Electrodriven transport of chromium (VI) using 1-octanol/PVC in polymer inclusion membrane under low voltage

Abstract

The transport behaviour of Cr(VI) from the aqueous phase through a polymer inclusion membrane (PO-PIM) containing 1-octanol (OCT) as carrier and polyvinyl chloride (PVC) as support at a low voltage drive (0–30 V) is investigated. The correlation between the OCT content and the surface or cross-sectional micromorphology of PO-PIM is also analysed. Under optimised mass transfer conditions, the transmission rules and mechanism of Cr(VI) under an electrodriven membrane extraction system are investigated. Results show that the surface and interior of PO-PIM exhibit micro/nanopores with an OCT content exceeding 50% (w/w). The mass transfer behaviour of OCT to Cr(VI) conforms to the proton coupling mechanism. The voltage drive effectively solves the residue problem of Cr(VI) in the membrane phase, and the permeability coefficient (P) of PO-PIM to Cr(VI) increases with the voltage. The P of PO-PIM to Cr(VI) reaches 43.38 μm·s−1 at 30 V when the OCT content is 82.8% and the feed and stripping phases are pH 2.0 HCl solution and 0.1 mol·L−1 NaOH solution environments, respectively. After the introduction of hydrophobic kerosene into the membrane phase, the stability of the membrane is significantly enhanced. When the composition ratio of kerosene/OCT/PVC is 0.8:2.2:0.5 and the voltage is 30 V, the initial current density rise is only 0.1 A and the pH increases slightly with the repeated use of PO-PIM to four cycles.