PVC/EVA-based polymer inclusion membranes with improved stability and Cr(VI) extraction capacity: Water plasticization effect

• Published in: Journal of hazardous materials 2022-08, Vol.436, p.129069-129069, Article 129069
• Main Authors: Sellami, Ferhat, Kebiche-Senhadji, Ounissa, Marais, Stéphane, Fatyeyeva, Kateryna
• Format: Article
• Language: English
• Subjects: Cr(VI) transport; EVA; Polymer inclusion membrane; PVC; Water plasticization
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.129069

Polymer inclusion membranes (PIMs) are far investigated for their ability to extract heavy metals and small organic compounds from aqueous media. Polyvinyl chloride (PVC) is one of the most widely used base polymers for the PIM elaboration. However, its use requires the incorporation of a relatively expensive liquid plasticizer. In the present work, poly(ethylene-co-vinyl acetate) (EVA) serves as a polymer plasticizer for the elaboration of PIMs based on PVC as a base polymer and Aliquat 336 as a carrier. The composition of PIMs was optimized in terms of the PVC/EVA ratio and the vinyl acetate (VA) groups content (x) of EVA (i.e. EVAx). Physical-chemical properties of the resulting membranes are analyzed and correlated with their structure. The results of SEM analysis revealed miscible PVC/EVA70 blends (i.e. with 70 wt% of VA groups) and partially miscible PVC/EVA40 blends. The plasticizing effect of the EVA copolymer was confirmed by the tensile test results. The results of transport measurements showed that PIMs containing EVA40 and PVC are more efficient for the Cr(VI) extraction than those with only PVC. Thus, EVA40 can effectively replace the conventional liquid plasticizers while improving the Cr(VI) permeability. Besides, it is stated that EVA40-based PIMs are more stable as compared with conventional PIMs due to the water plasticizing effect. After the membrane optimization, the highest Cr(VI) transport flux (54.7 µmol·m-2·s-1) was measured. Moreover, the addition of 10 wt% of tetradecanol causes the increase of the water plasticizing effect and allows obtaining a PIM with high stability (up to 24 cycles) required for the membrane long-term operation. [Display omitted] •Novel polymer inclusion membranes based on PVC/EVA blend were successfully prepared using Aliquat 336 as a carrier.•EVA polymer is used as an alternative to conventional liquid plasticizers.•Water molecules induce the membrane plasticization and long-term stability.•PVC/EVA membrane reveals improved stability and Cr(VI) permselectivity as compared with PVC- and CTA-based membranes.•Incorporation of tetradecanol (10 wt%) significantly improves PVC/EVA membrane stability (up to 24 cycles).