Improved Magnetite Nanoparticle Immobilization on a Carbon Felt Cathode in the Heterogeneous Electro-Fenton Degradation of Aspirin in Wastewater
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ABSTRACT:
SUBMITTER: Muzenda C
PROVIDER: S-EPMC9202057 | biostudies-literature | 2022 Jun
REPOSITORIES: biostudies-literature
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Project description:In this work, polytetrafluoroethylene coating was firstly conducted to make stable and effective magnetic-activated carbon as a heterogeneous electro-Fenton catalyst for diuron oxidation. The catalysts were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). In addition, the effects of operating parameters such as catalyst dosage, current intensity, substrate concentration and pH on the degradation of diuron were investigated. The removal efficiency of diuron was more than 95% within 120 min oxidation under the conditions of I = 100 mA, pH = 6.7 ± 0.2, catalyst loading 3 g L-1 and diuron concentration 10 mg L-1. Moreover, the catalyst durability test demonstrated that the modification of 5% PTFE on the catalyst indeed has a significant beneficial effect on the useful life of the catalyst. We compared the performance of catalysts with or without PTFE modification in consecutive experiments; the modified catalysts exhibited remarkable advantages in that the diuron removal efficiency was stable with relatively low iron leaching (<0.1 mg L-1) during ten consecutive degradation experiments, which proved the durability and reusability of the modified catalyst. This work demonstrates that such a heterogeneous EF using stable magnetic activated carbon catalyst with PTFE modification is promising for organic wastewater treatment in initial neutral pH conditions; at the same time, these good properties of the modified catalyst increase the possibility of practical application.
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Project description:The catalytic reactivity of synthetic bare magnetite nanoparticles, activated carbon supported magnetite (AC-Mt), and graphene oxide supported magnetite (GO-Mt) for heterogeneous Fenton-like oxidation of methylene blue (MB) were compared, in order to investigate how the structural features of the support impact catalytic activity of the nanocomposites. The different effects of AC and GO on MB removal rate, hydroxyl radical (˙OH) production, iron leaching, and surface deactivation have been systematically studied. The rate constant of MB removal by AC-Mt was 0.1161 min-1, one order of magnitude larger than the value of bare magnetite nanoparticles (0.0566 min-1). The higher catalytic activity of AC-Mt might be attributed to the larger reactive surface area of well-dispersed magnetite for ˙OH production and the recharge of the magnetite surface by the AC support via Fe-O-C bonds. However, the removal rate of MB by GO-Mt was one order of magnitude slower than that of bare magnetite nanoparticles under the same experimental conditions, presumably due to the wrapping of GO around magnetite nanoparticles or extensive aggregation of GO-Mt composites. These findings revealed the significant influence of support structure on the catalytic activity of carbon-supported magnetite nanocomposites, which is important for the development of efficient magnetite-based catalysts for wastewater treatments.
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