Adsorption of arsenate, phosphate and humic acids onto acicular goethite nanoparticles recovered from acid mine drainage

Acicular goethite nanoparticles (AGNs), obtained from the active treatment of acid mine drainage (AMD) on an industrial scale, were evaluated with respect to their capacity to adsorb the contaminants arsenate, phosphate and humic acids (HAs) in aqueous solution. Kinetics and equilibrium constants that describe the adsorption process were investigated. The adsorption capacity decreased in the order: HAs (37mgCg−1)>As(V) (20mgAs(V) g−1)>phosphate ions (13mgPO43−g−1). The adsorption capacity of the AGNs produced from acid mine drainage to remove arsenate, phosphate or humic acids are similar to those found for other synthetic iron oxides produced under controlled conditions at the laboratory scale. This study demonstrates the valorization of the AGNs product derived from acid mine drainage slurry waste arising from the mining of coal as an effective adsorbent materials for water treatment.