Highly efficient and selective transport of methylene blue through a bulk liquid membrane containing Cyanex 301 as carrier

A bulk liquid membrane (BLM) system contained bis(2,4,4-trimethyl pentyl) dithiophosphinic acid (cyanex 301) as carrier and Triton-X-114 as nonionic surfactant was utilized for transport of methylene blue (MB). Cyanex 301 was an efficient and selective carrier for the uphill transport of MB through chloroform and n-hexane in the bulk liquid membrane. Maximum extraction (85%) was observed at 0.0002 M concentration of Cyanex 301 in the membrane phase and 0.2 M concentration of H2SO4 in the receiving phase after 7 h. The selectivity and efficiency of MB transport from aqueous solutions contained mixtures of methylene blue (cationic dye) and methyl orange (anionic dye) were studied. The effect of parameters influencing the transport of MB such as pH and concentration of dye in the feed solution, carrier and surfactant concentrations in the membrane, type of organic solvent, nature and composition of the receiving phase, stirring speed and transport time on kinetic parameters of MB transport were elucidated for the interface assuming two consecutive, irreversible first-order reactions. The analysis of the accumulation of MB in the liquid membrane phase and the rate-controlling step under different experimental conditions were discussed. Finally, the proposed liquid membrane was successfully applied for MB separation from waste water.

► A new liquid membrane was utilized for dye (methylene blue) removal from solution.
► The system contained cyanex 301 as carrier.
► The carrier acts as an efficient and selective agent for uphill transport of dye.
► Maximum extraction (85%) was observed at optimum operating conditions.
► Optimum experimental conditions were obtained for the process.