Photocatalytic Degradation of Phenol by Polyaniline/ Phosphomolybdic acid/ Poly(vinyl pyrrolidone) Composite under Visible Light

Abstract

Our work is to infusing photocatalytic activity in polyaniline (PANI) by coupling its visible light absorption with the catalytic role of phosphomolybdic acid (PMA), a heteropoly acid. A neutral polymer poly(vinyl pyrrolidone) (PVP) was used as the soft template. By chemical oxidative polymerization method, the four materials viz., PANI, PANI–PVP, PANI–PMA and PANI–PMA–PVP were synthesized. UV-vis, FTIR, XRD and SEM techniques were used to characteristics PANI and its three composite materials.  XRD and SEM revealed the interaction of PANI with PMA and PVP. Photocatalytic activity of PANI and its composites was studied by visible light degradation of phenol using Haber inner irradiation photoreactor (λ > 380 nm, irradiation time = 160 min.  Experimental parameters for the influence of photocatalytic activity such as initial phenol concentration, pH and dosage of catalyst were investigated. The above four photocatalysts exhibited the phenol photodegradation of 6.8, 10.0, 31.2 and 64.0 % respectively at the optimized condition of initial phenol concentration of 50 mg/L, pH = 6, photocatalyst loading of 0.5 g/L, H₂O₂ 2 mL, constant air flow, at room temperature and atmospheric pressure. PANI-PMA-PVP showed the maximum decomposition of phenol. The combined effect of PMA and PVP is believed to play an important role in enhancing the photoreactivity of PANI in visible region.