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Preparation and application of magnetic nitrogen-doped rGO for persulfate activation

Author:
Pang, Ya, Luo, Kun, Tang, Lin, Li, Xue, Song, Yong, Li, Cheng-yong, Wang, Li-ping
Source:
Environmental science and pollution research international 2018 v.25 no.30 pp. 30575-30584
ISSN:
0944-1344
Subject:
X-ray diffraction, X-ray photoelectron spectroscopy, activation energy, catalysts, graphene oxide, hydroxyl radicals, iron oxides, magnetism, methylene blue, nanoparticles, oxidation, pH, pollutants, pollution control, scanning electron microscopy, sulfates, sulfuric acid, temperature, wastewater treatment
Abstract:
A heterogeneous catalyst (M-N-rGO) composed of stability enhanced magnetic iron oxide nanoparticles and nitrogen-doped reduced graphene oxide was synthesized and characterized by SEM, XRD, BET, and XPS. It showed excellent catalytic degradation properties in advanced oxidation technology. In the presence of 200 mg/L catalyst and 135 mg/L persulfate at pH 5, 95% of 10–20 mg/L methylene blue could be degraded in 90 min with the TOC removal efficiency of 50%. The rate constant based on pseudo-first-order kinetics ranged from 0.0227 to 0.0488/min in the temperature range of 15 to 32 °C, and the activation energy was 32.5 kJ/mol. Under the optimal operation conditions, 20 mg/L of 2,4-dichlorophneol (2,4-DCP) could be removed almost completely. EPR analysis showed that sulfate and hydroxyl radicals were responsible for degradation of pollutants, and radical quenching experiments indicated that nonradical pathway also played a role in pollutant removal. And a mechanism for M-N-rGO and persulfate system was elucidated. This catalyst was easy for preparation, low-cost, highly effective, convenient for separation, and could be used effectively for four times through 0.1 mol/L H₂SO₄ regeneration. It provided a choice for wastewater treatment in practice.
Agid:
6155434