Removal of Polycyclic Aromatic Hydrocarbons in a Heterogeneous Fenton Like Oxidation System Using Nanoscale Zero-Valent Iron as a Catalyst

Abstract

Oil and gas effluents contains highly toxic and harmful organic pollutants. Therefore, it is necessary to eliminate and/or reduced the concertation of organic pollutants to a technologically acceptable levels before their discharge into water streams. This study investigates the application of nanoscale zero-valent iron (nZVI), and hydrogen peroxide (H2O2) for removal of organic pollutants from real oily produced water. Batch studies were performed and effect of different operating parameters, including concentration of nZVI and H2O2, pH and reaction time were studied. Moreover, optimization of independent variables was performed using central composite design (CCD) in response surface methodology (RSM). The experimental set up provided maximum removal efficiencies of 89.5% and 75.3% for polycyclic aromatic hydrocarbons (PAHs) and chemical oxygen demand (COD), respectively. The optimum values of independent variables such as concentrations of nZVI, and H2O2, contact time and pH were obtained as 4.35 g/L, 1.60 g/L, 199.9 min and 2.9, respectively. Predicted PAHs and COD removal efficiencies at the optimum values of independent variables were found as 89.3% and 75.7%, respectively which are in line with the experimental values. The study indicates that application of heterogeneous Fenton like oxidation system using nZVI as a catalyst is an efficient treatment method for removal of organic pollutants from real produced water.

Optimization of Micro-Pollutants’ Removal from Wastewater Using Agricultural Waste-Derived Sustainable Adsorbent

“…The COD of the water sample was measured by the colorimetric method via a spectrophotometer DR2800 (HACH Company, Loveland, CO, USA). The concentration of PAHs was measured via gas chromatography-mass spectrometry (Agilent, model G7035A, combination of 7820A GC system with 5977E (MSD, Santa Clara, CA, USA)) following a previously described procedure in our study [7]. All the tests were performed in triplicate, and average values were utilized to minimize errors.…”

“…However, the p-values of the "Lack of Fit" for PAHs and COD models were 0.85 and 0.57, respectively, showing non-significance. Non-significant "Lack of Fit" is acceptable for the model [7,54], which implies that the quadratic regression model is significant/adequate to describe the relation between all three independent variables and responses (PAHs and COD).…”

“…The wastewater obtained from oil and gas exploration industries is known as produced water (PW) [5]. The range of PAH concentration in PW reported by various research is from 124 to 1000 µg L −1 [6][7][8][9], and these pollutants are precarious even in low concentrations (µg L −1 -mg L −1 ) [7]. In addition, the United States Environmental Protection Agency has declared 16 PAHs as priority chemicals because of their mutagenic and carcinogenic effects [3].…”

Application of the Response Surface Methodology (RSM) in the Optimization of Acenaphthene (ACN) Removal from Wastewater by Activated Carbon

“…PAHs have been removed using a number of techniques, such as ion exchange, electrochemical treatment, chemical oxidation, solvent extraction, reduction, precipitation, adsorption, and filtration [9][10][11]. Traditional wastewater treatment methods are insufficient to eliminate PAHs [12,13].…”

“…Traditional wastewater treatment methods are insufficient to eliminate PAHs [12,13]. Some technologies have a high removal efficiency but have a high operational cost and may create secondary pollutants, such as electrocoagulation, microfiltration combined with membrane-based technologies, and biological processes [11]. Adsorption is one of the most cost-effective strategies for removing PAHs, as it produces less waste and requires less energy [14].…”