Performance of Chlorella vulgaris in iron removal from mildly neutralized acid mine drainage

This research evaluated the performance of Chlorella vulgaris to remove Fe in acid coal mine drainage (AMD) as a resource-efficient treatment strategy. With nutrients and CO 2 , the microalgae tolerated up to 100% of AMD, showing growth rates similar to the control. In iron biosorption, after neutralization at pH 4, efficiencies of 79.8–90.8% in 1 h and up to 92.4% in 72 h were achieved. The Sips model best described adsorption (R 2 =0.995; 223 mg Fe/g). These results show that minimum neutralization combined with living biomass enhances treatment efficiency and reduces chemical inputs, providing the basis for the scale-up of sustainable phytoremediation systems. • Chlorella vulgaris can treat real AMD efficiently for Fe removal • Cell wall of Chlorella vulgaris is able to adsorb Fe even at low pH and diminished cell growth • Live biomass is not necessary for metals removal under AMD conditions • Chlorella vulgaris biorremediation is an economic and sustainable option for AMD