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Due to the strong electron-withdrawing nature of Cl atom in CCl4, CCl4 could not readily be degraded by oxidation process. In the present study, aqueous electron (eaq-), a powerful reducing agent generated in UV-Na2SO3 system, was applied to reductively degradation of CCl4. The effects of several crucial factors (e.g. Na2SO3 concentration, solution pH, inorganic ions and NOM) on CCl4 degradation as well as degradation mechanism and pathway were systematically investigated. Results indicated that CCl4 was efficiently degraded in UV-Na2SO3 system and the process could be well described by pseudo-first order kinetic model. The degradation rate increased with the elevated Na2SO3 concentration (0–10 mmol/L) and solution pH (6.0–8.0), while remained approximately constant in alkaline conditions (pH = 8.0, 9.0 and 10.0). Nevertheless, O2, inorganic ions and NOM exerted a negative effect on CCl4 degradation and the removal efficiency of CCl4 in groundwater was only 31.7%. Mechanistic study implied that degradation of CCl4 was primarily induced by eaq-. CCl4 (10 mg/L) was almost completely dechlorinated within 60 min and the predominant intermediate products were CHCl3, C2Cl4 and C2HCl3. CHCl3 and CH2Cl2 were also rapidly degraded in the UV-Na2SO3 system. [ABSTRACT FROM AUTHOR]

In this study, zirconia-coated magnetite magnetic nanoparticles (ZrO/FeO MNPs) were prepared, characterized, and used as an effective and reusable heterogeneous catalyst for 3,4-dichlorobenzotrifluoride (3,4-DCBTE) degradation. The catalytic potential of the FeO/ZrO-HO system for the removal of 3,4-DCBTE was tested in comparison with several other systems, and the effects of various operating parameters, including initial solution pH, catalyst addition, HO concentrations, and reaction temperature, were also evaluated with respect to the degradation efficiency of 3,4-DCBTE. Results showed that the FeO/ZrO composite could effectively enhance the oxidation of 3,4-DCBTE by the Fenton-like process, and there might be a synergetic effect in the FeO/ZrO composite. When the mass ratio of FeO and ZrO was 1:1, the FeO/ZrO exhibited the best catalytic activity, and the catalyst-driven Fenton process achieved high removal of 3,4-DCBTE (98.5%) and total organic carbon (TOC) (52.7%) at the operating conditions: pH 3.0, catalyst 2.0 g/L, HO 30 mM, temperature 30 °C, and reaction time 1 h. Furthermore, five successive runs of the Fenton oxidation using the same FeO/ZrO composite resulted in the steady removal of 3,4-DCBTE, further confirming the high stability of the catalyst. In addition, the possible catalytic mechanism and degradation pathways of 3,4-DCBTE were also investigated. [ABSTRACT FROM AUTHOR]

In this study, Co 3 O 4 -carbon composite was synthesized by calcined metal organic framework (MOF) ZIF-67 and used as efficient catalysts for ozonation of norfloxacin (NOF). The MOF-derived Co 3 O 4 -C composite remained similar polyhedrons structure of ZIF-67, suggesting that Co 3 O 4 was well-dispersed in Co 3 O 4 -C composite. Furthermore, a larger amount of surface carbon-oxygen functional groups were distributed on Co 3 O 4 -C composite, which resulted in the diversification of active sites for catalytic ozonation reaction. NOF degradation and mineralization could be effectively enhanced in Co 3 O 4 -C/O 3 process. Moreover, NOF mineralization by catalytic ozonation strongly depended on the solution pH, while other operational conditions, such as O 3 concentration and catalyst dosage had not obvious influence on it. Co 3 O 4 -C composite could significantly accelerate O 3 decomposition to produce active free radicals (such as •OH), which enhanced the mineralization of NOF. The possible catalytic mechanism of Co 3 O 4 -C composite was proposed. Additionally, after five consecutive use of Co 3 O 4 -C composite in catalytic ozonation process, there was no obvious decrease in TOC removal efficiency, indicating a stable performance of Co 3 O 4 -C composite, which was suitable for the catalytic ozonation for wastewater treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Due to the strong electron-withdrawing nature of Cl atom in CCl 4 , CCl 4 could not readily be degraded by oxidation process. In the present study, aqueous electron (e aq - ), a powerful reducing agent generated in UV-Na 2 SO 3 system, was applied to reductively degradation of CCl 4 . The effects of several crucial factors (e.g. Na 2 SO 3 concentration, solution pH, inorganic ions and NOM) on CCl 4 degradation as well as degradation mechanism and pathway were systematically investigated. Results indicated that CCl 4 was efficiently degraded in UV-Na 2 SO 3 system and the process could be well described by pseudo-first order kinetic model. The degradation rate increased with the elevated Na 2 SO 3 concentration (0-10 mmol/L) and solution pH (6.0-8.0), while remained approximately constant in alkaline conditions (pH = 8.0, 9.0 and 10.0). Nevertheless, O 2 , inorganic ions and NOM exerted a negative effect on CCl 4 degradation and the removal efficiency of CCl 4 in groundwater was only 31.7%. Mechanistic study implied that degradation of CCl 4 was primarily induced by e aq - . CCl 4 (10 mg/L) was almost completely dechlorinated within 60 min and the predominant intermediate products were CHCl 3 , C 2 Cl 4 and C 2 HCl 3 . CHCl 3 and CH 2 Cl 2 were also rapidly degraded in the UV-Na 2 SO 3 system.