Utilizing lignosulfonate from coconut husk as sacrificial agent to reduce surfactant adsorption

Abstract

The adsorption of surfactants from aqueous solutions in porous media is essential in enhanced oil recovery (EOR) from oil reservoirs. Surfactant loss that is due to adsorption by the reservoir rocks weakens the efficiency of the chemical slurry that is injected and decreases the oil-water interfacial tension (IFT). One of the ways to reduce the reduction is by using a sacrificial agent. This project will focus on utilizing the lignosulfonate (LS) from coconut husk as a sacrificial agent to reduce the surfactant adsorption. Lignin was extracted from coconut husk before sulfonated using sodium sulphite, Na2SO3 to form lignosulfonate. Fourier transform infrared (FTIR) spectroscopy was used to characterize the lignin and lignosulfonate and compare them with the commercial product. The batch experiment then conducted using a clay mineral of illite as the adsorbent. Two types of surfactants were studied; anionic (Sodium Dodecyl Sulfate-SDS) and non-ionic (4-octylphenol polyethoxylate-TX100). The amount of adsorbed surfactant was determined by measuring the surfactant critical micelle concentration (CMC) before and after the adsorption tests. The result in the batch experiment shows that LS reduced the surfactant adsorption on illite by about 54.2% for SDS and 42.6% for TX100. This showed that lignosulfonate has the potential as a sacrificial agent to minimize the surfactant adsorption, and agriculture waste like coconut husk can be utilized for this purpose.