Pilot plant studies for the removal of heavy metals from industrial wastewater using adsorbents

Abstract

Due to carcinogenic and toxic effects of heavy metals on the environment and living beings, the necessity of proper removal systems for these harmful elements is obvious. Additionally, conventional methods in wastewater treatment are mainly biological; therefore, removal of heavy metals should occur by using adsorbents. In this study, activated carbon along with other cheap and available materials such as sawdust and bentonite in seven different adsorbent mixtures is applied to remove heavy metals from wastewater. Wastewater was applied to the system with a flow rate of $0.2\, \frac{L}{min}$. Assuming fixed pH, biochemical oxygen demand, chemical oxygen demand, and total suspended solids, amounts of Fe, Mn, Cu, Al, and Mg from the wastewater were measured. Finally, adsorption capacity results were analyzed according to Langmuir and Freundlich theories for each mixture of adsorbents. Based on the results, sawdust is introduced as a desirable adsorbent for most heavy metals. For each element, an optimized adsorbent is also suggested, which, due to similar atomic and cationic properties, can be generalized for other similar elements.