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In this study, core-shell Fe0@polyaniline (PANI) nanoparticles were synthesized to remove Rhodamine B (RhB) in aqueous solution. The Fe0/PANI composites were characterized by X-ray diffraction, Fourier transform infrared spectra, and transmission electron microscopy. The performances of Fe0/PANI on the activation of molecular oxygen for the removal of RhB were investigated, and the effects of operating parameters, such as Fe0/PANI dosage, RhB initial concentration, and pH value on RhB removal were also discussed. The results indicated that the Fe0@PANI/O2 process exhibited significantly higher reactivity than did the Fe0/O2 process for the degradation of RhB. The oxidative degradation of RhB was further promoted by the presence of anthraquinone-2-sulfonic acid sodium salt working as an electron shuttle. In addition, the reaction mechanism was discussed by measuring the concentrations of Fe(II), and total Fe formed in the system and examining scavenging effect by tert-butyl alcohol and copper chlor...

In this study, the PANI-supported nanoscale zero-valent iron (PANI/nZVI) composites have been successfully synthesized to remove Rhodamine B (RhB) from aqueous solutions using a heterogeneous Fenton-like system. The synthetic PANI/nZVI composites were characterized using X-ray diffraction (XRD), Transmission electron microscope (TEM) and Fourier transform infrared (FTIR). The results showed that they were lamellar structures and nZVI nanoparticles were introduced into their structures. The performances of PANI/nZVI composites on the activation of molecular oxygen for removal of RhB were investigated and the effects of operating parameters, such as PANI/nZVI dosage, PANI and nZVI mass ratio, RhB initial concentration, and pH value on RhB removal were also discussed. The results indicate that PANI/nZVI was proved to be the most efficient in that more than 83.31% of RhB was removed, whereas only 11.15% when using nZVI after reacting for 120 min with an initial RhB concentration of 0.02 mmol L−1 (pH = 6.50). Furthermore, the reaction mechanism was discussed by measuring the concentrations of Fe(II), total Fe and H2O2 formed in the system and examining scavenging effects using copper chloride and methanol. Finally, the stability of PANI/nZVI nanocatalyst was studied. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 48–55, 2016

Polyhydroquinone, an immobilized quinone, was synthesized by oxidative polymerization of hydroquinone. The polymers obtained were characterized by Fourier-transform infrared spectra and cyclic voltammetry. Polyhydroquinone is a redox-active polymer with quinone/hydroquinone redox active units in the main chain. The influence of polyhydroquinone in the Fe3O4/persulfate system was examined. It was found that the addition of polyhydroquinone in Fe3O4/persulfate system increased the oxidation rate of Rhodamine B (RhB), which was ascribed to their role as an electron shuttle. The presence of polyhydroquinone successfully builds up two cycles, one semiquinone/quinone cycle, another cycle of Fe(III)/Fe(II) induced by quinone. The presence of phenolic and quinonoid moieties in the structure of polyhydroquinone provide for their ability to reduce Fe(III), thereby assisting the redox cycling of Fe and increasing degradation of the target substrate.