Recovery of petroleum sulfonate from petrochemical dispersion by modified three-compartment electrodialysis

Abstract Modified three-compartment electrodialysis (MTED), a novel process containing intermediate compartment with fluorinated ion exchange membrane, has been applied to the recovery of petroleum sulfonate from petrochemical dispersion. The fluorinated ion exchange membrane has higher degree of crosslinking than heterogeneous ion exchange membrane. The petroleum sulfonate is separated from the petrochemical dispersion during anion migration by the different steric effect of ion exchange membranes. In order to reduce the membrane fouling and increase the current efficiency, the 50 nm ceramic membrane was utilized as the pretreatment of MTED. The result indicated that in total of 99.4 wt% of petroleum sulfonate in the petrochemical dispersion could be recovered at the applied voltage 25 V, flux rate 30 L/h, temperature 40 °C and initial concentration 7.5 wt% (NH 4 ) 2 SO 4 . Simultaneously, the (NH 4 ) 2 SO 4 solution without petroleum sulfonate was received in concentrate compartment of MTED. The results verified the feasibility of MTED on separating the petroleum sulfonate and inorganic salt in petrochemical dispersion, and provided important technical basis for a large-scale procedure of MTED in petrochemical dispersion treatment.