Polypyrrole/CoFe2O4 Nanocomposite for the Removal of Basic Blue 3 Dye From Wastewater: Kinetic, Adsorption Isotherm, and Thermodynamic Study

ABSTRACT Water contamination constitutes a substantial global issue that affects the environment. Adsorption materials have demonstrated huge potential in wastewater treatment. For the efficient removal of a cationic dye, basic blue 3 (BB3), a polypyrrole‐coated cobalt ferrite (PPy@CoFe 2 O 4 ) magnetic nanosorbent is prepared via in situ polymerization of pyrrole on CoFe 2 O 4 nanoparticles. Scanning electron microscopy (SEM) analysis demonstrated spherical nanoparticles with sizes around 50 nm, which was further supported by XRD data. Zeta‐potential study showed that the surface charge of PPy@CoFe 2 O 4 is negative in alkaline media and positive in acidic media. The adsorption system adhered to a pseudo‐second‐order kinetic model, with the equilibrium time being determined at 50 min. The Langmuir model accurately simulated the adsorption isotherms. Under optimal conditions (pH—8.0, volume—30 mL, adsorbent dose—0.67 g/L, and at 303 K temperature), the maximum monolayer adsorption capacity of PPy/CoFe 2 O 4 is 130.1 mg g −1 . Even after five desorption–adsorption cycles, the removal efficiency remained above 92%. Negative Δ G ° and Δ H ° indicate spontaneous BB3 adsorption onto PPy/CoFe 2 O 4 , decreasing with temperature. These findings demonstrate that the PPy/CoFe 2 O 4 composite is a highly effective adsorbent with broad potential applications for treating wastewater containing cationic dye.