Microwave hydrothermal-assisted preparation of novel spinel-NiFe2O4/natural mineral composites as microwave catalysts for degradation of aquatic organic pollutants

Manli Shen; Lu Fu; Jianhua Tang; Mingyu Liu; Youtao Song; Fangyuan Tian; Zhigang Zhao; Zhaohong Zhang; Dionysios D Dionysiou

doi:10.1016/j.jhazmat.2018.02.014

Microwave hydrothermal-assisted preparation of novel spinel-NiFe₂O₄/natural mineral composites as microwave catalysts for degradation of aquatic organic pollutants

J Hazard Mater. 2018 May 15:350:1-9. doi: 10.1016/j.jhazmat.2018.02.014. Epub 2018 Feb 6.

Authors

Manli Shen¹, Lu Fu¹, Jianhua Tang¹, Mingyu Liu¹, Youtao Song¹, Fangyuan Tian¹, Zhigang Zhao², Zhaohong Zhang³, Dionysios D Dionysiou⁴

Affiliations

¹ School of Environment Science, Liaoning University, Shenyang, 110036, China.
² Xiamen Institute of Rare Earth Materials, Haixi Institutes, Chinese Academy of Sciences, Xiamen, 361021, China; Key Laboratory of Design and Assembly of Functional Nano Structures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.
³ School of Environment Science, Liaoning University, Shenyang, 110036, China. Electronic address: lnuhjhx@163.com.
⁴ Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH, 45221-0012, USA. Electronic address: dionysios.d.dionysiou@uc.edu.

PMID: 29448208
DOI: 10.1016/j.jhazmat.2018.02.014

Abstract

In this study, novel spinel-NiFe₂O₄/natural mineral (sepiolite, diatomite and kaolinite) composites were developed using microwave (MW) hydrothermal method, and applied in MW-induced catalytic degradation (NiFe₂O₄/natural mineral/MW) of organic pollutants such as sodium dodecyl benzene sulfonate (SDBS), azo fuchsine (AF), methyl parathion (MP), and crystal violet (CVL) in solution. Catalytic activities of three NiFe₂O₄/natural mineral composites were compared. The effects of material synthesis process parameters such as molar ratios of NiFe₂O₄ and natural mineral, and pH of precursor solutions for synthesizing catalysts, and degradation parameters such as MW irradiation time and catalyst reuse cycles were also investigated. The principle on NiFe₂O₄/natural mineral/MW degradation was provided. The results reveal that organic pollutants in wastewater can be removed completely using NiFe₂O₄/natural mineral/MW within minutes. NiFe₂O₄/sepiolite shows higher catalytic activity than the others. The calculated degradation rate constants are 1.865, 0.672, 0.472, and 0.329 min^-1 for SDBS, AF, MP, and CVL, respectively, using NiFe₂O₄/sepiolite/MW system. The performance of NiFe₂O₄/natural mineral can be maintained for three reuse cycles. Active species OH, O₂^-, and h⁺ play main roles in NiFe₂O₄/sepiolite/MW degradation. Hence, NiFe₂O₄/sepiolite/MW technology with rapid and cost-effective degradation, magnetic separation, and no secondary pollution, demonstrates to be promising in treating organic contaminants in wastewater.

Keywords: Advanced oxidation; Microwave degradation; Natural minerals; Nickel ferrite; Organic pollutant.