extraction of methylene blue (mb) from water solutions by a poly(vinyl chloride) based polymer inclusion membrane incorporating bis (2-ethylhexyl)phosphoric acid as the extractant

Polymer inclusion membranes (pims) have attracted the attention of many researchers around the world due to their high capability in the process of extraction, separation and removal of metal ions and also having special privileges compared to other liquid membrane methods [2]. the present paper reports on the first application of a polymer inclusion membrane (pims) for the extraction of methylene blue (mb). pims containing of 50% w/w poly(vinyl chloride) as the base polymer and 50% w/w bis(2-ethylhexyl)phosphoric acid (d2ehpa) as the extractant. the optimized pim was able to efficiently extract 92% of mb from 50 ml water solution containing 20 mg/l-1 (mb) at ph=3 after 2h. back extraction of mb from 50 ml of solution containing 0.15 mg/l-1 oxalic acid over time 2h. to achieve the highest efficiency, the parameters affecting the extraction process were investigated and optimized. these parameters were time, effect of shaking rate, ph, real sample, stability of the pim, extraction stoichiometry. the investigated pim exhibited excellent performance stability in 11 extraction/back-extraction cycles. the membrane was used for recovery of mb from some real samples. [1, 2]