Transport of Metallic Ions through Polyaniline-Containing Composite Membranes

Abstract

The extraction of Na + , Ni 2+ , and Cr 3+ using six different membranes made of polyaniline composited with high-impact polystyrene, which differ in the doping agent and/or the preparation method, has been investigated. The swelling and ion-exchange capacities of the six polyaniline composited with high-impact polysterene (HIPS/PAni) membranes have been determined and compared with that of the commercial Selemion membrane. Electrodialysis tests using a five-compartment cell evidenced that the extraction of ions depends on the electronic structure of the SO 3 -groups, which is modulated by the doping agent, and on both microstructure and electrical resistance of the membrane, which are regulated by the preparation method. The transport of ions through HIPS/PAni and Selemion membranes was found to be comparable. Quantum mechanical calculations on model complexes have been performed to characterize the electronic structure of the dopants. Results indicate that the strength of the interaction between the different doping agents and the polyaniline is inversely proportional to the concentration of negative charge in the SO 3 -group of the former. Moreover, both the binding energy and the distribution of charges calculated for dopant · · · PAni complexes have been compared with those predicted for dopant · · · metallic ion complexes.

New Sulfonated Polystyrene and Styrene–Ethylene/Butylene–Styrene Block Copolymers for Applications in Electrodialysis

“…For comparison, Na + extraction results recently obtained for HIPS/PAni membranes using the same experimental conditions (i.e., PAni doped with CSA, i lim = 3.5 mA•cm −2 and area of the membrane = 10 cm 2 ) have been included in Table 4. 28 Furthermore, electrodialysis control measurements have been also performed using Selemion CMT (Figure 1f), which is currently considered among the most advanced commercial membranes. For the membranes prepared in this work, the largest transport of Na + was found for the PS/SEBS (24.8%), the percent extraction obtained for HIPS/SEBS being ∼5% smaller.…”

“…Moreover, the percentage of Na + extracted using the membranes fabricated in this study ranges from 24.8% to 19.9%, which represents a very noticeable improvement with respect to HIPS/ PAni membranes previously studied. 28 Thus, SEBS modulates the impact resistance of HIPS facilitating the ion transport and, therefore, this triblock copolymer should be considered as a very effective material for the fabrication of CEMs. …”

Development of quaternarized poly(vinyl alcohol) anion‐exchange membranes for applications in electrodialysis

“…The tests were performed by applying a current density of 3.5 mA/cm 2 for all the processed membranes, with a 240 min test time, using a standard method reported elsewhere . All assays were performed at room temperature in duplicate.…”

Ion Exchange Membranes for Electrodialysis: A Comprehensive Review of Recent Advances

“…[ [103][104][105] originated from the components in the composite. The organic counterpart of the composite membrane provides opportunities of chemical modifications, structure flexibility, and processibility on large scale.…”