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, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate and 2-Hydroxyethyl-trimethylammonium L-(+)-lactate have been used for removal of RF. Various factors such as hydrophilicity/hydrophobicity of RTILs, concentration of used RTILs and pH of drug solutions, affecting removal of RF from its aqueous 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 have also been calculated and analyzed. Results showed that hydrophobicity plays a major role in extraction of RF from its aqueous solutions. The addition of just 2 % of hydrophobic RTIL; [BMIM][PF6] leads to almost complete precipitation (98.92 %) of RF in just 1 min. Also, it has been observed that extraction efficiency of [BMIM][PF6] is maximum at pH = 8.