Effect of <i>Atriplex halimus</i> Leaf as Ecofriendly Surfactant for Demulsification of Water in Crude Oil Emulsion

Summary Water-crude oil emulsion causes challenges, which the petrochemical sector solves using efficient, ecologically friendly, and cost-effective demulsifying chemicals. With this work, we aim to solve the problem of the presence of water in Algerian oil after it has left the producing well by adding a natural material, widely used in the country, as an environmentally friendly demulsifier. Atriplex halimus L. leaf ATP powder (ATP-P) and leaf extract (E-ATP) were studied. We first characterized the two biosurfactants ATP-P and E-ATP by attenuated total reflectance (ATR), X-ray diffraction (XRD), and thermogravimetry analysis (TGA). The effect of ATP-P and E-ATP on the emulsion (water/oil) was studied by Fourier transform infrared spectroscopy (FTIR) analysis, microscopic, rheological behavior, interfacial tension (IFT), and bottle tests. The results obtained show the ability of the two biosurfactants E-ATP and ATP-P to separate water, with water separation reaching 99% in 30 minutes with 500 ppm of E-ATP, while ATP-P separates 98% in 92 minutes. The mechanism of action of the two compounds as biodemulsifiers can be traced back to the rheological study, which showed a 33% reduction in emulsion viscosity at 500 ppm; ATR-FTIR analysis also shows the disappearance of carbon-carbon and carbon-oxygen bonds, responsible for the reduction in oil viscosity. A decrease in surface tension by 41.48% by adding P-ATP and 57.95% by adding E-ATP contributed to the integration of water molecules and increased separation speed. Microscopic analysis shows an increase in the volume diameter of the water droplets, more than threefold when E-ATP is added and more than twofold when ATP-P is added.