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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]

[Display omitted] • Oxygen doped CNT modified cathode enhanced the efficiency of electro-peroxone (OCNT-EP). • OCNT modified cathode achieved in-situ H 2 O 2 generation, activation and catalytic ozonation. • More hydroxyl and singlet oxygen improved atrazine degradation in OCNT-EP process. • The OCNT-EP process showed excellent stability and wide pH applicability. The oxygen-doped carbon nanotubes coated on the carbon felt acted as cathode to enhance the electro-peroxone (OCNT-EP) process. Owing to the introduction of oxygen-containing functional groups and defect sites, the OCNT modified cathode could achieve in-situ H 2 O 2 generation, activation, and catalytic ozonation in the EP process. The OCNT-EP showed a 2.3-folds apparent first-order rate constant (k) compared with the EP process using CNT cathode (CNT-EP) for atrazine (ATZ) degradation. According to the processes comparison, quenching experiments, electron paramagnetic resonance (EPR) analysis and determination of hydroxyl radical, it was proved that more . OH and 1O 2 were generated by the in-situ H 2 O 2 activation and catalytic ozonation in the OCNT-EP process. Especially, this process improved pollutants degradation under acidic condition for the in-situ H 2 O 2 activation and catalytic ozonation, expanding the pH application range of the EP process with a lower energy consumption (0.10 kWh/g ATZ). What' more, the OCNT modified cathode performed excellent stability with 20 cycle tests, and demonstrated all improved degradation rate (21.7%−78.0%) for various pollutants (carbamazepine, sulfamethazine, phenol and 2,4-dichlorophenol). Therefore, the OCNT-EP process could be considered as a promising and enhanced EP process for wastewater treatment. [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]

• F-Fe-MCM-41 possessed excellent activity in catalytic ozonation of NB. • F planting enhanced the hydrophobicity and Lewis acids of Fe-MCM-41. • The liquid and solid interface reaction mechanism was proposed. • OH scavenging effect of humic acid and carbonate were weakened by F-Fe-MCM-41. Heterogeneous catalytic ozonation had met the bottlenecks when treating low concentration but high toxic pollutants: (i) the low mass transfer efficiency of ozone and pollutants to hydrophilic catalyst; (ii) the negative impact of coexisted water matrixes. Herein, to enhance the mass transfer efficiency of reactants toward hydrophilic Fe-MCM-41 as well as enhance the interfacial reaction, the fluoride planting Fe-MCM-41 (F-Fe-MCM-41) was synthesized and employed as catalyst in catalytic ozonation for nitrobenzene (NB). Both NB and TOC removal were promoted in F-Fe-MCM-41/O 3 with 99.0 % NB removal in 60 min and 88.6 % TOC removal in 120 min, which were superior to the degradation efficiency by O 3 and Fe-MCM-41/O 3. FTIR, EPR, Mössbauer spectra, 29Si NMR, 19F NMR et al verified that the replacement of non-reactive silanols (-Si−OH) of Fe-MCM-41 with Si F groups could enhance its hydrophobicity, Lewis acidity and mass transfer effect. Comparative characterizations, experiments and theoretical calculations verified that interfacial reaction played the major role over liquid phase reaction for NB degradation in F-Fe-MCM-41/O 3. Moreover, the strengthened interfacial reaction also reduced the OH scavenging effect of water matrix, such as humic acid and carbonate. The interfacial adjustment method proposed in this study provided a novel insight into catalyst design and water treatment process. [ABSTRACT FROM AUTHOR]