removal of acid fuchsin dye by using pvc-based polymer inclusion membranes containing bis(2-ethylhexyl)phosphoric acid

Organic dyes are known as important water and environmental pollutions [1]. this stimulates research groups to find efficient, cost effective and simple methods for the removal of dyes from contaminated environmental samples. acid fuchsin (af) is a toxic dye with a great carcinogenic potential [2]. several techniques such as adsorption, ion exchange, photochemical degradation and membrane separation have been already employed for removing organic dyes from contaminated samples. polymer inclusion membranes (pims) are composed of a base polymer, an extractant and often a plasticizer. the selected composition of pims paly a decisive role on their selectivity and efficiency towards a target species. it also determines the physical properties of pims [3]. the possibility to employ different type of extractants allows accessing to a great variety of selectivity for separation aims by pims [4]. in this communication, the extraction of af from aqueous solutions by a non-plasticized polymer inclusion membrane is described. the optimized membrane composed of 50/50 wt% of polyvinyl chloride (pvc) base polymer and bis(2-ethylhexyl) phosphoric acid (dehpa) as extractant. the prepared pim was homogenous, transparent, and flexible. the average mass and thickness of a circular segment (3.5 cm in diameter) of the investigated pims were 0.09026±0.0059 g and 0.0801±0.0068 mm, respectively. the parameters affecting the extraction process such as ph, extraction time, shaking rate, type and concentration of the electrolyte and af initial concentration were optimized. the results showed that an extraction efficiency of 96% is achieved from 50 ml of a solution containing 20 mg l-1 of af adjusted to ph = 3 with 200 rpm shaking rate in 2 h. the loaded pims were stripped by using a solution of 0.5 m nitric acid. isotherm and kinetic investigations of the process were studied. these studies indicated that the extraction is well described by the langmuir isotherm, and pseudo-second order kinetic model suitably interpreted the process kinetics.