Keywords: natural nanostructured solids, sepiolite, clay, adsorption capacity, nickel, arsenic, wastewater treatment, nanotechnology, water pollution, cationic heavy metals, anionic metalloid species
Adsorption of nickel and arsenic from aqueous solution on natural sepiolite
The adsorption capacity of a natural nanostructured clay (sepiolite) for the inorganic species: Ni
2+and As(V) has been studied using a batch method. The different parameters affecting sorption such as the mass of adsorbent, contact time, sorbate concentration or pH have been investigated and optimal experimental conditions have been determined. Langmuir and Freundlich equations, which are commonly used to describe sorption equilibrium, were applied to model experimental results. The maximum sorption capacity of sepiolite towards Ni
2+and As(V) was 2.236 mg g
−1and 0.006 mg g
−1, respectively. The differences between the sorption capacities could be explained by different parameters like the charge of the ions or the free energy of hydration. The conclusion of this study is that natural sepiolite can adsorb cationic heavy metal and anionic metalloid species, which can have interesting applications in environmental applications such as the removal of these species from polluted waters.