Synthesis, characterization and photocatalytic activity of MnO2/Al2O3/Fe2O3 nanocomposite for degradation of malachite green

Abstract

photocatalyst was successfully synthesized by sol-gel method using metal salts as precursors in the presence of acid catalyst. The as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), atomic absorption spectroscopy (AAS) and UV-Vis diffuse reflectance spectroscopy. Elemental analyses of the assynthesized samples were similar to those expected from the initial concentrations of the solutions used during synthesis. The x-ray diffraction pattern indicated that all as-synthesized samples had a crystal size with a rhombohedral structure and finest particle size of the catalyst (20.096 nm) was obtained at 400°C calcination temperature. The band gap energy of the MnO 2 /Al 2 O 3 /Fe 2 O 3 photocatalyst was calculated to be 1.97 eV and indicated that the as-synthesize sample had high photoabsorption property in the visible light region. Fourier transform infrared spectra confirmed the presence of hydroxyl group and Fe-O bond vibration in the catalyst. Experimental result of the MnO 2 /Al 2 O 3 /Fe 2 O 3 photocatalyst calcined at 400°C in 180 min (the molar ratio of 10 wt% Mn/15 wt% Al/75 wt% Fe) exhibited high photocatalytic activity of 92.89% under visible light irradiation. This may be due to the coupling effect of semiconductors, small particle size of catalyst and low electron-hole pair recombination on the surface of the catalyst. The pseudo-first-order rate constants of MG dye degradation in the presence of the catalyst were calculated as 4 × 10 -4 , 6.56 × 10 -3 and 1.0 × 10 -2 min -1 under no light irradiation, UV and visible light irradiation, respectively.

Preparation of copper aluminum-biochar composite as adsorbent of malachite green in aqueous solution

“…Several treatments method have been investigated regarding pollutants removal such as water oxidation [5], photodegradation [6], membrane separation [7], biological method [8] and adsorption [9]. Among these methods, adsorption is more suitable in removing dyes from aqueous solution.…”

Nanocomposite Fiber Based on Natural Material for Water Disinfection under Visible Light Irradiation

“…The high photodegradation efficiency obtained in this study may be attributed to synergist and multiple effects of all metal oxides (Al 2 O 3 and SiO 2 ) that exist in the natural goethite sample, which positively affects the photocatalytic activity [49,50], but the greater role was played by iron due to its abundance, and the efficiency obtained under visible irradiation may be a promising key to enhance the solar disinfection process. Since the site of photocatalytic decomposition is physically separate from the reservoir containing contaminated water, the need for removal of the photocatalytic material is avoided.…”

New colorimetric method to determine catalase mimic activity

“…The bands at 3458 cm -1 and 1651 cm −1 can be assigned to the stretching and bending vibration of free water molecules in the sample. The peaks at 566 cm −1 and 474 cm −1 may be due to stretching of both O-Mn-O and Fe-O vibrations bond of hematite in the MnO 2 /Fe 2 O 3 nanocomposite of rhombohedral structure [28,29].…”