Methylene blue elimination from contaminated water solutions using a polyvinyl chloride based polymer inclusion membrane containing bis(2-ethylhexyl)phosphoric Acid

Organic dyes such as methylene blue (MB) are known as important water and environment pollutants. Several techniques have been employed for removing this dye from contaminated aqueous solutions. In this study, polymer inclusion membranes composed of polyvinyl chloride (PVC) and bis(2-ethylhexyl)phosphoric acid (DEHPA), respectively as the base polymer and extractant, without requiring to additional plasticizing reagent are prepared and assessed for the removal of methylene blue from aqueous solutions. The membrane with a composition of 50 wt.% of PVC and 50 wt.% of DEHPA is found to be flexible, physically stable. This PIM shows the best performance for the MB elimination from the solutions. Various techniques including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy SEM), atomic force microscopy (AFM), contact angle measurements, thermogravimetric analysis (TGA), and stress-strain analysis are employed for characterizing the optimized PIM. The parameters affecting the removal of MB from the solutions are optimized. It is found that a circular disc PIM with 3.5 cm diameter, an average mass of 0.0890±0.0046 g, with a thickness of 72.0±0.8 m removes quantitatively MB from 50 mL aqueous solution adjusted to pH 3, after 120 min orbital shaking. The PIM is stable for 6 times consecutive cycles. The kinetics of process is obeyed pseudo second-order model, while the Langmuir model interpret well the isotherm of the MB removal.