Synthesis of polymer-metal oxide (PANI/ZnO/MnO2) ternary nanocomposite for effective removal of water pollutants

Abstract

Current study describes the synthesis of novel PANI/ZnO/MnO2 ternary nanocomposite material and its application for catalytic reduction of 4-nitrophenol (4-NP) in presence of NaBH4, and adsorptive elimination of crystal violet (CV) dye from the aqueous phase. Due to the higher specific surface area (64 m2 g−1), and pore volume (0.3085 cm3 g−1) mesoporous nature of the prepared ternary nanocomposite (TNC), it exhibited amazing reduction and adsorption ability. 99.73 % of the total volume of pores is contributed by the mesopores for the constructed highly porous and granular TNC. 98.13 % of the yellow-colored 4-NP was catalytically reduced to colorless 4-aminophenol (4-AP) in 10 min of reaction time over TNC catalyst and the reduction reaction followed the pseudo-second-order kinetics with the 0.219 min−1 of kinetic rate constant. On the other hand, 96.13 % of CV dye was eliminated by adsorption over TNC in 60 min. The adsorption process followed the pseudo-second-order kinetics as validated by the qe and R2 values, and the kinetics of the adsorption reaction is found to be concurrently channeled by intraparticle and film diffusion processes, however, not directed by pore diffusion on heterogeneous adsorption sites. The adsorption equilibrium experimental data showed better fittingness to the Langmuir isotherm which validated the monolayer adsorption of CV dye on the homogeneous surface. The thermodynamic study confirmed the feasibility and spontaneity of the adsorption process, and the adsorption of CV over TNC is endothermic which increased disorderliness at the interface of the nanocomposite. Thus, the prepared TNC is a prominent candidate for catalytic and adsorption applications, and it can be utilized as an efficient material for water remediation purposes.