Kinetic model and thermodynamic study of Acid Red 1 entrapment at electropolymerised polypyrrole films

Md Mominul Haque, Danny K Y Wong*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


This work is focussed on the determination of a kinetic model and the thermodynamic study of the electrochemical entrapment of the model azo dye, Acid Red 1, at conducting polypyrrole films, which is proposed as a potential green technology for treatment of azo dyes in industrial effluents. The entrapment kinetic data were found to follow a pseudosecond order model involving an intra-particle diffusion. However, the equilibrium data obtained for Acid Red 1 entrapment at polypyrrole did not obey any common surface adsorption models such as the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. Accordingly, the entrapment process may lead to an enhanced quantity of dye embedded in a polypyrrole film, making it a more effective and efficient technology than those involving only adsorption. Similarly, dye leakage from polypyrrole film surface to a sample matrix will be easily prevented. For this treatment process, a negative δG{ring operator} range between -1.46±0.78 and -2.94±0.24kJmol-1 at the corresponding temperature range of 298-318K, and a δH{ring operator} of 20.5±2.5kJmol-1 indicate a spontaneous and endothermic entrapment process. Also, a positive δS{ring operator} (73.6±8.2Jmol-1K-1) reveals increased randomness of the interface and an affinity of Acid Red 1 towards polypyrrole films. A low activation energy (7.67±0.80kJmol-1) confirms a physical process for Acid Red 1 entrapment at polypyrrole films.

Original languageEnglish
Pages (from-to)188-194
Number of pages7
JournalJournal of Colloid and Interface Science
Publication statusPublished - 1 Nov 2015


  • Dye entrapment
  • Acid Red 1
  • Polypyrrole films
  • Kinetic model
  • Thermodynamics

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