Investigation of Polypyrrole and Polypyrrolepolyethyleneimine as Adsorbents for Methyl Orange Dye Adsorption

The present study has explored the adsorption properties of polypyrrole-based adsorbents (polypyrrole and polypyrrole-polyethyleneimine composite) as novel conducting polymers in adsorbing methyl orange (MO) (an anionic dye) effectively from aqueous solution. The adsorption characteristics of the prepared polymer-based adsorbents were characterized by BET, FTIR, FESEM, and XRD methods. The effectiveness of PPy-based adsorbents for MO dye adsorption was examined using the batch adsorption method. Different parameters were changed during the adsorption process, including contact time, solution pH, and adsorbent dosage. The highest BET surface area of the PPy-PEI composite was found to be 11.85 m2/g, which is much greater than that of the pristine PPy having 8.54 m2/g. The dye removal performance was obtained to be 79.1 % and 98.8 %, by pristine PPy adsorbent and PPy-PEI adsorbent, respectively, at the optimum condition of pH 3, adsorbent dosage of 0.1 g with a contact time of 120 minutes. The Langmuir isotherm model explained the adsorption data better than the Freundlich isotherm model, and the pseudo-second-order model adequately explained the kinetic data for both the adsorbents. The regeneration investigation demonstrated the effectiveness of reusing PPy-PEI composite adsorbents for up to three successive adsorption-desorption cycles. The prepared PPy-PEI composite adsorbents appeared to be very much effective in removing anionic dyes from aqueous solutions.