CuO/PANI nanocomposites: An efficient catalyst for degradation and reduction of pollutants

Abstract

Abstract Textile dyeing releases over 80% of industrial effluents without proper treatment. Dye discharged into effluents typically need 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 investigate their catalytic activity against organic dyes and nitro-compounds. CuO nanoparticles are 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 nanocomposites are characterized by using XRD. The XRD revealed that nanoparticles are extremely crystalline, but nanocomposites are 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 are 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 kapp, degradation/reduction time, % degradation/reduction, degraded/reduced concentration and half-life. Among all substrates, highest kapp 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 or reduction rate of substrates, the impact of functional group type and orientation, bond type and steric hindrance are also investigated.