Optimisation of heavy metals uptake from leachate using red seaweed gracilaria changii

Abstract

Heavy metal is one of the pollutants in landfill leachate besides organic and inorganic pollutants. The presence of heavy metal is alarming due to its harmful nature; makes it incompatible to be discharged into water bodies before treatments. There are many treatment techniques to remove heavy metals from wastewater, where some of them even involve the coupling of one or more techniques to facilitate and improve the removal efficiency. However, the adsorption using seaweed is one of the known techniques to eliminate heavy metals from wastewater efficiently. Therefore, this study introduced a new adsorbent for heavy metal adsorption: red seaweed Gracilari changii. The effect of operational parameters such as leachate pH (2-7), seaweed dosage (2-10 g), rpm (10-100), and contact time (10-60 min) on the optimum adsorption of Gracilaria changii was studied. At optimum pH (pH=5), seaweed dosage (10g), rpm (rpm=50) and contact time (30min), Gracilaria changii showed maximum metal ion removal of 45%, 35%, and 30% for Fe2+, Cr6+ and Ni2+ respectively. The adsorption was rapid and reached equilibrium after t=30min in general. This optimisation result can be used as a reference to study the effect of different dosages of the adsorbent towards the removal rate.