Magnetic polyindole-Ag composite for the catalytic reduction and removing of the organic pollutants

In this work, the preparation, characterization, and application of Fe3O4-polyindole-Ag composite are reported. The Fe3O4-PIN-Ag composite with the structure that Ag nanoparticles were decorated on the surface of Fe3O4-PIN was prepared via a facile in situ method. The nanocomposite was manufactured via oxidation in situ polymerization of indole on iron oxide nanoparticles in the presence of ammonium persulfate, (NH4)(2)S2O8, as an oxidant. Then, the formed silver nanoparticles without using external reductant were deposited on the surface of polyindole. The structure and the component of Fe3O4-PIN-Ag composite were well identified by FT-IR, UV-Vis, XRD, SEM, EDX, ICP-AES, and TEM techniques. The composites indicated excellent catalytic activities for the reduction of 4-nitrophenol and methylene blue in the presence of NaBH4 and removal of methylene blue with just a low amount of adsorbent (1 mg). The catalyst could complete reduction of 4-nitrophenol and methylene blue in 28 and 20 min, respectively, and adsorption of methylene blue in 140 min with apparent rate constants k(app) of 9.49 x 10(-2), 16 x 10(-2), and 1.2 x 10(-2) min(-1), respectively. The Fe3O4-PIN-Ag composite was able to capture the electrons/hydride ions and increased the opportunities to reduce 4-nitrophenol and methylene blue and could help to facilitate the contact of methylene blue by PIN chains and Ag nanoparticles. This catalyst exhibited superior durable catalytic stability so that no significant activity loss was observed in the consecutive six reaction runs.

Automated summary

The preparation, characterization, and application of Fe3O4-polyindole-Ag composite are reported. The composite exhibits excellent catalytic activities for the reduction of 4-nitrophenol and methylene blue as well as the adsorption of methylene blue.