Comprehensive study of Acid Yellow 42 adsorption by green synthesized polypyrrole/tannicacid/iron nanocomposites

Abstract

ABSTRACT In this study, a green synthesis of polypyrrole/tannic acid/iron (PTI) nanocomposites was performed, using adsorption for the removal of Acid Yellow 42 (AY42) dye. The characteristics of PTI nanocomposites were defined applying scanning electron microscope (SEM), X-ray diffraction (XRD), zeta potential and Fourier transform infrared spectrometer (FTIR). The effects of different parameters such as pH, initial concentration of dye, temperature, adsorbent dose, and adsorption time were investigated. The process optimization was performed through L18 orthogonal array using the Taguchi design method. The initial concentration 30 ppm, temperature 55°C, adsorbent dose 0.06 g, adsorption time 30 min, and pH 2 were found as the optimal conditions for the removal of AY42 in batch mode. Kinetic studies illustrated that the AY42 dye adsorption process onto PTI nanocomposites followed the General order model. The obtained value of q e using the general order model (24.39 mg/g) is identical to the experimental value of q e (24.89 mg/g). The Langmuir adsorption isotherm and three-parameter isotherms (Hill, Sip, Redlich–Peterson, Khan, Toth, and Koble-Corrigan) show the best fit to AY42 dye adsorption data on PTI nano-adsorbent as compared to the two-parameter isotherm (Freundlich, and Temkin) models. The isothermal analysis showed that the maximum adsorption capacity of the Langmuir model would be as 116.5, 119.1, and 140.1 mg/g at 40, 50, and 60°C, respectively. Adsorption-desorption tests showed stable adsorption efficiency. The adsorption efficiency at the first stage is 98.19%, which reaches 95% at the seventh step.