Process Synthesizes Janus Carbon Nanofluids From Waste Plastics for EOR
Authors: Carpenter Chris 
Published: November 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214799, “Novel Janus Carbon Nanofluids From Waste Plastics as Sustainable Nanoagents for Enhanced Oil Recovery: Scaleup Synthesis and Performance Evaluation,” by Wei Wang, Sehoon Chang, SPE, and Ayrat Gizzatov, SPE, Saudi Aramco, et al. The paper has not been peer reviewed.

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The complete paper describes nanomaterials—Janus carbon nanofluids—derived from waste plastics and demonstrates the potential of the nanofluids as highly effective alternative nanoagents for enhanced oil recovery (EOR) applications at reservoir conditions. A novel, sustainable, cost-effective method has been developed to scale up synthesis of Janus carbon nanoparticles (JC-NPs) from waste plastic feedstock by combined pyrolysis, chemical functionalization, and pulverization, which allows for production of the JC-NPs in mass quantities at an industrial scale.

Introduction
Recent research has demonstrated that nanoparticles with asymmetric surface properties (i.e., Janus nanoparticles) could achieve a much higher efficiency of oil recovery factors with very low concentrations of loading compared with homogeneous nanoparticle fluids. To date, however, major challenges facing the exploration and use of Janus nanoparticles exist, impeding scalability of synthesis, tailored chemical functionalization, and the ability to introduce a diverse set of functionalities. Therefore, new methods for production of Janus nanomaterials on an industrial scale are desired.
The authors present a novel technique to convert waste plastic materials into carbon-based nanomaterials for EOR applications. Waste plastics, as a low-cost feedstock, can be converted into high-value-added carbon-based microparticles through the controlled carbonization of polymers. Furthermore, the carbon microparticles (C-MPs) can be surface-functionalized by post-chemical treatment and then their chemical symmetry reduced to nanosize by a ball-milling technique. The resulting asymmetrically surface-functionalized carbon nanoparticles (i.e., Janus C-NPs) exhibit both nanoparticulate and surfactant-like properties that can be used as new nanoagents in nanofluid flooding for EOR applications. Experimental materials and measurement methodology are detailed in the complete paper.

Results and Discussion
Synthesis of C-MPs From Waste Polymers.
Approximately 90% of the plastics produced globally consist of six types: low-density polyethylene, high-density polyethylene, polypropylene, polyvinylchloride, polystyrene, and polyethylene terephthalate (PET). Given their widespread use, these waste polymers constitute a substantial proportion of global plastic waste. Therefore, they present an opportunity to be used as precursors in the synthesis of C-MPs.
This study offers an approach for repurposing these ubiquitous waste polymers. As depicted in Fig. 1, the authors propose synthesis of C-MPs through carbonization reactions using these waste polymers as feedstock. This methodology offers dual benefits. First, it presents a practical solution to the growing environmental concern posed by plastic waste. Second, it provides a cost-effective way to produce C-MPs, an essential component in many technological applications.