Hydrophilic PEEK-WC hollow fibre membrane contactors for chromium (VI) removal

Hydrophilic hollow fibre membranes based on a modified polyether ether ketone (PEEK-WC) were prepared and used as membrane contactors for chromium (VI) removal from aqueous solutions using Aliquat-336 as carrier. The hollow fibres, having different morphologies and properties, were prepared by dry/wet phase inversion varying different parameters. It should be underlined that gamma-butyrolactone (GBL) was used as solvent for PEEK-WC for the first time. Several techniques were used to characterize the produced hollow fibre membranes in terms of morphology, porosity and mechanical strength. The prepared fibres were used for Cr(VI) extraction by a liquid/liquid membrane contactor working with an aqueous phase, containing K2Cr2O7 dissolved in water at concentration ranging from 15 to 100 ppm, and an organic phase, prepared using Aliquat-336 dissolved in kerosene in concentrations ranging from 10% to 50% (v/v). The influence of several parameters on the extraction process, such as the metal concentration, the pH of feed solution, the temperature and operating mode, was investigated. It was demonstrated that the prepared hydrophilic fibres are very effective for Cr(VI) removal, since an extraction value up to 99% was achieved. A comparison study with commercial polypropylene hollow fibres was also carried out.