Green synthesis of red mud based ZnOFe2O3 composite used for photo-Fenton reaction under visible light

• Published in: Journal of cleaner production Vol. 207; pp. 717 - 727
• Main Authors: Li, Yunshang, Wei, Guangtao, Shao, Luhua, Li, Zhongmin, Yu, Fengjian, Liu, Jialiang, Yang, Xianli, Lu, Qiaoling, Li, Anpei, Huang, Yu, Zhang, Linye
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.01.2019
• Subjects: Green synthesis; Photo-Fenton; Red mud; Visible light; ZnO; α-Fe2O3; Red mud; α-Fe2O3; Photo-Fenton; Visible light; ZnO; Green synthesis
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2018.10.051

In this work, using solid waste red mud (RM) as main raw material and without addition of chemical reagents of alkali and ferric salt, a new method of flocculation-calcination was introduced as a green and facile process to produce RM based ZnOFe2O3 composite (RM-C) which can be used as a catalyst for photo-Fenton reaction under visible light. The prepared catalyst was characterized by SEM, EDS, XRD, BET, UV–Vis DRS and XPS. The characterization results showed the iron phase in RM-C was mainly α-Fe2O3, and ZnO formed in RM-C was amorphous and highly dispersed. RM-C showed a good response to the visible light, and the order of absorbance in 373–542 nm was RM-C > RM > ZnO. RM-C had an excellent long-term stability in the photo-Fenton process. The possible mechanisms in photo-Fenton system catalyzed by RM-C under visible light were presented. Using RM-C as catalyst, the toxicity of Orange II was greatly weakened by the photon-Fenton system under visible light. The method of flocculation-calcination was a green and feasible process for the preparation of RM-C, and the prepared RM-C was an effective composite catalyst for the photon-Fenton reaction under visible light. [Display omitted] •Synthesis of red mud based composite by flocculation-calcination is proposed.•The flocculation-calcination is a green and feasible process.•Red mud based ZnOFe2O3 composite is successfully prepared by this method.•The composite is a good catalyst for photon-Fenton reaction under visible light.•The toxicity of Orange II is greatly weakened by using the composite.