Effect of solvent immobilization on membrane separation of ibuprofen metabolite: A green and organic solvent analysis

• Immobilized solvents in membranes were used to remove ibuprofen metabolite.
• Both traditional and green solvents were used in flat and hollow fiber membranes.
• Process intensification occurs by concurrent membrane separation and regeneration.
• About 70 mL of canola oil removed an average of 80% drug from 40 L of water.
• Existing correlations for hollow fiber can be used for immobilized solvent.

The removal of pharmaceutical micropollutant 4-isobutylacetophenone (4-IBAP) from water using immobilized solvent was investigated. In the first part, extraction performance of flat membrane sheets with two immobilized solvents, a green solvent (canola oil) and octanol, was characterized in batch operation. Sodium hydroxide (≈0.1 M) solution was used to regenerate the saturated sheets with 4-IBAP. Experiments were conducted with varying aqueous feed pH, initial aqueous concentration of 4-IBAP, and the initial concentration of sodium hydroxide. While octanol had a faster initial extraction rate Kov = 1.83 × 10−7 m/s of 4-IBAP compared to canola oil, the flat sheet impregnated with canola oil exhibited better renewal capacity rinsing with NaOH stripping solution with mass transfer coefficient of 1.33 × 10−7 m/s in repeated experiments. In the second part, continuous extraction of 4-IBAP in the immobilized solvent and simultaneous regeneration of the solvent were carried out in a hollow fiber membrane contactor. Canola oil was impregnated into the pores of the membrane to extract 4-IBAP from the aqueous phase passing through the shell side of the fiber with simultaneous regeneration of the immobilized solvent using a 0.1 M NaOH stripping solution passing through the lumen of the fibers. Using this continuous membrane process with a green solvent, about 70–100 mL of canola oil removed an average of 80% of 4-IBAP from 40 L of water.