Polyaniline/Fe0 composite nanofibers: An excellent adsorbent for the removal of arsenic from aqueous solutions

• Novel nano-scale PANI/Fe0 was fabricated by supporting Fe0 onto PANI nanofibers.
• PANI/Fe0 is highly effective in removing As over a wide pH range.
• Maximum adsorption capacities were 227.3 mg/g for As(V) and 232.5 mg/g for As(III).
• The adsorption capacity is significantly higher compared to most of the adsorbents.
• Coexisting HCO3−, SiO32− and SO42− ions have no significant effect on As removal.

A novel nano-scale polyaniline/Fe0 composite (termed as PANI/Fe0) was synthesized via reductive deposition of nano-Fe0 onto the PANI nanofibers matrix at room temperature. PANI/Fe0 was characterized by SEM, TEM, XRD, FTIR and XPS. PANI/Fe0 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-Fe0 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/Fe0 is a promising adsorbent for safe drinking provision in low-income communities owing to its excellent performance, simple and low-cost synthesis process.

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