Removal of As(V) by PVDF hollow fibers membrane contactors using Aliquat-336 as extractant

In this work, the removal of As(V) from an aqueous stream by non-dispersive solvent extraction in a hollow fibre membrane contactor was investigated. To this purpose, microporous hydrophobic poly(vinylidene fluoride) hollow fibres were prepared by the dry/wet spinning technique. Fibres were spun, changing the pore forming additives, to obtain micro-porous sponge-like structure membranes, with pore diameters of about 0.2 μm and porosity of 80%. The produced fibres were used to perform As(V) extraction experiments in a membrane contactor device, using Aliquat-336 as extractant. Different tests were carried out in order to study the effect of temperature, initial concentration, pH of the feed solution and membrane properties. The results showed that the extraction of As(V) by non-dispersive solvent extraction was influenced by the pH of the feed, with an optimum reached for neutral values, increased with the arsenic content in the feed and was not affected by temperature. The extraction was favoured by working with thinner membranes. The highest removal of arsenic achieved was around 70% after 6 h of operation. The produced fibres kept their performance for all the experimental activity, giving reproducible results with time.