Extraction of diclofenac and tetracycline from simulated aqueous wastewater using ionic liquids as carriers by pseudo-emulsion hollow fiber strip dispersion

Abstract

Diclofenac (DCF) and Tetracycline (TC) are used as non-steroidal anti-inflammatory drugs (NSAID) and antibiotics, respectively. Both these drugs, when released into the environment through various routes, cause adverse effects on aquatic life and humans. The traditional approaches employed for the removal of these drugs have various drawbacks and adverse effects on the environment. The present work gives a deeper insight into the potential application of ionic liquids as carriers in the pseudo-emulsion hollow fiber strip dispersion (PEHFSD) technique for removing these compounds from the simulated aqueous solution. The extraction of DCF and TC was performed using different organic carriers, Di-(2-ethylhexyl)phosphoric acid (D2EHPA), Tributyl phosphate (TBP), Trioctyl amine (TOA), and also using ionic liquids, 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide ([EMIM][[TFSI]), 1-Butyl-1-methylpyrrolidinium Bis(trifluoromethanesulfonyl)imide ([BMPy][[TFSI]) and 1-Octyl-3-methylimidazolium Hexafluorophosphate ([OMIM][PF₆]). Comparing the performance of all carriers, it was found that [OMIM][PF₆] showed 100 % extraction of DCF, while for TC, the maximum extraction obtained was 91.85 %. Effective extraction of DCF and TC up to the 4^th cycle indicated the stability of the membrane phase inside the micropore. Membrane phase and pseudo-emulsion are also characterized by FTIR, micrograph images and Turbiscan. A recyclability study of pseudo-emulsion showed that with the increase in the number of cycles for extraction, the stripping phase was gradually saturated by extracting feed (DCF/TC), which led to a drop in extraction efficiency.