Electro-separation of synthetic azo dyes from a simulated wastewater using polypyrrole/polyacrylonitrile conductive membranes

Polypyrrole/polyacrylonitrile (PPy/PAN) conducting electroactive polymer membranes (CEPMs) were fabricated and evaluated for their potential use as electro-separation of synthetic azo dyes from simulated wastewaters. The PAN substrate films were prepared from a N,N-dimethylformamide (DMF) solution at 25 °C. The PPy/PAN CEPMs were fabricated by synthesizing of PPy layer on both sides of the PAN substrate films from an ethanol solution containing 5 wt% pyrrole monomer using aqueous FeCl3 solution as a strong oxidant. The structure and morphology of the prepared PPy/PAN membranes were investigated using Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The electrical conductivity of PPy/PAN CEPMs was measured at room temperature. The PPy/PAN CEPMs were installed in a designed electrochemical cell including two separate compartments, each with a capacity of 750 cm3. The effect of applying electrical current across the prepared PPy/PAN CEPMs on the transport flux of synthetic azo dyes, i.e. Basacryl Red GL, Basacryl Blue GL and Direct Yellow 12 from the simulated wastewater was investigated. Electrochemically controlled transport of the dyes was monitored by measuring the dye concentrations in the permeate solution. The diffusion coefficients of the dyes in the PPy/PAN membranes were determined by the concentration profile of pseudo-steady state data points.