Polyaniline/Fe-0 composite nanofibers: An excellent adsorbent for the removal of arsenic from aqueous solutions

Abstract

A novel nano-scale polyaniline/Fe-0 composite (termed as PANI/Fe-0) was synthesized via reductive deposition of nano-Fe-0 onto the PANI nanofibers matrix at room temperature. PANI/Fe-0 was characterized by SEM, TEM, XRD, FTIR and XPS. PANI/Fe-0 was tested for arsenic removal in batch experiments. The effects of initial pH value, adsorbent mass loading, As initial concentration, and co-solutes on As removal were explored. Results showed nano-Fe-0 particles with average diameter 6.4 nm embedded onto the PANI matrix. As removal was rapid for both As(III) and As(V) species. The equilibrium isotherm data fitted well with Langmuir isotherm model. The maximum adsorption capacities at pH 7.0 for As(III) and As(V) were 232.5 and 227.3 mg/g, respectively. These capacities are significantly higher than most of the reported adsorbents. The co-existing HCO3-, SiO32-, and SO42- ions had no significant effect on As removal. However, the presence of NO3- and PO43- significantly reduced the As removal efficiencies. Achieved results further show that PANI/Fe-0 is a promising adsorbent for safe drinking provision in low-income communities owing to its excellent performance, simple and low-cost synthesis process. (C) 2015 Elsevier B.V. All rights reserved.