Adsorption of Nickel(II) and Copper(II) Ions by Modified Aluminosilicates

According to X-ray phase analysis, modification of natural aluminosilicates with hydrogen chloride is accompanied by the destruction of the main component—calcium heulandite—the content of which decreases from 64.3 to 42.9%. An increase in temperature during the modification process contributes to the packing of the cristobalite structure, which positively affects the adsorption properties of the materials. In the process of activation of aluminosilicates by hydrogen chloride, their texture characteristics change: the specific surface (from 33 to 75 m2/g) and the specific pore volume (from 0.015 to 0.036 cm3/g) increase more than double. The average pore size is reduced from 1.8 to 1.6 nm. The result of such changes is an increase in the adsorption capacity. Adsorption of nickel(II) and copper(II) ions on modified aluminosilicates is most adequately described by the Langmuir adsorption model.