Ultrasound-assisted heterogeneous Fenton-like process for methylene blue removal using magnetic MnFe2O4/biochar nanocomposite

• Published in: Applied surface science 2021-11, Vol.566, p.150654, Article 150654
• Main Authors: Cheng, Zhuoying, Luo, Suyue, Li, Xiaojuan, Zhang, Shuo, Thang Nguyen, Tat, Guo, Minghui, Gao, Xing
• Format: Article
• Language: English
• Subjects: Biochar; heterogeneous Fenton; Nanocomposites; Sonocatalysis; Ultrasound
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.150654

In this study, wood waste wood powder was used as carbon material carrier for the first time, and MnFe2O4 was successfully loaded on biochar. A magnetic heterogeneous Fenton catalyst was prepared. Compared with MnFe2O4, MnFe2O4/BC could degrade methylene blue more effectively with the aid of ultrasound. This proves that the environmentally friendly and low-cost wood-based carrier can effectively prevent the agglomeration of MnFe2O4 particles and accelerate the heterogeneous Fenton catalysis process to a certain extent. We believe that this work will provide positive impact on the research of sewage treatment and photocatalysis and we hope this paper is suitable for “ Applied Surface Science”. [Display omitted] •Wood powder waste with low cost and environmental protection was selected as carbon carrier firstly.•A synergistic effect between sonolysis and Fenton-like reaction has been achieved.•MnFe2O4/BC showed good catalytic activity in Ultrasound-assisted heterogeneous Fenton-like system.•MnFe2O4 provides nucleation site for ultrasonic cavitation and promotes catalytic reduction.•A mechanism of MB degradation by MnFe2O4/BC/H2O2/US system was summarized. In this study, a MnFe2O4 nanocomposite (MnFe2O4/BC) using biochar as the carrier was prepared by a simple hydrothermal method, and then an ultrasound-assisted heterogeneous Fenton-like process was used to catalytically degrade methylene blue (MB). The catalyst was characterized by SEM, TEM, BET, XRD, FTIR, VSM, and XPS. The results showed that spherical MnFe2O4 was successfully loaded onto the biochar surface. The introduction of biochar inhibited the aggregation of MnFe2O4 and greatly increased the specific surface area from 41.4 m2/g to 95.1 m2/g. When using the MnFe2O4/BC composite as an ultrasound-assisted heterogeneous Fenton-like catalyst, 95% of MB (20 mg/L) was degraded at pH = 5 in the presence of 15 mmol/L H2O2 in 20 min, exhibiting a reaction rate constant of 0.09 min−1 much larger than that over MnFe2O4 (0.00995 min−1). This efficiency may be due to the synergistic effect of ultrasound and MnFe2O4/BC, which simultaneously induced the generation of reactive radicals and increased the mass transfer rate at the solid–liquid interface. Compared with other catalysts, the degradation and mineralization levels of MB over MnFe2O4/BC catalyst are greatly improved. These results indicate that MnFe2O4/BC has significant potential for use as a highly efficient and low-cost catalyst for ultrasound-assisted h