Mechanochemically activated saponite as materials for Cu2+ and Ni2+ removal from aqueous solutions

Abstract Saponites are nanosized layered aluminosilicates from the smectite group of clay minerals, which can be further functionalized to prepare low-cost materials for water purification. Mechanochemical activation of saponite was achieved by high-energy grinding in a planetary ball mill. X-ray diffraction, infrared spectroscopy, scanning electron microscopy, thermal analysis, and the determination of cation-exchange capacity and specific surface area were used to characterize parent and functionalized solids. Prepared adsorbents were used for Cu 2 + and Ni 2 + removal from aqueous solutions. Compared to the untreated sample, activated saponites had significantly increased capacity to take away metal cations. The equilibrium data showed the maximum of Cu 2 + and Ni 2 + uptake of 295 and 129 mg/g, respectively. In comparison with the pristine material, the measured values increased by 764% and 170% for Cu 2 + and Ni 2 + respectively. The formation of reactive Mg(OH) 2 as the saponite decomposition product was also discussed.