Diclofenac Transport through Stagnant Sandwich and Supported Liquid Membrane Systems

Abstract

The removal of a drug, diclofenac (DCF), from aqueous media by using a supported liquid membrane (SLM) and a stagnant sandwich LM (SSwLM) has been investigated. The two systems were compared in terms of flux and stability. Optimal chemical conditions were determined by means of liquid-liquid extraction tests. In the transport tests, the obtained results indicated a higher initial flux J 0 (2.4 vs 1.3 mmol/h‚m 2 ) and a faster transport (counter transport reached at 1.75 vs 26.3 h) for the SLM system than for the SSwLM system. The diclofenac transport in the SLM from the feed to the strip was quite complete after 3 h, whereas in the SSwLM, only 39% of the initial drug was recovered in the strip phase after 30 h. Higher system stability was obtained using the SSwLM system (>120 vs 47.5 h). The overall results obtained in this work showed that liquid membrane systems can effectively be used to remove pharmaceuticals present at low concentration in wastewaters.

Flux enhancement of stagnant sandwich compared to supported liquid membrane systems in the removal of Gemfibrozil from waters

“…Data from L-L extraction tests were used to calculate the extraction percentage (E%) from the equation reported in our previous works [26][27][28].…”

“…The SSwLM system was prepared by injection of the organic phase, previously sonicated (Transonic T 460/H, from Hellma) for 20 min to eliminate the presence of air bubbles, inside a chamber with a volume of 57.6 L and initial thickness of 100 m. The chamber was obtained by interposition, between two membrane supports, of a commercial triacetate sheet employed for transparency film on which a rectangular surface was opportunely cut out, thus the remaining part acted as a spacer at the periphery of the organic liquid phase [26,27]. The sandwich so obtained was assembled in the same permeation cell of the SLM.…”

“…Feed and strip phases were recirculated thanks to two peristaltic pumps with equal flow-rates of 75 mL min −1 in the two circuits made with tygon pipes (Masterflex, 6429-15 Tygon LFL, MFG By Norton) [26][27][28]. The feed and strip reservoirs had a volume of 75 mL and were immersed in a thermostated water bath at 25 • C temperature, so that the process took place in isothermal condition, at the same temperature used in solubility and L-L extractions tests.…”

“…In the exponential method (the first one) J(t) evaluation was based on the following equation introduced in our previous works [26,27] obtained by differentiating Eq. (3) and substituting it in Eq.…”

“…In our previous works [26,27] we studied the use of Stagnant Sandwich Liquid Membranes (SSwLM) as a possible alternative to minimize the organic solvent loss. In this configuration, the organic LM phase is confined between two hydrophilic membranes, that separate feed and strip phases.…”