Room temperature ionic liquid based extraction and recovery of Rifampicin from water and its mechanistic study

Abstract

An attempt has been made to develop a fast, efficient and eco-friendly process for extraction of drug; Rifampicin (RF) from its aqueous solutions using room temperature ionic liquids (RTILs). RTILs viz. 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf₂]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]) and 2-Hydroxyethyl-trimethylammonium L-(+)-lactate ([(C₂H₄OH)-(CH₃)₃N][Lactate])/CL have been applied for removal of RF. Factors affecting removal of this contaminant from its aqueous solution such as effect of hydrophilicity/hydrophobicity of RTILs, concentration of used RTILs and effect of pH of drug solution have been studied to investigate mechanism of extraction process. Partition coefficient,  of RF between RTILs and aqueous phases as well as its extraction efficiency E% have been calculated and analyzed.  Results showed that hydrophobic RTILs; [BMIM][PF₆] and [EMIM][NTf₂] are more efficient in extraction of RF from its aqueous solutions in just 1 minute as compared to hydrophilic RTILs; [BMIM][BF₄] and [(C₂H₄OH)-(CH₃)₃N][Lactate].