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A novel CoNi 3 O 4 /diatomite hybrid is constructed through vertically oriented growth of 2D CoNi 3 O 4 nanoribbons with atomic layer-thickness on cost-effective diatomite template. Distinct from stacked CoNi 3 O 4 with a large portion of "dead surface", diatomite derived CoNi 3 O 4 nanoribbons possess abundant exposed edges, sharp corners, and open diffusion channels. These unique characteristics offer CoNi 3 O 4 /diatomite hybrid excellent peroxymonosulfate activation efficiency in real water bodies. • 2D CoNi 3 O 4 nanoribbons were fabricated via vertically oriented growth on diatomite. • CoNi 3 O 4 /diatomite showed rich exposed edges, sharp corners and diffusion channels. • CoNi 3 O 4 /diatomite presented excellent PMS catalytic activity in real water bodies. • S O 4 - • , OH and 1O 2 were generated and functioned in CoNi 3 O 4 /diatomite/PMS system. • O 2 − contributed to reversible redox cycle of Co2+/Co3+ and Ni2+/Ni3+. The reactive oxygen radicals generated by peroxymonosulfate (PMS) activation exhibit great potential to deal with refractory contaminants of emerging concern. However, mass production of efficient and cost-effective catalysts for PMS activation is still a long-term goal for its widespread practical application. Herein, a novel CoNi 3 O 4 /diatomite hybrid is constructed through vertically oriented growth of 2D CoNi 3 O 4 nanoribbons with atomic layer-thickness on cost-effective diatomite template. Distinct from stacked CoNi 3 O 4 , CoNi 3 O 4 /diatomite composite possesses abundant exposed edges, sharp corners, and open diffusion channels. Abundant exposed edges and sharp corners create more open space and active sites for PMS activation. Open diffusion channels accelerate the migration of PMS and contaminants. Such characteristics offer CoNi 3 O 4 /diatomite hybrid excellent PMS activation efficiency. Furthermore, sulfate radical plays the dominant role in atrazine degradation. Superoxide radical contributes to reversible redox cycle of Co2+/Co3+ and Ni2+/Ni3+. This study provides a novel strategy for cost-effective mass production of various Fenton-like 2D catalysts. [ABSTRACT FROM AUTHOR]

• Diatomite and CoFe 2 O 4 was effectively assembled to activate peroxymonosulfate. • CoFe 2 O 4 /diatomite catalyst has lower metal dissolution rate. • Surface structure and crystallization dispersion improve activation performance. • The 1O 2 was the primary active substance for BPA degradation. • Weak basic condition enhanced PMS activation and increased BPA degradation. Porous magnetic CoFe 2 O 4 /diatomite catalyst (CFD) was rationally synthesized via a facile citrate combustion process. The relationship between catalytic performance and material properties of the prepared catalysts was comprehensively investigated by various characterizations, especially for the interface interaction between CoFe 2 O 4 and diatomite as well as crystallization regulation of CoFe 2 O 4. Overall, higher specific surface area, overspreading surface hydroxyl groups, better crystal dispersion and abundant surface-active sites make CFD have better degradation performance of bisphenol A (BPA) than pure CoFe 2 O 4 in the presence of peroxymonosulfate (PMS), and the pseudo-first-order reaction rate constant of 40-CFD (40% CoFe 2 O 4 /diatomite) is almost 5.32 times higher than that of pure CoFe 2 O 4. Besides, CFD has excellent magnetic properties, lower metal dissolution rate and good reusability. In addition, electron paramagnetic resonance (EPR) and radical quenching experiments show that sulfate radicals (SO 4 −) and singlet oxygen radicals (1O 2) generated from the electron transfer of BPA molecule and valence state change of transition metals should be the predominant oxidation species. Moreover, possible degradation pathways of BPA are determined by the detection of intermediates derived from the results of liquid chromatograph–mass spectrometer (LC–MS). In brief, it is indicated that the CoFe 2 O 4 /diatomite composite material is an efficient and environmentally friendly catalyst, which has a great potential application in wastewater treatment by activating PMS. [ABSTRACT FROM AUTHOR]

• Oxygen-vacancy-rich Co 3 O 4 /illite can activate peroxymonosulfate (PMS) efficiently. • Modulating crystallization of Co 3 O 4 by illite resulted in rich oxygen vacancies. • Theoretical calculations were employed to elucidate catalytic mechanism for PMS. • Rich oxygen vacancies accelerated electron-transfer and reduced adsorption energy. • S O 4 - • , OH and 1O 2 were generated and functioned in Co 3 O 4 /illite/PMS system. Natural illite microsheets were firstly utilized to induce oxygen vacancies into ultrafine cobalt oxide (Co 3 O 4) for highly efficient Fenton-like catalysis via activation of peroxymonosulfate (PMS). The results indicated that presence of illite microsheets regulated multi-directional crystallization of Co 3 O 4 nanospheres and resulted in reduced grain size and crystallinity. The smaller grain size provided more reactive edge sites for PMS catalysis. The numerous indistinct lattice boundaries caused by reduced crystallinity created abundant oxygen vacancies. Density functional theory (DFT) calculations illustrated that presence of oxygen vacancies significantly reduced adsorption energy and accelerated electron transfer, which further faciliated PMS activation. The oxygen vacancy-rich Co 3 O 4 /illite exhibited superior catalytic efficiency in real water matrix. Apart from sulfate and hydroxyl radicals, singlet oxygen generated from oxygen vacancy-based reaction pathway also played a significant role in atrazine degradation. This strategy provided a new insight for future designing of natural mineral-based catalysts for efficient wastewater treatment via Fenton-like process. [ABSTRACT FROM AUTHOR]