Design and optimization of a sequential and hybrid advanced oxidation process system using response surface methodology

Abstract

Of different approaches for refinery effluent treatment, the application of Advanced Oxidation Processes (AOPs) (e.g. electro-Fenton) and nano Zero-Valent Iron (nZVI) particles have been of great interest lately. Associated constraints with these methods inspired the design of a sequential hybrid system by which higher treatment efficiency and less energy consumption were acquired compared to a conventional system. The hybrid system consisted of an electro-Fenton and an nZVI slurry system working in sequence. Both sub-systems were first optimized using the Response Surface Methodology (RSM), and the hybrid system was then designed accordingly. 94.06% of COD removal was achieved by the hybrid system in only 47.5 min at its optimum condition (COD_initial = 500 mg/L, [nZVI] = 0.9 g/L, and H₂O₂/Fe²⁺ = 3.6). Whereas it took more than 75 min for the single electro-Fenton system to acquire similar efficiency. GC–MS analysis also supported the superiority of the hybrid system over the conventional one.

KEYWORDS:

• Refinery effluent
• electro-Fenton
• nZVI
• hybrid system
• energy efficiency

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Dissolved oxygen.

2 Brunauer-Emmet-Teller.

3 Round per minute.

4 One factor at a time.

5 Part per billion.

Additional information

Notes on contributors

Mirmehdi Seyyedi

Mirmehdi Seyyedi is a PhD candidate in Environmental Engineering at the Department of Civil and Architectural Engineering, University of Wyoming, Laramie, Wyoming, USA.

Bita Ayati

Bita Ayati is an associate professor at the Civil and Environmental Engineering Faculty, Tabriat Modares University, Tehran, Iran.