Gas permeation behaviour of CTA Polymer Inclusion Membrane (PIM) containing an acidic carrier for metal recovery (DEHPA)

CTA polymer inclusion membranes (PIMs) containing an acidic carrier (D2EHPA) were prepared and characterized by Fourier transform infrared resonance (FT-IR) spectroscopy and thermogravimetric analyses (TGA). The surface and cross-section morphology of the membrane was inspected by scanning electron microscopy (SEM). The gas transport properties of the membranes were obtained by using pure gases. The permeability and permselectivity coefficients of He, H2, N2, O2, CH4 and CO2 in PIMs were determined at two temperature values (25 °C and 50 °C), feeding single gases (purity level 99.998%) at atmospheric pressure and keeping the permeate side under vacuum (10-2 mbar). The gas permeability of the pure CTA polymer membrane increases with the temperature for all species considered and the permeation rate order is the following: He>H2 >CO2>O2>CH4>N2.The same trend with the temperature was also observed for the samples where the plasticizer (2-NPOE) and D2EHPA were added and a significant increase of the permeation rate of all gases was recorded. In most cases, the ideal permselectivity values, measured through these membranes, result lower than those calculated in neat polymer. However, CO2/H2 permselectivity increases during the addition of the plasticizer and extractant.