Improved dye entrapment–liberation performance at electrochemically synthesised polypyrrole–reduced graphene oxide nanocomposite films

In this work, we have reported the application of electropolymerised polypyrrole–reduced graphene oxide (Ppy–RGO) nanocomposite films as an effective tool for entrapping and liberating the model dye Acid Red 1, and thereby proposed this as an ecofriendly treatment for dye-containing textile effluents. Initially, a polypyrrole–graphene oxide (Ppy–GO) nanocomposite film was anodically synthesised by an in situ electropolymerisation of pyrrole and GO. The Ppy–GO film was then electrochemically reduced to form a Ppy–RGO nanocomposite film. The synthesised nanocomposite films were characterised by spectroscopy, microscopy, surface analysis and thermogravimetry. Brunauer, Emmett and Teller surface area analysis showed a 7.4-fold increase in surface area of Ppy–RGO films compared to that of NO^-₃-polypyrrole films. In addition, based on tensile strength, Ppy–RGO films were demonstrated to be 12.7-folds mechanically stronger than NO^-₃–Ppy films. When Acid Red 1 was entrapped in these films, an entrapment efficiency of as high as 95% for Acid Red 1 was achieved at Ppy–RGO films, which is significantly higher than 56% achieved at Ppy films. Similarly, while liberating the entrapped Acid Red 1 from the Ppy–RGO nanocomposite films, a liberation efficiency of 73% was estimated compared to 36% from the Ppy films.