Polymeric Waste-Based Ion-Exchange Resins: A Sustainable Solution for Produced Water Treatment

Abstract

Abstract One of the most crucial strategies for reducing the negative environmental effects of water production in oil operations is to identify innovative and cost-efficient techniques for purifying produced water while minimizing the amount of its disposal into the environment. The proposed solution for polymeric waste and its recycling into ion exchange resin allows the removal of monovalent ions from produced water. The obtained purified produced water can be utilized as injection water for waterflooding/smart water flooding or frac-water for unconventionals to contribute towards circular water economy in alignment with the Zero-Liquid-Discharge (ZLD) water management strategy. Discarded expanded polystyrene was selected as a viable substitute material source for ion exchange resins due to its abundance and low cost. Polymeric matrixes are made by collecting and dissolving polystyrene waste in an organic solvent, then forming beads using a microdroplet precipitation technique. A strongly basic anion-exchange resin (SBA) containing amine groups is produced using the amine plasma modification method combined with chemical treatment. Using the plasma sulfonation approach with surface treatment, a strongly acidic cation-exchange resin (SAC) with a high surface area and sulfonic groups is created. The SBA resin is utilized for sulfate-ions removal, while SAC can be applied to remove the sodium-ions. The polystyrene beads production process was scaled up using an in-house state-of-the-art encapsulator instrument. It has been demonstrated that achieving spherical beads without agglomeration requires the proper concentration of polystyrene waste and a filler in a solution. To increase surface area and functionalization efficiency, polystyrene beads were milled. The resultant porous beads are 300–750 microns in size. The performance of the resulting resin samples was analyzed according to industry standards using column tests. The optimal parameters of plasma sulfonation and chemical treatment procedures for SAC formation and plasma amination process for SBA creation were identified. The resins prepared from expanded polystyrene waste demonstrated effective capacity for both cation and anion exchange processes. More than 80% of the sodium ions and the sulfate ions in synthetic brine could be removed by the created strong-acidic cation-exchange and strong base anion-exchange resins, respectively. A new method of polymeric waste-based ion-exchange resins creation with characteristics similar to commercially available ion-exchange resins has been discovered. The development of these sustainable ion-exchange resins holds great promise for produced water treatment and recycle, providing an environmentally friendly and effective solution and reusing plastic waste.