First Report on a Solvent-Free Preparation of Polymer Inclusion Membranes with an Ionic Liquid

Abstract

A novel and environmentally-friendly procedure for the preparation of polymer inclusion membranes (PIMs) containing an ionic liquid is presented for the first time. Traditionally, PIMs are prepared by a solvent casting method with the use of harmful organic solvents. Here we report a new solvent-free procedure based on a thermal-compression technique which involve the melting of the components of the PIM and the application of a high pressure to the melted specimen to form a flat-sheet film. In our study, we have tested different polymers, such as two cellulose derivatives as well as two thermoplastic polymers, polyurethane (TPU) and poli ε-caprolactone (PCL). The ionic liquid (IL) trioctylmethylammonium chloride (Aliquat 336) has been used to produce PIMs with a fixed composition of 70% polymer–30% IL (w/w). Both TPU and PCL polymers provide successful membranes, which have been thoroughly characterized. PIMs based on the polymer PCL showed a high stability. To test whether the properties of the IL were affected by the preparation conditions, the extraction ability of Aliquat 336 was investigated for both PCL and TPU membranes in terms of Cr(VI) extraction. Satisfactory values (90% extraction) were obtained for both membranes tested, showing this novel procedure as a green alternative for the preparation of PIMs with ILs.

Graphene Oxide-Doped Polymer Inclusion Membrane for Remediation of Pharmaceutical Contaminant of Emerging Concerns: Ibuprofen

“…A critical and well-known drawback of PIM is its chemical instability due to leaching out of the carrier from the membrane into the aqueous solution. The rate of mass loss of the membrane under a specific condition, such as the pH of the media and membrane constituents, is strongly related to the loss of efficiency of the membrane during application [41,61]. The result obtained for the chemical stability of the optimum PIM (G3) and the control PIM (GO) in acidic, neutral, and alkaline solutions is presented in Figure 5.…”

Recent advances in polymer membranes employing non-toxic solvents and materials

“…There are two routes to avoid using these toxic solvents. The "solvent-free" method for polymer fabrication [41][42][43][44] is relatively green and related to the properties of polymer materials that will be discussed in Section 3.3. The other method is to use non-toxic or harmless solvents for membranes.…”

Statistical analysis and optimal design of polymer inclusion membrane for water treatment by Co(II) removal

“…There are several techniques to remove the cobalt ions from wastewater [6] including adsorption [7][8][9], solvent extraction [10,11], liquid membranes (i.e., SLM) [12] and polymer inclusion membranes (PIMs) [6]. PIMs as a simple technique for preparation [13,14], possess high stability, selectivity and efficiency, as well as they can be easily designed based on the nature of heavy metals [15]. On the other hand, a high percentage of extractant is not required in this technique, which introduces this strategy as an environmentally green method [16].…”