Enhancing clay adsorption properties: A comparison between chemical and combined chemical/thermal treatments

Abstract A Moroccan bentonite was activated by sodium carbonate (Na–Be), and by a combined chemical and thermal activation (Na–Be450). The materials characterization was performed by XRD, EDS, FTIR, SEM and porosity measurements. The efficiency of Na–Be and Na–Be450 as low-cost adsorbents to remove nickel and silver from aqueous solution was checked. The Langmuir, Freundlich and Langmuir-Freundlich models were used for the analysis of equilibrium isotherms. Na–Be and Na–Be450 demonstrated a good removal efficiency towards nickel and silver, even in complex effluents (industrials wastewaters). The regeneration study proved that Na–Be450 presented all the characteristics of an efficient material for nickel removal.