Sea shell derived adsorbent and its potential for treating acid mine drainage

• Sea shell adsorbent is capable of treating metal laden AMD.
• Sea shell is stable under slightly acidic conditions.
• Sea shell adsorbent has more affinity for iron than manganese.
• Initial solution concentration had greatest effect on metal removal performance.

Acid mine drainage (AMD) treatment remains a virgin area for extensive research owing to the limitations of the existing and proposed AMD treatment technologies. Hence, the current study aims to apply crushed sea shells as an efficient and cost effective adsorption medium for AMD treatment in batch and column studies. The metal–adsorption medium interaction was characterized using FTIR and XRF analyses. The effects of adsorbent mass and solution pH were investigated in batch studies whilst initial concentration, flow rate and adsorbent bed mass were considered during fixed bed column studies. A close analysis of all parameters varied showed that initial metal concentration had the greatest effect on metal removal from AMD, with lower initial concentration resulting in more water being treated at breakthrough point. The experimental breakthrough curves for the removal of iron from AMD were fully described by the Yoon-Nelson and Thomas models. The preliminary results showed that sea shell derived adsorbent has a great potential as an alternative low cost material in the treatment of AMD.