Effect of Rhamnolipid Amidation on Biosurfactant Adsorption Loss and Oil-Washing Efficiency

Abstract

Surfactant adsorption loss seriously hinders the economy of surfactant binary flooding technology for enhancing oil recovery, especially for biosurfactants with higher manufacturing costs. Here, biosurfactant rhamnolipid (RL) is chemically modified to develop a more efficient surfactant, rhamnolipid monoethanol amide (RL-MEA), which is characterized by decreased adsorption loss and increased oil-washing efficiency for enhanced oil recovery at a laboratory scale. Synthesis and characterization of the rhamnolipid monoethanol amide are carried out using high-performance liquid chromatography (HPLC), HPLC/MS, 1H nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy. The aggregation behavior is disclosed by surface tension, dynamic light scattering, and fluorescence spectra with pyrene as the probe. The applied performances of RL-MEA in the simulated enhanced oil recovery are researched, including the efficiency of oil washing, wettability to crude oil, and adsorption isotherms on silicates. Compared with the critical micelle concentration (CMC) of rhamnolipid of 14.23 × 10–5 M in pure water and 9.02 × 10–5 M in 0.2 M NaCl solution, the modified RL-MEA shows a significantly lower CMC of 7.15 × 10–5 M in pure water and 5.34 × 10–5 M in 0.2 M NaCl solution. More importantly, the modified RL-MEA reduces adsorption loss by 20% and enhanced oil-washing efficiency at higher temperatures and salt concentrations compared with the parent RLs. These findings would provide valuable information for developing efficient surfactant flooding agents for harsh reservoir geological conditions.

Microbial Biosurfactant as an Alternate to Chemical Surfactants for Application in Cosmetics Industries in Personal and Skin Care Products: A Critical Review

“…Micelles are produced once monomers of surfactant aggregate at a specific concentration and temperature in a solution. This surfactant concentration is called the critical micelle concentration (CMC) [ 50 ]. Chemical surfactants, monomers, and micelles permeate skin layers and cells; however, due to their unstable nature, micelles disintegrate after contact with the skin.…”

“…Researchers reported microbial biosurfactants' effectiveness during several in vitro investigations, including suppressing new biofilms formation, preventing surface adhesion, and destroying biofilms that have already been formed [ 28 , 50 , 125 ]. Table 3 summarizes the multiple studies conducted to investigate the broad spectrum of microbial surfactants and their possible uses in the cosmetic sector, having various antimicrobial and other activities.…”

“…Several studies [ 117 , 166 , 167 ] recommend the beneficial application of prebiotic and probiotic bacteria in cosmetics. Currently, prebiotics are more commonly used, while probiotics are mostly used as a cutaneous treatment or an added ingredient in various beverages [ 5 , 50 , 138 ]. Biosurfactants, which are useful in microbial biotechnology, have been obtained from specific types of organisms that generate probiotics and prebiotics.…”