Using a New Fe3O4@CPAM Magnetic Flocculant and Microwave to Demulsify Heavy Oil-in-Water Emulsions

Nana Sun; Huina Sun; Jianbo Hu; Shiqi Xu; Lisha Shen; Yuli Ma

doi:10.1021/acsomega.3c08238

Using a New Fe₃O₄@CPAM Magnetic Flocculant and Microwave to Demulsify Heavy Oil-in-Water Emulsions

ACS Omega. 2024 Feb 15;9(8):9202-9215. doi: 10.1021/acsomega.3c08238. eCollection 2024 Feb 27.

Authors

Nana Sun¹, Huina Sun², Jianbo Hu¹, Shiqi Xu¹, Lisha Shen¹, Yuli Ma¹

Affiliations

¹ College of Petroleum Engineering, Xi'an Shiyou University, Xi'an 710312, Shaanxi, P. R. China.
² Gas Production Plant No. 1, North China Oil & Gas Branch, North China Petroleum Bureau, Zhengzhou 450000, Henan, P. R. China.

Abstract

In this study, cationic polyacrylamide (CPAM)-coated magnetic nanoparticles (MNPs) Fe₃O₄@CPAM were synthesized for treating heavy O/W emulsions. This Fe₃O₄@CPAM was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM) techniques, and its synergistic performances with microwaves were evaluated in detail with respect to the microwave radiation power, radiation time, and magnetic nanoparticle concentration. On this basis, the distribution of oil droplets and the wettability and chargeability of magnetic nanoparticles were measured without or with microwave radiation using biomicroscopy, contact angle measurement instrument, and a ζ-potential analyzer, thus revealing the synergistic demulsification mechanism between microwave and magnetic nanoparticles. The results showed that excessively high or low microwave radiation parameters had an inhibitory effect on the magnetic nanoparticle demulsification, and microwave promoted the magnetic nanoparticle demulsification only when the radiation parameters were in the optimal range. In addition, the water separation rate showed an increasing and then decreasing trend with the increase of magnetic nanoparticles concentration, with or without microwave action. As an example, the water separation rate of the emulsion for 1 h was 21.34% when the Fe₃O₄ concentration was 175 mg/L without microwave action, while it increased to 55.56% with microwave action. In contrast, when the concentration of Fe₃O₄@CPAM was 175 mg/L, the water separation rate was 42.86% without microwave radiation, while it was further increased to 77.38% under microwave radiation. These results indicate that magnetic nanoparticles and their complexes significantly affect the water separation process under different conditions. There is a more obvious coupling synergistic effect between Fe₃O₄@CPAM and microwave. This was due to the lower absolute potential of Fe₃O₄@CPAM and its higher hydrophobicity.