An Efficient photocatalyst based on Polyaniline Decorated MWCNT/CeO2 for degradation of Methylene Blue (MB) Dye

Abstract This industrial waste contain organic dye was dropped without previous treatment which result a serious environmental pollution. Among many organic dye, methylene blue (MB) dye is an aromatic heterocyclic chemical compound and is harmful if swallowed or inhaled and also causes skin and eye irritation on contact. This study aims the degradation of this harmful dye by unique PANI-MWCNT/CeO2 nanocomposite. The PANI decorated binary nanocomposite was synthesized by polymerization of aniline on the surface of MWCNT/CeO2. The optical, structures, surface morphology and functional groups of the developed composites were studied using UV–Vis diffuse reflectance, powdered X-ray diffraction (XRD), SEM and FT-IR spectroscopic techniques respectively. The synthesized nanocomposite shows effective degradation of MB. This is due to unique properties of PANI which is the delocalized π-conjugated structures is beneficial to rapid charge separation, thus the separation efficiency of photogenerated electron (e-)– hole (h+) pairs. The operational parameter is optimized, such as effects of pH, initial dye concentration, effect of irradiation time, effect of light and catalyst load were investigated using photocatalytic degradation of PANI-MWCNT/CeO2. The results obtained indicated the efficient degradation at pH= 8 which extents to 92.5%, at 10 ppm extent to 90.93 %, at 35 min interval extent to 95.01 %, MB with PANI-MWCNT/CeO2 on light extent to 89.52 % and at 0.12 g/L extent to 97.48 % respectively. Moreover, the mechanism of scavenger reaction was performed and it confirm the most important species in the degradation process would be (-*O2) and (*OH). The recyclability of PANI-MWCNT/CeO2 for photocatalytic degradation MB was also evaluated for three consecutive cycles at optimum condition (10 ppm MB, 0.12 g/L of catalyst, at pH=8) and the results shows only an 14 % decrement was observed after three cyclic run. The practical application was evaluated on a real sewage sample solution collected from Kombolcha Textile Industry, which shows a good performance about 71.74 % degradation.