Search

[Display omitted] • The metal–oxygen-carbon bonds boosted interfacial electron transfer. • Ozone utilization efficiency was higher (ΔTOC/ΔO 3 = 1.23–0.68) in Fe 2 Co@CS/EP compared with EP. • Catalytic ozonation played the dominant role in · OH, · O 2 − and 1O 2 generation. • Fe 2 Co@CS/EP presented an enormous potential in wastewater treatment. We fabricated a novel Fe-Co bimetal encapsulated inside carbon aerogel sphere (Fe 2 Co@CS) to improve the electro-peroxone (EP) process. The degradation and mineralization of p -nitrophenol (p -NP) were 100% (15 min) with rate constant of 0.314 min−1 and 83.8% (60 min) in Fe 2 Co@CS/EP, respectively. Fe 2 Co@CS was composed of defective graphite carbon and Fe 2 Co alloy. The presence of metal–oxygen-carbon (M-O-C, M Fe/Co) bonds promoted interface electron transfer from carbon layer towards Fe 2 Co alloy, which was advantageous to the reduction of ≡Fe3+/≡Co3+. Moreover, the Fe-Co synergistic effect also accelerated the interfacial catalytic reaction for activating O 3 and H 2 O 2. The quenching experiment and EPR test indicated that · OH, · O 2 - and 1O 2 were main reactive oxygen species (ROSs). DFT calculations showed that O 3 had lower adsorption energy on Fe 2 Co@CS than H 2 O 2 , manifesting that catalytic ozonation played the key role in ROSs generation. In addition, ozone utilization efficiency in Fe 2 Co@CS/EP (ΔTOC/ΔO 3 = 1.23–0.68) revealed 66-36% increase relative to those of EP (0.74–0.5). Fe 2 Co@CS was an efficient catalyst over a wide pH range (3–11) with permissible iron and cobalt releases. The Fe 2 Co@CS/EP process exhibited high-performance for degrading different pollutants under high salinity condition with coexistence of Cl−, NO 3 − and SO 4 2−. For treating real coal wastewater, the TOC removal was 52.7% at 4 h with low EEC (0.038 kWh (g TOC)−1). This study provided an efficient method for the development of EP in wastewater treatment. [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]