Contents lists available at ScienceDirect Journal of Petroleum Science and Engineering journal homepage: www.elsevier.com/locate/petrol Static adsorption and interfacial tension of Sodium dodecyl sulfate via magnetic field application Hashem Hosseini a , Hossein Hosseini b , Mehrdad Jalili a , Saeid Norouzi Apourvari a,* , Mahin Schaffie a , Mohammad Ranjbar a a Department of Petroleum Engineering, Shahid Bahonar University of Kerman, Kerman, Iran b Department of Petroleum Engineering, University of Garmsar, Garmsar, Iran ARTICLE INFO Keywords: Magnetic field Magnetized water Surface tension Interfacial tension SDS surfactant Adsorption isotherm and kinetic models ABSTRACT Magnetic field exposure could change the properties of fluids, such as water. The application of the magnetic field for wettability alteration of carbonate rocks was investigated in the first part of our study. In this part, however, the interfacial tension of surfactant with crude oil and its static adsorption onto calcite surfaces under the magnetic field application were studied. From the results of this study, it can be pointed out that the magnetic field-treated water, the so-called magnetized water decreased the surface tension. The interfacial tension between crude oil and magnetized water did not significantly change. The value of the CMC for SDS surfactant solution with magnetized water as the solvent was decreased by about 7%. However, magnetic field treatment of surfactant solutions did not change the value of CMC. Besides, the interfacial tension between surfactant solutions and crude oil did not remarkably change via the magnetic field application. Magnetized water increased the equilibrium adsorption of surfactant solutions onto calcite at concentrations above the CMC. As for kinetic behaviors of the surfactant solutions, the pseudo-second-order kinetic model was found to be the best one to predict the kinetic behavior of surfactant solutions prepared with magnetized water and deionized water. Moreover, magnetized water increased the adsorption rate at early times and expedited it onto the ad- sorbent. The magnetic field could increase the SDS surfactant adsorption (at concentrations above the CMC) onto calcite surfaces only if the adsorbent was maintained in the solutions during the magnetic field treatment. 1. Introduction It is estimated that about two third of the oil remains in reservoirs after primary and secondary oil recovery. Capillary forces trap the re- sidual oil in the reservoir pore structures, and conventional means cannot recover it (Qiao et al., 2012). Interfacial Tension (IFT) is very important to determine that forces acting on trapped oil in porous media (Liu et al., 2014). Surfactant flooding has been considered as a tertiary oil recovery method in depleted reservoirs after water flooding (Zargartalebi et al., 2015). In a surfactant flooding process, the oil is recovered by reducing the interfacial tension between oil and water phases or wettability alteration of reservoir rocks. Recent advances in surfactant flooding in Enhanced Oil Recovery (EOR) were reviewed by (Hirasaki et al., 2011). Besides, the subject of polymer-surfactant in- teractions has attracted much attention. Touhami et al. (2001b) stated that the addition of polymer changed the CMC of surfactant, and the CMC rose with the increase of polymer concentrations. More details on the polymer-surfactant interactions could be found in the literature (e.g. Amaya et al., 2002; Ng et al., 2003; Rana et al., 2002; Touhami et al., 2001a; Touhami et al., 2001b). Surfactant adsorption in porous media is a fundamental issue in surfactant flooding. The loss of surfactant eventually reduces the ef- fectiveness of the surfactant solution for reducing the IFT of oil-water (Curbelo et al., 2007; Schramm, 2000). Various studies have been de- voted to investigate the adsorption of different surfactants onto re- servoir rocks (Ahmadi and Shadizadeh, 2013; Amirianshoja et al., 2013; Ananthapadmanabhan and Somasundaran, 1983; Blokhus et al., 1996; Koopal et al., 1995; Lv et al., 2011; Somasundaran and Krishnakumar, 1997). (Ma et al., 2013) investigated the adsorption of SDS and CPC surfactants on natural and synthetic carbonate materials. They con- cluded that CPC shows negligible adsorption on synthetic calcite in deionized water compared to that of SDS. Understanding the mechanisms of surfactant transport through porous media is very important and could be facilitated by studying the isotherm and kinetic adsorption of surfactants (Zendehboudi et al., 2013). (Bera et al., 2013) investigated the isotherm and kinetics https://doi.org/10.1016/j.petrol.2019.03.040 Received 4 October 2018; Received in revised form 28 January 2019; Accepted 14 March 2019 * Corresponding author. E-mail address: snorouzi@uk.ac.ir (S. Norouzi Apourvari). Journal of Petroleum Science and Engineering 178 (2019) 205–215 Available online 19 March 2019 0920-4105/ © 2019 Elsevier B.V. All rights reserved. T