A feasible approach for azo-dye methyl orange degradation in siderite/H2O2 assisted by persulfate: Optimization using response surface methodology and pathway

Wei Song; Ji Li; Xiaolei Zhang; Jianpei Feng; Xing Du; Qiao Wang; Caixia Fu; Wenhui Qiu; Zhihong Wang; Xinlei Gao

doi:10.1016/j.jenvman.2021.114397

A feasible approach for azo-dye methyl orange degradation in siderite/H₂O₂ assisted by persulfate: Optimization using response surface methodology and pathway

J Environ Manage. 2022 Apr 15:308:114397. doi: 10.1016/j.jenvman.2021.114397. Epub 2022 Feb 2.

Authors

Wei Song¹, Ji Li², Xiaolei Zhang², Jianpei Feng², Xing Du¹, Qiao Wang¹, Caixia Fu³, Wenhui Qiu⁴, Zhihong Wang⁵, Xinlei Gao⁶

Affiliations

¹ School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, PR China.
² School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
³ School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China. Electronic address: 11849589@mail.sustech.edu.cn.
⁴ School of Public Health and Emergency Management, Southern University of Science and Technology, Shenzhen, 518055, China.
⁵ School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, PR China. Electronic address: wzhihong@gdut.edu.cn.
⁶ School of Civil and Environmental Engineering, Shenzhen Key Laboratory of Water Resource Application and Environmental Pollution Control, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China; Guangdong Water Co., Ltd, Shenzhen, 518021, China.

PMID: 35121467
DOI: 10.1016/j.jenvman.2021.114397

Abstract

Siderite was applied to the binary oxidant system of siderite-catalyzed hydrogen peroxide (H₂O₂) and enhanced with persulfate (PS). In the absence of PS, methyl orange (MO) almost could not be degraded by the siderite/H₂O₂ process. However, adding PS significantly improved the capacity of MO to oxidize azo-dye. The influence of individual and interaction of reaction factors have been explored with a simple response surface methodology (RSM) based on central composite design (CCD). The quadratic model with low probabilities (<0.0001) at a confidence level of 95% was satisfactory to predict MO degradation in siderite/H₂O₂/PS system, whose correlation coefficients of R² and R²-adj were 0.9569 and 0.9264, respectively. Moreover, the optimum operation conditions of 21.20 mM, 2.75 g/L, 3.86 mM, and 4.69 for H₂O₂, siderite, PS and initial pH, respectively with the response of C/C₀ around 0.047. Radical scavenging experiments and electron spin resonance (ESR) determined that ·OH was crucial for MO degradation, while the contribution of SO₄^·- was minor. The surface morphology and iron content of siderite before and after the oxidation process showed clear differences. Possible intermediates and a degradation pathway were proposed based on the results of UV-Vis spectral and GC-MS analysis. Moreover, the toxicity to Vibrio fischeri bioluminescent bacterium has increased in the earlier degradation stage due to the generated by-products and weaken with the continuous treatment. This study demonstrated that the siderite/H₂O₂/PS system was effective over a relatively wide pH range without producing secondary pollutants, making it a promising technology and potential environmentally benign approach to azo-dye wastewater treatment.

Keywords: Central composite design; Degradation mechanism; Methyl orange; Persulfate; Response surface methodology; Siderite/H(2)O(2).

MeSH terms

Azo Compounds / chemistry
Carbonates
Ferric Compounds
Hydrogen Peroxide* / chemistry
Oxidation-Reduction
Water Pollutants, Chemical* / chemistry

Substances

Azo Compounds
Carbonates
Ferric Compounds
Water Pollutants, Chemical
methyl orange
Hydrogen Peroxide
siderite