Natural diatomite as an effective adsorbent for heavy metals in water and wastewater treatment (a batch study)

This study presents an evaluation of Egyptian diatomite as a low cost adsorbent for the removal of heavy metal under different conditions (pH, weight of diatomite and contact time). The adsorption of heavy metals was investigated under various pH values ranged from 2 to 8 at 25 °C. The obtained results indicate that at low pH (2-4), the removal efficiency of diatomite for heavy metal increased slightly as the pH, adsorbent dose and contact time increased, while at pH > 4, the percentage of metal ions adsorbed decreased with increasing pH due to precipitation of heavy metals. At pH equal 4, with using 2 g L−1 of diatomite and 75 min as contact time, the maximum adsorption capacity of diatomite was obtained. The high adsorption capacity of diatomite makes it a suitable low cost material for the removal of different heavy metals from aqueous solutions.