Removal of sulphates from acid mine drainage using desilicated fly ash slag

Abstract: The removal of sulphates from acid mine drainage (AMD) using desilicated fly ash (DFA) was investigated. The effects of DFA solid loading, residence time and removal temperature were investigated. A 2% DFA solid loading gave the highest sulphate removal of 75% at a temperature and residence time of 35ºC and 90 min respectively. The maximum adsorption capacity for DFA was found to be 147.06 mg/g DFA. The sorption mechanism followed the Langmuir isotherm and pseudo second order kinetics. The Gibbs free energy and enthalpy for the sorption was found to be 17.26 and 125.096 J/mol respectively. This research showed that DFA was an attractive alternative adsorbent for sulphates in AMD