Eco-friendly process for the removal of Pb (II), Ni (II) and Zn (II) using different adsorbents: sepiolite and modified cedar

Abstract

[Excerpt] Heavy metal contamination in groundwater and sediments is one of the most relevant threats to environmental quality and human health. Their presence in the aquatic environment has attracted global attention due to their toxicity, persistence in nature, non-biodegradability and ability to bio-accumulate in food chains. The traditional treatment methods for their removal have been used but chemical methods are often restricted due to the technical or economic restraints. Various biomaterials have been used to entrap those ions from water and wastewater such as clays, zeolites, industrial and/or agriculture wastes, becoming a good alternative to industrial wastewater treatment [1, 2]. The capacity of natural sepiolite (clay) and modified cedar (wood) sawdust for heavy metals adsorption, lead (Pb), nickel (Ni) and zinc (Zn), has been assessed using a batch method. Natural sepiolite was supplied by TOLSA and cedar was obtained from Morocco. Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was used to characterize the morphology and chemical composition of both adsorbents. Cedar was subjected to an alkaline chemical pre-activation with of 0.2 M solution of potassium hydroxide, as suggested by literature. [...]