Poly(dimethylsiloxane)-Doped Alkylated Reduced Graphene Oxide Nanostructured Antifoam for Oil Phase

Abstract

Foam formation in surface facilities of oil production units, especially central separators, may interrupt or even disrupt the oil production process. In this work, an innovative approach was developed to enhance the performance of poly(dimethylsiloxane) (PDMS) as a widely used antifoam in the oil/gas industry. Alkylated reduced graphene oxide (RGO-ODA) nanosheets were synthesized and incorporated into the PDMS solution to prepare PDMS-doped RGO-ODA antifoam for the oil phase. Graphene oxide (GO) nanosheets were prepared from a graphite powder following the modified Hummers’ method. The GO was alkylated and reduced via a reactive reduction by octadecyl amine to synthesize RGO-ODA branched nanosheets, readily dispersed in the oil phase. The textural and structural characteristics of the nanostructures were characterized by field emission scanning electron microscopy/energy dispersive spectroscopy (FESEM/EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, and thermogravimetric analysis/derivative thermogravimetry (TGA/DTG) analyses. A foamy dead oil sample was blended with xylene, and the foamability and foam stability of the model oil in the presence and absence of the antifoam were measured in a standard gas bubbling column. In addition, dynamic surface tension was employed to reveal the mechanism of antifoaming. Results indicate that the synthesized RGO-ODA has lower oxygen-containing groups, higher disorder structure, and almost the same sheet domains when compared with starting GO. The almost amorphous structure of the RGO-ODA arises from the exfoliation and alkylation of the graphene nanosheets. The RGO-ODA nanosheets have rough surfaces with sharp edges. Incorporation of the RGO-ODA nanosheets into the PDMS solution enhances the entrance, spreading, and bridging of oil-phase foaming films, as observed in the dynamic surface tension data. This synergistic effect leads to higher antifoaming efficiencies and stronger thermal durability when compared to the PDMS alone, offering a promising solution for industrial applications requiring oil-phase foam elimination, achieved with reduced silicone contamination.