Performance Evaluation of Ultra-Violet Light and Iron Oxide Nanoparticles for the Treatment of Synthetic Petroleum Wastewater: Kinetics of COD Removal.

Cecilia O Akintayo,Olushola S Ayanda,Wilfred N Igboama,Simphiwe M Nelana,Omolola H Aremu

doi:10.3390/ma14175012

Cecilia O Akintayo, Olushola S Ayanda + Show 3 more

Open Access

https://doi.org/10.3390/ma14175012

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Abstract

In this study, the use of ultra-violet (UV) light with or without iron oxide nanoparticles (IONPs) for the degradation of synthetic petroleum wastewater was investigated. The IONPs was synthesised by sodium borohydride reduction of ferric chloride solution and was characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FTIR), x-ray fluorescence spectrophotometry (XRF), and energy dispersive spectroscopy (EDS). The amount of degradation was evaluated by chemical oxygen demand (COD) determination. Experimental results show that the COD removal from synthetic petroleum wastewater by IONPs/UV system was more effective than they were independently. The combination of UV light at a wavelength of 254 nm, pH of 8, and 1.0 g of IONPs resulted in COD removal from 10.5% up to 95.5%. The photocatalytic degradation of synthetic petroleum wastewater is about 1.3–2.0 times faster in comparison to UV light only. The removal of COD from synthetic petroleum wastewater by UV light and IONPs follows the pseudo-first-order kinetic model with rate constant k ranging from 0.0133 min−1 to 0.0269 min−1. Consequently, this study has shown that the use of UV light in the presence of IONPs is favourable and effective for the removal of organic pollutants from petroleum refinery wastewater.

Highlights

Petroleum refineries are complex systems of multiple operations [1] that depend on the type of crude refined, the desired products, composition of condensate, and the treatment processes; the characteristics of refinery wastewater vary according to these complex patterns [2,3]
iron oxide nanoparticles (IONPs) was synthesized from commercial reagents, characterized by modern instrumental techniques and was combine with UV light to degrade pollutants present in synthetic petroleum wastewater
The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs of the IONPs show regular spherical shaped particles, the energy dispersive spectroscopy (EDS), selective area electron diffraction (SAED), and x-ray fluorescence spectrophotometry (XRF) analyses confirm the synthesis of the nanoparticles, with mean particle size of 12.5 nm

Summary

Introduction

Petroleum refineries are complex systems of multiple operations [1] that depend on the type of crude refined, the desired products, composition of condensate, and the treatment processes; the characteristics of refinery wastewater vary according to these complex patterns [2,3]. Refineries generate solid wastes and sludges, 80% of which may be considered hazardous because of the presence of toxic organics and heavy metals [8,9]. Tertiary treatments are considered if the refinery needs to meet stringent limits for different contaminants such as total suspended solids (TSS), COD, dissolved and suspended metals, and trace organics such as polyaromatic hydrocarbons (PAHs). Petroleum refineries discharge a large amount of wastewater that contains potentially toxic compounds into the environment, and these compounds are difficult to degrade. The use of the advanced oxidation processes (AOPs) will serve as a new feasible method for treating petroleum process wastewater for reuse and/or before the wastewater is discharge into the environment

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