RESEARCH ARTICLE Improved waste-sourced biocomposite for simultaneous removal of crude oil and heavy metals from synthetic and real oilfield-produced water Razegheh Akhbarizadeh 1 & Farid Moore 1 & Dariush Mowla 2 & Behnam Keshavarzi 1 Received: 17 June 2018 /Accepted: 3 September 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract 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 spec- troscopy, energy dispersive X-ray (EDX) analysis, and SEM-EDX technique indicated that the chitosan-activated montmoril- lonite (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). Keywords Oilfield-produced water . Chitosan-modified montmorillonite . Crude oil . Adsorption . Heavy metals . Treatment Introduction Oil- and gas-produced water (PW) is a byproduct of petroleum production (Fakhru’l-Razi et al. 2009; Shpiner et al. 2009b). Physical and chemical properties of PW can be affected by various parameters including geological setting of the field, reservoir characteristics, reservoirs lifetime, characteristics of the hydraulic fracturing process, hydrocarbon types, opera- tional conditions, and the used additives (Fakhru’l-Razi et al. 2009; Olsson et al. 2013). The brine to oil-produced ratio is 2:1 for conventional oil wells, while it is 35% less for uncon- ventional wells (Farag and Harper 2014; Phan et al. 2015). The salinity of PW is also much higher for conventional res- ervoirs compared with that for unconventional ones (for ex- ample, average total-dissolved solids in PWs from conven- tional Devonian age reservoirs in Pennsylvania and West Virginia are reported to be 165 g/L, while it is 25.3 g/L for Marcellus Shale) (Skalak et al. 2014). However, PWs from unconventional reservoirs tend to exhibit high concentrations of Sr, Ba, and Ra relative to conventional wells (Skalak et al. 2014). For instance, the range of Ba in conventional reservoir PW is from a few mg/L to 4370 mg/L, but brine from uncon- ventional wells ranges from 76 to 13,600 mg/L (Phan et al. 2015; Skalak et al. 2014). Similarly, the concentration of Ra in PWs from Marcellus is 2–5 times higher than conventional Responsible editor: Tito Roberto Cadaval Jr Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-018-3136-2) contains supplementary material, which is available to authorized users. * Razegheh Akhbarizadeh akhbarizade@shirazu.ac.ir 1 Department of Earth Sciences, College of Science, Shiraz University, Shiraz 71454, Iran 2 School of Chemical and Petroleum Engineering, Shiraz University, Mollasadra Ave., Shiraz 71345, Iran Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-3136-2