Performance of Resins Based on Poly(Divinylbenzene-co-Methyl Methacrylate) for Removal of Calcium and Magnesium Ions from Water

Abstract

Background: The mixing of the formation water present in oil and gas reservoirs and the injected water (often seawater) can form inorganic incrustations, during enhanced oil recovery operations. In this case, the cations (calcium, barium, strontium, iron, magnesium, etc.) of the injected water react with the anions (mainly sulfate and carbonate) of the formation water and produce inorganic salts that can precipitate in the reservoir rock, damaging the oil production by clogging the pipes and production lines. One of the ways to prevent this problem is to remove the cations from the injected water, but this is a challenging procedure. Objective: In this study, the Sulfonated polymer(divinylbenzene) (DVBS) and the copolymer sulfonated poly(methyl methacrylate-co-divinylbenzene (MMA-DVB) were compared in their efficiencies in reducing, to a very low level, the concentration of removing, chemically modified with sulfonic (S) groups to ascertain their performance, the calcium and magnesium ions present in water. Method: The resins were modified with sulfonic groups and characterized. We used central composition planning with batch tests to evaluate the adsorption, which occurred significantly for both ions using both resins with contact time of 10 minutes. Results: For both resins, calcium was preferentially adsorbed in relation to magnesium. Conclusion: Taking is account cost benefit, the copolymer MMA-DVBS (a less expensive adsorbent than the polymer DVBS) presented a satisfactory behavior, making it a potential material for treatment of water.