Application of an Ionic Liquid as a Bulk Liquid Membrane for Nicotinic Acid Separation: Determination and Optimization Study

Nicotinic acid (NA) is a crucial molecule that is commonly employed in the pharmaceutical, biochemical, and food sectors. It is essential to separate nicotinic acid from both industrial effluents and production broth. In this study, the separation of NA from aqueous media by bulk ionic liquid membrane (BILM) has been investigated. 1-Butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], has been utilized as a membrane solvent and tributyl phosphate (TBP), has been utilized as a carrier in ionic liquid membrane. The effects of nicotinic acid concentration (0.02-0.1 mol/L) in aqueous solution, the carrier concentration (0-2 mol/L) in ionic liquid membrane, and the stripping phase type (water/NaOH) and NaOH concentration (0.1-0.2 mol/L) have been examined. Furthermore, Box-Behnken design (BBD) has been applied to determine the relationship between these parameters. The effects of these parameters on the separation were determined by calculating the feed and stripping phase efficiencies. Maximum extraction and stripping efficiencies have been obtained at optimum BILM conditions of nicotinic acid concentration in aqueous solution of 0.02 mol/L, carrier concentration ionic liquid membrane of 2 mol/L, and NaOH concentration of 0.2 mol/L. These efficiency values have also been determined as 90.05% (experimental value) and 95.21% (BBD value) for extraction and 93.92% (experimental value) and 82.36% (BBD value) for stripping, respectively.