Application of Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (HS-SPME-GC/MS) on the Evaluation of Degradation Efficiency of Phenolic Compounds and Identification of By-Products from Produced Water

Cesar A Silva,Luiz A S Madureira

doi:10.5935/0103-5053.20150026

Abstract

Application of the headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC/MS) technique as an analytical tool to monitoring the degradation of phenolic compounds and the formation of by-products in produced water by UV photolysis and UV/peroxide is proposed. All of the experimental conditions for the degradation tests were carried out according to the response of the surface modeling methods developed. The direct photolysis and the UV/H2O2 processes were capable to degrade more than 99% of the initial concentrations of total phenolic components of produced water. The main by-product found was 2,6-di-tert-butylbenzoquinone (DBQ). The presence of DBQ and other hydroxy compounds, constituting the major fraction of by-products identified, demonstrates that the degradations are initiated by the oxidation of the aromatic phenolic ring generating quinones, diphenols, benzoic acids and phenones.

Highlights

Produced water is co-produced during recovery of natural gas and crude oil from onshore and offshore operations
The present study describes the application of SPME as an analytical tool to monitoring the degradation of phenolic compounds and by-products in produced water exposed to direct UV and UV/peroxide photolysis
The longer is the period of storage in these tanks, the higher is the concentration of phenolic compounds partitioned from the oil into the aqueous fraction

Summary

Introduction

Produced water is co-produced during recovery of natural gas and crude oil from onshore and offshore operations. The RSM uses quantitative data obtained from properly designed experiments to solve multivariable equations being simultaneously used in several studies.[18,19,20,21,22,23] The results depicted in Figures 2a and 2b describe the response surface plot as function of time and pH for the highest efficiency removal of phenol at 180 min, as described in the first test (Figure 1a).

Results

Conclusion