Synthesis of catalytically important manganese oxide nano-particles and their dispersion onto a polymeric matrix

Abstract

Mn304 nanoparticles were prepared by forced hydrolysis of aqueous manganese(lJ) acetate, Mn(OOCCH3h, solution. Starch was used as capping agent to prevent the agglomeration of the nanoparticles thus formed in the colloidal mixture, 0.4 M Mn(OOCCH3)2 precursor in saturated aqueous solution of starch was aged for 2,6, and 12 h at a temperature 80 °C . The nanoparticles were then collected by reducing the volume of suspension on mild heating followed by ethanol extraction. The more uniform and well-dispersed particles were obtained by heating the reaction mixture for 2 h. The nanoparticles thus obtained were characterized by means of EDX, XRD, IR, and SEM. The results showed that the Mn304 nanoparticles were single phase, spherical, and uniformly dispersed. The average crystallite size was calculated from the XRD data to be approximately 10 nm. Polyaniline (PAN!) was synthesized from aniline by using potassium dichromate, K2Cr207, as an oxidizing agent. The dispersion of the Mn304 nanoparticles into PANI matrix was achieved by the addition of nanoparticles suspension to the sediment of PAN!. The conductivity of the PANI/Mn304 matrix was measured to be 20.82 x 10-6 Scm-1 and found to be higher than that of PANI, 3.72 x 10-6 Scm"l. Mn304 nanoparticles were tested to perform the polymerization of aniline instead of conventional chemical polymerization by an oxidant. The nanoparticles can effectively polymerize aniline to yield PAN!. The PANI thus prepared was found to be more conductive because of its compact and modified morphology as seen from SEM, {.f The efficiency of the Mn304 nanoparticles on the decolorization of methylene blue (MB) dye has been studied in presence of H2S04. Effect of MB concentration, amount of nanoparticles required, influence of acid concentration, and function of time on MB decolorization were also investigated by employing UV-Visible spectroscopy, It was found from these investigations that Mn304 nanoparticles can efficiently and rapidly decolorize MB in adequately acidic media. The Mn304 nanoparticles was also successfully employed to deco!orize another-textile dye procion red {PRJ and an industrial dye effluent. UV-Visible spectra of the solutions were taken in all cases to measure the extent of decolorization. Sensitivity of the Mn304 nanoparticles suspension was tested on various pathogenic organisms at two different pH, 3.3 and 6.2. The nanoparticles were found to be sensitive against Vibrio cholerae, Shigella sp., Salmonella sp., and Escherichi coli bacteria, which are responsible for cholera, dysentery, typhoid, and diarrhoea diseases, respectively.