Removal of organic compounds and trace metals from oil sands process-affected water using zero valent iron enhanced by petroleum coke

• Published in: Journal of environmental management 2014-06, Vol.139, p.50-58
• Main Authors: Pourrezaei, Parastoo, Alpatova, Alla, Khosravi, Kambiz, Drzewicz, Przemysław, Chen, Yuan, Chelme-Ayala, Pamela, Gamal El-Din, Mohamed
• Format: Article
• Language: English
• Subjects: Adsorption; Aliivibrio fischeri - drug effects; Aliivibrio fischeri - metabolism; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biological assays; Carboxylic Acids - chemistry; Carboxylic Acids - toxicity; Coke; Conservation, protection and management of environment and wildlife; Environmental impact; Fundamental and applied biological sciences. Psychology; General aspects; Industrial Waste; Iron - chemistry; Iron - toxicity; Metals; Metals - chemistry; Metals - toxicity; Oil and Gas Fields; Oil sands; Oil sands process-affected water; Organic chemicals; Oxidation; Petroleum; Petroleum coke; Toxicity; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Zero valent iron
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2014.03.001

The oil production generates large volumes of oil sands process-affected water (OSPW), referring to the water that has been in contact with oil sands or released from tailings deposits. There are concerns about the environmental impacts of the release of OSPW because of its toxicity. Zero valent iron alone (ZVI) and in combination with petroleum coke (CZVI) were investigated as environmentally friendly treatment processes for the removal of naphthenic acids (NAs), acid-extractable fraction (AEF), fluorophore organic compounds, and trace metals from OSPW. While the application of 25 g/L ZVI to OSPW resulted in 58.4% removal of NAs in the presence of oxygen, the addition of 25 g petroleum coke (PC) as an electron conductor enhanced the NAs removal up to 90.9%. The increase in ZVI concentration enhanced the removals of NAs, AEF, and fluorophore compounds from OSPW. It was suggested that the electrons generated from the oxidation of ZVI were transferred to oxygen, resulting in the production of hydroxyl radicals and oxidation of NAs. When OSPW was de-oxygenated, the NAs removal decreased to 17.5% and 65.4% during treatment with ZVI and CZVI, respectively. The removal of metals in ZVI samples was similar to that obtained during CZVI treatment. Although an increase in ZVI concentration did not enhance the removal of metals, their concentrations effectively decreased at all ZVI loadings. The Microtox® bioassay with Vibrio fischeri showed a decrease in the toxicity of ZVI- and CZVI-treated OSPW. The results obtained in this study showed that the application of ZVI in combination with PC is a promising technology for OSPW treatment. [Display omitted] •Zero valent iron (ZVI) combined with petroleum coke (PC) was used to treat OSPW.•PC was used as an electron conductor to provide adsorption and oxidation sites.•Increase in the ZVI concentration enhanced the removal of organic compounds.•The presence of oxygen in OSPW promoted the generation of hydroxyl radicals.•The toxicity of OSPW toward Vibrio fischeri decreased after treatment.