Supported liquid membranes for the removal of pharmaceuticals from aqueous solutions

Abstract

In the following study, the extraction of three pharmaceutical compounds: Diclofenac (DCF), ibuprofen (IBP), and carbamazepine (CBZ) by liquid-liquid extraction and their transport by supported liquid membrane (SLM) using different commercial extractants (Cyanex 923 (Cy923), trioctylamine (TOA), tributylphosphate (TBP), and Versatic Acid 10 (neodecanoic acid)) were evaluated.Cy923 was demonstrated to be an efficient extractant for diclofenac and ibuprofen removal through a facilitated transport mechanism from the aqueous feed phase to the aqueous stripping phase using hydroxide ions as stripping agent. Around 80 % of these pharmaceuticals were extracted in 4 h with 10 % of Cy923 and without extreme alteration in the pH. As for carbamazepine, the stripping conditions were achieved with 10 % of Versatic Acid 10. Variation of concentration of different extractants indicates that a higher transport of diclofenac can be obtained by using 40 % of Cy923. In addition, two commercial polymeric supports (PTFE and PVDF) were compared for the selected operational conditions. Finally, the lifetime of the membrane was extended by soaking the polymeric material in the organic solution under vacuum for 24 h and compared with the membrane prepared with an ultrasound-assisted method. Supported liquid membranes present many advantages and can easily be manipulated and integrated for the treatment of persistent pharmaceutical contaminants from water.