Improved waste-sourced biocomposite for simultaneous removal of crude oil and heavy metals from synthetic and real oilfield-produced water
- 86 Downloads
Oil- and gas-produced water (PW) which contains various pollutants is an enormous threat to the environment. In this study, a novel low-cost bio-adsorbent was prepared from shrimp shell and acid-activated montmorillonite. The results of FT-IR spectroscopy, energy dispersive X-ray (EDX) analysis, and SEM-EDX technique indicated that the chitosan-activated montmorillonite (CTS-A-MMT) was prepared successfully. The synthesized CTS-A-MMT was applied to remove simultaneously five cationic and anionic metal species and crude oil from synthetic and real oilfield PW. The adsorption data indicated that crude oil and all studied metals (except As) were adsorbed to CTS-A-MMT in a monolayer model (best fitted by Langmuir model), while As adsorption fits well with Freundlich model. Kinetic models’ evaluation demonstrated that the adsorption kinetics of metals on CTS-A-MMT are initially controlled by the chemical reaction (film diffusion) followed by intra-particle diffusion. Application of the prepared CTS-A-MMT in real oilfield PW indicated removal efficiency of 65 to 93% for metals and 87% for crude oil in simultaneous removal experiments. Presence of additional ions in PW decreased the removal of studied metals and crude oil considerably; however, the concentration of the investigated pollutants in treated PW is less than the ocean discharge criteria. It is concluded that the prepared CTS-A-MMT composite is a low-cost and effective adsorbent for treating wastewater contaminated with crude oil and heavy metals (i.e., PW).
KeywordsOilfield-produced water Chitosan-modified montmorillonite Crude oil Adsorption Heavy metals Treatment
The authors would like to express their gratitude to medical geology research center of Shiraz University for logistic support. Thanks are also extended to the Iranian Oil Terminal Company for facilitating the fieldwork and financially supporting this research.
- Arthur JD, Langhus BG, Patel C (2005) Technical summary of oil and gas produced water treatment technologies. All Consulting, LLC, TulsaGoogle Scholar
- Department of Environment (2013) Environmental Procedure. Environmental Regulations And Standards, Islamic Republic of Iran (In Persian)Google Scholar
- Iler KR (1979) The chemistry of silica. Solubility, polymerization, colloid and surface properties and biochemistry of silica. Wiley, New YorkGoogle Scholar
- Jones F, Leuterman A, Still I (2000) Discharge practices and standards for offshore operations around the world, proceedings of the 7th International Petroleum Environmental Conference, Albuquerque, NM 903–938Google Scholar
- USEPA (1993) Final Development Document for Effluent Limitations Guidelines and New Source Performance Standards for the Offshore Subcategory of the Oil and Gas Extraction Point Source category. EPA 821-R-93-003. U.S. Environmental Protection Agency, Office of Water, Washington, DCGoogle Scholar
- USEPA E (1999) Method 1664 revision A: N-hexane extractable material (HEM; oil and grease) and silica gel treated N-hexane extractable material (SGT-HEM; non-polar material) by extraction and gravimetry. United States Environmental Protection Agency, Washington DCGoogle Scholar