Synthesis of a demulsifier for treating crude oil-in-water emulsion through a straightforward low-temperature process

Abstract

The separation of oily wastewater is a significant issue in the petroleum industry. In current work, a highly efficient demulsifier (TCDA) was synthesized through a one-step low-temperature method for the purpose of demulsifying O/W emulsions. The structure was characterized using FT-IR and 1H NMR spectra. The oil–water separation ability was evaluated through light transmittance (T%) and oil removal rate (η%) of separated water. The results showed that T% of 88.6 % and η% of 99.8 % could be obtained with the dosage of 30 mg/L at ambient temperature. In addition, TCDA demonstrated good acid and salt resistance. The relative solubility number (RSN), three-phase contact angle, dynamic interfacial tension, zeta potential and optical micrograph were characterized to explore possible demulsification mechanism. It was found that TCDA effectively reduced interfacial tension and penetrated the interfacial membrane, thereby facilitating the separation of O/W emulsion. Overall, these results indicate that the TCDA demulsifier shows promise for using in the demulsification of oily wastewater.