CuO/PANI nanocomposite: an efficient catalyst for degradation and reduction of pollutants

Textile dyeing releases over 80% of industrial effluents without proper treatment. Dye discharged into effluents typically needs degradation before release into aquatic environments. In this regard, the present paper reports the nanocomposite copper oxide/polyaniline (CuO/PANI) is successfully synthesized by in situ chemical oxidative polymerization method and investigates their catalytic activity against organic dyes and nitro compounds. CuO is synthesized by colloidal sol–gel method using oxalic acid as capping agent to obtained desired morphology. The elemental composition, unit cell and lattice parameters of nanocomposite are characterized by using XRD. The XRD revealed that nanoparticles are extremely crystalline, but nanocomposite is amorphous because of the presence of polymer. The structural and elemental analysis of CuO and CuO/PANI is confirmed by SEM and EDX analysis. FTIR spectra of CuO showed bending vibration, while CuO/PANI showed the presence of benzenoid and quinoid rings. Catalytic productivity of the CuO and CuO/PANI as catalysts in degradation of dyes and reduction of nitro compounds is also studied. The degradation and reduction processes are monitored through the utilization of UV–Vis spectrophotometer. The catalytic activity of both catalysts is evaluated by several parameters including k_app, degradation/reduction time, % degradation/reduction, degraded/reduced concentration and half-life. Among all substrates, highest k_app is 0.0653 min⁻¹ for CV by CuO, while 0.0502 min⁻¹ for EBT by CuO/PANI due to large surface area. On degradation and reduction rate of substrates, the impact of functional group type and orientation, bond type and steric hindrance is also investigated.