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[Display omitted] • Co 3 O 4 loaded on cobalt-nitrogen doped ordered mesoporous carbon (Co 3 O 4 @Co-N-CMK3) was prepared. • Atrazine (ATZ) removal was 99.6% at 15 min with rate constant of 0.354 min−1 in Co 3 O 4 @Co-N-CMK3/O 3. • Co2+ and Co N x were active sites for O 3 decomposition and O 2 /OH generation. • The synergy between Co 3 O 4 and Co-N-CMK3 promoted interface electron transfer. • ATZ degradation pathway and toxicity evaluation of intermediates were proposed. The strategy of coupling transition metal and N-doped carbon catalysts have garnered great attention in catalytic ozonation. To overcome the inferior mass transfer of O 3 , we prepared a hetero-structure catalyst (Co 3 O 4 @Co-N-CMK3), which was composed of Co 3 O 4 nanoparticles (NPs) and cobalt-nitrogen doped ordered mesoporous carbon. Co 3 O 4 @Co-N-CMK3 displayed a uniformly arranged long-range mesoporous channel structure with large surface area (537.24 m2/g). The adsorption efficiency of ATZ (10 μM) was 55% at 15 min in presence of 0.05 g/L catalyst. After aeration of 3.5 mg/L O 3 gas (50 mL min-1), the ATZ removal increased to 99.6% with rate constant of 0.354 min-1 in Co 3 O 4 @Co-N-CMK3/O 3 , 35.4-fold that in ozonation. The turnover frequency (TOF) value of Co 3 O 4 @Co-N-CMK3 reached 7.08 min-1 g-1, which was 2.2-93.2 folds higher than the reported ozonation catalysts. Co 3 O 4 @Co-N-CMK3 displayed the adsorption performance for ATZ and could activate O 3 into O 2 - and OH effectively. The ≡Co2+ and ≡Co-N x were main active sites. The synergy between Co 3 O 4 and Co-N-CMK3 accelerated interface electron transfer, which was conducive to the redox of ≡Co2+/≡Co3+. The degradation pathway and intermediates toxicity were speculated using HPLC-MS measurement and Toxicity Estimation Software Tool simulation. The stability of Co 3 O 4 @Co-N-CMK3 for ATZ removal was certified by five consecutive experiments in catalytic ozonation. Moreover, the Co 3 O 4 @Co-N-CMK3/O 3 process had good applicability to common anions and humic acid, real water and different pollutants. [ABSTRACT FROM AUTHOR]

Recognizing the high energy consumption for in-situ generation of H 2 O 2 and low mass transfer of O 3 in electro-peroxone (EP), Fe0 embedded in carbon sphere (Fe0@CS) was synthesized to fulfill the efficient treatment of various pollutants. At optimal condition, the degradation and mineralization of 100 mg/L phenol were 100% with k (0.20 min−1) at 15 min and 72.1% at 60 min with iron dissolution (1.61 mg/L) and low energy consumption (0.067 kWh (g TOC)−1). The utilization efficiency of O 3 and H 2 O 2 increased by 1.9 – 11.5% and 16.8 – 27.1%, respectively. Fe2+ originated from the faster H 2 O 2 corrosion, initiated heterogeneous Fenton-like and catalytic ozonation reaction. The quenching and electron paramagnetic resonance experiments manifested the existence and mutual transformation of •OH, •O 2 - and 1O 2 , among which •OH was dominant. Fe0@CS/EP realized the simultaneous catalysis of O 3 and H 2 O 2 over wide pH 3 – 10, which had broad prospects for wastewater purification. [Display omitted] • Fe0 embeded in carbon sphere was synthesized for electro-peroxone (EP). • Fe0@CS facilitated pollulant removal with low Fe leaching and energy consumption. • Fe0@CS/EP realized the simultaneous catalysis of O 3 and H 2 O 2 over wide pH 3–10. • H 2 O 2 corrosion to Fe0 played the key role in Fe0@CS/EP. • •OH, •O2- and 1O 2 were involved in Fe0@CS/EP, while •OH was dominant. [ABSTRACT FROM AUTHOR]

• O 3 /CeO x @SiO 2 enhanced SA mineralization and behaved well at acidic/basic condition. • Si OH shell effectively transported ozone to inner CeO x core. • O 3 decomposition occurred at Lewis sites and oxygen defect of CeO x. • OH was accounted for the enhancement of SA mineralization. In this work, a hollow mesoporous CeO x @SiO 2 was synthesized and used to promote sulfanilamide (SA) mineralization in ozonation. SA mineralization was promoted to 68.2% by O 3 /CeO x @SiO 2 in 120 min, but only 30.0% in O 3 process. O 3 /CeO x @SiO 2 behaved the better at acidic and alkaline condition than that at neutral condition. CeO x @SiO 2 had the great ability in enhancing O 3 utility rate. Silanol (Si OH) in pore channel of SiO 2 shell was non-reactive with O 3 but could provide transmission way for O 3 to reach the inner CeO x core. Lewis sites, oxygen vacancies and surface hydroxyl groups induced by CeO x favored for the activation of O 3. The excess electron at oxygen vacancies would be transferred to the absorbed O 3 molecular, which then generated reactive oxygen species (ROS) to mineralize SA. Hydroxyl radicals (OH) and superoxide radicals (O 2 −) were the main ROS, which were recorded by EPR. The interfacial electron transfer process was revealed by LSV and ESI characterizations. SA degradation intermediates were also identified by HPLC-MS and IC, a possible degradation pathway was proposed. Moreover, CeO x @SiO 2 showed a good reusability, no obvious decline of TOC removal was found in four times' uses. Water matrix would complete ROS with SA, which inhibited the SA removal of both O 3 and O 3 /CeO x @SiO 2 processes, but the better TOC removal efficiency was still obtained by O 3 /CeO x @SiO 2 in actual water. [ABSTRACT FROM AUTHOR]

• OA was efficiently mineralized by ·OH in O 3 /H 2 O 2 /CeO x @SiO 2. • pH played an important role in OA mineralization. • The complexed H 2 O 2 activated the decomposition of ozone into ·OH. • OA removal followed the interface reaction mechanism in O 3 /H 2 O 2 /CeO x @SiO 2. • CeO x @SiO 2 possessed stable structure and catalytic activity. The mesoporous core-shell CeO x @SiO 2 was synthesized and characterized by XRD, pyridine-FTIR, BET, SEM, TEM and XPS. CeO x @SiO 2 was the hollow nanosphere with high surface area of 1291.4 m2 g−1, which benefited for mass transfer of reactants. CeO x @SiO 2 exhibited the excellent catalytic activity for oxidizing oxalic acid (OA) in O 3 /H 2 O 2 /CeO x @SiO 2. The greatest OA mineralization (91.2%) was achieved at pH = 3.2 in O 3 /H 2 O 2 /CeO x @SiO 2 , which was 5.5 times higher than that in peroxone (O 3 /H 2 O 2 , 15.9%). Influence of pH, HSO 3 −, PO 4 3− and detection of ozone and H 2 O 2 concentration were conducted to explore the mechanism. The interface reaction played vital role for OA removal in O 3 /H 2 O 2 /CeO x @SiO 2 process. Protonated surface hydroxyl groups (Ce-OH 2 +) was the active sites, where OA, O 3 and H 2 O 2 were chemi-absorbed. The peroxide-like species (≡(Ce(IV)-O 2 H 2)) formed by the complex of H 2 O 2 with active sites were the important intermediates, which initiated ozone decomposition into hydroxyl radical (·OH) and led to the high OA mineralization. Moreover, Lewis acid sites and electron transfer effect of Ce(III)/Ce(IV) also accounted for the high catalytic activity of CeO x @SiO 2. In addition, CeO x @SiO 2 maintained stable structure and catalytic activity in three cycles. [ABSTRACT FROM AUTHOR]