Ag NPs supported on the magnetic Al-MOF/PDA as nanocatalyst for the removal of organic pollutants in water

Abstract

A novel composite catalyst (Al-MOF/Fe3O4/PDA@Ag) was successfully synthesized through the deposition of Ag nanoparticles onto the magnetic Al-MOF/Fe3O4/PDA and characterized by several techniques, such as SEM, TEM, EDS, FT-IR, XRD, elemental analysis, AAS, XPS, BET, PES and VSM. The resulting Al-MOF/Fe3O4/PDA@Ag had rough surface, mesoporous structure, large surface area and magnetic property. Al-MOF/Fe3O4/PDA@Ag exhibited excellent catalytic performances, which removed 81.7% of ciprofloxacin (CIP), 80.1% of norfloxacin (NOR) and 98.2% of methyl orange (MO) within 40 min in the presence of 10 mM of NaBH4. The catalyst could be separated easily with a magnet and reused effectively after reaction. Furthermore, the intermediate products of CIP degradation by Al-MOF/Fe3O4/PDA@Ag were detected and the possible degradation pathways were proposed. Additionally, the catalytic ability of Al-MOF/Fe3O4/PDA@Ag was further explored in practical application. MO, as a typical pollutant in river water, was rapidly decolorized with decolorization efficiency higher than 97.1% even at high initial concentration of 150 mg/L. Therefore, Al-MOF/Fe3O4/PDA@Ag could be regarded as a promising catalyst for the removal of organic pollutants due to its high catalytic activity, good reusability, easy preparation, rapid separation and high stability.