Efficient remediation of acid mine drainage through sustainable and economical biochar-CaO composite derived from solid waste

The present study aims to develop a low-cost and sustainable composite material from solid waste to efficiently treat acid mine drainage (AMD). A modified reactor was used to produce the biochar-CaO composite from solid waste, which was characterized using XRD and SEM to determine the crystal structure, size, and surface morphology. The composite exhibited high adsorption capacity for AMD species, including Fe, Mn, and Mg metals, with an equilibrium point achieved at 300 min of contact time. The percent removal of AMD species varied with pH conditions, and the Langmuir isotherm model was found to describe the adsorption behavior of the composite adequately. The biochar-CaO composite showed a maximum adsorption capacity of 440 mg/g and held significant potential as an economical and efficient solution for AMD remediation.