Solar-Fenton removal of malachite green with novel Fe0-activated carbon nanocomposite

• Fe0-AC nanocomposite was prepared under ambient reaction conditions.
• Solar light, H2O2 and citrate enhanced oxidative dye removal during Fenton process.
• Citrate was used a buffer to maintain circumneutral pH of reaction.
• Hydroxyl radicals (OH) were the main oxidizing species for dye removal.
• Fe0-AC showed significant recycle efficiency and stability.

Zero valent iron-activated carbon nanocomposite (Fe0-AC) was synthesized using liquid phase reduction method. Both Fe0-AC and micro zero valent iron (ZVI) were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), UV-visible (UV-vis) spectral techniques. The size of Fe0-AC was observed to be 50 nm. The catalytic efficiency of Fe0-AC was explored for the removal of malachite green dye (MG) from aqueous phase. Fe0-AC induced solar-Fenton removal of MG was investigated in the presence of H2O2 and citrate (cit.). Solar/H2O2/cit./Fe0-AC system exhibited highest removal efficiency among investigated photocatalytic systems. The dye removal was strongly influenced by solar light, pH, Fe0-AC dosage, H2O2 and citrate concentration in reaction system. The reaction was maximal at pH 6.75. MG was completely decolorized in 60 min using solar/H2O2/cit./Fe0-AC system. Hydroxyl radicals (OH) were the main oxidizing specie during solar–Fenton process.Fe0-AC proved to be a potential adsorbent for MG. Fe0-AC showed high recycle efficiency due to easier separation from aqueous phase. The lower concentration of dissolved Fe(II) ions in reaction solution indicated the stability of Fe0-AC during MG removal. On the basis of obtained results, the most plausible mechanism for oxidative removal MG of was proposed.

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