Synergistic effect of lactam, ammonium and hydroxyl ammonium based ionic liquids with and without NaCl on the surface phenomena of crude oil/water system

Abstract

Typical surfactants have been found to be less efficient in harsh conditions of temperature and salinity. The need for alternatives is in great demand which is expected to be resolved through the use of ionic liquids, being the area of the present research. In the present investigation, eleven different ionic liquids (ILs) from three various families, namely, lactam, ammonium and hydroxyl ammonium based ionic liquids with various anions, such as, [HCOO]−, [CH3COO]−, [C6H13COO]− and [CF3COO]− are studied to understand the surface phenomenon of water and crude oil–water system. In addition, the synergistic effects of NaCl on the surface tension (SFT) and interfacial tension (IFT) are also investigated in the presence of ionic liquid. The impacts of the ring size, alkyl chain length, temperature, concentration of ILs, the nature of cation and anions on the SFT/IFT are evaluated in the temperature range of 288.15–318.15 K with various concentrations of ILs. In addition, the electrical conductivity of aqueous solution of ILs are also presented to understand the critical aggregation concentration (cac) range of studied ILs. The exploration of SFT/IFT of water and crude oil–water systems divulge the fact that the ILs with NaCl are useful in minimizing the surface forces and thus, it could assist in impressively augmenting oil recovery, flow assurance and oil/gas production operations as well as being environment friendly.