Role of Zn and Polyaniline in Magnetic Nanocomposites and Enhanced Arsenic Adsorption Capacity in Wastewater

Abstract The nanoparticles of Polyaniline/Fe0.90Zn0.10Fe2O4 (PANI/Fe0.90Zn0.10Fe2O4) were synthesized by a co-precipitation method and an in-situ polymerization method. XRD patterns showed that the Fe0.90Zn0.10Fe2O4 grain size about 11.8 nm, while TEM image showed grain size from 10 to 18 nm. The results of FT-IR spectra and DTA analyses showed that PANI participated in nanocomposite samples. The grain size of PANI/Fe0.90Zn0.10Fe2O4 samples measured by SEM was about 35–50 nm. The magnetization measurements showed that the saturation magnetic moment of PANI/Fe0.90Zn0.10Fe2O4 samples at 300 K decreased from 71.5 to 43 emu/g when PANI/Fe0.90Zn0.10Fe2O4 mass ratio increased from 0–40%. The arsenic adsorption capacity of nanocomposite samples with different PANI concentration was investigated in solutions of pH 1 to pH 14. The qmax maximum arsenic adsorption capacities were calculated by the Langmuir isotherm equation at pH 7 and 300 K. The evaluated results show that with mass ratio of 0.9%, the sample S1 with qmax = 43.48 mg/g is higher than that Fe3O4 nanoparticles. In addition, the substitution of Fe2+ ions by Zn2+ ions in Fe0.90Zn0.10Fe2O4 and PANI coating were improving more magnetic and chemical stable of samples over time. Other hand, these materials could be reused after desorption in solution at pH 14.