ and NO3− accumulated obviously simultaneously. EPR study and chemical probe method, depending on scavenging revealed that SO4•−, •OH and 1O2 were generated and contributed to the degradation system. Based on the capture of eleven decomposition by-products by LC/MS, two different degradation pathways of SMX were determined, mainly consisting of cleavage of the S–N bond, hydroxylation of benzene and heterocyclic ring, oxidation of amino group and ring-opening cleavage processes. The nanoparticle reuse tests showed that the porous magnetic manganese ferrite nanoparticles could still maintain a high degradation efficiency after five oxidative degradation reactions. The magnetic porous manganese ferrite nanocrystals could activate the PMS to oxidize SMX antibiotic residue without additional energy. [ABSTRACT FROM AUTHOR]

Non-radical oxidation pathways in the Fenton-like process have a superior catalytic activity for the selective degradation of organic contaminants under complicated water matrices. Whereas the synthesis of high-performance catalysts and research on reaction mechanisms are unsatisfactory. Herein, it was the first report on copper-cobalt selenide (CuCoSe) that was well-prepared to activate hydrogen peroxide (H 2 O 2) for non-radical species generation. The optimized CuCoSe+H 2 O 2 system achieved excellent removal of chlortetracycline (CTC) in 10 min at neutral pH along with pleasing reusability and stability. Moreover, it exhibited great anti-interference capacity to inorganic anions and natural organic matters even in actual applications. Multi-surveys verified that singlet oxygen (1O 2) was the dominant active species in this reaction and electron transfer on the surface-bound of CuCoSe and H 2 O 2 likewise played an important role in direct CTC oxidation. Where the synergetic metals of Cu and Co accounted for the active sites, and the introduced Se atoms accelerated the circulation efficiency of Co3+/Co2+, Cu2+/Cu+ and Cu2+/Co2+. Simultaneously, the produced Se/O vacancies further facilitated electron mediation to enhance non-radical behaviors. With the aid of intermediate identification and theoretical calculation, the degradation pathways of CTC were proposed. And the predicted ecotoxicity indicated a decrease in underlying environmental risk. [Display omitted] • Selenization creates hollow microstructures as well as Se/O vacancies in CuCoSe. • 1O 2 and electron transfer co-dominate the non-radical Fenton-like reaction. • The synergism between Cu and Co species is linked to the activation of H 2 O 2. • Surface-bound defects promote electron mediation for the direct oxidation of CTC. • CuCoSe+H 2 O 2 achieves superior CTC elimination in complicated water matrices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hollow amorphous Co/C composites were prepared via one-step solvothermal method. • Co/C-3 + H 2 O 2 system achieved great OTC degradation under complicated water matrices. • 1O 2 converted from ·O 2 – was the dominated ROS in this Fenton-like process. • The electron cycle of ≡Co2+/3+-O-C/H played a vital effect on the generation of 1O 2. Singlet oxygen (1O 2) is an electrophilic species that has great selectivity for breaking down electron-rich refractory organic pollutants. However, in most cases, 1O 2 plays a minor role in the Fenton-like process due to its low yield, the contributions of which are usually covered by free radicals. Here, we provide the first report on a type of hollow amorphous Co/C composites prepared for the efficient generation of 1O 2 to degrade oxytetracycline (OTC) selectively in the Fenton-like system. The optimized Co/C samples (Co/C-3) obtained the best degradation performance of OTC near to 100% under neutral conditions, along with satisfactory reusability and stability. Additionally, it exhibited a high anti-interference capacity for inorganic anions and natural organic matter s in the different water qualities. XPS spectrum revealed that the electron cycle of ≡Co2+-O-C/H and ≡Co3+-O-C/H played a vital effect on the formation of 1O 2. Quenching experiments and EPR testing further verified that 1O 2 converted from ·O 2 – was the dominant oxidative species, and no hydroxyl radical (·OH) appeared in this reaction. Moreover, the results of the Fukui function and T.E.S.T (Toxicity Estimation Software Tool) analysis provided significant assistance in the exploration of degradation pathways and ecological risks of OTC and its intermediates. [ABSTRACT FROM AUTHOR]