Journal of Colloid and Interface Science 279 (2004) 36–45 www.elsevier.com/locate/jcis Calcium lignosulfonate adsorption and desorption on Berea sandstone Reid B. Grigg ∗ , Baojun Bai New Mexico Petroleum Recovery Research Center, New Mexico Institute ofMining and Technology, 801 LeroyPlace, Socorro, NM 87801, USA Received 19 December 2003; accepted 9 June 2004 Available online 17 July 2004 Abstract This paper describes adsorption and desorption studies carried out with calcium lignosulfonate (CLS) on Berea sandstone. Circulation experiments were performed to determine CLS adsorption isotherms and the effects of CLS concentration, temperature, salinity, brine hard- ness, and injection rate on adsorption density. Flow-through experiments were performed to assess the reversibility of CLS adsorption and the influence of postflush rate, brine concentration, brine hardness, brine pH, and temperature on the desorption process. Results indicate that CLS adsorption isotherms on Berea sandstone follow the Freundlich isotherm law. The results presented in this paper on the effects of CLS adsorption and desorption on Berea sandstone show that: (1) increasing CLS concentration and salinity increases CLS adsorption density; (2) increasing temperature will decrease adsorption density; (3) increasing injection rate of CLS solution will slightly decrease CLS adsorp- tion density; (4) postflush rate and salinity of brine have a large impact on the CLS desorption process; (5) the adsorption and desorption process are not completely reversible; and (5) temperature and pH of the postflush brine have little effect on desorption.  2004 Elsevier Inc. All rights reserved. Keywords: Calcium lignosulfonate; Berea sandstone; Adsorption; Desorption; Effects of concentration and temperature on sorption 1. Introduction The petroleum industry has demonstrated the usefulness of surfactant-based enhanced oil recovery processes [1]. This work focuses on surfactants intended for the appli- cation of mobility control and fluid diversions caused by foam [2–7]. Propagation of foam depends on the propagation of the surfactant, which is strongly affected by adsorption losses at the solid/liquid interface. Surfactant loss in a reser- voir due to adsorption in porous media represents the largest consumption of chemicals in a flood, and is thus a major fea- ture governing the economic viability of CO 2 -foam flooding [4]. In general, there are three kinds of adsorption: ion ex- change adsorption, physical adsorption and chemical ad- sorption [1,8–12]. Exchange adsorption is the result of elec- trostatic attraction, having the ion charge as the principal determining factor of the strength of the attraction to a site of opposite charge. Physical adsorption results from van der Waals forces. The adsorbed molecule is not affixed to * Corresponding author. Fax: +505-835-6031. E-mail address: reid@prrc.nmt.edu (R.B. Grigg). a specific site at the surface but is free to undergo transla- tional movement within the interface. It is predominantly a low temperature phenomenon, characterized by a relatively low energy of adsorption. Physical adsorption is usually a reversible process; an increase in temperature causes a de- crease in adsorption efficiency and capacity. Chemical ad- sorption is a chemical interaction between the surfactant and surface mineral. This bonding leads to a change in the chem- ical form of the adsorbed compound, and is not reversible. Adsorption of surfactants at the solid/liquid interface is strongly influenced by the following factors [13–24]: (1) The type of surfactant and the specific properties of the molecule. (2) The solvent conditions, such as pH, salinity (Na + , Cl − ) and hardness (Ca 2+ , Mg 2+ ). (3) The surface nature of the adsorbing substrate, such as surface area, type of surface (silica, calcium carbonate, clay, etc.), and surface charge. (4) The environment of the aqueous phase, temperature, re- dox environment, and flow rate in the reservoir. Three approaches may be used to minimize surfactant ad- sorption [25]: 0021-9797/$ – see front matter  2004 Elsevier Inc. All rights reserved. doi:10.1016/j.jcis.2004.06.035