Adsorption of Metal Ions on Aluminosilicates

The ODM-2F sorbent based on diatomite with a porosity of ~75% is used as a filter material for effective wastewater treatment at a thermal power plant. At pH 6.0‒8.0, when metals Ni, Zn, Cu are in the form of Me 2+ and MeON + cations, the process of their separation per MM is described by two types of adsorption isotherms – Langmuir and S-shaped. For unmodified MM in the Ca-form, S-shaped isotherms are characteristic. For MM, partially and completely converted to the Na-form, metal adsorption isotherms acquire a Langmuir appearance. An increase in the salt background of the solution (100‒800 mg/dm 3 NaCl) does not reduce the sorption capacity for copper (120‒130 mg/g), unlike organic resins. The adsorption of nickel, zinc, and copper cations at a pH of 7‒8 per MM in the Ca-form (11‒46 mg/g) is lower than in the Na-form (17‒75 mg/g), which is due to the high energy costs when replacing Ca 2+ with metal counterions compared to Na + .