Ma Yulin,Gu Na,Gao Jinlong,Wang Kuitao,Wu Yunxia,Meng Xiaoyu
Fe 3 O 4 -CuO@montmorillonite was prepared using coprecipitation method, and its structure was determined by XRD, IR, and transmission electron micrograph (TEM). Montmorillonite in Fe 3 O 4 -CuO@montmorillonite nanocomposite allowed the silicate layer of montmorillonite to behave as a barrier, which prevented the agglomeration and natural crystallization of Fe 3 O 4 and CuO. Furthermore, the chlorine dioxide (ClO 2 ) oxidative degradation of anthracene-contaminated soil was studied in detail using Fe 3 O 4 -CuO@montmorillonite as a magnetic heterogeneous catalyst. The operating parameters such as ClO 2 concentration, catalyst dosage, reaction time, and pH were evaluated. Compared with the conventional ClO 2 oxidation process without the catalyst, the ClO 2 catalytic oxidation system could significantly enhance the degradation efficiency. Under the optimal condition (anthracene concentration 89.8 mg/kg, water soil mass ratio 3:1, initial pH 7, ClO 2 concentration 1 mol/kg, catalyst dosage 1 g/kg, reaction time 30 min, and reaction temperature 25 °C), anthracene degradation efficiency achieved 96.2 %. The catalyst could be easily reused by magnetic separation and used at least 8 cycles without obvious loss of activity. The kinetic studies revealed that the ClO 2 catalytic oxidation degradation of anthracene-contaminated soil with Fe 3 O 4 -CuO@montmorillonite as catalyst followed pseudo-first-order kinetics with respect to ClO 2 concentration. Thus, this study showed potential application of ClO 2 catalytic oxidation process in remediation of organic pollutant-contaminated soil.
Abstract Fe 3 O 4 @Cu/C and Fe 3 O 4 @CuO composites were achieved using nanoparticle-encapsulated MOFs Fe 3 O 4 @HKUST-1 as both a precursor and a self-sacrificing template. Fe 3 O 4 @HKUST-1 was thermally converted into magnetic Fe 3 O 4 @Cu/C and Fe 3 O 4 @CuO composites in different atmosphere (N 2 and air). The resulting composites not only kept superparamagnetic characteristics, but also exhibited improved peroxidase-like catalytic activity and high stability when compared to the precursor Fe 3 O 4 @HKUST-1. The morphology, crystal structure, magnetic and porous properties of Fe 3 O 4 @Cu/C and Fe 3 O 4 @CuO composites were characterized, and the kinetics parameters and the influence factors on the peroxidase-mimicking activity such as temperature, pH and H 2 O 2 concentration were evaluated. On account of the excellent peroxidase-like activity, the as-prepared Fe 3 O 4 @Cu/C and Fe 3 O 4 @CuO composites were successfully used for the catalytic removal of methylene blue (MB) dye with H 2 O 2 oxidant. This work provides an effective way to fabricate highly reactive MOFs-derived biomimetic catalysts, which have potential applications in bioassays and pollutant degradation. Graphic Abstract Fe 3 O 4 @Cu/C and Fe 3 O 4 @CuO composites were achieved using Fe 3 O 4 nanoparticle-encapsulated HKUST-1 as self-sacrificial templates and demonstrated excellent peroxidase-like activity.
In this study, lignite activated coke (LAC) was used as the carrier for the first time, Fe 3 O 4 –CuO composite metal oxide was used as the main active material, and the nano-scale magnetic supported composite metal oxide Fe 3 O 4 –CuO@LAC catalyst was synthesized for the first time, which can effectively activate the active oxygen in peroxodisulfate (PS). XRD, FTIR , BET, SEM , XPS and other analysis results showed that there was particulate matter with spherical structure on the surface of the active coke, and its diffraction peaks matched well with the characteristic peaks of Fe 3 O 4 and CuO, and it was a mesoporous structure with a specific surface area of 619.090 m 2 g −1 . By optimizing the experimental conditions, the results showed that more than 92% of hydroquinone can be removed under the conditions of hydroquinone concentration of 50 mg/L, pH = 5, adding 0.1 g/L catalyst and 3 mmol/L PS. EPR and quenching experiments proved that there were four reactive oxygen species in the reaction system ·OH, SO 4 − ·, O 2 − · and 1 O 2 . According to the degradation products of hydroquinone detected by LC-MS, the possible degradation path was deduced which laid a foundation for solving the problem of difficult treatment of phenol-containing wastewater in coal chemical industry.
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