Catalytic photodegradation of organic dye using polyaniline modified Ni-CdO nanocomposite

Abstract

This study investigates the photocatalytic efficiency of a newly synthesized Ni-CdO/PANI nanocomposite (NC), for the removal of malachite green dye (MGD) from aqueous media. The composite was synthesized employing sol-gel method followed by in-situ polymerization technique. Several analytical methods (XRD, SEM, FT-IR, and Uv-Vis Spec.) were used for the characterization of the nanocomposite. SEM analysis showed an agglomerated micro-scaled particle of Ni-CdO/PANI material, which was smaller in particle size as compared to CdO nanoparticle (NP) and Ni-CdO composite. Ni-O bond was observed in Ni-doped CdO NP, and C-N plane deformation in polyaniline from FT-IR spectrum, confirming the effective surface alteration of Ni-CdO composite with the polymer. The pattern observed in XRD analysis shows the presence of cubic CdO and Ni-CdO NC structure with lowering crystalline sizes from 37.48 nm (CdO NP) to 35.21 nm (Ni-CdO NC) and to 2.78 nm (Ni-CdO/PANI NC). Ni-CdO/PANI nanocomposite showed high degradation efficiency (98.73%) to remove MGD dye from aqueous solution, at optimal conditions dye concentration (10 mg/L), catalyst dose (0.14 g), pH (8.0), and visible light irradiation time (120 min.). This catalytic photo-degradation of the NC has followed pseudo-first-order reaction rate, where the calculated k app and r 2 values are 8.0×10 -3 min −1 and 0.999, respectively. Ni-CdO/PANI is potential nanocomposite for the photocatalytic degradation of organic micro-pollutants released as wastewater into water bodies from various industrial and agricultural activities. • Successful synthesis of CdO NP and Ni-CdO/PANI NC were achieved via sol-gel method. • The crystal structure of CdO NP was cubic and retained after modified with Ni metal and PANI. • The crystalline size and energy bandgap of CdO NP was substantially reduced following its modification with Ni and PANI. • Photodegradation performance of Ni-CdO/PANI is significantly high compared to CdO NP