Adsorption of mercury cation on chemically modified clay

A montmorillonite clay (M) sample from the Amazon region, Brazil, was intercalated with pyridine (Py), dimethyl sulfoxide (DS) and 3-aminopropyltriethoxysilane (APS). The chemically modified montmorillonite (MP/APS) sample showed modification of its physical–chemical properties including: specific area 41.39 m2 g−1 (M) to 198.45 m2 g−1 (MP/APS). Solid-state 29Si CPMAS/NMR of the silylated montmorillonite samples showed Q2 and Q3 signals as well as T2 and T3 signals. The appearance of T2 and T3 signals can be attributed to the grafting of APS to the interlayer surface silanol groups. The natural and modified clays were used for mercury cation adsorption from aqueous solutions at room temperature and pH 3.0. The energetic effects (ΔintH°, ΔintG° and ΔintS°) caused by mercury cation adsorption were determined through calorimetric titrations.