title: Conducting polypyrrole films as a potential tool for electrochemical treatment of azo dyes in textile wastewaters.
abstract: In this paper, we demonstrate conducting polypyrrole films as a potential green technology for electrochemical treatment of azo dyes in wastewaters using Acid Red 1 as a model analyte. These films were synthesised by anodically polymerising pyrrole in the presence of Acid Red 1 as a supporting electrolyte. In this way, the anionic Acid Red 1 is electrostatically attracted to the cationic polypyrrole backbone formed to maintain electroneutrality, and is thus entrapped in the film. These Acid Red 1-entrapped polypyrrole films were characterised by electrochemical, microscopic and spectroscopic techniques. Based on a two-level factorial design, the solution pH, Acid Red 1 concentration and polymerisation duration were identified as significant parameters affecting the entrapment efficiency. The entrapment process will potentially aid in decolourising Acid Red 1-containing wastewaters. Similarly, in a cathodic process, electrons are supplied to neutralise the polypyrrole backbone, liberating Acid Red 1 into a solution. In this work, following an entrapment duration of 480 min in 2000 mg L(-1) Acid Red 1, we estimated 21% of the dye was liberated after a reduction period of 240 min. This allows the recovery of Acid Red 1 for recycling purposes. A distinctive advantage of this electrochemical Acid Red 1 treatment, compared to many other techniques, is that no known toxic by-products are generated in the treatment. Therefore, conducting polypyrrole films can potentially be applied as an environmentally friendly treatment method for textile effluents.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia.
authors.forename: Md Mominul
authors.initials: MM
authors.lastname: Haque
authors.affiliation: Samadha Pacifica Pty Ltd, Woonona, NSW 2517, Australia.
authors.forename: Warren T
authors.initials: WT
authors.lastname: Smith
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia. Electronic address: Danny.Wong@mq.edu.au.
authors.forename: Danny K Y
authors.initials: DK
authors.lastname: Wong
mesh_terms: D001391:Azo Compounds / Q000032:analysis* / Q000737:chemistry; D007220:Industrial Waste; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013784:Textiles; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D007220:Industrial Waste; D011108:Polymers; D011758:Pyrroles; D062065:Wastewater; D014874:Water Pollutants, Chemical; C067635:polypyrrole
keywords: Acid Red 1; Dye entrapment–liberation; Electrochemical treatment; Environmentally friendly treatment; Polypyrrole films