polymer inclusion membrane composed of cellulose triacetate and trioctylamine for removal of the anionic dye congo red

Organic dyes are pollutants which widely used in several industries that finally dumped as wastewater, contributing to environmental and water pollution [1]. synthetic dyes, including azo dyes, are considered to be more toxic, mutagenic, and carcinogenic in nature. therefore, the removal of the dyes from wastewaters is a serious challenge. congo red is an anionic type of the azo dyes [2]. a variety of the physical, chemical and biological techniques was employed for the removal of the pollutants from wastewaters. membranes based process have attracted attention as a valuable technology for many industries. polymer inclusion membranes (pims) are a type of liquid membranes which have been widely used for purifying wastewaters. pims are thin films that are formed by mixing an extractant, a base polymer and sometimes a plasticizer, in an organic solvent [3]. the films which are transparent, flexible, homogeneous and mechanically strength is suitable for the extraction experiments. in the present study a pim containing 40% w/w cellulose triacetate (cta) as the base polymer, 25% w/w trioctylamine (toa) as the extractant, and 35% w/w tributyl phosphate (tbp) as a plasticizer were fabricated, characterized and used for the removal of congo red from aqueous solution [3]. the average mass and thickness of a circular segments (3.5 cm in diameter) of the ten pims which employed in the experiments were 0.07306±0.00292 g and 0.0748±0.0054 mm, respectively. sample solution ph, contact time, shaking rate, type and concentration of the electrolyte and initial concentration of dye solution, as effective parameters on the process efficiency, were evaluated. the results indicated that, highest extraction percentage was achieved from 50 ml of a solution containing 20 mg l-1 of congo red in ph = 7 with 200 rpm shaking rate in 6 h. isotherm and kinetic of the process were studied and shown that the extraction isotherm and kinetic were well described by the langmuir isotherm and pseudo-second order kinetic model, respectively.